Signal transmission method and device

Abstract

The invention discloses a signal transmission method and device. In the method, a first communication device generates a full-wave radio-frequency electric signal and converts the full-wave radio-frequency electric signal into a half-wave radio-frequency optical signal, and the half-wave radio-frequency optical signal is a radio-frequency optical signal with a positive half amplitude or a negative half amplitude of the full-wave radio-frequency electric signal; the first communication device transmits a half-wave radio frequency optical signal. The second communication device receives the half-wave radio frequency optical signal and converts the half-wave radio frequency optical signal into a full-wave radio frequency electric signal. Therefore, compared with a radio frequency optical signal with all amplitudes of a full-wave radio frequency electric signal, the average optical power of the half-wave radio frequency optical signal is lower, the transmission optical power between the second communication device and the first communication device is reduced, and the power consumption of an optical device is reduced. When optical signals are transmitted between the second communication device and the first communication device through optical fibers, the reduction of the transmission optical power is also beneficial to reducing the nonlinear effect of optical fiber transmission, so that the signal distortion caused by the nonlinear effect of optical fiber transmission is reduced.

Description

Signal transmission method and device Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a signal transmission method and device. Background Art

[0002] RF photonics technology combines radio frequency (RF) and photonics technologies. RF photonics utilizes photonics to generate, transmit, detect, and process RF signals. This enables direct fiber-optic transmission of RF signals, eliminating digital-to-analog conversion and analog-to-digital conversion, as well as complex data processing, and improving transmission efficiency. RF photonics, in particular, allows the use of photodiodes (PDs) to directly drive antennas, expanding operating frequency bands and bandwidths.

[0003] In a PD direct-drive antenna architecture, the antenna's RF radiation power and coverage range are determined by the electrical signal power of the PD input to the antenna. To increase the antenna's RF radiation power, the optical power transmitted in the wireless fronthaul downlink can be increased to increase the optical power input to the PD, thereby increasing the electrical signal power at the PD input to the antenna. However, high optical transmission power can lead to severe signal distortion caused by severe nonlinear effects in optical fiber transmission and a sharp increase in the power consumption of optical components in the link. Reducing the optical transmission power while maintaining high RF radiation power is a technical challenge that needs to be addressed.

[0004] Summary of the Invention

[0005] The embodiments of the present application provide a signal transmission method and device that can reduce the transmission optical power, which is beneficial to reducing the power consumption of optical devices and the nonlinear effects of optical fiber transmission, and is also beneficial to achieving higher antenna RF radiation power with lower transmission optical power.

[0006] In a first aspect, embodiments of the present application provide a signal transmission method, which can be applied to a first communication device, a chip in the first communication device, or a logic module or software capable of implementing all or part of the functions of the first communication device. The method is described below using the first communication device as an example. The signal transmission method includes: the first communication device generating a full-wave radio frequency electrical signal; the first communication device converting the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, wherein the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal; and the first communication device transmitting the half-wave radio frequency optical signal.

[0007] It can be seen that the half-wave RF optical signal transmitted between the first communication device and the second communication device has the positive half amplitude or negative half amplitude of the full-wave RF electrical signal; compared with the RF optical signal having the full amplitude of the full-wave RF electrical signal, the average optical power of the half-wave RF optical signal is lower, thereby reducing the transmission optical power between the first communication device and the second communication device, thereby helping to reduce the power consumption of optical devices. In addition, in the scenario where optical fiber is used to transmit optical signals between the first communication device and the second communication device, the reduction in transmission optical power is also conducive to reducing the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by the nonlinear effects of optical fiber transmission. In the scenario where the second communication device also outputs the full-wave RF electrical signal to the antenna for signal radiation, this signal transmission method is conducive to achieving higher RF radiation power of the antenna with lower transmission optical power.

[0008] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0009] In an optional embodiment, the first communication device converts a full-wave RF electrical signal into a half-wave RF optical signal, including: the first communication device superimposing a first bias electrical signal on the full-wave RF electrical signal, where the first bias electrical signal is a first bias voltage signal or a first bias current signal; and the first communication device optically modulating the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal. In other words, the first communication device can convert the full-wave RF electrical signal into a half-wave RF optical signal having lower average optical power by superimposing the full-wave RF electrical signal and the first bias electrical signal and then optically modulating the signal, thereby facilitating reduced optical power transmitted between the first communication device and the second communication device.

[0010] In an optional embodiment, the first bias electrical signal is a first bias voltage signal. The first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias electrical signal to obtain a half-wave radio frequency optical signal, including: the first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal using an electro-absorption modulated laser to obtain the half-wave radio frequency optical signal.

[0011] In an optional embodiment, the electro-absorption modulated laser includes a laser diode and an electro-absorption modulator; the first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal through the electro-absorption modulated laser to obtain a half-wave radio frequency optical signal, including: the first communication device generates a continuous light wave signal through the laser diode; the first communication device modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal through the electro-absorption modulator to obtain a half-wave radio frequency optical signal. It can be seen that in the electro-absorption modulated laser, the laser diode generates the light source and the electro-absorption modulator realizes the light modulation, that is, the light source generation and light modulation are decoupled, which is beneficial to reduce the influence of the light source bandwidth on the high-frequency modulation when the voltage corresponding to the first bias voltage signal is low.

[0012] In an optional embodiment, the first bias electrical signal is a first bias current signal. The first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal, including: the first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias current signal through a directly modulated laser to obtain the half-wave RF optical signal; the current corresponding to the first bias current signal is greater than or equal to a threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

[0013] In an optional embodiment, the first bias electrical signal satisfies: the coefficient ratios of multiple spectral components corresponding to the electrical signal obtained by photoelectrically converting the first optical signal satisfy a first ratio; and the first optical signal is an optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the first bias electrical signal. In other words, when the first bias electrical signal superimposed on the full-wave RF electrical signal satisfies the conditions described in this embodiment, it facilitates conversion of the full-wave RF electrical signal into a half-wave RF optical signal having lower average optical power, thereby reducing the transmission optical power between the first communication device and the second communication device.

[0014] In an optional embodiment, the bias point detection electrical signal is a low-frequency sinusoidal wave signal; and an error between a ratio of a coefficient corresponding to a DC component, a coefficient corresponding to a first-order harmonic component, a coefficient corresponding to a second-order harmonic component, and a coefficient corresponding to a third-order harmonic component of an electrical signal obtained by photoelectric conversion of the first optical signal and 0.32:0.5:0.21:0 is within a second range.

[0015] In an optional embodiment, the method further includes: the first communication device generates a bias point detection electrical signal; the first communication device superimposes a second bias electrical signal on the bias point detection electrical signal; the first communication device optically modulates the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal; if the coefficient ratio between the multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the second optical signal satisfies a first ratio, the first communication device determines that the first bias electrical signal is the second bias electrical signal; otherwise, the first communication device adjusts the second bias electrical signal and superimposes the adjusted second bias electrical signal on the bias point detection electrical signal. It can be seen that the first communication device can adjust the bias electrical signal superimposed on the bias point detection electrical signal to determine the bias electrical signal that satisfies the aforementioned ratio condition, that is, to determine the first bias electrical signal that can convert the full-wave RF electrical signal into a half-wave RF optical signal, thereby facilitating the reduction of the transmission optical power between the first communication device and the second communication device.

[0016] In an optional embodiment, the first communication device converts a full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, including: the first communication device converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, the first half-wave radio frequency electrical signal being a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; the first communication device modulates a laser to superimpose a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal after superimposing the third bias electrical signal to obtain a half-wave radio frequency optical signal. It can be seen that the first communication device can convert the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal having a lower average optical power by converting the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal and then converting the half-wave radio frequency electrical signal into a half-wave radio frequency optical signal, thereby facilitating reduction of the transmission optical power between the first communication device and the second communication device.

[0017] In an optional embodiment, the first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

[0018] In one optional embodiment, the full-wave RF electrical signal is an analog signal. The first communication device converts the full-wave RF electrical signal into a first half-wave RF electrical signal, including: the first communication device converts the full-wave RF electrical signal into the first half-wave RF electrical signal using a low-noise power amplifier; the low-noise power amplifier is a Class B low-noise power amplifier, a Class C low-noise power amplifier, or a Class AB low-noise power amplifier. Thus, the first communication device can convert the full-wave RF electrical signal into a half-wave RF electrical signal with lower average optical power in the analog domain using the low-noise power amplifier.

[0019] In an optional embodiment, the full-wave RF electrical signal is a digital signal. The first communication device converts the full-wave RF electrical signal into a first half-wave RF electrical signal, including: the first communication device converts the full-wave RF electrical signal into a second half-wave RF electrical signal; the second half-wave RF electrical signal is an RF electrical signal having the positive half-amplitude or the negative half-amplitude of the full-wave RF electrical signal in the digital domain; and the first communication device performs digital-to-analog conversion on the second half-wave RF electrical signal to obtain the first half-wave RF electrical signal. This indicates that the first communication device can convert the full-wave RF electrical signal into a half-wave RF electrical signal with lower average optical power in the digital domain.

[0020] In an optional embodiment, the second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

[0021] In an optional embodiment, the method further includes: the first communication device uses a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal. The first communication device superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal after superimposing the third bias electrical signal to obtain a half-wave radio frequency optical signal, including: the first communication device superimposes the third bias electrical signal on the first half-wave radio frequency electrical signal after spectrum adjustment, and optically modulates the first half-wave radio frequency electrical signal after spectrum adjustment and superimposition of the third bias electrical signal to obtain a half-wave radio frequency optical signal. This embodiment can adjust the amplitude of each order spectral component in the first half-wave radio frequency electrical signal by performing spectrum adjustment on the first half-wave radio frequency electrical signal, so as to optimize the waveform of the first half-wave radio frequency electrical signal, which is beneficial to improving the optical modulation effect.

[0022] In an optional embodiment, the modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. Alternatively, the modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

[0023] In an optional embodiment, the second bias current signal is the third bias current signal corresponding to the third optical signal with the highest signal-to-noise ratio among the multiple third optical signals; the multiple third optical signals correspond one-to-one to the multiple third bias current signals; each of the multiple third optical signals is obtained by optically modulating the first half-wave RF electrical signal superimposed with the third bias current signal corresponding to the third optical signal; the currents corresponding to the multiple third bias current signals are different from each other, and the currents corresponding to the multiple third bias current signals are all greater than or equal to the threshold current. It can be seen that the second bias current signal determined by this embodiment is conducive to improving the signal-to-noise ratio of the half-wave RF optical signal and improving communication quality.

[0024] In an optional embodiment, the second bias voltage signal is the third bias voltage signal corresponding to the fourth optical signal with the smallest adjacent channel leakage power ratio among the multiple fourth optical signals; the multiple fourth optical signals correspond one-to-one to the multiple third bias voltage signals; each of the multiple fourth optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; the voltages corresponding to the multiple third bias voltage signals are different from each other, and the voltages corresponding to the multiple third bias voltage signals are all greater than or equal to the first voltage. It can be seen that the second bias voltage signal determined by this embodiment is conducive to reducing the adjacent channel leakage power ratio of the half-wave radio frequency optical signal and is conducive to improving communication quality.

[0025] In an optional embodiment, the full-wave RF electrical signal is a signal that has undergone digital pre-distortion processing. Digital pre-distortion processing helps correct the nonlinear effects of optical modulation and reduce signal distortion caused by such nonlinear effects. Furthermore, in scenarios where optical signals are transmitted between the first and second communication devices via optical fiber, digital pre-distortion processing also helps correct the nonlinear effects of the optical fiber, thereby reducing signal distortion caused by nonlinear effects of optical fiber transmission.

[0026] In a second aspect, embodiments of the present application provide a signal transmission method, which can be applied to a second communication device, a chip in the second communication device, or a logic module or software capable of implementing all or part of the functions of the second communication device. The method is described below using the second communication device as an example. The signal transmission method includes: the second communication device receiving a half-wave radio frequency optical signal, where the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of a full-wave radio frequency electrical signal; and the second communication device converting the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal.

[0027] It can be seen that the half-wave radio frequency optical signal transmitted between the second communication device and the first communication device has the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal; compared with the radio frequency optical signal with the full amplitude of the full-wave radio frequency electrical signal, the average optical power of the half-wave radio frequency optical signal is lower, thereby reducing the transmission optical power between the second communication device and the first communication device, thereby helping to reduce the power consumption of optical devices. In addition, in the scenario where optical fiber is used to transmit optical signals between the second communication device and the first communication device, the reduction in transmission optical power is also conducive to reducing the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by the nonlinear effects of optical fiber transmission. In addition, the second communication device also restores the half-wave radio frequency optical signal with lower average optical power to a full-wave radio frequency electrical signal with higher power. In the scenario where the second communication device also needs to output the full-wave radio frequency electrical signal to the antenna for signal radiation, this signal transmission method can achieve higher radio frequency radiation power for the antenna with lower transmission optical power.

[0028] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0029] In an optional embodiment, the full-wave radio frequency electrical signal obtained by converting the half-wave radio frequency optical signal by the second communication device is: the baseband signal in the electrical signal obtained by performing photoelectric conversion on the half-wave radio frequency optical signal.

[0030] In one optional embodiment, the second communication device converts the half-wave RF optical signal into a full-wave RF electrical signal, including: the second communication device performs photoelectric conversion on the half-wave RF optical signal using a photodetector to obtain a first electrical signal, wherein the passband of the photodetector covers the spectrum of the baseband signal; and the second communication device filters the first electrical signal using a bandpass filter to obtain a full-wave RF electrical signal, wherein the passband of the bandpass filter only contains the spectrum of the baseband signal. Thus, the second communication device can restore the half-wave RF optical signal to a full-wave RF electrical signal using the photodetector and bandpass filter without performing complex algorithmic processing, thereby simplifying the method for restoring the full-wave RF electrical signal.

[0031] In one optional embodiment, the second communication device converts the half-wave RF optical signal into a full-wave RF electrical signal, including: the second communication device performs photoelectric conversion on the half-wave RF optical signal using a photodetector to obtain a first electrical signal, and determines the full-wave RF electrical signal from the first electrical signal; the passband of the photodetector only includes the spectrum of the baseband signal. As can be seen, when the photodetector not only performs photoelectric conversion but also directly filters out the baseband signal, the second communication device can directly restore the half-wave RF optical signal to a full-wave RF electrical signal using the photodetector, eliminating the need for complex algorithmic processing and simplifying the method for restoring the full-wave RF electrical signal.

[0032] In a third aspect, an embodiment of the present application provides a signal transmission method, which is described from the perspective of interaction between a first communication device and a second communication device. The method includes: the first communication device generates a full-wave radio frequency electrical signal; the first communication device converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, where the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal; the first communication device transmits the half-wave radio frequency optical signal; the second communication device receives the half-wave radio frequency optical signal; and the second communication device converts the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal.

[0033] It can be seen that the half-wave radio frequency optical signal transmitted between the first communication device and the second communication device has the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal; compared with the radio frequency optical signal with the full amplitude of the full-wave radio frequency electrical signal, the average optical power of the half-wave radio frequency optical signal is lower, thereby reducing the transmission optical power between the first communication device and the second communication device, thereby helping to reduce the power consumption of optical devices. In addition, in the scenario where optical fiber is used to transmit optical signals between the first communication device and the second communication device, the reduction in transmission optical power is also conducive to reducing the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by the nonlinear effects of optical fiber transmission. In addition, the second communication device also restores the half-wave radio frequency optical signal with lower average optical power to a full-wave radio frequency electrical signal with higher power. In the scenario where the second communication device also needs to output the full-wave radio frequency electrical signal to the antenna for signal radiation, this signal transmission method can achieve higher antenna radio frequency radiation power with lower transmission optical power.

[0034] In an optional embodiment, the half-wave radio frequency optical signal is obtained by the first communication device optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by the first communication device optically modulating the negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component after inverting it.

[0035] In an optional embodiment, the first communication device converts a full-wave RF electrical signal into a half-wave RF optical signal, including: the first communication device superimposes a first bias electrical signal on the full-wave RF electrical signal, where the first bias electrical signal is a first bias voltage signal or a first bias current signal; and the first communication device optically modulates the full-wave RF electrical signal after superimposing the first bias electrical signal to obtain a half-wave RF optical signal.

[0036] In an optional embodiment, the first bias electrical signal is a first bias voltage signal. The first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias electrical signal to obtain a half-wave radio frequency optical signal, including: the first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal using an electro-absorption modulated laser to obtain the half-wave radio frequency optical signal.

[0037] In an optional embodiment, the electro-absorption modulated laser includes a laser diode and an electro-absorption modulator. The first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal using the electro-absorption modulated laser to obtain a half-wave radio frequency optical signal, including: the first communication device generates a continuous light wave signal using the laser diode; and the first communication device modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal using the electro-absorption modulator to obtain the half-wave radio frequency optical signal.

[0038] In an optional embodiment, the first bias electrical signal is a first bias current signal. The first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal, including: the first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias current signal through a directly modulated laser to obtain the half-wave RF optical signal; the current corresponding to the first bias current signal is greater than or equal to a threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

[0039] In an optional embodiment, the first bias electrical signal satisfies: the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by the first communication device performing photoelectric conversion on the first optical signal satisfies a first ratio; the first optical signal is an optical signal obtained by the first communication device performing optical modulation on the bias point detection electrical signal after superimposing the first bias electrical signal.

[0040] In an optional embodiment, the bias point detection electrical signal is a low-frequency sine wave signal. An error between a ratio of a coefficient corresponding to a DC component, a coefficient corresponding to a first-order harmonic component, a coefficient corresponding to a second-order harmonic component, and a coefficient corresponding to a third-order harmonic component of an electrical signal obtained by photoelectrically converting the first optical signal by the first communication device and 0.32:0.5:0.21:0 is within a second range.

[0041] In an optional embodiment, the method further includes: the first communication device generates a bias point detection electrical signal; the first communication device superimposes a second bias electrical signal on the bias point detection electrical signal; the first communication device optically modulates the bias point detection electrical signal after superimposing the second bias electrical signal to obtain a second optical signal; if the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by the first communication device performing photoelectric conversion on the second optical signal satisfies a first ratio, the first communication device determines that the first bias electrical signal is the second bias electrical signal; otherwise, the first communication device adjusts the second bias electrical signal and superimposes the adjusted second bias electrical signal on the bias point detection electrical signal.

[0042] In an optional embodiment, the first communication device converts the full-wave RF electrical signal into a half-wave RF optical signal, including: the first communication device converts the full-wave RF electrical signal into a first half-wave RF electrical signal, the first half-wave RF electrical signal is a RF electrical signal having the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal in the analog domain; the first communication device superimposes a third bias electrical signal on the first half-wave RF electrical signal by a modulating laser, and optically modulates the first half-wave RF electrical signal after the third bias electrical signal is superimposed to obtain a half-wave RF optical signal.

[0043] In an optional embodiment, the first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

[0044] In an optional embodiment, the full-wave radio frequency electrical signal is an analog signal. The first communication device converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, including: the first communication device converts the full-wave radio frequency electrical signal into the first half-wave radio frequency electrical signal through a low-noise power amplifier, wherein the low-noise power amplifier is a class B low-noise power amplifier, a class C low-noise power amplifier, or a class AB low-noise power amplifier.

[0045] In an optional embodiment, the full-wave radio frequency electrical signal is a digital signal. The first communication device converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, including: the first communication device converts the full-wave radio frequency electrical signal into a second half-wave radio frequency electrical signal, the second half-wave radio frequency electrical signal being a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the digital domain; and the first communication device performs digital-to-analog conversion on the second half-wave radio frequency electrical signal to obtain the first half-wave radio frequency electrical signal.

[0046] In an optional embodiment, the second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

[0047] In an optional embodiment, the method further includes: the first communication device using a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal. The first communication device superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal after superimposing the third bias electrical signal to obtain a half-wave radio frequency optical signal, including: the first communication device superimposes the third bias electrical signal on the first half-wave radio frequency electrical signal after the spectrum adjustment, and optically modulates the first half-wave radio frequency electrical signal after the spectrum adjustment and superimposition of the third bias electrical signal to obtain the half-wave radio frequency optical signal.

[0048] In an optional embodiment, the modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. Alternatively, the modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

[0049] In an optional embodiment, the second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; the plurality of third optical signals correspond one-to-one to the plurality of third bias current signals; each of the plurality of third optical signals is obtained by: optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal by the first communication device; the currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to the threshold current.

[0050] In an optional embodiment, the second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; the plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; the voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

[0051] In an optional implementation manner, the full-wave radio frequency electrical signal generated by the first communication device is a signal that has been digitally predistorted by the first communication device.

[0052] In an optional embodiment, the full-wave radio frequency electrical signal obtained by the second communication device converting the half-wave radio frequency optical signal is: the baseband signal in the electrical signal obtained by the second communication device performing photoelectric conversion on the half-wave radio frequency optical signal.

[0053] In an optional embodiment, the second communication device converts the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal, including: the second communication device performs photoelectric conversion on the half-wave radio frequency optical signal through a photodetector to obtain a first electrical signal, and the passband of the photodetector covers the spectrum of the baseband signal; the second communication device filters the first electrical signal through a bandpass filter to obtain a full-wave radio frequency electrical signal, and the passband of the bandpass filter only contains the spectrum of the baseband signal.

[0054] In an optional embodiment, the second communication device converts the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal, including: the second communication device performs photoelectric conversion on the half-wave radio frequency optical signal through a photoelectric detector to obtain a first electrical signal, and determines the full-wave radio frequency electrical signal from the first electrical signal; the passband of the photoelectric detector only contains the spectrum of the baseband signal.

[0055] In addition, in this aspect, the beneficial effects of the above-mentioned various optional implementations can be referred to the beneficial effects of the relevant implementations in the first and second aspects, and will not be repeated here.

[0056] In a fourth aspect, an embodiment of the present application provides a communication device, which includes a radio frequency signal generating module, a bias point control module, and a modulation laser. The radio frequency signal generating module is used to generate a full-wave radio frequency electrical signal and output the full-wave radio frequency electrical signal to the modulation laser. The bias point control module is used to output a first bias electrical signal to the modulation laser. The modulation laser is used to optically modulate the full-wave radio frequency electrical signal after superimposing the first bias electrical signal to obtain a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal with the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal. The modulation laser is also used to send the half-wave radio frequency optical signal.

[0057] As can be seen, the first communication device can convert the full-wave RF electrical signal into a half-wave RF optical signal with lower average optical power by superimposing the full-wave RF electrical signal and the first bias electrical signal and then performing optical modulation. This reduces the optical power transmitted between the first and second communication devices, thereby helping to reduce the power consumption of optical devices. Furthermore, in scenarios where optical fiber is used to transmit optical signals between the first and second communication devices, reducing the optical power transmission also helps to reduce the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by these nonlinear effects.

[0058] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0059] In an optional embodiment, the modulated laser is an electro-absorption modulated laser, and the first bias electrical signal is a first bias voltage signal. Alternatively, the modulated laser is a directly modulated laser, and the first bias electrical signal is a first bias current signal.

[0060] In an optional embodiment, the electro-absorption modulated laser includes a laser diode and an electro-absorption modulator. The electro-absorption modulated laser optically modulates a full-wave radio frequency electrical signal superimposed with a first bias voltage signal to obtain a half-wave radio frequency optical signal. Specifically, the electro-absorption modulated laser is configured to: generate a continuous light wave signal via the laser diode; and modulate the full-wave radio frequency electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal via the electro-absorption modulator to obtain a half-wave radio frequency optical signal.

[0061] In an optional embodiment, the current corresponding to the first bias current signal is greater than or equal to the threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

[0062] In an optional embodiment, the first bias electrical signal satisfies: the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the first optical signal satisfies a first ratio; and the first optical signal is an optical signal obtained by optically modulating the bias point detection electrical signal after superimposing the first bias electrical signal.

[0063] In an optional embodiment, the bias point detection electrical signal is a low-frequency sinusoidal wave signal. An error between a ratio of a coefficient corresponding to a DC component, a coefficient corresponding to a first-order harmonic component, a coefficient corresponding to a second-order harmonic component, and a coefficient corresponding to a third-order harmonic component of an electrical signal obtained by photoelectrically converting the first optical signal and 0.32:0.5:0.21:0 is within a second range.

[0064] In an optional embodiment, the bias point control module is further configured to generate a bias point detection electrical signal and output the bias point detection electrical signal to the modulating laser. The bias point control module is further configured to output a second bias electrical signal to the modulating laser. The modulating laser is further configured to optically modulate the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal, and output the second optical signal to the bias point control module. The bias point control module is further configured to: determine that the first bias electrical signal is the second bias electrical signal if the coefficient ratio between the multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the second optical signal satisfies a first ratio; otherwise, adjust the second bias electrical signal and output the adjusted second bias electrical signal to the modulating laser.

[0065] In an optional embodiment, the radio frequency signal generating module includes a digital pre-distortion module. The full-wave radio frequency electrical signal is a signal that has been digitally pre-distorted by the digital pre-distortion module.

[0066] In addition, in this aspect, the beneficial effects of the above-mentioned various optional implementations can be referred to the beneficial effects of the relevant implementations in the first aspect, and will not be repeated here.

[0067] In a fifth aspect, an embodiment of the present application provides a communication device comprising a radio frequency signal generation module, a low-noise power amplifier, and a modulated laser. The radio frequency signal generation module is configured to generate a full-wave radio frequency electrical signal and output the full-wave radio frequency electrical signal to the low-noise power amplifier. The full-wave radio frequency electrical signal is an analog signal. The low-noise power amplifier is configured to convert the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal and output the first half-wave radio frequency electrical signal to the modulated laser. The first half-wave radio frequency electrical signal is an radio frequency electrical signal having the positive half-amplitude or the negative half-amplitude of the full-wave radio frequency electrical signal in the analog domain. The low-noise power amplifier is a Class B low-noise power amplifier, a Class C low-noise power amplifier, or a Class AB low-noise power amplifier. The modulated laser is configured to superimpose a third bias electrical signal on the first half-wave radio frequency electrical signal and optically modulate the first half-wave radio frequency electrical signal after superimposition of the third bias electrical signal to obtain a half-wave radio frequency optical signal. The half-wave radio frequency optical signal is an radio frequency optical signal having the positive half-amplitude or the negative half-amplitude of the full-wave radio frequency electrical signal. The modulated laser is also configured to transmit the half-wave radio frequency optical signal.

[0068] As can be seen, the low-noise power amplifier converts the full-wave RF electrical signal into a lower-power half-wave RF electrical signal in the analog domain, and the modulated laser then converts the half-wave RF electrical signal into a half-wave RF optical signal. Compared to an RF optical signal with the full amplitude of the full-wave RF electrical signal, the half-wave RF optical signal has a lower average optical power, thereby reducing the optical power transmitted between the first and second communication devices, thereby helping to reduce the power consumption of optical devices. Furthermore, in scenarios where optical fiber is used to transmit optical signals between the first and second communication devices, reducing the transmitted optical power also helps to reduce the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by these nonlinear effects.

[0069] In an optional implementation, the radio frequency signal generating module includes a digital pre-distortion module; the full-wave radio frequency electrical signal is a signal that has been digitally pre-distorted by the digital pre-distortion module.

[0070] In an optional embodiment, the first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

[0071] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0072] In an optional embodiment, the device further includes: a waveform adjustment module for using a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal, and outputting the spectrum-adjusted first half-wave radio frequency electrical signal to a modulation laser. The modulation laser superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal after superimposing the third bias electrical signal to obtain a half-wave radio frequency optical signal. Specifically, the modulation laser is configured to: superimpose the third bias electrical signal on the spectrum-adjusted first half-wave radio frequency electrical signal, and optically modulate the spectrum-adjusted and superimposed first half-wave radio frequency electrical signal to obtain the half-wave radio frequency optical signal.

[0073] In an optional embodiment, the modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. Alternatively, the modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

[0074] In an optional embodiment, the second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; the plurality of third optical signals correspond one-to-one to the plurality of third bias current signals; each of the plurality of third optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal; the currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to a threshold current.

[0075] In an optional embodiment, the second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; the plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; the voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

[0076] In addition, in this aspect, the beneficial effects of the above-mentioned various optional implementations can be referred to the beneficial effects of the relevant implementations in the first aspect, and will not be repeated here.

[0077] In a sixth aspect, an embodiment of the present application provides a communication device comprising a half-wave RF signal generation module and a modulated laser. The half-wave RF signal generation module is configured to convert a full-wave RF electrical signal into a second half-wave RF electrical signal, and perform digital-to-analog conversion on the second half-wave RF electrical signal to obtain a first half-wave RF electrical signal. The full-wave RF electrical signal and the second half-wave RF electrical signal are digital signals. The second half-wave RF electrical signal is an RF electrical signal having the positive half amplitude or negative half amplitude of the full-wave RF electrical signal in the digital domain, and the first half-wave RF electrical signal is an RF electrical signal having the positive half amplitude or negative half amplitude of the full-wave RF electrical signal in the analog domain. The half-wave RF signal generation module is further configured to output the first half-wave RF electrical signal to the modulated laser. The modulated laser is configured to superimpose a third bias electrical signal on the first half-wave RF electrical signal and optically modulate the first half-wave RF electrical signal after superimposition of the third bias electrical signal to obtain a half-wave RF optical signal. The half-wave RF optical signal is an RF optical signal having the positive half amplitude or negative half amplitude of the full-wave RF electrical signal. Modulated lasers are also used to send half-wave RF optical signals.

[0078] As can be seen, the half-wave RF signal generation module converts the full-wave RF electrical signal into a lower-power half-wave RF electrical signal in the digital domain, and the modulated laser then converts the half-wave RF electrical signal into a half-wave RF optical signal. Compared to an RF optical signal with the full amplitude of the full-wave RF electrical signal, the half-wave RF optical signal has a lower average optical power, thereby reducing the optical power transmitted between the first communication device and the second communication device, thereby helping to reduce the power consumption of optical devices. In addition, in scenarios where optical fiber is used to transmit optical signals between the first and second communication devices, the reduction in transmission optical power can also help reduce the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by nonlinear effects of optical fiber transmission.

[0079] In an optional embodiment, the second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

[0080] In an optional implementation, the half-wave radio frequency signal generating module includes a digital pre-distortion module; the full-wave radio frequency electrical signal is a signal that has been digitally pre-distorted by the digital pre-distortion module.

[0081] In an optional embodiment, the first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

[0082] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0083] In an optional embodiment, the device further includes: a waveform adjustment module for using a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal, and outputting the spectrum-adjusted first half-wave radio frequency electrical signal to a modulation laser. The modulation laser superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal after superimposing the third bias electrical signal to obtain a half-wave radio frequency optical signal. Specifically, the modulation laser is configured to: superimpose the third bias electrical signal on the spectrum-adjusted first half-wave radio frequency electrical signal, and optically modulate the spectrum-adjusted and superimposed first half-wave radio frequency electrical signal to obtain the half-wave radio frequency optical signal.

[0084] In an optional embodiment, the modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. Alternatively, the modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

[0085] In an optional embodiment, the second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; the plurality of third optical signals correspond one-to-one to the plurality of third bias current signals; each of the plurality of third optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal; the currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to a threshold current.

[0086] In an optional embodiment, the second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; the plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; the voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

[0087] In addition, in this aspect, the beneficial effects of the above-mentioned various optional implementations can be referred to the beneficial effects of the relevant implementations in the first aspect, and will not be repeated here.

[0088] In a seventh aspect, an embodiment of the present application provides a communication device, which includes a photodetector and a bandpass filter. The photodetector is used to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal with the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal. The photodetector is also used to perform photoelectric conversion on the half-wave radio frequency optical signal to obtain a first electrical signal, and output the first electrical signal to the bandpass filter; the passband of the photodetector covers the spectrum of the baseband signal. The bandpass filter is used to filter the first electrical signal to obtain a full-wave radio frequency electrical signal; the passband of the bandpass filter only contains the spectrum of the baseband signal, and the full-wave radio frequency electrical signal is the baseband signal in the first electrical signal.

[0089] It can be seen that the half-wave radio frequency optical signal transmitted between the second communication device and the first communication device has the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal; compared with the radio frequency optical signal with the full amplitude of the full-wave radio frequency electrical signal, the average optical power of the half-wave radio frequency optical signal is lower, thereby reducing the transmission optical power between the second communication device and the first communication device, thereby helping to reduce the power consumption of optical devices. In the scenario where optical fiber is used to transmit optical signals between the second communication device and the first communication device, the reduction in transmission optical power is also conducive to reducing the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by the nonlinear effects of optical fiber transmission. In addition, the photodetector and the bandpass filter realize the recovery of the half-wave radio frequency optical signal with lower average optical power into a full-wave radio frequency electrical signal with higher power, simplifying the method of recovering the full-wave radio frequency electrical signal, and in the scenario where the second communication device needs to output the full-wave radio frequency electrical signal to the antenna for signal radiation, it can achieve higher radio frequency radiation power of the antenna with lower transmission optical power.

[0090] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0091] In an eighth aspect, an embodiment of the present application provides a communication device comprising a photodetector. The photodetector is configured to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal. The photodetector is further configured to perform photoelectric conversion on the half-wave radio frequency optical signal to obtain a first electrical signal, and to determine a full-wave radio frequency electrical signal from the first electrical signal; the passband of the photodetector only includes the spectrum of the fundamental frequency signal in the first electrical signal, and the full-wave radio frequency electrical signal is the fundamental frequency signal in the first electrical signal.

[0092] It can be seen that the half-wave radio frequency optical signal transmitted between the second communication device and the first communication device has the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal; compared with the radio frequency optical signal with the full amplitude of the full-wave radio frequency electrical signal, the average optical power of the half-wave radio frequency optical signal is lower, thereby reducing the transmission optical power between the second communication device and the first communication device, thereby helping to reduce the power consumption of optical devices. In the scenario where optical fiber is used to transmit optical signals between the second communication device and the first communication device, the reduction in transmission optical power is also conducive to reducing the nonlinear effects of optical fiber transmission, thereby reducing the signal distortion caused by the nonlinear effects of optical fiber transmission. In addition, the photodetector realizes the recovery of the half-wave radio frequency optical signal with lower average optical power into a full-wave radio frequency electrical signal with higher power, which simplifies the method of recovering the full-wave radio frequency electrical signal. In the scenario where the second communication device needs to output the full-wave radio frequency electrical signal to the antenna for signal radiation, it can achieve higher radio frequency radiation power of the antenna with lower transmission optical power.

[0093] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0094] In a ninth aspect, the present application also provides a communication device. The communication device may be a first communication device or a first communication device, or may be a chip in the first communication device or the first communication device, or may be a logic module or software that can implement all or part of the functions of the first communication device or the first communication device. The communication device has the function of implementing some or all of the implementation methods described in the first aspect above, or has the function of implementing some or all of the functional implementation methods described in the second aspect above. The functions may be implemented by hardware, or may be implemented by hardware executing corresponding software. The hardware or software includes one or more units or modules corresponding to the above functions.

[0095] In one possible design, the communication device may include a processing unit and a communication unit. The processing unit is configured to support the communication device in performing the corresponding functions in the above method. The communication unit is configured to support communication between the communication device and other communication devices. The communication device may also include a storage unit, which is coupled to the processing unit and the communication unit and stores program instructions and data necessary for the communication device.

[0096] In one embodiment, the communication device includes: a processing unit and a communication unit; the processing unit is used to control the communication unit to send and receive data / signaling.

[0097] The processing unit is used to generate a full-wave radio frequency electrical signal.

[0098] The processing unit is further used to convert the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal with the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal.

[0099] The communication unit is used to send half-wave radio frequency optical signals.

[0100] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the first aspect above and will not be described in detail here.

[0101] In another embodiment, the communication device includes: a communication unit and a processing unit; the processing unit is used to control the communication unit to send and receive data / signaling.

[0102] The communication unit is used to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal.

[0103] The processing unit is used to convert the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal.

[0104] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0105] As an example, the communication unit may be a transceiver or a communication interface, the storage unit may be a memory, and the processing unit may be a processor. The processor is coupled to the memory, the memory being used to store programs or instructions to the processor. The processor may be configured to cause the communication device to perform the method described in the first or second aspect above when the programs or instructions are executed by the processor. The transceiver or communication interface may be configured to transmit and receive signals and / or data.

[0106] In one embodiment, the communication device includes: a processor and a transceiver.

[0107] A processor is used to generate a full-wave radio frequency electrical signal.

[0108] The processor is further configured to convert the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal.

[0109] Transceiver, used to transmit half-wave RF optical signals.

[0110] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the first aspect above and will not be described in detail here.

[0111] In another embodiment, the communication device includes: a processor and a transceiver.

[0112] The transceiver is used to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal.

[0113] A processor is used to convert the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal.

[0114] In addition, in this aspect, other optional implementations of the communication device can refer to the relevant content of the second aspect above and will not be described in detail here.

[0115] In another embodiment, the communication device is a chip or a chip system. The processing unit may also be embodied as a processing circuit or a logic circuit; and the transceiver unit may be an input / output interface, an interface circuit, an output circuit, an input circuit, a pin, or a related circuit on the chip or chip system.

[0116] During implementation, the processor can be used to perform, for example, but not limited to, baseband-related processing, and the transceiver or communication interface can be used to perform, for example, but not limited to, radio frequency transceiver. The above-mentioned devices can be provided on separate chips, or at least partially or entirely on the same chip. For example, the processor can be further divided into an analog baseband processor and a digital baseband processor. The analog baseband processor can be integrated with the transceiver (or communication interface) on the same chip, while the digital baseband processor can be provided on a separate chip. With the continuous development of integrated circuit technology, more and more devices can be integrated on the same chip. For example, a digital baseband processor can be integrated with multiple application processors (such as, but not limited to, a graphics processor, a multimedia processor, etc.) on the same chip. Such a chip can be called a system on a chip (SoC). Whether each device is provided independently on different chips or integrated on one or more chips often depends on the needs of the product design. The embodiments of the present application do not limit the implementation form of the above-mentioned devices.

[0117] In the tenth aspect, the present application also provides a processor for executing the various methods described above. In the process of executing these methods, the process of sending the above-mentioned signal and receiving the above-mentioned signal in the above-mentioned method can be understood as the process of outputting the above-mentioned signal by the processor, and the process of inputting the above-mentioned signal by the processor. When outputting the above-mentioned signal, the processor outputs the above-mentioned signal to the transceiver so that it is transmitted by the transceiver (or communication interface). After being output by the processor, the above-mentioned signal may also need to undergo other processing before reaching the transceiver (or communication interface). Similarly, when the processor receives the above-mentioned input signal, the transceiver (or communication interface) receives the above-mentioned signal and inputs it into the processor. Furthermore, after the transceiver (or communication interface) receives the above-mentioned signal, the above-mentioned signal may need to undergo other processing before being input into the processor.

[0118] For the sending and receiving operations involved in the processor, unless otherwise specified, or unless they conflict with their actual functions or internal logic in the relevant descriptions, they can be more generally understood as processor output, reception, input and other operations, rather than sending and receiving operations directly performed by the RF circuit and antenna.

[0119] During implementation, the processor may be a processor specifically configured to execute these methods, or may be a processor that executes computer instructions in a memory to execute these methods, such as a general-purpose processor. The memory may be a non-transitory memory, such as a read-only memory (ROM), which may be integrated with the processor on the same chip or disposed on separate chips. The embodiments of the present application do not limit the type of memory or the configuration of the memory and the processor.

[0120] In an eleventh aspect, the present application further provides a communication system, comprising the first communication device and the first communication device of the above aspects. In another possible design, the system may further include other devices that interact with the first communication device and / or the first communication device in the solution provided by the present application.

[0121] In a twelfth aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is run, the method described in any one of the first or second aspects above is executed.

[0122] In a thirteenth aspect, the present application further provides a computer program product comprising instructions, the computer program product comprising: computer program code, which, when the computer program code is run, enables the method described in any one of the first or second aspects above to be executed.

[0123] In a fourteenth aspect, the present application provides a chip system, which includes a processor and an interface, wherein the interface is used to obtain a program or instruction, and the processor is used to call the program or instruction to implement the functions involved in the first aspect, or to call the program or instruction to implement the functions involved in the second aspect. In one possible design, the chip system also includes a memory, which is used to store program instructions and data necessary for the terminal. The chip system can be composed of a chip, or it can include a chip and other discrete devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0124] FIG1 is a schematic diagram of a system architecture provided in an embodiment of the present application;

[0125] FIG2 is a schematic diagram of an EML light modulation provided in an embodiment of the present application;

[0126] FIG3 is a schematic diagram of a DML optical modulation provided in an embodiment of the present application;

[0127] FIG4 is a schematic diagram of a radio frequency electrical signal provided in an embodiment of the present application;

[0128] FIG5 is a schematic structural diagram of a communication system provided in an embodiment of the present application;

[0129] FIG6 is a schematic flow chart of a signal transmission method provided in an embodiment of the present application;

[0130] FIG7 is a schematic diagram of a half-wave radio frequency optical signal provided in an embodiment of the present application;

[0131] FIG8 is a schematic diagram of light modulation by an electro-absorption modulated laser provided in an embodiment of the present application;

[0132] FIG9 is a schematic diagram of light modulation by a directly modulated laser provided in an embodiment of the present application;

[0133] FIG10 is a schematic diagram of another directly modulated laser for light modulation provided in an embodiment of the present application;

[0134] FIG11 is a schematic diagram of light modulation by another electro-absorption modulated laser provided in an embodiment of the present application;

[0135] FIG12 is a schematic diagram of spectrum adjustment provided in an embodiment of the present application;

[0136] FIG13a is a schematic diagram of performing spectrum adjustment on a first half-wave radio frequency electrical signal according to an embodiment of the present application;

[0137] FIG13b is a schematic diagram of another directly modulated laser performing light modulation provided in an embodiment of the present application;

[0138] FIG13c is a schematic diagram of another directly modulated laser performing light modulation provided in an embodiment of the present application;

[0139] FIG14a is a schematic diagram of another method of performing spectrum adjustment on a first half-wave radio frequency electrical signal provided by an embodiment of the present application;

[0140] FIG14b is a schematic diagram of another directly modulated laser performing light modulation provided in an embodiment of the present application;

[0141] FIG14c is a schematic diagram of another directly modulated laser performing light modulation provided in an embodiment of the present application;

[0142] FIG15 is a schematic diagram of a filtering process provided by an embodiment of the present application;

[0143] FIG16 is a schematic diagram of a first communication device 1600 provided in an embodiment of the present application;

[0144] FIG17 is a schematic diagram of a bias point control module 1602 provided in an embodiment of the present application;

[0145] FIG18 is a schematic diagram of another first communication device 1600 provided in an embodiment of the present application;

[0146] FIG19 is a schematic diagram of another first communication device 1600 provided in an embodiment of the present application;

[0147] FIG20 is a schematic diagram of a first communication device 2000 provided in an embodiment of the present application;

[0148] FIG21 is a schematic diagram of another first communication device 2000 provided in an embodiment of the present application;

[0149] FIG22 is a schematic diagram of another first communication device 2000 provided in an embodiment of the present application;

[0150] FIG23 is a schematic diagram of another first communication device 2000 provided in an embodiment of the present application;

[0151] FIG24 is a schematic diagram of another first communication device 2000 provided in an embodiment of the present application;

[0152] FIG25 is a schematic diagram of a first communication device 2500 provided in an embodiment of the present application;

[0153] FIG26 is a schematic diagram of another first communication device 2500 provided in an embodiment of the present application;

[0154] FIG27 is a schematic diagram of another first communication device 2500 provided in an embodiment of the present application;

[0155] FIG28 is a schematic diagram of another first communication device 2500 provided in an embodiment of the present application;

[0156] FIG29 is a schematic diagram of another first communication device 2500 provided in an embodiment of the present application;

[0157] FIG30 is a schematic diagram of a second communication device 3000 provided in an embodiment of the present application;

[0158] FIG31 is a schematic diagram of a second communication device 3100 provided in an embodiment of the present application;

[0159] FIG32 is a schematic structural diagram of a communication device provided in an embodiment of the present application;

[0160] FIG33 is a schematic structural diagram of another communication device provided in an embodiment of the present application;

[0161] Figure 34 is a structural diagram of another communication device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0162] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0163] First, in order to better understand the signal transmission method disclosed in the embodiment of the present application, a communication system to which the embodiment of the present application is applicable is described.

[0164] The technical solutions of the embodiments of the present application can be applied to various communication systems. For example, global mobile communication systems, long term evolution (LTE) systems, universal mobile communication systems, fourth generation mobile communication technology (4G) systems, next generation radio access networks (NG-RAN), new radio (NR) systems, fifth generation mobile communication technology (5G) systems, and with the continuous development of communication technology, the technical solutions of the embodiments of the present application can also be used for subsequent evolved communication systems, such as sixth generation mobile communication technology (6G) systems, seventh generation mobile communication technology (7G) systems, and the like.

[0165] The technical solutions provided by the embodiments of the present application can be applied to wireless access scenarios based on radio frequency optical transmission, for example, they can be applied to wireless fronthaul systems, wireless base station systems, wireless access point systems, high optical power downlinks of radio frequency optical transmission systems, and so on. The technical solutions provided by the embodiments of the present application can also be applied to centralized wireless fidelity (Wi-Fi) access networks (C-WANs) of fiber to the room (FTTR) or fiber to the radio (C-WANs). In addition, the technical solutions provided by the embodiments of the present application can support not only radio frequency signal transmission for communication, but also radio frequency signal transmission for sensing.

[0166] Please refer to Figure 1, which is a schematic diagram of a system architecture provided in an embodiment of the present application. This system architecture may include a central end, an optical fiber transmission segment, and an antenna end. The central end may be used to generate RF electrical signals, convert RF electrical signals into RF optical signals, and perform wavelength division multiplexing (WDM) of RF channels; the optical fiber transmission segment may be used to transmit and amplify RF optical signals; and the antenna end may be used to perform WDM, convert RF optical signals into RF electrical signals, and transmit RF electrical signals via the antenna.

[0167] For example, the central end may include an electro-optical conversion device and a wavelength division multiplexer (WDM), the optical fiber transmission section may include an optical parametric amplifier (OPA) and an optical fiber, and the antenna end may include a dense wavelength division multiplexer (DWDM), a photoelectric diode (PD), and an antenna. The electro-optical conversion device may be used to convert radio frequency electrical signals into radio frequency optical signals. For example, the electro-optical conversion device may be a directly modulated laser (DML), an electroabsorption-modulated laser (EML), or a Mach-Zehnder modulator (MZM). WDM may be used to combine optical signals of different wavelengths, and DWDM may be used to demultiplex optical signals of multiple wavelengths. Optical amplifiers may be used to amplify the optical power of optical signals. Optical fibers may connect the central end and the antenna end to achieve long-distance, low-loss transmission of radio frequency optical signals. The PD may be used to convert radio frequency optical signals into radio frequency electrical signals. The antenna may be used to achieve spatial radiation and reception of radio frequency electrical signals.

[0168] Among them, EML realizes optical modulation by changing voltage, and DML realizes optical modulation by changing current. Taking the DC component of the RF electrical signal input to EML or DML as 0 as an example, the embodiment of the present application provides a schematic diagram of EML optical modulation as shown in Figure 2, and a schematic diagram of DML optical modulation as shown in Figure 3. In Figure 2, the power-voltage curve represents the relationship between the operating voltage and optical power of the EML, and the voltage-time curve represents the RF electrical signal input to the EML superimposed on the bias voltage signal (the voltage corresponding to the bias voltage signal is V bias), the power-time curve represents the RF optical signal obtained by EML optically modulating the RF electrical signal superimposed with the bias voltage signal. In Figure 3, the power-current curve represents the relationship between the operating current and optical power of the DML, and the current-time curve represents the RF electrical signal input to the DML superimposed with the bias current signal (the current corresponding to the bias current signal is I bias ), the power-time curve represents the RF optical signal obtained by DML optically modulating the RF electrical signal superimposed with the bias current signal.

[0169] The following explanation uses the EML optical modulation shown in Figure 2 as an example. DML optical modulation is similar and will not be further described. Referring to Figure 2, applying a bias voltage signal to the EML causes the EML's bias voltage to be the voltage corresponding to the bias voltage signal. Therefore, when the EML performs optical modulation, its operating voltage is set according to the electrical signal represented by the voltage-time curve in Figure 2 (i.e., the electrical signal resulting from the superposition of the bias voltage signal and the RF electrical signal input to the EML), resulting in an RF optical signal represented by the power-time curve in Figure 2. If the voltage corresponding to the bias voltage signal is set to an appropriate value (i.e., the EML's bias voltage is set to an appropriate value) so that the EML's operating voltage falls within the linear region of the power-voltage curve, the EML can perform linear optical modulation, and the resulting optical signal can have the same waveform as the complete RF electrical signal input to the EML. For example, if the RF electrical signal shown in Figure 4 is input to the EML, and the EML's bias voltage is set to a voltage midway within the linear region of the power-voltage curve, the EML can perform optical modulation to produce an RF optical signal with a waveform identical or substantially identical to the complete waveform of the RF electrical signal shown in Figure 4.

[0170] Please refer to Figure 5, which is a structural diagram of a communication system provided in an embodiment of the present application, wherein the communication system includes a first communication device and a second communication device. The first communication device can be used to convert a full-wave radio frequency electrical signal into a half-wave radio frequency optical signal and send a half-wave radio frequency optical signal; the second communication device can be used to receive a half-wave radio frequency optical signal and convert the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal. The communication system may also include a channel between the first communication device and the second communication device for transmitting the half-wave radio frequency optical signal, such as an optical fiber, space or other transmission medium; the optical fiber transmission link based on the optical fiber transmission of the optical signal may adopt single-wave transmission or wavelength division multiplexing transmission, which may include optical fiber, optical amplifier, wavelength division multiplexer, wavelength demultiplexer, etc. In addition, in an embodiment of the present application, the first communication device may also be referred to as a half-wave radio frequency light generation module, and the second communication device may also be referred to as a waveform recovery module.

[0171] For example, the first communication device may be installed in a building baseband unit (BBU), a centralized unit (CU), or a distributed unit (DU), and the second communication device may be installed in a remote radio unit (RRU) or a remote radio head (RRH). Alternatively, the first communication device may be installed in an RRU or RRH, and the second communication device may be installed in a BBU, a DU, or a CU. Alternatively, the first communication device may be installed in a BBU, and the second communication device may be installed in an active antenna unit (AAU). Alternatively, the first communication device may be installed in an AAU, and the second communication device may be installed in a BBU.

[0172] In the embodiment of the present application, a full-wave signal is a signal whose waveform is envelope-symmetrical relative to a DC component. For example, the signal shown in FIG4 is envelope-symmetrical relative to the DC component shown by the black dotted line, so the signal shown in FIG4 is a full-wave signal. A half-wave signal is a signal having a positive half-amplitude or a negative half-amplitude of a full-wave signal relative to a DC component. The positive half-amplitude of the full-wave signal relative to the DC component, that is, the upper half-amplitude of the full-wave signal relative to the DC component, is greater than or equal to the amplitude of the DC component. The negative half-amplitude of the full-wave signal relative to the DC component, that is, the lower half-amplitude of the full-wave signal relative to the DC component, is less than or equal to the amplitude of the DC component. The full-wave radio frequency electrical signal involved in the embodiment of the present application is a full-wave signal, and the half-wave radio frequency optical signal, the first half-wave radio frequency electrical signal, and the second half-wave radio frequency electrical signal are all half-wave signals.

[0173] The following is a detailed description of the embodiments of the present application in conjunction with the accompanying drawings. The flowchart in the present application uses the first communication device and the second communication device as an example to illustrate the corresponding method, but the present application does not limit the execution subject of the interactive diagram. For example, the first communication device in the figure can also be a chip or chip system or processor that supports the first communication device to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the first communication device; the second communication device in the figure can also be a chip or chip system or processor that supports the second communication device to implement the corresponding method, or a logic module or software that can implement all or part of the functions of the second communication device.

[0174] Please refer to FIG6 , which is a flow chart of a signal transmission method provided in an embodiment of the present application. The signal transmission method is described from the perspective of interaction between a first communication device and a second communication device. The signal transmission method includes the following steps:

[0175] S101: A first communication device generates a full-wave radio frequency electrical signal. For example, the full-wave radio frequency electrical signal may be an AC-coupled radio frequency electrical signal with a zero DC component.

[0176] Optionally, the full-wave radio frequency electrical signal may be a signal that has been subjected to digital pre-distortion (DPD) processing. Digital pre-distortion processing is beneficial for correcting the nonlinear effects produced by the subsequent optical modulation operation, thereby reducing the signal distortion caused by the nonlinear effects of the modulation. In addition, in the scenario where an optical signal is transmitted between the first communication device and the second communication device via an optical fiber, digital pre-distortion processing is also beneficial for correcting the nonlinear effects of the optical fiber, thereby reducing the signal distortion caused by the nonlinear effects of the optical fiber transmission. Among them, the nonlinear effects of optical fiber transmission are, for example, stimulated Brillouin scattering (SBS), self-phase modulation (SPM), cross-phase modulation (XPM), and four-wave mixing (FWM).

[0177] In an optional embodiment, the full-wave RF electrical signal may be an analog signal obtained through baseband signal modulation, digital pre-distortion processing, digital-to-analog conversion, local oscillator mixing, and amplification. In this embodiment, the first communication device generating the full-wave RF electrical signal may include: the first communication device modulating the baseband signal and performing digital pre-distortion processing on the modulated baseband signal; performing digital-to-analog conversion on the digital signal obtained through the digital pre-distortion processing to obtain an analog signal at an intermediate frequency; then, mixing the analog signal with a local oscillator, and amplifying the electrical signal obtained through the mixing to obtain the full-wave RF electrical signal.

[0178] In another optional embodiment, the full-wave RF electrical signal may be an analog signal obtained through baseband signal modulation, digital pre-distortion processing, digital-to-analog conversion, and local oscillator mixing. In this embodiment, the first communication device generating the full-wave RF electrical signal may include: the first communication device modulating the baseband signal and performing digital pre-distortion processing on the modulated baseband signal; performing digital-to-analog conversion on the digital signal obtained by the digital pre-distortion processing to obtain an analog signal at an intermediate frequency; and then mixing the analog electrical signal with a local oscillator to obtain the full-wave RF electrical signal.

[0179] In another optional embodiment, the full-wave RF electrical signal may be a digital signal obtained through baseband signal modulation, RF modulation, and digital pre-distortion processing. In this embodiment, the first communication device generating the full-wave RF electrical signal may include: the first communication device modulating the baseband signal and performing RF modulation on the modulated baseband signal; and then performing digital pre-distortion processing on the electrical signal obtained by RF modulation to obtain the full-wave RF electrical signal.

[0180] In another optional embodiment, the full-wave RF electrical signal may be an electrical signal obtained by amplifying an analog signal received by the first communication device via an antenna. In this embodiment, the first communication device may amplify the analog signal received via the antenna to obtain the full-wave RF electrical signal. Exemplarily, this embodiment may be applied in a scenario where the first communication device is installed in an RRU, RRH, or AAU.

[0181] In another optional embodiment, the full-wave RF electrical signal may be an electrical signal obtained by amplifying and mixing an analog signal received by the first communication device via an antenna with a local oscillator. In this embodiment, the first communication device may amplify the analog signal received via the antenna, and then mix the amplified electrical signal with the local oscillator to obtain a full-wave RF electrical signal. For example, this embodiment may be applied in a scenario where the first communication device is installed in an RRU, RRH, or AAU.

[0182] S102. The first communication device converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal.

[0183] Among them, the positive half amplitude of the full-wave radio frequency electrical signal refers to the positive half amplitude of the full-wave radio frequency electrical signal relative to the DC component, which is greater than or equal to the amplitude of the DC component; the negative half amplitude of the full-wave radio frequency electrical signal refers to the negative half amplitude of the full-wave radio frequency electrical signal relative to the DC component, which is less than or equal to the amplitude of the DC component. It can be seen that compared with the radio frequency optical signal with the full amplitude of the full-wave radio frequency electrical signal, the average optical power of the half-wave radio frequency optical signal is lower, thereby reducing the transmission optical power between the first communication device and the second communication device, thereby helping to reduce the power consumption of optical devices. In addition, in the scenario where optical fiber is used to transmit optical signals between the first communication device and the second communication device, the reduction in transmission optical power is also conducive to reducing the nonlinear effect of optical fiber transmission, thereby reducing the signal distortion caused by the nonlinear effect of optical fiber transmission.

[0184] In addition, the embodiments of the present application do not limit the half-wave radio frequency optical signal to have the absolute positive half amplitude or absolute negative half amplitude of the full-wave radio frequency electrical signal relative to the DC component. It is understandable that, in addition to having the entire positive half amplitude or the entire negative half amplitude of the full-wave radio frequency electrical signal relative to the DC component, the half-wave radio frequency optical signal may also have most of the positive half amplitude or most of the negative half amplitude of the full-wave radio frequency electrical signal relative to the DC component; it may also have all of the positive half amplitude and a small portion of the negative half amplitude of the full-wave radio frequency electrical signal relative to the DC component, or it may have all of the negative half amplitude and a small portion of the positive half amplitude of the full-wave radio frequency electrical signal relative to the DC component; it may also have most of the positive half amplitude and a small portion of the negative half amplitude of the full-wave radio frequency electrical signal relative to the DC component, or it may have most of the negative half amplitude and a small portion of the positive half amplitude of the full-wave radio frequency electrical signal relative to the DC component.

[0185] For example, taking the full-wave RF electrical signal as shown in FIG4 as an example, possible waveforms of a half-wave RF optical signal are shown in parts (A) to (D) of FIG7 . The dotted lines in parts (A) to (D) of FIG7 represent the power of the DC component corresponding to the RF electrical signal shown in FIG4 after optical modulation. In FIG7 , the half-wave RF optical signal shown in part (A) has all the positive half amplitudes of the full-wave RF electrical signal relative to the DC component, the half-wave RF optical signal shown in part (B) has all the positive half amplitudes and a small portion of the negative half amplitudes of the full-wave RF electrical signal relative to the DC component, the half-wave RF optical signal shown in part (C) has most of the positive half amplitudes of the full-wave RF electrical signal relative to the DC component, and the half-wave RF optical signal shown in part (D) has most of the positive half amplitudes and a small portion of the negative half amplitudes of the full-wave RF electrical signal relative to the DC component.

[0186] Optionally, the half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component. The positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component is an radio frequency electrical signal having the positive half-amplitude of the full-wave radio frequency electrical signal relative to the DC component; the negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component is an radio frequency electrical signal having the negative half-amplitude of the full-wave radio frequency electrical signal relative to the DC component.

[0187] In an optional embodiment, the first communication device converts a full-wave RF electrical signal into a half-wave RF optical signal, which may include: the first communication device superimposing a first bias electrical signal on the full-wave RF electrical signal, where the first bias electrical signal is a first bias voltage signal or a first bias current signal; and the first communication device optically modulating the full-wave RF electrical signal after superimposing the first bias electrical signal to obtain a half-wave RF optical signal. This embodiment can be applied to the case where the full-wave RF electrical signal is an analog signal obtained through baseband signal modulation, digital predistortion processing, digital-to-analog conversion, local oscillator mixing, and amplification processing. It can also be applied to the case where the full-wave RF electrical signal is an electrical signal obtained by amplifying an analog signal received by the first communication device via an antenna. It can also be applied to the case where the full-wave RF electrical signal is an electrical signal obtained by amplifying an analog signal received by the first communication device via an antenna and performing local oscillator mixing. Optionally, the first communication device superimposing the first bias electrical signal on the full-wave RF electrical signal can be achieved by the first communication device using a coupler.

[0188] In the two cases where the first bias electrical signal is a first bias voltage signal and the first bias electrical signal is a first bias current signal, the specific manner in which the first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal may differ. The following describes the two cases where the first bias electrical signal is a first bias voltage signal and the first bias electrical signal is a first bias current signal, respectively, as described in the following optional embodiments 1.1 and 1.2.

[0189] In embodiment 1.1, the first bias electrical signal is a first bias voltage signal. In this case, the first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal. This may include: the first communication device optically modulating the full-wave RF electrical signal superimposed with the first bias voltage signal using an electro-absorption modulated laser to obtain a half-wave RF optical signal.

[0190] Understandably, the first bias voltage signal acting on the electro-absorption modulated laser can cause the bias voltage of the electro-absorption modulated laser to be the voltage corresponding to the first bias voltage signal. The electro-absorption modulated laser optically modulates the full-wave RF electrical signal superimposed with the first bias voltage signal. That is, the electro-absorption modulated laser, whose bias voltage is the voltage corresponding to the first bias voltage signal, optically modulates the full-wave RF electrical signal. During this optical modulation process, the operating voltage of the electro-absorption modulated laser is set according to the full-wave RF electrical signal superimposed with the first bias voltage signal. The electro-absorption modulated laser is a laser that achieves optical modulation through voltage changes. For example, the electro-absorption modulated laser can be an EML.

[0191] For example, taking the case where the DC component corresponding to the full-wave RF electrical signal is 0 as an example, in conjunction with FIG8 , in FIG8 , the power-voltage curve represents the relationship between the operating voltage and optical power of the electro-absorption modulated laser, the voltage-time curve represents the full-wave RF electrical signal after superimposing the first bias voltage signal, and the power-time curve represents the half-wave RF optical signal. It can be seen that the smaller the operating voltage of the electro-absorption modulated laser, the greater the optical power obtained by the electro-absorption modulated laser through optical modulation; the greater the operating voltage of the electro-absorption modulated laser, the smaller the optical power obtained by the electro-absorption modulated laser through optical modulation. Based on this characteristic of the electro-absorption modulated laser, the bias voltage of the electro-absorption modulated laser is set to the low output optical power point (high voltage) corresponding to the first bias voltage signal, so that the operating voltage of the electro-absorption modulated laser is set according to the electrical signal after superimposing the first bias voltage signal and the full-wave RF electrical signal, so that the electro-absorption modulated laser through optical modulation can obtain a half-wave RF optical signal.

[0192] Optionally, the electro-absorption modulated laser may include a laser diode and an electro-absorption modulator. The first communication device may generate a continuous light wave signal through a laser diode; and modulate the full-wave radio frequency electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal through the electro-absorption modulator to obtain a half-wave radio frequency light signal. It can be seen that the first communication device may generate a light source through a laser diode and realize light modulation through an electro-absorption modulator, that is, the light source generation and light modulation are decoupled, which is beneficial to reduce the influence of the light source bandwidth on high-frequency modulation when the voltage corresponding to the first bias voltage signal is large. In addition, the laser diode included in the electro-absorption modulated laser may be, for example, a laser diode (LD) with low relative intensity noise (RIN), and the electro-absorption modulator may be, for example, an electro-absorption modulator (EAM).

[0193] Implementation 1.2, where the first bias electrical signal is a first bias current signal. In this case, the first communication device optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal. This may include: the first communication device optically modulating the full-wave RF electrical signal superimposed with the first bias current signal using a directly modulated laser to obtain a half-wave RF optical signal; the current corresponding to the first bias current signal is greater than or equal to a threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

[0194] Understandably, the first bias current signal acts on the direct-modulated laser, causing the bias current of the direct-modulated laser to be the current corresponding to the first bias current signal. The direct-modulated laser optically modulates the full-wave RF electrical signal superimposed with the first bias current signal. That is, the direct-modulated laser, whose bias current is the current corresponding to the first bias current signal, optically modulates the full-wave RF electrical signal. During this optical modulation process, the operating current of the direct-modulated laser is set according to the full-wave RF electrical signal superimposed with the first bias current signal. A direct-modulated laser is a laser that achieves optical modulation by changing the current. For example, the direct-modulated laser can be a DML.

[0195] Among them, the first range satisfies: when the difference between the current corresponding to the first bias current signal and the threshold current is within the first range, there is an RF electrical signal whose corresponding current is less than the threshold current in the full-wave RF electrical signal after the first bias current signal is superimposed; it can ensure that the DC laser can cut off this part of the RF electrical signal whose corresponding current is less than the threshold current when performing optical modulation, thereby obtaining a half-wave RF optical signal. The first range can be predefined or determined based on the performance of the direct-modulated laser, without limitation. In addition, the first range can be set to be smaller, that is, the current corresponding to the first bias current signal is equal to the threshold current or slightly greater than the threshold current, which is conducive to the first communication device optically modulating the full-wave RF electrical signal after the first bias current signal is superimposed through the direct-modulated laser, and can obtain a half-wave RF optical signal with lower average optical power.

[0196] For example, taking the case where the DC component corresponding to the full-wave RF electrical signal is 0 as an example, in conjunction with Figure 9, in Figure 9, the power-current curve represents the relationship between the operating current and optical power of the direct-modulated laser, the current-time curve represents the full-wave RF electrical signal after superimposing the first bias current signal, and the power-time curve represents the half-wave RF optical signal. It can be seen that when the operating current of the direct-modulated laser is less than or equal to the threshold current, the optical power obtained by optical modulation of the direct-modulated laser is zero; for the case where the operating current of the direct-modulated laser is greater than the threshold current, the greater the operating current of the direct-modulated laser, the greater the optical power obtained by optical modulation of the direct-modulated laser. Based on this characteristic of the directly modulated laser, the full-wave RF electrical signal and the first bias current signal whose difference between the corresponding current and the threshold current is within a first range are superimposed, so that the working current of the directly modulated laser is set according to the electrical signal after the superposition of the first bias current signal and the full-wave RF electrical signal. In this way, the directly modulated laser can cut off the RF electrical signal whose corresponding current is less than the threshold current in the full-wave RF electrical signal after the superposition of the first bias current signal, and optically modulate the RF electrical signal whose corresponding current is greater than the threshold current in the full-wave RF electrical signal after the superposition of the first bias current signal, thereby obtaining a half-wave RF optical signal.

[0197] The first bias electrical signal is further described below. The following description of the first bias electrical signal applies both to the case where the first bias electrical signal is a first bias voltage signal and to the case where the first bias electrical signal is a first bias current signal.

[0198] Optionally, the first bias electrical signal satisfies: the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the first optical signal satisfies a first ratio, and the first optical signal is an optical signal obtained by optically modulating the bias point detection electrical signal after superimposing the first bias electrical signal. The coefficient of each spectral component in the multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the first optical signal can be obtained by the first communication device performing photoelectric conversion on the first optical signal, and then performing filtering processing, amplification processing, analog-to-digital conversion, and spectrum analysis on the electrical signal obtained by photoelectric conversion. In addition, the first ratio can be determined based on the type of bias point detection electrical signal, and the first ratio may be different when different types of bias point detection electrical signals are used.

[0199] Exemplarily, the bias point detection electrical signal may be a low-frequency sinusoidal wave signal having a frequency much lower than the frequency of the full-wave RF electrical signal. For example, the low-frequency sinusoidal wave signal may be a low-frequency single-frequency sinusoidal wave signal. In the case where the bias point detection electrical signal is a low-frequency sinusoidal wave signal, the first bias electrical signal satisfies the following conditions: the error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component, and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by photoelectric conversion of the first optical signal and 0.32:0.5:0.21:0 is within a second range. That is to say, the first communication device can optically modulate the low-frequency sinusoidal wave signal after superimposing the first bias electrical signal to obtain a first optical signal; then perform photoelectric conversion on the first optical signal, and perform filtering processing, amplification processing, analog-to-digital conversion and spectrum analysis on the electrical signal after photoelectric conversion in sequence to obtain coefficients corresponding to each spectral component corresponding to the electrical signal obtained by photoelectric conversion of the first optical signal, wherein the error between the ratio between the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component and the coefficient corresponding to the third-order harmonic component and 0.32:0.5:0.21:0 is within the second range.

[0200] The second range may be predefined or determined based on performance requirements for the first communication device. Optionally, the second range may be set to be smaller so that the error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component, and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by photoelectric conversion of the first optical signal and the ratio of 0.32:0.5:0.21:0 is smaller. The smaller the error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component, and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by photoelectric conversion of the first optical signal and 0.32:0.5:0.21:0, the closer the waveform of the half-wave RF optical signal obtained based on the first bias current signal is to the waveform of the full positive half amplitude or the full negative half amplitude of the full-wave RF electrical signal relative to the DC component, thereby obtaining a half-wave RF optical signal with a lower average optical power. This lowers the transmission optical power between the first communication device and the second communication device, which can more effectively reduce the power consumption of optical devices and more effectively reduce the nonlinear effect of optical fiber transmission in a scenario where optical fiber is used to transmit optical signals between the first communication device and the second communication device.

[0201] Optionally, the first communication device may determine the first bias electrical signal by the following operation: the first communication device generates a bias point detection electrical signal, which is an analog signal that has undergone digital-to-analog conversion. The first communication device superimposes the second bias electrical signal on the bias point detection electrical signal, and optically modulates the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal. If the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the second optical signal satisfies a first ratio, the first communication device may determine that the first bias electrical signal is the second bias electrical signal. Otherwise, the first communication device may adjust the second bias electrical signal, superimpose the adjusted second bias electrical signal on the bias point detection electrical signal, and optically modulate the bias point detection electrical signal superimposed with the adjusted second bias electrical signal. The first communication device then determines whether the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the optically modulated optical signal satisfies the first ratio. If so, the first communication device may determine that the first bias electrical signal is the adjusted second bias electrical signal.

[0202] When the conditions are not met, the first communication device again performs the operations of adjusting the second bias electrical signal, superimposing the adjusted second bias electrical signal on the bias point detection electrical signal, optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal, and judging whether the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the optically modulated optical signal satisfies the first ratio; until the adjusted second bias electrical signal can achieve: when the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the optically modulated optical signal by the first communication device satisfies the first ratio, the first communication device determines the adjusted second bias electrical signal as the first bias electrical signal, and no longer performs the operations of adjusting the second bias electrical signal, superimposing the adjusted second bias electrical signal on the bias point detection electrical signal, optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal, and judging whether the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the optically modulated optical signal satisfies the first ratio.

[0203] In addition, in time division duplexing (TDD) mode, the process of the first communication device determining the first bias electrical signal through the above operation can be performed during an idle time when the first communication device does not generate a full-wave radio frequency electrical signal. During this idle time, the first communication device can continuously or periodically generate a bias point detection electrical signal until a non-idle time when the first communication device generates a full-wave radio frequency electrical signal or the first communication device determines the first bias electrical signal. At this time, the first communication device can stop generating the bias point detection electrical signal.

[0204] In addition, the operations of the first communication device optically modulating the bias point detection electrical signal superimposed with the second bias electrical signal and the first communication device optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal are similar to the operation of the first communication device optically modulating the full-wave RF electrical signal superimposed with the first bias electrical signal. For specific explanations, please refer to the aforementioned related explanations and will not be repeated here.

[0205] The following describes how the first communication device determines the first bias electrical signal by taking the case where the first bias electrical signal is a first bias voltage signal as an example. The case where the first bias electrical signal is a first bias current signal is similar and will not be described in detail.

[0206] For example, a first communication device generates a bias point detection electrical signal. The first communication device superimposes voltage signal #1 (the voltage corresponding to voltage signal #1 is V1) on the bias point detection electrical signal and optically modulates the bias point detection electrical signal after superimposing voltage signal #1 to obtain optical signal #1. The coefficient ratios between the multiple spectral components corresponding to the electrical signal obtained by the first communication device through photoelectric conversion of optical signal #1 do not satisfy a first ratio. Therefore, the first communication device may adjust the bias voltage signal to be superimposed on the bias point detection electrical signal to voltage signal #2 (the voltage corresponding to voltage signal #2 is V2). The first communication device then superimposes voltage signal #2 on the bias point detection electrical signal and optically modulates the bias point detection electrical signal after superimposing voltage signal #2 to obtain optical signal #2. The coefficient ratios between the multiple spectral components corresponding to the electrical signal obtained by the first communication device through photoelectric conversion of optical signal #2 still do not satisfy the first ratio. Therefore, the first communication device may further adjust the bias voltage signal to be superimposed on the bias point detection electrical signal to voltage signal #3 (the voltage corresponding to voltage signal #3 is V3). Next, the first communications device superimposes voltage signal #3 on the bias point detection electrical signal and optically modulates the bias point detection electrical signal superimposed with voltage signal #3 to obtain optical signal #3. If the coefficient ratios of the multiple spectral components corresponding to the electrical signal obtained by the first communications device through photoelectric conversion of optical signal #3 satisfy a first ratio, the first communications device can determine that voltage signal #3 is the first bias voltage signal.

[0207] In another optional embodiment, the first communication device converts the full-wave RF electrical signal into a half-wave RF optical signal, which may include: the first communication device converting the full-wave RF electrical signal into a first half-wave RF electrical signal, the first half-wave RF electrical signal being an RF electrical signal having the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal in the analog domain; the first communication device superimposing a third bias electrical signal on the first half-wave RF electrical signal by modulating a laser, and optically modulating the first half-wave RF electrical signal superimposed with the third bias electrical signal to obtain a half-wave RF optical signal. It can be seen that the first communication device can convert the full-wave RF electrical signal into a half-wave RF optical signal by first converting the full-wave RF electrical signal as a full-wave signal into a first half-wave RF electrical signal as a half-wave signal, and then converting the first half-wave RF electrical signal as a half-wave signal into a half-wave RF optical signal as a half-wave signal.

[0208] The positive half-amplitude of the full-wave RF electrical signal in the analog domain refers to the positive half-amplitude of the full-wave RF electrical signal relative to the DC component in the analog domain, and the negative half-amplitude of the full-wave RF electrical signal in the analog domain refers to the negative half-amplitude of the full-wave RF electrical signal relative to the DC component in the analog domain. Furthermore, embodiments of the present application do not limit the first half-wave RF electrical signal to having the absolute positive half-amplitude or absolute negative half-amplitude of the full-wave RF electrical signal relative to the DC component in the analog domain. Similar to the half-wave RF optical signal, a detailed description thereof can be found in the aforementioned description of the half-wave RF optical signal, which will not be repeated here.

[0209] Optionally, the first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

[0210] The following describes the operation of the first communication device converting the full-wave radio frequency electrical signal into the first half-wave radio frequency electrical signal for the two cases where the full-wave radio frequency electrical signal is an analog signal and the full-wave radio frequency electrical signal is a digital signal, as described in the following optional implementation 2.1 and implementation 2.2.

[0211] In embodiment 2.1, the full-wave RF electrical signal is an analog signal. For example, the full-wave RF electrical signal is an analog signal obtained through baseband signal modulation, digital predistortion processing, digital-to-analog conversion, and local oscillator mixing. Alternatively, the full-wave RF electrical signal is an electrical signal obtained by amplifying an analog signal received by the first communication device via an antenna, or the full-wave RF electrical signal is an electrical signal obtained by amplifying an analog signal received by the first communication device via an antenna, and local oscillator mixing. In this case, the first communication device converts the full-wave RF electrical signal into a first half-wave RF electrical signal, which may include: the first communication device converting the full-wave RF electrical signal into the first half-wave RF electrical signal through a low-noise power amplifier. Thus, the first communication device can convert the full-wave RF electrical signal into the first half-wave RF electrical signal in the analog domain through the low-noise power amplifier. The low-noise power amplifier can be used to process the RF electrical signal as a full-wave signal to obtain the RF electrical signal as a half-wave signal. The low-noise power amplifier can be, for example, a low-noise amplifier (LNA).

[0212] For example, the low-noise power amplifier can be a Class B low-noise power amplifier (e.g., a Class B LNA), which has a small adjacent channel leakage power ratio (ACLR). The first half-wave RF electrical signal generated by the Class B low-noise power amplifier can accurately intercept the amplitude midpoint of the full-wave RF electrical signal (i.e., the position of the DC component corresponding to the full-wave RF electrical signal). In other words, the first half-wave RF electrical signal obtained using the Class B low-noise power amplifier can have all the positive half-amplitude or all the negative half-amplitude of the full-wave RF electrical signal relative to the DC component. For another example, if the ACLR performance requirements permit, the low-noise power amplifier can also be a Class AB low-noise power amplifier (e.g., a Class AB LNA) or a Class C low-noise power amplifier (e.g., a Class C LNA). The ACLR of the Class AB low-noise power amplifier and the ACLR of the Class C low-noise power amplifier are both slightly higher than the ACLR of the Class B low-noise power amplifier.

[0213] In embodiment 2.2, the full-wave RF electrical signal is a digital signal. For example, the full-wave RF electrical signal is a digital signal obtained through baseband signal modulation, RF modulation, and digital pre-distortion processing. In this case, the first communication device converts the full-wave RF electrical signal into a first half-wave RF electrical signal, which may include: the first communication device converts the full-wave RF electrical signal into a second half-wave RF electrical signal; the second half-wave RF electrical signal is an RF electrical signal having the positive half-amplitude or negative half-amplitude of the full-wave RF electrical signal in the digital domain; and the first communication device performs digital-to-analog conversion on the second half-wave RF electrical signal to obtain the first half-wave RF electrical signal. It can be seen that the second half-wave RF electrical signal is a digital signal. The first communication device can convert the full-wave RF electrical signal into a second half-wave RF electrical signal in the digital domain, and then perform digital-to-analog conversion on the second half-wave RF electrical signal as a digital signal to obtain the first half-wave RF electrical signal as an analog signal.

[0214] The positive half-amplitude of the full-wave RF electrical signal in the digital domain refers to the positive half-amplitude of the full-wave RF electrical signal in the digital domain relative to the DC component, and the negative half-amplitude of the full-wave RF electrical signal in the digital domain refers to the negative half-amplitude of the full-wave RF electrical signal in the digital domain relative to the DC component. Furthermore, embodiments of the present application do not limit the second half-wave RF electrical signal to having the absolute positive half-amplitude or absolute negative half-amplitude of the full-wave RF electrical signal in the digital domain relative to the DC component. Similar to the half-wave RF optical signal, a detailed description thereof can be found in the aforementioned description of the half-wave RF optical signal, which will not be repeated here.

[0215] Optionally, the second half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the digital domain relative to the DC component, or the second half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the digital domain relative to the DC component.

[0216] The following describes the operation of the first communication device superimposing a third bias electrical signal on a first half-wave RF electrical signal through a modulated laser, and optically modulating the first half-wave RF electrical signal after superimposing the third bias electrical signal to obtain a half-wave RF optical signal, for the two cases where the modulated laser is a directly modulated laser and the modulated laser is an electro-absorption modulated laser, as described in the following optional embodiments 3.1 and 3.2.

[0217] Implementation 3.1: The modulated laser is a directly modulated laser. In this case, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. The first communication device can use the directly modulated laser to superimpose the second bias current signal on the first half-wave RF electrical signal, and optically modulate the first half-wave RF electrical signal after superimposing the second bias current signal, to obtain a half-wave RF optical signal.

[0218] For example, taking the DC component corresponding to the full-wave RF electrical signal as 0 as an example, combined with Figure 10, in Figure 10, the power-current curve represents the relationship between the working current and the optical power of the direct-modulated laser. The relationship between the working current and the optical power of the direct-modulated laser can be found in the aforementioned relevant explanation of the direct-modulated laser, which will not be repeated here; the current-time curve represents the first half-wave RF electrical signal after the second bias current signal is superimposed, and the power-time curve represents the half-wave RF optical signal. Based on the relationship between the working current and the optical power of the direct-modulated laser, the first half-wave RF electrical signal is superimposed with the second bias current signal whose corresponding current is greater than or equal to the threshold current, so that the working current of the direct-modulated laser is set according to the first half-wave RF electrical signal after the second bias current signal is superimposed, so that the direct-modulated laser can obtain a half-wave RF optical signal by optical modulation.

[0219] Optionally, the second bias current signal is a third bias current signal corresponding to a third optical signal with the largest signal-to-noise ratio among multiple third optical signals. The multiple third optical signals correspond one-to-one to the multiple third bias current signals, and each third optical signal among the multiple third optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal after superimposing the third bias current signal corresponding to the third optical signal. The currents corresponding to the multiple third bias current signals are different from each other, and the currents corresponding to the multiple third bias current signals are all greater than or equal to the threshold current. It is understandable that the first communication device can be set to multiple third bias current signals corresponding to different currents. The first communication device optically modulates the first half-wave radio frequency electrical signal after superimposing the third bias current signal for each third bias current signal among the multiple third bias current signals, thereby obtaining multiple third optical signals. The third bias current signal used by the third optical signal with the largest signal-to-noise ratio among the multiple third optical signals can be used as the second bias current signal.

[0220] Optionally, the currents corresponding to the multiple third bias current signals are all greater than or equal to the threshold current and are also less than or equal to the first current. Accordingly, the average optical power of the multiple third optical signals is less than or equal to the optical power obtained by optically modulating the direct-modulated laser when the operating current is the first current. The first current can be predefined or determined based on a predefined optical power (the first current can be the operating current required for the direct-modulated laser to perform optical modulation to obtain the predefined optical power).

[0221] Exemplarily, the second bias current signal can be determined based on the relative intensity noise and modulation bandwidth characteristics of the direct-modulated laser. Specifically, the bias current of the direct-modulated laser can be scanned from the threshold current in an increasing direction. Since the bias current is constantly changing, the third bias current signal corresponding to the bias current is also constantly changing; the direct-modulated laser will continue to optically modulate the first half-wave RF electrical signal after superimposing the third bias current signal to obtain a third optical signal; when the obtained third optical signal has a maximum signal-to-noise ratio, the third bias current signal corresponding to the current bias current of the direct-modulated laser can be the second bias current signal. Optionally, when the first current is determined, the bias current of the direct-modulated laser can be scanned from the threshold current in an increasing direction within the range of the threshold current and the first current.

[0222] In addition, if the signal-to-noise ratio performance requirement allows, the second bias current signal may also be a third bias current signal corresponding to a third optical signal among multiple third optical signals whose signal-to-noise ratio is greater than a first value, and the first value may be predefined according to the signal-to-noise ratio performance requirement.

[0223] Implementation 3.2 involves the case where the modulated laser is an electro-absorption modulated laser. In this case, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage. The first communication device can use the electro-absorption modulated laser to superimpose the second bias voltage signal on the first half-wave RF electrical signal, and optically modulate the first half-wave RF electrical signal superimposed with the second bias voltage signal to obtain a half-wave RF optical signal.

[0224] For example, taking the case where the DC component corresponding to the full-wave RF electrical signal is 0 as an example, in conjunction with FIG11 , in FIG11 , the power-voltage curve represents the relationship between the operating voltage and optical power of the electro-absorption modulated laser. The relationship between the operating voltage and optical power of the electro-absorption modulated laser can be found in the aforementioned description of the electro-absorption modulated laser, which will not be repeated here. The voltage-time curve represents the first half-wave RF electrical signal after the second bias voltage signal is superimposed, and the power-time curve represents the half-wave RF optical signal. Based on the relationship between the operating voltage and optical power of the electro-absorption modulated laser, the first half-wave RF electrical signal is superimposed with the second bias voltage signal having a corresponding voltage greater than the first voltage, so that the operating voltage of the electro-absorption modulated laser is set according to the first half-wave RF electrical signal after the second bias voltage signal is superimposed, so that the electro-absorption modulated laser performs optical modulation to obtain a half-wave RF optical signal.

[0225] The first voltage can be predefined or determined based on a predefined optical power (the first voltage can be the operating voltage required for an electro-absorption modulated laser to perform optical modulation to obtain a predefined optical power). For example, the first voltage is greater than the middle voltage in the linear region of the power-voltage curve. In addition, the voltage corresponding to the second bias voltage signal can be set at a low output optical power point (high voltage), which is conducive to obtaining a half-wave RF optical signal with lower average optical power, thereby more effectively reducing the power consumption of optical devices and, in scenarios where optical fiber is used to transmit optical signals between the first communication device and the second communication device, more effectively reducing the nonlinear effects of optical fiber transmission.

[0226] Optionally, the second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal with the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; the plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; and each of the plurality of fourth optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal. The voltages corresponding to the plurality of third bias voltage signals are different from one another, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage. Accordingly, the average optical power of the plurality of fourth optical signals is less than or equal to the optical power obtained by optically modulating the electro-absorption modulated laser when the operating voltage is the first voltage. It is understood that the first communication device may be provided with multiple third bias voltage signals corresponding to different voltages. The first communication device optically modulates the first half-wave radio frequency electrical signal superimposed with the third bias voltage signal for each of the plurality of third bias voltage signals, thereby obtaining a plurality of fourth optical signals. The third bias voltage signal used to obtain the fourth optical signal with the smallest ACLR among the plurality of fourth optical signals may be used as the second bias voltage signal.

[0227] For example, the bias voltage of the electro-absorption modulated laser can be scanned in an increasing direction starting from a first voltage. Since the bias voltage is constantly changing, the third bias voltage signal corresponding to the bias voltage is also constantly changing. The electro-absorption modulated laser will continue to optically modulate the first half-wave RF electrical signal superimposed with the third bias voltage signal to obtain a fourth optical signal. When the obtained fourth optical signal has a minimum ACLR, the third bias voltage signal corresponding to the current bias voltage of the electro-absorption modulated laser can be the second bias voltage signal.

[0228] In addition, if the ACLR performance requirements allow, the second bias voltage signal may also be the third bias voltage signal corresponding to the fourth optical signal among the plurality of fourth optical signals whose adjacent channel leakage power ratio is less than a second value. The second value may be predefined according to the ACLR performance requirements.

[0229] In addition, embodiments 3.1 and 3.2 can be arbitrarily combined with embodiments 2.1 and 2.2. For example, the first communication device may adopt embodiment 2.1 to convert the full-wave RF electrical signal into a first half-wave RF electrical signal, and adopt embodiment 3.1 to obtain a half-wave RF optical signal; or, the first communication device may adopt embodiment 2.1 to convert the full-wave RF electrical signal into a first half-wave RF electrical signal, and adopt embodiment 3.2 to obtain a half-wave RF optical signal; or, the first communication device may adopt embodiment 2.2 to convert the full-wave RF electrical signal into a first half-wave RF electrical signal, and adopt embodiment 3.1 to obtain a half-wave RF optical signal; or, the first communication device may adopt embodiment 2.2 to convert the full-wave RF electrical signal into a first half-wave RF electrical signal, and adopt embodiment 3.2 to obtain a half-wave RF optical signal.

[0230] Optionally, the method may further include: the first communication device uses a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal. Then, the first communication device can modulate the laser to superimpose a third bias electrical signal on the first half-wave radio frequency electrical signal after spectrum adjustment, and optically modulate the first half-wave radio frequency electrical signal after spectrum adjustment and superimposition of the third bias electrical signal to obtain a half-wave radio frequency optical signal. This embodiment can adjust the amplitude of each spectral component (such as a DC component, a baseband component, and a harmonic component) in the first half-wave radio frequency electrical signal by performing spectrum adjustment on the first half-wave radio frequency electrical signal, as shown in FIG12 , thereby optimizing the waveform of the first half-wave radio frequency electrical signal. Optionally, the filter function can be implemented by a bandpass filter whose base frequency is the center frequency point of the full-wave radio frequency electrical signal (i.e., the carrier frequency of the full-wave radio frequency electrical signal), and the first communication device can perform spectrum adjustment on the first half-wave radio frequency electrical signal by using the bandpass filter whose base frequency is the center frequency point. Exemplarily, the first communication device can adjust the amplitude ratio of the DC component, baseband component and harmonic component in the first half-wave RF electrical signal by designing the roll-off coefficient of the bandpass filter to achieve spectrum adjustment of the first half-wave RF electrical signal.

[0231] For example, for the portion of the first half-wave RF electrical signal whose amplitude is smaller than the corresponding amplitude of the DC component, if the difference between the amplitude of this portion of the signal and the corresponding amplitude of the DC component is large, the first communication device may use a filter function to adjust the amplitudes of the baseband component and harmonic components in the first half-wave RF electrical signal to reduce the difference between the amplitude of this portion of the signal and the corresponding amplitude of the DC component. When the modulated laser is a directly modulated laser, this approach can reduce signals in the first half-wave RF electrical signal after the second bias current signal is superimposed that have a corresponding current less than the threshold current, thereby reducing the signals with a corresponding current less than the threshold current that are truncated during optical modulation of the DC laser, thereby reducing the impact of the DC laser's truncated signal on ACLR degradation.

[0232] For example, taking the DC component corresponding to the full-wave radio frequency electrical signal as 0 as an example, as shown in FIG13a, part (A) of FIG13a shows a first half-wave radio frequency electrical signal obtained by converting the full-wave radio frequency electrical signal by the first communication device. In the first half-wave radio frequency electrical signal, there is a portion of the signal whose amplitude is smaller than the amplitude corresponding to the DC component and whose difference with the amplitude corresponding to the DC component is large. The first communication device can use a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal to obtain the spectrum-adjusted first half-wave radio frequency electrical signal as shown in part (B) of FIG13a. It can be seen that for the portion of the signal in the first half-wave radio frequency electrical signal whose amplitude is smaller than the amplitude corresponding to the DC component, the difference between the amplitude of this portion of the signal in the spectrum-adjusted first half-wave radio frequency electrical signal shown in part (B) of FIG13a and the amplitude corresponding to the DC component is smaller than the difference between the amplitude of this portion of the signal in the first half-wave radio frequency electrical signal before spectrum adjustment shown in part (A) and the amplitude corresponding to the DC component.

[0233] The current-time curve in Figure 13b represents the electrical signal obtained by superimposing the first half-wave RF electrical signal shown in part (A) of Figure 13a on the second bias current signal, and the power-time curve represents the optical signal obtained by optically modulating the electrical signal shown in the current-time curve in Figure 13b by the direct-modulated laser. The current-time curve in Figure 13c represents the electrical signal obtained by superimposing the first half-wave RF electrical signal after spectrum adjustment shown in part (B) of Figure 13a on the second bias current signal, and the power-time curve represents the optical signal obtained by optically modulating the electrical signal shown in the current-time curve in Figure 13c by the direct-modulated laser. It can be seen that compared to Figure 13b, the direct-modulated laser cuts off less signal when performing optical modulation based on Figure 13c, and the DC laser's cutoff signal has less impact on the degradation of ACLR.

[0234] For example, in a scenario where the modulated laser is a directly modulated laser and the current corresponding to the second bias current signal is greater than the threshold current in order to increase the modulation bandwidth of the directly modulated laser and reduce the RIN noise, the first communication device can use a filtering function to reduce the amplitude of the baseband component and the harmonic component in the first half-wave RF electrical signal, thereby adjusting part of the amplitude of the first half-wave RF electrical signal to be smaller than the amplitude corresponding to the DC component, so that the waveform of the first half-wave RF electrical signal after spectrum adjustment is better adapted to the power-current curve of the directly modulated laser, which is beneficial to improving the utilization rate of the current between the threshold current and the current corresponding to the second bias current signal.

[0235] For example, take the case where the DC component corresponding to the full-wave RF electrical signal is 0. As shown in FIG14a, part (A) of FIG14a shows the first half-wave RF electrical signal obtained by the first communication device converting the full-wave RF electrical signal, and part (B) shows the first half-wave RF electrical signal obtained after the first communication device uses a filter function to reduce the amplitude of the baseband component and the harmonic component in the first half-wave RF electrical signal. The current-time curve in FIG14b represents the electrical signal obtained by superimposing the second bias current signal on the first half-wave RF electrical signal shown in part (A) of FIG14a. It can be seen that during the optical modulation process of the direct-modulated laser, the time during which its operating current is between the threshold current and the current corresponding to the second bias current signal is relatively short. In other words, the current between the threshold current and the current corresponding to the second bias current signal is used less during the optical modulation process. The current-time curve in Figure 14c represents the electrical signal obtained by superimposing the first half-wave RF electrical signal after spectrum modulation shown in part (B) of Figure 14a on the second bias current signal. It can be seen that the first communication device uses a filtering function to reduce the amplitude of the baseband component and the harmonic component in the first half-wave RF electrical signal, which can increase the time during which the working current of the direct-modulated laser is between the threshold current and the current corresponding to the second bias current signal during the optical modulation process, thereby increasing the use of the current between the threshold current and the current corresponding to the second bias current signal during the optical modulation process, that is, increasing the utilization rate of the current between the threshold current and the current corresponding to the second bias current signal.

[0236] S103: The first communication device sends a half-wave radio frequency optical signal; correspondingly, the second communication device receives the half-wave radio frequency optical signal.

[0237] S104: The second communication device converts the half-wave radio frequency optical signal into a full-wave radio frequency electrical signal.

[0238] In an optional embodiment, the full-wave RF electrical signal obtained by the second communication device from converting the half-wave RF optical signal is a baseband signal within the electrical signal obtained by photoelectrically converting the half-wave RF optical signal. The center frequency of the baseband signal is the same as the carrier frequency of the full-wave RF electrical signal generated by the first communication device. Alternatively, the carrier frequency of the full-wave RF electrical signal generated by the first communication device may be the carrier frequency transmitted by the first communication device to the second communication device.

[0239] In one optional method, the second communication device converts the half-wave RF optical signal into a full-wave RF electrical signal, which may include: the second communication device performs photoelectric conversion on the half-wave RF optical signal through a photodetector to obtain a first electrical signal, wherein the passband of the photodetector covers the spectrum of the baseband signal; and the second communication device filters the first electrical signal through a bandpass filter to obtain a full-wave RF electrical signal, wherein the passband of the bandpass filter only contains the spectrum of the baseband signal. The photodetector may be, for example, a PD. It can be seen that the second communication device can convert the half-wave RF optical signal into a full-wave RF electrical signal through a photodetector and a bandpass filter, without using complex algorithmic processing, thereby simplifying the method of recovering the full-wave RF electrical signal.

[0240] The bandpass filter's passband encompasses only the fundamental frequency spectrum, excluding the DC component, baseband components, and second-order and higher harmonic components. The photodetector's passband encompasses only the fundamental frequency spectrum, as discussed later, and is not further discussed here.

[0241] It can be understood that, as shown in Figure 15, the first electrical signal obtained by performing photoelectric conversion on the half-wave RF optical signal through the photoelectric detector may include: a DC component, a baseband component, a fundamental frequency component, and second-order and higher harmonic components. Since the passband of the bandpass filter only contains the spectrum of the fundamental frequency signal, but does not contain the DC component, the baseband component and the second-order and higher harmonic components, the bandpass filter can filter out the fundamental frequency signal in the first electrical signal, thereby obtaining a full-wave RF electrical signal.

[0242] In another optional manner, the second communication device converts the half-wave RF optical signal into a full-wave RF electrical signal, which may include: the second communication device performs photoelectric conversion on the half-wave RF optical signal through a photoelectric detector to obtain a first electrical signal, and determines the full-wave RF electrical signal from the first electrical signal; the passband of the photoelectric detector only contains the spectrum of the baseband signal. The photoelectric detector can be, for example, a PD. It can be seen that in addition to having the function of photoelectric conversion, the photoelectric detector can also filter out the baseband signal in the first electrical signal to obtain the full-wave RF electrical signal. The second communication device can convert the half-wave RF optical signal into a full-wave RF electrical signal directly through a photoelectric detector, without using complex algorithm processing, thereby simplifying the method of recovering the full-wave RF electrical signal.

[0243] In summary, in this signal transmission method, the first communication device generates a full-wave RF electrical signal and converts the full-wave RF electrical signal into a half-wave RF optical signal, where the half-wave RF optical signal is a RF optical signal having the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal; the first communication device sends the half-wave RF optical signal. The second communication device receives the half-wave RF optical signal and converts the half-wave RF optical signal into a full-wave RF electrical signal. It can be seen that the half-wave RF optical signal transmitted between the second communication device and the first communication device has the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal; compared to the RF optical signal having the full amplitude of the full-wave RF electrical signal, the average optical power of the half-wave RF optical signal is lower, thereby reducing the transmission optical power between the second communication device and the first communication device, thereby helping to reduce the power consumption of optical devices and improve power conversion efficiency.

[0244] For example, in a scenario where optical fiber is used to transmit optical signals between a second communication device and a first communication device, and the optical fiber transmission link between the first and second communication devices includes an optical amplifier, reducing the optical power transmitted between the second and first communication devices helps reduce the power consumption of the optical amplifier. Furthermore, reducing the optical power also helps reduce signal distortion caused by the optical amplifier easily entering a gain saturation region. For another example, in a scenario where the second communication device performs photoelectric conversion on a half-wave RF optical signal using a photodetector, reducing the optical power transmitted between the second and first communication devices helps reduce the DC current of the photodetector, thereby reducing the power consumption of the photodetector and improving the power conversion efficiency of the photodetector.

[0245] In scenarios where optical fiber is used to transmit optical signals between a second communication device and a first communication device, reducing the transmitted optical power can also help reduce the nonlinear effects of optical fiber transmission, thereby reducing signal distortion caused by these effects. In scenarios where the second communication device also needs to output a full-wave RF electrical signal to an antenna for signal radiation, a half-wave RF optical signal with lower average optical power can also help keep the optical fiber's transmitted optical power below the power threshold that produces nonlinear effects in optical fiber transmission. Therefore, the range between the average optical power of the half-wave RF optical signal and the power threshold can serve as a transmission optical power amplification factor, which can help reduce the nonlinear effects of optical fiber transmission while also obtaining an optical signal with a larger optical modulation amplitude, thereby improving the antenna's RF radiation power and signal quality.

[0246] In addition, the second communication device also restores the half-wave RF optical signal with lower average optical power into a full-wave RF electrical signal with higher power. In the scenario where the second communication device needs to output the full-wave RF electrical signal to the antenna for signal radiation, this signal transmission method can achieve higher RF radiation power of the antenna with lower transmission optical power.

[0247] It is understandable that in order to implement the functions in the above method, the first communication device or the second communication device includes hardware structures and / or software modules corresponding to the execution of each function. It should be readily apparent to those skilled in the art that, in combination with the units and method steps of each example described in the embodiments disclosed in this application, this application can be implemented in the form of hardware or a combination of hardware and computer software. Whether a function is executed in hardware or in a computer software-driven hardware manner depends on the specific application scenario and design constraints of the technical solution.

[0248] The following describes possible structures of the first communication device and the second communication device provided in the embodiments of the present application in conjunction with the accompanying drawings.

[0249] Please refer to FIG. 16 , which is a schematic structural diagram of a first communication device 1600 provided in an embodiment of the present application. The first communication device 1600 includes a radio frequency signal generating module 1601 , a bias point control module 1602 , and a modulated laser 1603 .

[0250] RF signal generation module 1601 is configured to generate a full-wave RF electrical signal and output the full-wave RF electrical signal to modulation laser 1603. Bias point control module 1602 is configured to output a first bias electrical signal to modulation laser 1603. Modulation laser 1603 is configured to optically modulate the full-wave RF electrical signal superimposed with the first bias electrical signal to generate a half-wave RF optical signal. The half-wave RF optical signal is an RF optical signal having either the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal. Modulation laser 1603 is also configured to transmit the half-wave RF optical signal.

[0251] In an optional embodiment, the RF signal generation module 1601 may include: a baseband signal modulation module, a digital pre-distortion module, a digital-to-analog converter, a mixer, and a Class A low-noise power amplifier (e.g., a Class A LNA). The baseband signal modulation module may be used to modulate the baseband signal and output the modulated baseband signal to the digital pre-distortion module. The digital pre-distortion module may be used to perform digital pre-distortion processing on the modulated baseband signal and output the digital signal obtained by the digital pre-distortion processing to the digital-to-analog converter. The digital-to-analog converter may be used to convert the digital signal obtained by the digital pre-distortion processing into an analog signal and output the analog signal to the mixer. The digital-to-analog converter may be, for example, a digital-to-analog converter (DAC). The mixer may be used to mix the received analog signal with a local oscillator and output the electrical signal obtained by the mixing to the Class A low-noise power amplifier. The Class A low-noise power amplifier may be used to amplify the received electrical signal to obtain a full-wave RF electrical signal. It can be seen that in this embodiment, the full-wave RF electrical signal generated by the RF signal generating module 1601 is an analog signal obtained through baseband signal modulation, digital predistortion processing, digital-to-analog conversion, local oscillator mixing and amplification processing.

[0252] In another optional embodiment, the RF signal generating module 1601 may include a Class A low-noise power amplifier (e.g., a Class A LNA), and the first communication device 1600 may further include an antenna. The antenna may be configured to receive an analog signal and output the analog signal to the Class A low-noise power amplifier in the RF signal generating module 1601. The Class A low-noise power amplifier may be configured to amplify the analog signal from the antenna to obtain a full-wave RF electrical signal. Thus, in this embodiment, the full-wave RF electrical signal generated by the RF signal generating module 1601 is an electrical signal obtained by amplifying the analog signal received by the antenna.

[0253] In another optional embodiment, the RF signal generating module 1601 may include a Class A low noise power amplifier (e.g., Class A LNA) and a mixer, and the first communication device 1600 may further include an antenna. The antenna may be used to receive an analog signal and output the analog signal to the Class A low noise power amplifier in the RF signal generating module 1601. The Class A low noise power amplifier may be used to amplify the analog signal from the antenna and output the electrical signal obtained by the amplification to the mixer. The mixer may be used to mix the electrical signal obtained by the amplification with a local oscillator to obtain a full-wave RF electrical signal. It can be seen that under this embodiment, the full-wave RF electrical signal generated by the RF signal generating module 1601 is an electrical signal obtained by amplifying the analog signal received by the antenna and mixing it with the local oscillator.

[0254] In an optional embodiment, the modulated laser 1603 can be an electro-absorption modulated laser (e.g., EML), and accordingly, the first bias electrical signal is a first bias voltage signal. Optionally, in this case, the modulated laser 1603 can include a laser diode (e.g., LD) and an electro-absorption modulator (e.g., EAM). The laser diode can be used to generate a continuous light wave signal and output the continuous light wave signal to the electro-absorption modulator. The electro-absorption modulator can be used to modulate the full-wave RF electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal to obtain a half-wave RF optical signal. The RF signal generating module 1601 outputs the first bias electrical signal to the modulated laser 1603. Specifically, the RF signal generating module 1601 outputs the first bias electrical signal to the electro-absorption modulator in the modulated laser 1603.

[0255] In another optional embodiment, the modulated laser 1603 can be a directly modulated laser (e.g., DML), and accordingly, the first bias electrical signal is a first bias current signal. Optionally, in this case, the modulated laser 1603 can include a laser diode (e.g., LD), which can be used to optically modulate the full-wave RF electrical signal superimposed with the first bias current signal to obtain a half-wave RF optical signal. The RF signal generation module 1601 outputs the first bias electrical signal to the modulated laser 1603. Specifically, the RF signal generation module 1601 outputs the first bias electrical signal to the laser diode in the modulated laser 1603.

[0256] In an optional embodiment, the bias point control module 1602 is further configured to generate a bias point detection electrical signal and output the bias point detection electrical signal to the modulating laser 1603. The bias point control module 1602 is further configured to output a second bias electrical signal to the modulating laser 1603. The modulating laser 1603 is further configured to optically modulate the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal, and output the second optical signal to the bias point control module 1602. The bias point control module 1602 is further configured to: determine that the first bias electrical signal is the second bias electrical signal if a coefficient ratio between multiple spectral components corresponding to an electrical signal obtained by photoelectrically converting the second optical signal satisfies a first ratio; otherwise, adjust the second bias electrical signal and output the adjusted second bias electrical signal to the modulating laser 1603.

[0257] Modulation laser 1603 is further configured to, after receiving the adjusted second bias electrical signal from bias point control module 1602, optically modulate the bias point detection electrical signal superimposed with the adjusted second bias electrical signal, and output the optical signal obtained by optical modulation to bias point control module 1602. Bias point control module 1602 is further configured to determine whether a coefficient ratio between multiple spectral components corresponding to an electrical signal obtained by photoelectrically converting the received optical signal satisfies a first ratio. If so, bias point control module 1602 is further configured to determine the adjusted second bias electrical signal as the first bias electrical signal.

[0258] When the condition is not satisfied, the bias point control module 1602 is further configured to again perform the operations of adjusting the second bias electrical signal, superimposing the adjusted second bias electrical signal on the bias point detection electrical signal, and outputting the bias point detection electrical signal superimposed with the adjusted second bias electrical signal to the modulated laser 1603. The modulated laser 1603 is further configured to again perform the operations of optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal, and outputting the optical signal obtained by optical modulation to the bias point control module 1602. Until the bias point control module 1602 determines that the coefficient ratio between the multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the received optical signal satisfies the first ratio, the current adjusted second bias electrical signal is determined as the first bias electrical signal, and the operations of adjusting the second bias electrical signal, superimposing the adjusted second bias electrical signal on the bias point detection electrical signal, and outputting the bias point detection electrical signal superimposed with the adjusted second bias electrical signal to the modulated laser 1603 are no longer performed.

[0259] Optionally, in TDD mode, the bias point control module 1602 sends a bias point detection electrical signal to the modulated laser 1603 during an idle period when the RF signal generating module 1601 does not send a full-wave RF electrical signal to the modulated laser 1603. That is, during the period when the RF signal generating module 1601 sends a full-wave RF electrical signal to the modulated laser 1603, the bias point control module 1602 does not send a bias point detection electrical signal to the modulated laser 1603. During the period when the RF signal generating module 1601 does not send a full-wave RF electrical signal to the modulated laser 1603, the bias point control module 1602 may send a bias point detection electrical signal to the modulated laser 1603 until the RF signal generating module 1601 starts sending a full-wave RF electrical signal to the modulated laser 1603 or the bias point control module 1602 determines the first bias electrical signal, at which point the bias point control module 1602 may stop sending the bias point detection electrical signal to the modulated laser 1603.

[0260] Optionally, as shown in FIG17 , the bias point control module 1602 may include: a photodiode (e.g., a PD), a filter, a class A low-noise power amplifier (e.g., a class A LNA), an analog-to-digital converter, a processor, a first digital-to-analog converter (e.g., a DAC), and a second digital-to-analog converter (e.g., a DAC). The analog-to-digital converter may be, for example, an analog-to-digital converter (ADC). The photodiode may be configured to perform photoelectric conversion on an optical signal input to the photodiode, and output the electrical signal obtained by the photoelectric conversion to the filter. The filter may be configured to filter the electrical signal obtained by the photoelectric conversion, and output the electrical signal obtained by the filtering to the class A low-noise power amplifier. The class A low-noise power amplifier may be configured to amplify the electrical signal obtained by the filtering, and output the electrical signal obtained by the amplification to the analog-to-digital converter. The analog-to-digital converter may be configured to convert the electrical signal (analog signal) obtained by the filtering into a digital signal, and output the digital signal to the processor.

[0261] The processor may be configured to perform spectrum analysis on a received digital signal and determine whether a coefficient ratio between multiple spectrum components obtained from the spectrum analysis satisfies a first ratio. The processor may also be configured to: adjust the second bias electrical signal when the first ratio is not satisfied and output the adjusted second bias electrical signal to the first digital-to-analog converter; and determine the second bias electrical signal (or the adjusted second bias electrical signal) as the first bias electrical signal when the first ratio is satisfied and output the first bias electrical signal to the first digital-to-analog converter. Furthermore, the processor may be configured to generate a bias point detection electrical signal in the digital domain and output the bias point detection electrical signal in the digital domain to the second digital-to-analog converter.

[0262] The first digital-to-analog converter may be configured to convert the second bias electrical signal in the digital domain (or the adjusted second bias electrical signal) into the second bias electrical signal in the analog domain (or the adjusted second bias electrical signal), and output the second bias electrical signal in the analog domain (or the adjusted second bias electrical signal) to the modulated laser 1603. The first digital-to-analog converter may also be configured to convert the first bias electrical signal in the digital domain into the first bias electrical signal in the analog domain, and output the first bias electrical signal in the analog domain to the modulated laser 1603. The second digital-to-analog converter may be configured to convert the bias point detection electrical signal in the digital domain into the bias point detection electrical signal in the analog domain, and output the bias point detection electrical signal in the analog domain to the modulated laser 1603.

[0263] In an optional embodiment, the first communication device 1600 may further include a device (e.g., a coupler) having two input terminals and one output terminal. One input terminal of the device is connected to an output terminal of the RF signal generating module 1601 and can be used to receive the full-wave RF electrical signal from the RF signal generating module 1601; the other input terminal is connected to an output terminal of the bias point control module 1602 and can be used to receive the bias point detection electrical signal from the bias point control module 1602. One output terminal of the device is connected to an input terminal of the modulated laser 1603 and can be used to output the full-wave RF electrical signal or the bias point detection electrical signal to the modulated laser 1603.

[0264] Optionally, when the bias point control module 1602 outputs the bias point detection electrical signal, the operation is performed during the idle time when the RF signal generating module 1601 does not output the full-wave RF electrical signal. The device can receive the full-wave RF electrical signal or the bias point detection electrical signal at the same time, but will not receive the full-wave RF electrical signal and the bias point detection electrical signal at the same time; accordingly, the device outputs the full-wave RF electrical signal or the bias point detection electrical signal to the modulated laser 1603 at the same time, but will not output the full-wave RF electrical signal and the bias point detection electrical signal to the modulated laser 1603 at the same time.

[0265] In an optional embodiment, the first communication device 1600 may further include a device (e.g., an optical splitter) having one input end and two output ends. One input end of the device is connected to the modulated laser 1603 and can be used to receive a half-wave RF optical signal, or a second optical signal, or an optical signal obtained by optically modulating a bias point detection electrical signal superimposed with an adjusted second bias electrical signal from the modulated laser 1603. One output end of the device can be used to output a half-wave RF optical signal to transmit the half-wave RF optical signal to the second communication device; the other output end is connected to the bias point control module 1602 and can be used to output the second optical signal to the bias point control module 1602, or can be used to output an optical signal obtained by optically modulating a bias point detection electrical signal superimposed with an adjusted second bias electrical signal to the bias point control module 1602.

[0266] Optionally, when the bias point control module 1602 outputs the bias point detection electrical signal, the operation is performed during the idle time when the RF signal generating module 1601 does not output the full-wave RF electrical signal. The modulation laser 1603 will not simultaneously perform optical modulation on the full-wave RF electrical signal superimposed with the first bias electrical signal and optical modulation on the bias point detection electrical signal superimposed with the second bias electrical signal, nor will it simultaneously perform optical modulation on the full-wave RF electrical signal superimposed with the first bias electrical signal and optical modulation on the bias point detection electrical signal superimposed with the adjusted second bias electrical signal. Therefore, the modulation laser 1603 will not simultaneously output the half-wave RF optical signal and the second optical signal, nor will it simultaneously output the half-wave RF optical signal and the optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal. When receiving a half-wave RF optical signal, the device having one input end and two output ends outputs the half-wave RF optical signal through one of the output ends; when receiving a second optical signal or an optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal, the device outputs the signal to the bias point control module 1602 through the other output end.

[0267] For example, based on the first communication device 1600 shown in FIG16 , for the case where the modulated laser 1603 is an electro-absorption modulated laser, an embodiment of the present application provides another first communication device 1600 as shown in FIG18 ; for the case where the modulated laser 1603 is a directly modulated laser, an embodiment of the present application provides another first communication device 1600 as shown in FIG19 . The first communication devices 1600 shown in FIG18 and FIG19 both include a radio frequency signal generating module 1601, a bias point control module 1602, a modulated laser 1603, a coupler, and an optical splitter.

[0268] The RF signal generation module 1601 in the first communication device 1600 shown in Figures 18 and 19 both includes a baseband signal modulation module, a digital pre-distortion module, a digital-to-analog converter, a mixer, and a Class A low-noise power amplifier. In the coupler, the input end connected to the RF signal generation module 1601 is used to receive the full-wave RF electrical signal from the RF signal generation module 1601, the input end connected to the bias point control module 1602 is used to receive the bias point detection electrical signal from the bias point control module 1602, and the output end connected to the modulated laser 1603 is used to output the full-wave RF electrical signal or the bias point detection electrical signal to the modulated laser 1603. In the optical splitter, an input end connected to the modulated laser 1603 is used to receive the half-wave RF optical signal, or the second optical signal, or the optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal from the modulated laser 1603. An output end connected to the bias point control module 1602 is used to output the second optical signal or the optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the adjusted second bias electrical signal to the bias point control module 1602. The other output end is used to output the half-wave RF optical signal.

[0269] In the first communication device 1600 shown in FIG18 , the modulated laser 1603 is an electro-absorption modulated laser comprising a laser diode and an electro-absorption modulator. The output terminal of the coupler connected to the modulated laser 1603 is specifically connected to the electro-absorption modulator. The input terminal of the optical splitter connected to the modulated laser 1603 is specifically connected to the electro-absorption modulator. In addition to the output terminal connected to the coupler, another output terminal of the bias point control module 1602 is connected to the electro-absorption modulator in the modulated laser 1603 to output the second bias electrical signal or the adjusted second bias electrical signal to the electro-absorption modulator in the modulated laser 1603.

[0270] In the first communication device 1600 shown in FIG19 , the modulated laser 1603 is a directly modulated laser including a laser diode. The output terminal of the coupler connected to the modulated laser 1603 is specifically connected to the laser diode. The input terminal of the optical splitter connected to the modulated laser 1603 is specifically connected to the laser diode. In addition to the output terminal connected to the coupler, another output terminal of the bias point control module 1602 is connected to the laser diode in the modulated laser 1603 to output the second bias electrical signal or the adjusted second bias electrical signal to the laser diode in the modulated laser 1603.

[0271] For the detailed description of each module / device in Figures 18 and 19, please refer to the above-mentioned related descriptions and will not be repeated here.

[0272] In addition, the specific description of each of the above-mentioned embodiments can also refer to the relevant description in the aforementioned signal transmission method. The first communication device 1600 shown in Figures 16, 18 and 19 can also be used to implement the function of the first communication device in the aforementioned signal transmission method, and also has corresponding beneficial effects, which will not be repeated here.

[0273] Please refer to Figure 20, which is a structural diagram of a first communication device 2000 provided in an embodiment of the present application. The first communication device 2000 includes a radio frequency signal generating module 2001, a low noise power amplifier 2002 and a modulated laser 2003.

[0274] The RF signal generating module 2001 is used to generate a full-wave RF electrical signal and output the full-wave RF electrical signal to the low-noise power amplifier 2002 . The full-wave RF electrical signal is an analog signal.

[0275] The low-noise power amplifier 2002 is used to convert the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, and output the first half-wave radio frequency electrical signal to the modulated laser 2003; the first half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; the low-noise power amplifier is a class B low-noise power amplifier, a class C low-noise power amplifier, or a class AB low-noise power amplifier.

[0276] Modulation laser 2003 is configured to superimpose a third bias electrical signal on the first half-wave RF electrical signal and optically modulate the first half-wave RF electrical signal superimposed with the third bias electrical signal to generate a half-wave RF optical signal. The half-wave RF optical signal is a RF optical signal having either the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal. Modulation laser 2003 is also configured to transmit the half-wave RF optical signal.

[0277] In an optional embodiment, the RF signal generation module 2001 may include: a baseband signal modulation module, a digital pre-distortion module, a digital-to-analog converter (e.g., a DAC), and a mixer. The baseband signal modulation module may be used to modulate the baseband signal and output the modulated baseband signal to the digital pre-distortion module. The digital pre-distortion module may be used to perform digital pre-distortion processing on the modulated baseband signal and output the digital signal obtained by the digital pre-distortion processing to the digital-to-analog converter. The digital-to-analog converter may be used to perform digital-to-analog conversion on the digital signal obtained by the digital pre-distortion processing and output the analog signal obtained by the digital-to-analog conversion to the mixer. The mixer may be used to mix the received analog signal with the local oscillator to obtain a full-wave RF electrical signal. It can be seen that in this embodiment, the full-wave RF electrical signal generated by the RF signal generation module 2001 is an analog signal obtained through baseband signal modulation, digital pre-distortion processing, digital-to-analog conversion, and local oscillator mixing.

[0278] In another optional embodiment, the RF signal generating module 2001 may include a Class A low-noise power amplifier (e.g., a Class A LNA), and the first communication device 2000 may further include an antenna. The antenna may be configured to receive an analog signal and output the analog signal to the Class A low-noise power amplifier in the RF signal generating module 2001. The Class A low-noise power amplifier may be configured to amplify the analog signal from the antenna to generate a full-wave RF electrical signal. Thus, in this embodiment, the full-wave RF electrical signal generated by the RF signal generating module 2001 is an electrical signal obtained by amplifying the analog signal received by the antenna.

[0279] In another optional embodiment, the RF signal generating module 2001 may include a Class A low noise power amplifier (e.g., Class A LNA) and a mixer, and the first communication device 2000 may further include an antenna. The antenna may be used to receive an analog signal and output the analog signal to the Class A low noise power amplifier in the RF signal generating module 2001. The Class A low noise power amplifier may be used to amplify the analog signal from the antenna and output the electrical signal obtained by the amplification to the mixer. The mixer may be used to mix the electrical signal obtained by the amplification with a local oscillator to obtain a full-wave RF electrical signal. It can be seen that under this embodiment, the full-wave RF electrical signal generated by the RF signal generating module 2001 is an electrical signal obtained by amplifying the analog signal received by the antenna and mixing it with the local oscillator.

[0280] In an optional embodiment, the modulated laser 2003 is a directly modulated laser (e.g., DML), and the third bias electrical signal is a second bias current signal. The current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. In this case, the modulated laser 2003 may include a laser diode (e.g., LD), which can be used to superimpose the second bias current signal on the first half-wave RF electrical signal and optically modulate the first half-wave RF electrical signal after superimposing the second bias current signal to obtain a half-wave RF optical signal. The low-noise power amplifier 2002 outputs the first half-wave RF electrical signal to the modulated laser 2003. Specifically, the low-noise power amplifier 2002 outputs the first half-wave RF electrical signal to the laser diode in the modulated laser 2003.

[0281] In another optional embodiment, the modulated laser 2003 is an electro-absorption modulated laser (e.g., EML), and the third bias electrical signal is a second bias voltage signal, where the voltage corresponding to the second bias voltage signal is greater than the first voltage. In this case, the modulated laser 2003 may include a laser diode (e.g., LD) and an electro-absorption modulator (e.g., EAM). The laser diode may be used to generate a continuous light wave signal and output the continuous light wave signal to the electro-absorption modulator. The electro-absorption modulator may be used to modulate the first half-wave RF electrical signal, after superimposing the second bias voltage signal, onto the continuous light wave signal to obtain a half-wave RF optical signal. The low-noise power amplifier 2002 outputs the first half-wave RF electrical signal to the modulated laser 2003. Specifically, the low-noise power amplifier 2002 outputs the first half-wave RF electrical signal to the electro-absorption modulator in the modulated laser 2003.

[0282] For example, based on the first communication device 2000 shown in FIG20 , for the case where the modulated laser 2003 is a directly modulated laser, an embodiment of the present application provides another first communication device 2000 as shown in FIG21 ; for the case where the modulated laser 2003 is an electro-absorption modulated laser, an embodiment of the present application provides another first communication device 2000 as shown in FIG22 . The first communication devices 2000 shown in FIG21 and FIG22 both include a radio frequency signal generating module 2001, a low-noise power amplifier 2002, and a modulated laser 2003. The radio frequency signal generating module 2001 in the first communication devices 2000 shown in FIG21 and FIG22 both includes: a baseband signal modulation module, a digital pre-distortion module, a digital-to-analog converter, and a mixer. The modulated laser 2003 in the first communication device 2000 shown in FIG21 includes a laser diode. The modulated laser 2003 in the first communication device 2000 shown in FIG22 includes a laser diode and an electro-absorption modulator. For the detailed description of each module / device in Figures 21 and 22, please refer to the above-mentioned related descriptions and will not be repeated here.

[0283] In an optional embodiment, the first communication device 2000 may further include a waveform adjustment module 2004, which may be configured to perform spectrum adjustment on the first half-wave RF electrical signal using a filter function. That is, after the low-noise power amplifier 2002 converts the full-wave RF electrical signal into a first half-wave RF electrical signal, it may output the first half-wave RF electrical signal to the waveform adjustment module 2004. After the waveform adjustment module 2004 performs spectrum adjustment on the first half-wave RF electrical signal using a filter function, the spectrum-adjusted first half-wave RF electrical signal is output to the modulation laser 2003. The modulation laser 2003 may then be configured to superimpose a third bias electrical signal on the spectrum-adjusted first half-wave RF electrical signal and optically modulate the spectrum-adjusted and superimposed first half-wave RF electrical signal to obtain a half-wave RF optical signal.

[0284] For example, in the case where the modulated laser 2003 is a directly modulated laser, an embodiment of the present application provides another first communication device 2000 as shown in FIG23 ; in the case where the modulated laser 2003 is an electro-absorption modulated laser, an embodiment of the present application provides another first communication device 2000 as shown in FIG24 . Compared to the first communication device 2000 shown in FIG21 , the first communication device 2000 shown in FIG23 further includes a waveform adjustment module 2004. Compared to the first communication device 2000 shown in FIG22 , the first communication device 2000 shown in FIG24 further includes a waveform adjustment module 2004.

[0285] In addition, the specific description of each of the above-mentioned embodiments can also refer to the relevant description in the aforementioned signal transmission method. The first communication device 2000 shown in Figures 20 to 24 can also be used to implement the functions of the first communication device in the aforementioned signal transmission method, and also has corresponding beneficial effects, which will not be repeated here.

[0286] Please refer to Figure 25, which is a structural diagram of a first communication device 2500 provided in an embodiment of the present application. The first communication device 2500 includes a half-wave RF signal generating module 2501 and a modulated laser 2502.

[0287] The half-wave RF signal generation module 2501 is configured to convert the full-wave RF electrical signal into a second half-wave RF electrical signal and perform digital-to-analog conversion on the second half-wave RF electrical signal to obtain a first half-wave RF electrical signal. The full-wave RF electrical signal and the second half-wave RF electrical signal are digital signals. The second half-wave RF electrical signal has the positive half amplitude or negative half amplitude of the full-wave RF electrical signal in the digital domain, while the first half-wave RF electrical signal has the positive half amplitude or negative half amplitude of the full-wave RF electrical signal in the analog domain. The half-wave RF signal generation module 2501 is further configured to output the first half-wave RF electrical signal to the modulated laser 2502.

[0288] Modulation laser 2502 is configured to superimpose a third bias electrical signal on the first half-wave RF electrical signal and optically modulate the first half-wave RF electrical signal superimposed with the third bias electrical signal to generate a half-wave RF optical signal. The half-wave RF optical signal is a RF optical signal having either the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal. Modulation laser 2502 is also configured to transmit the half-wave RF optical signal.

[0289] In an optional embodiment, the half-wave RF signal generation module 2501 may include: a baseband signal modulation module, an RF modulation module, a digital pre-distortion module, a half-wave processing module, and a digital-to-analog converter (e.g., a DAC). The baseband signal modulation module may be configured to modulate the baseband signal and output the modulated baseband signal to the RF modulation module. The RF modulation module may be configured to perform RF modulation on the modulated baseband signal and output the electrical signal obtained by RF modulation to the digital pre-distortion module. The digital pre-distortion module may be configured to perform digital pre-distortion processing on the electrical signal obtained by RF modulation to obtain a full-wave RF electrical signal and output the full-wave RF electrical signal to the half-wave processing module. The half-wave processing module may be configured to convert the full-wave RF electrical signal into a second half-wave RF electrical signal and output the second RF electrical signal to the digital-to-analog converter. The digital-to-analog converter may be configured to perform digital-to-analog conversion on the second half-wave RF electrical signal to obtain a first half-wave RF electrical signal and output the first half-wave RF electrical signal to the modulated laser 2502. It can be seen that in this embodiment, the full-wave RF electrical signal is a digital signal obtained through baseband signal modulation, RF modulation, digital predistortion processing and digital-to-analog conversion.

[0290] In an optional embodiment, the modulated laser 2502 is a directly modulated laser (e.g., DML), and the third bias electrical signal is a second bias current signal. The current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. In this case, the modulated laser 2502 may include a laser diode (e.g., LD), which can be used to superimpose the second bias current signal on the first half-wave RF electrical signal and optically modulate the first half-wave RF electrical signal after superimposing the second bias current signal to obtain a half-wave RF optical signal. The half-wave RF signal generating module 2501 outputs the first bias electrical signal to the modulated laser 2502. Specifically, the half-wave RF signal generating module 2501 outputs the first bias electrical signal to the laser diode in the modulated laser 2502.

[0291] In another optional embodiment, the modulated laser 2502 is an electro-absorption modulated laser (e.g., EML), and the third bias electrical signal is a second bias voltage signal, where the voltage corresponding to the second bias voltage signal is greater than the first voltage. In this case, the modulated laser 2502 may include a laser diode (e.g., LD) and an electro-absorption modulator (e.g., EAM). The laser diode may be used to generate a continuous light wave signal and output the continuous light wave signal to the electro-absorption modulator; the electro-absorption modulator may be used to superimpose a second bias voltage signal on the first half-wave RF electrical signal and optically modulate the first half-wave RF electrical signal after superimposing the second bias voltage signal to obtain a half-wave RF optical signal. The half-wave RF signal generating module 2501 outputs the first bias electrical signal to the modulated laser 2502. Specifically, the half-wave RF signal generating module 2501 outputs the first bias electrical signal to the electro-absorption modulator in the modulated laser 2502.

[0292] For example, based on the first communication device 2500 shown in FIG25 , for the case where the modulated laser 2502 is a directly modulated laser, an embodiment of the present application provides another first communication device 2500 as shown in FIG26 ; for the case where the modulated laser 2502 is an electro-absorption modulated laser, an embodiment of the present application provides another first communication device 2500 as shown in FIG27 . The first communication devices 2500 shown in FIG26 and FIG27 both include a half-wave RF signal generating module 2501 and a modulated laser 2502. The half-wave RF signal generating module 2501 in the first communication devices 2500 shown in FIG26 and FIG27 both includes: a baseband signal modulation module, an RF modulation module, a digital pre-distortion module, a half-wave processing module, and a digital-to-analog converter. The modulated laser 2502 in the first communication device 2500 shown in FIG26 includes a laser diode. The modulated laser 2502 in the first communication device 2500 shown in FIG27 includes a laser diode and an electro-absorption modulator. For the detailed description of each module / device in Figures 26 and 27, please refer to the above-mentioned related descriptions and will not be repeated here.

[0293] In an optional embodiment, the first communication device 2500 may further include a waveform adjustment module 2503, which may be configured to perform spectrum adjustment on the first half-wave RF electrical signal using a filter function. That is, after converting the full-wave RF electrical signal into the first half-wave RF electrical signal, the half-wave RF signal generation module 2501 may output the first half-wave RF electrical signal to the waveform adjustment module 2503. The waveform adjustment module 2503 then performs spectrum adjustment on the first half-wave RF electrical signal using a filter function and outputs the spectrum-adjusted first half-wave RF electrical signal to the modulation laser 2502. The modulation laser 2502 may then be configured to superimpose a third bias electrical signal on the spectrum-adjusted first half-wave RF electrical signal and optically modulate the spectrum-adjusted and superimposed first half-wave RF electrical signal to obtain a half-wave RF optical signal.

[0294] For example, in the case where the modulated laser 2502 is a directly modulated laser, an embodiment of the present application provides another first communication device 2500 as shown in FIG28 . In the case where the modulated laser 2502 is an electro-absorption modulated laser, an embodiment of the present application provides another first communication device 2500 as shown in FIG29 . Compared to the first communication device 2500 shown in FIG26 , the first communication device 2500 shown in FIG28 further includes a waveform adjustment module 2503. Compared to the first communication device 2500 shown in FIG27 , the first communication device 2500 shown in FIG29 further includes a waveform adjustment module 2503.

[0295] In addition, the specific description of each of the above-mentioned embodiments can also refer to the relevant description in the aforementioned signal transmission method. The first communication device 2500 shown in Figures 25 to 29 can also be used to implement the functions of the first communication device in the aforementioned signal transmission method, and also has corresponding beneficial effects, which will not be repeated here.

[0296] Please refer to Figure 30, which is a structural diagram of a second communication device 3000 provided in an embodiment of the present application. The second communication device 3000 includes a photodetector 3001 and a bandpass filter 3002. The photodetector 3001 is used to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal with the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal. The photodetector 3001 is also used to perform photoelectric conversion on the half-wave radio frequency optical signal to obtain a first electrical signal, and output the first electrical signal to the bandpass filter; the passband of the photodetector covers the spectrum of the baseband signal. The bandpass filter 3002 is used to filter the first electrical signal to obtain a full-wave radio frequency electrical signal; the passband of the bandpass filter only contains the spectrum of the baseband signal, and the full-wave radio frequency electrical signal is the baseband signal in the first electrical signal.

[0297] Please refer to Figure 31, which is a schematic diagram of the structure of a second communication device 3100 provided in an embodiment of the present application. The second communication device 3100 includes a photodetector 3001. The photodetector 3101 is used to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal. The photodetector 3101 is also used to perform photoelectric conversion on the half-wave radio frequency optical signal to obtain a first electrical signal, and to determine the full-wave radio frequency electrical signal from the first electrical signal; the passband of the photodetector only includes the spectrum of the fundamental frequency signal in the first electrical signal, and the full-wave radio frequency electrical signal is the fundamental frequency signal in the first electrical signal.

[0298] Optionally, the second communication device 3000 or the second communication device 3100 may further include an antenna, which may be used to radiate the full-wave radio frequency electrical signal.

[0299] In addition, the second communication device shown in Figures 30 and 31 can be used to implement the function of the second communication device in the aforementioned signal transmission method, and also has corresponding beneficial effects. For detailed description, please refer to the aforementioned related description, and will not be repeated here.

[0300] In addition to having the structure shown in any one of Figures 16 and 18 to 29, the first communication device may have the structure shown in any one of Figures 30 or 31, and the second communication device may also have the structure shown in any one of Figures 32 to 34.

[0301] As shown in Figure 32, an embodiment of the present application provides a communication device 3200. The communication device 3200 can be a first communication device or a second communication device; the communication device 3200 can also be a component of the first communication device (for example, an integrated circuit, a chip, etc.), or a component of the second communication device (for example, an integrated circuit, a chip, etc.), used to implement the method in the method embodiment of the present application. The communication device 3200 may include: a communication unit 3201 and a processing unit 3202. Among them, the processing unit 3202 is used to control the communication unit 3201 to send and receive data / signaling. Optionally, the communication device 3200 may also include a storage unit 3203.

[0302] In one possible design, the communication device 3200 is used to implement the function of the first communication device in the embodiment of the present application:

[0303] The communication unit 3201 may have the function of transmitting a half-wave radio frequency optical signal by the modulated laser 1603 in the first communication device 1600 shown in any one of Figures 16, 18, and 19. The processing unit 3202 may have the function of the radio frequency signal generating module 1601, the function of the bias point control module 1602, and other functions of the modulated laser 1603 except transmitting a half-wave radio frequency optical signal in the first communication device 1600 shown in any one of Figures 16, 18, and 19.

[0304] Alternatively, the communication unit 3201 may have the function of the modulated laser 2003 in the first communication device 2000 shown in any one of Figures 20 to 24 to send a half-wave radio frequency optical signal, and the processing unit 3202 may have the function of the radio frequency signal generating module 2001 in the first communication device 2000 shown in any one of Figures 20 to 24, the function of the low-noise power amplifier 2002, and other functions of the modulated laser 2003 except sending a half-wave radio frequency optical signal.

[0305] Alternatively, the communication unit 3201 may have the function of the modulated laser 2502 in the first communication device 2500 shown in any one of Figures 25 to 29 to send a half-wave radio frequency optical signal, and the processing unit 3202 may have the function of the half-wave radio frequency signal generating module 2501 in the first communication device 2500 shown in any one of Figures 25 to 29 and other functions of the modulated laser 2502 except sending a half-wave radio frequency optical signal.

[0306] In another possible design, the communication device 3200 is used to implement the function of the second communication device in the embodiment of the present application:

[0307] The communication unit 3201 can have the function of receiving half-wave radio frequency light signals of the photodetector 3101 in Figure 30, and the processing unit 3202 can have other functions of the photodetector 3001 in the second communication device 3000 shown in Figure 30 except receiving half-wave radio frequency light signals and the function of the bandpass filter 3002.

[0308] Alternatively, the communication unit 3201 may have the function of receiving half-wave RF light signals of the photodetector 3101 in FIG. 31 , and the processing unit 3202 may have other functions of the photodetector 3101 in the second communication device 3100 shown in FIG. 31 except receiving half-wave RF light signals.

[0309] In another possible design, the communication device 3200 is used to implement the function of the first communication device in the embodiment of the present application:

[0310] Processing unit 3202 is configured to generate a full-wave RF electrical signal. Processing unit 3202 is also configured to convert the full-wave RF electrical signal into a half-wave RF optical signal; a half-wave RF optical signal is an RF optical signal having either the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal. Communication unit 3201 is configured to transmit the half-wave RF optical signal.

[0311] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0312] In an optional embodiment, the processing unit 3202 converts the full-wave RF electrical signal into a half-wave RF optical signal, specifically for: superimposing a first bias electrical signal on the full-wave RF electrical signal, where the first bias electrical signal is a first bias voltage signal or a first bias current signal; and optically modulating the full-wave RF electrical signal after superimposing the first bias electrical signal to obtain a half-wave RF optical signal.

[0313] In an optional embodiment, the first bias electrical signal is a first bias voltage signal. The processing unit 3202 optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal, specifically by optically modulating the full-wave RF electrical signal superimposed with the first bias voltage signal using an electro-absorption modulated laser to obtain a half-wave RF optical signal.

[0314] In an optional embodiment, the electro-absorption modulated laser includes a laser diode and an electro-absorption modulator. The processing unit 3202 optically modulates the full-wave RF electrical signal superimposed with the first bias voltage signal using the electro-absorption modulated laser to obtain a half-wave RF optical signal. The processing unit 3202 is specifically configured to: generate a continuous light wave signal using the laser diode; and modulate the full-wave RF electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal using the electro-absorption modulator to obtain a half-wave RF optical signal.

[0315] In an optional embodiment, the first bias electrical signal is a first bias current signal. The processing unit 3202 optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain a half-wave RF optical signal, specifically for: optically modulating the full-wave RF electrical signal superimposed with the first bias current signal through a direct-modulated laser to obtain a half-wave RF optical signal; the current corresponding to the first bias current signal is greater than or equal to a threshold current of the direct-modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

[0316] In an optional embodiment, the first bias electrical signal satisfies: the coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the first optical signal satisfies a first ratio; and the first optical signal is an optical signal obtained by optically modulating the bias point detection electrical signal after superimposing the first bias electrical signal.

[0317] In an optional embodiment, the bias point detection electrical signal is a low-frequency sinusoidal wave signal. An error between a ratio of a coefficient corresponding to a DC component, a coefficient corresponding to a first-order harmonic component, a coefficient corresponding to a second-order harmonic component, and a coefficient corresponding to a third-order harmonic component of an electrical signal obtained by photoelectrically converting the first optical signal and 0.32:0.5:0.21:0 is within a second range.

[0318] In an optional embodiment, the processing unit 3202 is further configured to generate a bias point detection electrical signal. The processing unit 3202 is further configured to superimpose a second bias electrical signal on the bias point detection electrical signal. The processing unit 3202 is further configured to optically modulate the bias point detection electrical signal after superimposing the second bias electrical signal to obtain a second optical signal. The processing unit 3202 is further configured to: if the coefficient ratio between the multiple spectral components corresponding to the electrical signal obtained by performing photoelectric conversion on the second optical signal satisfies a first ratio, determine that the first bias electrical signal is the second bias electrical signal; otherwise, adjust the second bias electrical signal and superimpose the adjusted second bias electrical signal on the bias point detection electrical signal.

[0319] In an optional embodiment, the processing unit 3202 converts the full-wave RF electrical signal into a half-wave RF optical signal, specifically for: converting the full-wave RF electrical signal into a first half-wave RF electrical signal; the first half-wave RF electrical signal is an RF electrical signal having the positive half amplitude or negative half amplitude of the full-wave RF electrical signal in the analog domain; by modulating the laser, superimposing the third bias electrical signal on the first half-wave RF electrical signal, and optically modulating the first half-wave RF electrical signal after superimposing the third bias electrical signal to obtain a half-wave RF optical signal.

[0320] In an optional embodiment, the first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

[0321] In an optional embodiment, the full-wave RF electrical signal is an analog signal. The processing unit 3202 converts the full-wave RF electrical signal into a first half-wave RF electrical signal, specifically by: converting the full-wave RF electrical signal into the first half-wave RF electrical signal via a low-noise power amplifier, wherein the low-noise power amplifier is a class B low-noise power amplifier, a class C low-noise power amplifier, or a class AB low-noise power amplifier.

[0322] In an optional embodiment, the full-wave RF electrical signal is a digital signal. The processing unit 3202 converts the full-wave RF electrical signal into a first half-wave RF electrical signal, specifically configured to: convert the full-wave RF electrical signal into a second half-wave RF electrical signal, the second half-wave RF electrical signal being an RF electrical signal having the positive half amplitude or the negative half amplitude of the full-wave RF electrical signal in the digital domain; and perform digital-to-analog conversion on the second half-wave RF electrical signal to obtain the first half-wave RF electrical signal.

[0323] In an optional embodiment, the second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

[0324] In an optional embodiment, the processing unit 3202 is further configured to perform spectrum adjustment on the first half-wave RF electrical signal using a filter function. The processing unit 3202 superimposes a third bias electrical signal on the first half-wave RF electrical signal and optically modulates the first half-wave RF electrical signal after superimposing the third bias electrical signal to obtain a half-wave RF optical signal. The processing unit 3202 is specifically configured to: superimpose the third bias electrical signal on the spectrum-adjusted first half-wave RF electrical signal, and optically modulate the spectrum-adjusted first half-wave RF electrical signal after superimposing the third bias electrical signal to obtain a half-wave RF optical signal.

[0325] In an optional embodiment, the modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser. Alternatively, the modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

[0326] In an optional embodiment, the second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the multiple third optical signals; the multiple third optical signals correspond one-to-one to the multiple third bias current signals; each of the multiple third optical signals is obtained by: the processing unit 3202 optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal; the currents corresponding to the multiple third bias current signals are different from each other, and the currents corresponding to the multiple third bias current signals are all greater than or equal to the threshold current.

[0327] In an optional embodiment, the second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; the plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating a first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; the voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

[0328] In an optional implementation manner, the full-wave radio frequency electrical signal is a signal that has undergone digital predistortion processing.

[0329] In another possible design, the communication device 3200 is used to implement the function of the second communication device in the embodiment of the present application:

[0330] The communication unit 3201 is configured to receive a half-wave RF optical signal, which is a RF optical signal having the positive half amplitude or the negative half amplitude of a full-wave RF electrical signal. The processing unit 3202 is configured to convert the half-wave RF optical signal into a full-wave RF electrical signal.

[0331] In an optional embodiment, the half-wave RF optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave RF electrical signal relative to the DC component, or the half-wave RF optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave RF electrical signal relative to the DC component.

[0332] In an optional embodiment, the full-wave radio frequency electrical signal obtained by converting the half-wave radio frequency optical signal is: the baseband signal in the electrical signal obtained by performing photoelectric conversion on the half-wave radio frequency optical signal.

[0333] In an optional embodiment, the processing unit 3202 converts the half-wave RF optical signal into a full-wave RF electrical signal, specifically for: performing photoelectric conversion on the half-wave RF optical signal through a photoelectric detector to obtain a first electrical signal; the passband of the photoelectric detector covers the spectrum of the baseband signal; and filtering the first electrical signal through a bandpass filter to obtain a full-wave RF electrical signal; the passband of the bandpass filter only contains the spectrum of the baseband signal.

[0334] In an optional embodiment, the processing unit 3202 converts the half-wave RF optical signal into a full-wave RF electrical signal, specifically for: performing photoelectric conversion on the half-wave RF optical signal through a photoelectric detector to obtain a first electrical signal, and determining the full-wave RF electrical signal from the first electrical signal; the passband of the photoelectric detector only contains the spectrum of the baseband signal.

[0335] The embodiments of the present application and the above-mentioned method embodiments are based on the same concept, and the technical effects they bring are also the same. For the specific principles, please refer to the description of the above-mentioned embodiments, which will not be repeated here.

[0336] The present application also provides a communication device 3300, as shown in FIG33. The communication device 3300 can be a first communication device or a second communication device, or can be a chip, chip system, or processor that supports the first communication device to implement the above method, or a chip, chip system, or processor that supports the second communication device to implement the above method. The device can be used to implement the method described in the above method embodiment. For details, please refer to the description of the above method embodiment.

[0337] The communication device 3300 may include a processor 3301. The processor 3301 may be a general-purpose processor or a dedicated processor. The processor 3301 may be, for example, a baseband processor, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or a central processing unit (CPU). The baseband processor may be used to process communication protocols and communication data, and the central processing unit may be used to control a communication device (such as a base station, a baseband chip, a terminal, a terminal chip, a DU or CU, etc.), execute software programs, and process data from the software programs. The communication device 3300 may also include a transceiver 3302. The transceiver 3302 may include a communication interface, or the transceiver 3302 may include a communication interface and a radio frequency processing module; the communication interface may be an input / output interface or an input interface or an output interface. The communication device 3300 may also include a memory 3303.

[0338] In one possible design, the communication device 3300 is used to implement the functions of the first communication device shown in FIG. 18 or FIG. 19 in the embodiment of the present application:

[0339] Processor 3301 has the functions of the baseband signal modulation module, digital predistortion module, and digital-to-analog converter in RF signal generation module 1601. Transceiver 3302 includes a RF processing module and a communication interface. The RF processing module has the functions of the mixer and Class A low-noise power amplifier in RF signal generation module 1601, while the communication interface has the functions of a coupler, bias point control module 1602, modulated laser 1603, and optical splitter.

[0340] In another possible design, the communication device 3300 is used to implement the function of the first communication device shown in any one of Figures 21 to 24 in the embodiments of the present application:

[0341] Processor 3301 performs the functions of the baseband signal modulation module, digital predistortion module, and digital-to-analog converter in RF signal generation module 2001. Transceiver 3302 includes a RF processing module and a communication interface. The RF processing module performs the functions of the mixer and low-noise power amplifier 2002 in RF signal generation module 2001, while the communication interface performs the function of modulating laser 2003. Furthermore, when communication device 3300 is used to implement the functions of the first communication device shown in FIG. 23 or FIG. 24 in the embodiments of the present application, the RF processing module also performs the functions of waveform adjustment module 2004.

[0342] In another possible design, the communication device 3300 is used to implement the function of the first communication device shown in any one of Figures 26 to 29 in the embodiments of the present application:

[0343] Processor 3301 functions as half-wave RF signal generator module 2501. Transceiver 3302 includes a communication interface that functions as modulator laser 2502. Furthermore, when communication device 3300 is used to implement the functions of the first communication device shown in FIG. 28 or FIG. 29 in the embodiments of the present application, transceiver 3302 also includes a RF processing module that functions as waveform adjustment module 2503.

[0344] In another possible design, the communication device 3300 is used to implement the function of the second communication device shown in Figure 30 in the embodiment of the present application: the transceiver 3302 includes a communication interface and a radio frequency processing module, the communication interface has the function of the photodetector 3001, and the radio frequency processing module has the function of the bandpass filter 3002.

[0345] In another possible design, the communication device 3300 is used to implement the function of the second communication device shown in Figure 31 in the embodiment of the present application: the transceiver 3302 includes a communication interface, and the communication interface has the function of the photodetector 3001.

[0346] The embodiment of the present application further provides a communication device 3400, as shown in Figure 34. The communication device 3400 may include a transceiver 3401 and an antenna 3402. The communication device 3400 may have the functions of the first communication device or the second communication device in the above method embodiment.

[0347] In one possible design, the communication device 3400 is used to implement the functions of the first communication device shown in FIG. 16 or FIG. 20 in the embodiments of the present application:

[0348] Antenna 3402 can be used to receive analog signals. Transceiver 3401 includes a radio frequency processing module and a communication interface. Antenna 3402 can be connected to the radio frequency processing module; the radio frequency processing module can have the functions of a Class A low-noise power amplifier in the radio frequency signal generation module, amplifying the analog signal received by antenna 3402 to generate a full-wave radio frequency electrical signal. Alternatively, the radio frequency processing module can have the functions of a Class A low-noise power amplifier and mixer in the radio frequency signal generation module, amplifying the analog signal received by antenna 3402 and mixing the amplified electrical signal with a local oscillator to generate a full-wave radio frequency electrical signal.

[0349] In the case where the communication device 3400 is used to implement the functions of the first communication device shown in FIG. 16 in the embodiment of the present application, the communication interface has the functions of the bias point control module 1602 and the modulated laser 1603. In the case where the communication device 3400 is used to implement the functions of the first communication device shown in FIG. 20 in the embodiment of the present application, the RF processing module also has the function of the low-noise power amplifier 2002, and the communication interface has the function of the modulated laser 2003.

[0350] In another possible design, the communication device 3400 is used to implement the functions of the second communication device shown in Figure 30 in the embodiment of the present application: the transceiver 3401 includes a communication interface and a radio frequency processing module, the communication interface has the function of the photodetector 3001, and the radio frequency processing module has the function of the bandpass filter 3002. The transceiver 3401 can also be used to output the obtained full-wave radio frequency electrical signal to the antenna 3402.

[0351] In another possible design, the communication device 3400 is used to implement the functions of the second communication device shown in Figure 31 in the embodiment of the present application: the transceiver 3401 includes a communication interface, and the communication interface has the function of the photodetector 3001. Optionally, the transceiver 3401 can also be used to output the obtained full-wave radio frequency electrical signal to the antenna 3402.

[0352] In addition, the communication device 3400 may further include a processor 3403, on which instructions 3404 may be stored. The instructions 3404 may be executed to enable the communication device 3400 to perform the method described in the above method embodiment. The instructions 3404 may be fixed in the processor 3403. In this case, the processor 3403 may be implemented by hardware.

[0353] Optionally, the communication device 3400 may include one or more memories 3405, on which instructions 3406 may be stored. The instructions may be executed to cause the communication device 3400 to perform the method described in the above method embodiment. Optionally, the memory 3405 may also store data. The processor 3403 and the memory 3405 may be provided separately or integrated together.

[0354] The memory 3405 may include, but is not limited to, non-volatile memories such as a hard disk drive (HDD) or a solid-state drive (SSD), random access memory (RAM), erasable programmable ROM (EPROM), ROM or compact disc read-only memory (CD-ROM), etc.

[0355] Optionally, the communication device 3300 or the communication device 3400 may further include a circuit that can implement the function of sending or receiving or communicating in the aforementioned method embodiment. The processor and transceiver described in the embodiments of the present application can be implemented in an integrated circuit (integrated circuit, IC), an analog IC, a radio frequency integrated circuit (radio frequency integrated circuit, RFIC), a mixed signal IC, an application specific integrated circuit (application specific integrated circuit, ASIC), a printed circuit board (printed circuit board, PCB), an electronic device, etc. The processor and transceiver can also be manufactured using various IC process technologies, such as complementary metal oxide semiconductor (CMOS), N-type metal oxide semiconductor (nMetal-oxide-semiconductor, NMOS), P-type metal oxide semiconductor (positive channel metal oxide semiconductor, PMOS), bipolar junction transistor (bipolar junction transistor, BJT), bipolar CMOS (BiCMOS), silicon germanium (SiGe), gallium arsenide (GaAs), etc.

[0356] Those skilled in the art will also appreciate that the various illustrative logical blocks and steps listed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of the present application.

[0357] The embodiment of the present application and the above-mentioned signal transmission method are based on the same concept, and the technical effects they bring are also the same. For the specific principles, please refer to the description in the above-mentioned signal transmission method, which will not be repeated here.

[0358] Those skilled in the art will also appreciate that the various illustrative logical blocks and steps listed in the embodiments of the present application can be implemented by electronic hardware, computer software, or a combination of both. Whether such functions are implemented by hardware or software depends on the specific application and the design requirements of the entire system. Those skilled in the art may use various methods to implement the described functions for each specific application, but such implementation should not be construed as exceeding the scope of protection of the embodiments of the present application.

[0359] The present application also provides a computer-readable storage medium for storing computer software instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0360] The present application also provides a computer program product for storing computer software instructions, which, when executed by a communication device, implements the functions of any of the above method embodiments.

[0361] The present application also provides a computer program that, when executed on a computer, implements the functions of any of the above method embodiments.

[0362] The present application also provides a communication system, which includes the first communication device and the second communication device of the above aspect. In another possible design, the system may also include other devices that interact with the first communication device and / or the second communication device in the solution provided by the present application.

[0363] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated therein. The available medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a high-density digital video disc (DVD)), or a semiconductor medium (eg, an SSD).

[0364] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

[0365] In the various embodiments of the present application, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other. The technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0366] In this application, "at least one" means one or more, and "more" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the previous and next related objects are in an "or" relationship; in the formulas of this application, the character " / " indicates that the previous and next related objects are in a "division" relationship.

[0367] It is understood that the various numbers used in the embodiments of this application are merely for ease of description and are not intended to limit the scope of the embodiments of this application. The order of the sequence numbers of the above-mentioned processes does not necessarily imply a specific order of execution; the order of execution of the processes should be determined by their functions and inherent logic.

Claims

1. A signal transmission method, characterized in that: The method comprises: generating a full-wave radio frequency electrical signal; Converting the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal; The half-wave radio frequency optical signal is transmitted.

2. The method according to claim 1, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

3. The method according to claim 1 or 2, characterized in that The converting of the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal comprises: superimposing a first bias electrical signal on the full-wave RF electrical signal; the first bias electrical signal is a first bias voltage signal or a first bias current signal; The full-wave radio frequency electrical signal superimposed with the first bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

4. The method according to claim 3, characterized in that The first bias electrical signal is the first bias voltage signal; and optically modulating the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain the half-wave RF optical signal includes: The full-wave radio frequency electrical signal superimposed with the first bias voltage signal is optically modulated by an electro-absorption modulated laser to obtain the half-wave radio frequency optical signal.

5. The method according to claim 4, characterized in that The electro-absorption modulated laser includes a laser diode and an electro-absorption modulator; the electro-absorption modulated laser performs optical modulation on the full-wave radio frequency electrical signal superimposed with the first bias voltage signal to obtain the half-wave radio frequency optical signal, including: generating a continuous light wave signal through the laser diode; The full-wave radio frequency electrical signal superimposed with the first bias voltage signal is modulated onto the continuous light wave signal by the electro-absorption modulator to obtain the half-wave radio frequency optical signal.

6. The method according to claim 3, characterized in that The first bias electrical signal is the first bias current signal; and optically modulating the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain the half-wave RF optical signal includes: Optically modulating the full-wave radio frequency electrical signal superimposed with the first bias current signal through a direct modulation laser to obtain the half-wave radio frequency optical signal; The current corresponding to the first bias current signal is greater than or equal to the threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

7. The method according to any one of claims 3 to 6, characterized in that The first bias electrical signal satisfies: a coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectrically converting the first optical signal satisfies a first ratio; and the first optical signal is an optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the first bias electrical signal.

8. The method according to claim 7, characterized in that The bias point detection electrical signal is a low-frequency sine wave signal; The error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component, and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by photoelectric conversion of the first optical signal and 0.32:0.5:0.21:0 is within the second range.

9. The method according to any one of claims 3 to 8, characterized in that The method further comprises: generating a bias point detection electrical signal; superimposing a second bias electrical signal on the bias point detection electrical signal; optically modulating the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal; If a coefficient ratio between a plurality of spectral components corresponding to an electrical signal obtained by photoelectrically converting the second optical signal satisfies a first ratio, determining that the first bias electrical signal is the second bias electrical signal; Otherwise, the second bias electrical signal is adjusted, and the adjusted second bias electrical signal is superimposed on the bias point detection electrical signal.

10. The method according to claim 1 or 2, characterized in that The converting of the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal comprises: Converting the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal; wherein the first half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; By modulating the laser, a third bias electrical signal is superimposed on the first half-wave radio frequency electrical signal, and the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

11. The method according to claim 10, characterized in that The first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

12. The method according to claim 10 or 11, characterized in that The full-wave radio frequency electrical signal is an analog signal; and converting the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal comprises: converting the full-wave radio frequency electrical signal into the first half-wave radio frequency electrical signal through a low-noise power amplifier; The low noise power amplifier is a class B low noise power amplifier, a class C low noise power amplifier, or a class AB low noise power amplifier.

13. The method according to claim 10 or 11, characterized in that The full-wave radio frequency electrical signal is a digital signal; and converting the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal comprises: Converting the full-wave radio frequency electrical signal into a second half-wave radio frequency electrical signal; wherein the second half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the digital domain; Perform digital-to-analog conversion on the second half-wave radio frequency electrical signal to obtain the first half-wave radio frequency electrical signal.

14. The method according to claim 13, characterized in that The second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

15. The method according to any one of claims 10 to 14, characterized in that The method further comprises: using a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal; The step of superimposing a third bias electrical signal on the first half-wave radio frequency electrical signal and optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal to obtain the half-wave radio frequency optical signal includes: The first half-wave radio frequency electrical signal after spectrum adjustment is superimposed with the third bias electrical signal, and the first half-wave radio frequency electrical signal after spectrum adjustment and superimposition of the third bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

16. The method according to any one of claims 10 to 15, characterized in that The modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser; or, The modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

17. The method according to claim 16, characterized in that The second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; The plurality of third optical signals correspond one to one with the plurality of third bias current signals; each of the plurality of third optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal; The currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to the threshold current.

18. The method according to claim 16, characterized in that The second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; The plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; The voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

19. The method according to any one of claims 1 to 18, characterized in that The full-wave radio frequency electrical signal is a signal that has been subjected to digital predistortion processing.

20. A signal transmission method, characterized in that: The method comprises: Receiving a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of a full-wave radio frequency electrical signal; The half-wave radio frequency optical signal is converted into the full-wave radio frequency electrical signal.

21. The method according to claim 20, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

22. The method according to claim 20 or 21, characterized in that The full-wave radio frequency electrical signal obtained by converting the half-wave radio frequency optical signal is: a baseband signal in the electrical signal obtained by performing photoelectric conversion on the half-wave radio frequency optical signal.

23. The method according to claim 22, characterized in that The converting the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal comprises: Performing photoelectric conversion on the half-wave radio frequency optical signal through a photodetector to obtain a first electrical signal; the passband of the photodetector covers the spectrum of the baseband signal; The first electrical signal is filtered through a bandpass filter to obtain the full-wave radio frequency electrical signal; the passband of the bandpass filter only contains the frequency spectrum of the baseband signal.

24. The method according to claim 22, characterized in that The converting the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal comprises: The half-wave radio frequency optical signal is photoelectrically converted by a photoelectric detector to obtain a first electrical signal, and the full-wave radio frequency electrical signal is determined from the first electrical signal; the passband of the photoelectric detector only contains the spectrum of the baseband signal.

25. A signal transmission method, characterized in that: The method comprises: The first communication device generates a full-wave radio frequency electrical signal; The first communication device converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or negative half amplitude of the full-wave radio frequency electrical signal; The first communication device sends the half-wave radio frequency optical signal; The second communication device receives the half-wave radio frequency optical signal; The second communication device converts the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal.

26. The method according to claim 25, characterized in that The half-wave radio frequency optical signal is obtained by the first communication device optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by the first communication device optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

27. The method according to claim 25 or 26, characterized in that The first communication device converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, including: The first communication device superimposes a first bias electrical signal on the full-wave RF electrical signal; the first bias electrical signal is a first bias voltage signal or a first bias current signal; The first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias electrical signal to obtain the half-wave radio frequency optical signal.

28. The method according to claim 27, characterized in that The first bias electrical signal is the first bias voltage signal; and the first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias electrical signal to obtain the half-wave radio frequency optical signal, including: The first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal through an electro-absorption modulated laser to obtain the half-wave radio frequency optical signal.

29. The method according to claim 28, characterized in that The electro-absorption modulated laser includes a laser diode and an electro-absorption modulator; the first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal by the electro-absorption modulated laser to obtain the half-wave radio frequency optical signal, including: The first communication device generates a continuous light wave signal through the laser diode; The first communication device modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal onto the continuous light wave signal through the electro-absorption modulator to obtain the half-wave radio frequency optical signal.

30. The method according to claim 27, wherein The first bias electrical signal is the first bias current signal; and the first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias electrical signal to obtain the half-wave radio frequency optical signal, including: The first communication device optically modulates the full-wave radio frequency electrical signal superimposed with the first bias current signal through a directly modulated laser to obtain the half-wave radio frequency optical signal; The current corresponding to the first bias current signal is greater than or equal to the threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

31. The method according to any one of claims 27 to 30, characterized in that The first bias electrical signal satisfies: a coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by the first communication device performing photoelectric conversion on the first optical signal satisfies a first ratio; and the first optical signal is an optical signal obtained by the first communication device performing optical modulation on the bias point detection electrical signal superimposed with the first bias electrical signal.

32. The method according to claim 31, characterized in that The bias point detection electrical signal is a low-frequency sine wave signal; The error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by the first communication device performing photoelectric conversion on the first optical signal and 0.32:0.5:0.21:0 is within the second range.

33. The method according to any one of claims 27 to 32, characterized in that The method further comprises: The first communication device generates a bias point detection electrical signal; The first communication device superimposes a second bias electrical signal on the bias point detection electrical signal; The first communication device optically modulates the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal; If a coefficient ratio between multiple spectral components corresponding to an electrical signal obtained by performing photoelectric conversion on the second optical signal by the first communication device satisfies a first ratio, the first communication device determines that the first bias electrical signal is the second bias electrical signal; Otherwise, the first communication device adjusts the second bias electrical signal and superimposes the adjusted second bias electrical signal on the bias point detection electrical signal.

34. The method according to claim 25 or 26, characterized in that The first communication device converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, including: The first communication device converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal; the first half-wave radio frequency electrical signal is a radio frequency electrical signal having a positive half amplitude or a negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; The first communication device modulates the laser to superimpose a third bias electrical signal on the first half-wave RF electrical signal, and optically modulates the first half-wave RF electrical signal superimposed with the third bias electrical signal to obtain the half-wave RF optical signal.

35. The method according to claim 34, wherein The first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

36. The method according to claim 34 or 35, characterized in that The full-wave radio frequency electrical signal is an analog signal; and the first communication device converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, including: The first communication device converts the full-wave radio frequency electrical signal into the first half-wave radio frequency electrical signal through a low-noise power amplifier; The low noise power amplifier is a class B low noise power amplifier, a class C low noise power amplifier, or a class AB low noise power amplifier.

37. The method according to claim 34 or 35, characterized in that The full-wave radio frequency electrical signal is a digital signal; the first communication device converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, including: The first communication device converts the full-wave radio frequency electrical signal into a second half-wave radio frequency electrical signal; the second half-wave radio frequency electrical signal is a radio frequency electrical signal having a positive half amplitude or a negative half amplitude of the full-wave radio frequency electrical signal in the digital domain; The first communication device performs digital-to-analog conversion on the second half-wave radio frequency electrical signal to obtain the first half-wave radio frequency electrical signal.

38. The method according to claim 37, wherein The second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

39. The method according to any one of claims 34 to 38, characterized in that The method further includes: the first communication device using a filter function to perform spectrum adjustment on the first half-wave radio frequency electrical signal; The first communication device superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal to obtain the half-wave radio frequency optical signal, including: The first communication device superimposes the third bias electrical signal on the first half-wave radio frequency electrical signal after spectrum adjustment, and optically modulates the first half-wave radio frequency electrical signal after spectrum adjustment and superimposition of the third bias electrical signal to obtain the The half-wave radio frequency optical signal.

40. The method according to any one of claims 34 to 39, characterized in that The modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser; or, The modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

41. The method according to claim 40, wherein The second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; The plurality of third optical signals correspond one-to-one to the plurality of third bias current signals; each of the plurality of third optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal by the first communication device; The currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to the threshold current.

42. The method according to claim 40, wherein The second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; The plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; The voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

43. The method according to any one of claims 25 to 42, characterized in that The full-wave radio frequency electrical signal generated by the first communication device is a signal that has been digitally predistorted by the first communication device.

44. The method according to claim 25 or 43, characterized in that The full-wave radio frequency electrical signal obtained by the second communication device converting the half-wave radio frequency optical signal is: the baseband signal in the electrical signal obtained by the second communication device performing photoelectric conversion on the half-wave radio frequency optical signal.

45. The method according to claim 44, wherein The second communication device converts the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal, including: The second communication device performs photoelectric conversion on the half-wave radio frequency optical signal through a photoelectric detector to obtain a first electrical signal; the passband of the photoelectric detector covers the spectrum of the baseband signal; The second communication device filters the first electrical signal through a bandpass filter to obtain the full-wave radio frequency electrical signal; the passband of the bandpass filter only includes the frequency spectrum of the baseband signal.

46. ​​The method according to claim 44, wherein The second communication device converts the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal, including: The second communication device performs photoelectric conversion on the half-wave RF optical signal through a photoelectric detector to obtain a first electrical signal, and determines the full-wave RF electrical signal from the first electrical signal; the passband of the photoelectric detector only contains the spectrum of the baseband signal.

47. A communication device, characterized in that The device comprises: The RF signal generating module is used to generate a full-wave RF electrical signal and output the full-wave RF electrical signal to the modulated optical device; a bias point control module, configured to output a first bias electrical signal to the modulated laser; The modulating laser is used to optically modulate the full-wave radio frequency electrical signal after superimposing the first bias electrical signal to obtain a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal; The modulated laser is also used to send the half-wave radio frequency optical signal.

48. The device according to claim 47, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

49. The device according to claim 47 or 48, characterized in that The modulated laser is an electro-absorption modulated laser, and the first bias electrical signal is a first bias voltage signal; or, The modulated laser is a directly modulated laser, and the first bias electrical signal is a first bias current signal.

50. The device according to claim 49, characterized in that The electro-absorption modulated laser includes a laser diode and an electro-absorption modulator; the electro-absorption modulated laser optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal to obtain the half-wave radio frequency optical signal, specifically for: generating a continuous light wave signal through the laser diode; The full-wave radio frequency electrical signal superimposed with the first bias voltage signal is modulated onto the continuous light wave signal by the electro-absorption modulator to obtain the half-wave radio frequency optical signal.

51. The device according to claim 49, characterized in that The current corresponding to the first bias current signal is greater than or equal to the threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

52. The device according to any one of claims 47 to 51, characterized in that The first bias electrical signal satisfies: a coefficient ratio between multiple spectral components corresponding to the electrical signal obtained by photoelectrically converting the first optical signal satisfies a first ratio; and the first optical signal is an optical signal obtained by optically modulating the bias point detection electrical signal superimposed with the first bias electrical signal.

53. The device according to claim 52, characterized in that The bias point detection electrical signal is a low-frequency sine wave signal; The error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component, and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by photoelectric conversion of the first optical signal and 0.32:0.5:0.21:0 is within the second range.

54. The device according to any one of claims 47 to 53, characterized in that The bias point control module is further configured to generate a bias point detection electrical signal and output the bias point detection electrical signal to the modulated laser; The bias point control module is further configured to output a second bias electrical signal to the modulated laser; The modulated laser is further configured to optically modulate the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal, and output the second optical signal to the bias point control module; The bias point control module is further configured to: determine that the first bias electrical signal is the second bias electrical signal if a coefficient ratio between a plurality of spectral components corresponding to an electrical signal obtained by performing photoelectric conversion on the second optical signal satisfies a first ratio; Otherwise, the second bias electrical signal is adjusted, and the adjusted second bias electrical signal is output to the modulated laser.

55. The device according to any one of claims 47 to 54, characterized in that The radio frequency signal generating module includes a digital predistortion module; The full-wave radio frequency electrical signal is a signal that has been digitally predistorted by the digital predistortion module.

56. A communication device, characterized in that The device comprises: A radio frequency signal generating module, configured to generate a full-wave radio frequency electrical signal and output the full-wave radio frequency electrical signal to a low-noise power amplifier, wherein the full-wave radio frequency electrical signal is an analog signal; The low-noise power amplifier is configured to convert the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, and output the first half-wave radio frequency electrical signal to a modulated laser; the first half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; the low-noise power amplifier is a class B low-noise power amplifier, a class C low-noise power amplifier, or a class AB low-noise power amplifier; The modulating laser is configured to superimpose a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulate the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal to obtain a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of the full-wave radio frequency electrical signal; The modulated laser is also used to send the half-wave radio frequency optical signal.

57. The device according to claim 56, characterized in that The radio frequency signal generating module includes a digital predistortion module; The full-wave radio frequency electrical signal is a signal that has been digitally predistorted by the digital predistortion module.

58. A communication device, characterized in that The device comprises: a half-wave radio frequency signal generating module, configured to convert the full-wave radio frequency electrical signal into a second half-wave radio frequency electrical signal, and perform digital-to-analog conversion on the second half-wave radio frequency electrical signal to obtain a first half-wave radio frequency electrical signal; The full-wave radio frequency electrical signal and the second half-wave radio frequency electrical signal are digital signals, the second half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the digital domain, and the first half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; The half-wave radio frequency signal generating module is further configured to output the first half-wave radio frequency electrical signal to the modulated laser; The modulating laser is configured to superimpose a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulate the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal to obtain a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of the full-wave radio frequency electrical signal; The modulated laser is also used to send the half-wave radio frequency optical signal.

59. The device according to claim 58, characterized in that The second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

60. The device according to any one of claims 58 or 59, characterized in that The half-wave radio frequency signal generating module includes a digital predistortion module; The full-wave radio frequency electrical signal is a signal that has been digitally predistorted by the digital predistortion module.

61. The device according to any one of claims 56 to 60, characterized in that The first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

62. The device according to any one of claims 56 to 61, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

63. The device according to any one of claims 56 to 62, characterized in that The device further comprises: a waveform adjustment module, configured to perform spectrum adjustment on the first half-wave radio frequency electrical signal using a filter function, and output the spectrum-adjusted first half-wave radio frequency electrical signal to the modulated laser; The modulated laser superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal to obtain the half-wave radio frequency optical signal, specifically for: The first half-wave radio frequency electrical signal after spectrum adjustment is superimposed with the third bias electrical signal, and the first half-wave radio frequency electrical signal after spectrum adjustment and superimposition of the third bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

64. The device according to any one of claims 56 to 63, characterized in that The modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser; or, The modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

65. The device according to claim 64, characterized in that The second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; The plurality of third optical signals correspond one to one with the plurality of third bias current signals; each of the plurality of third optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias current signal corresponding to the third optical signal; The currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to the threshold current.

66. The device according to claim 64, characterized in that The second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; The plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; The voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

67. A communication device, characterized in that The device comprises: A photoelectric detector for receiving a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of a full-wave radio frequency electrical signal; The photodetector is further configured to perform photoelectric conversion on the half-wave RF optical signal to obtain a first electrical signal, and output the first electrical signal to a bandpass filter; the passband of the photodetector covers the spectrum of the baseband signal in the first electrical signal; The bandpass filter is used to filter the first electrical signal to obtain the full-wave radio frequency electrical signal; the passband of the bandpass filter only contains the spectrum of the baseband signal, and the full-wave radio frequency electrical signal is the baseband signal in the first electrical signal.

68. A communication device, characterized in that The device comprises: A photoelectric detector for receiving a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of a full-wave radio frequency electrical signal; The photoelectric detector is also used to perform photoelectric conversion on the half-wave radio frequency optical signal to obtain a first electrical signal, and The full-wave radio frequency electrical signal is determined in the first electrical signal; the passband of the photodetector only includes the spectrum of the baseband signal in the first electrical signal, and the full-wave radio frequency electrical signal is the baseband signal in the first electrical signal.

69. The device according to claim 67 or 68, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

70. A communication device, characterized in that The device comprises: a processing unit for generating a full-wave radio frequency electrical signal; The processing unit is further configured to convert the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of the full-wave radio frequency electrical signal; A communication unit is used to send the half-wave radio frequency optical signal.

71. The device according to claim 70, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

72. The device according to claim 70 or 71, characterized in that The processing unit converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, specifically for: superimposing a first bias electrical signal on the full-wave RF electrical signal; the first bias electrical signal is a first bias voltage signal or a first bias current signal; The full-wave radio frequency electrical signal superimposed with the first bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

73. The device according to claim 72, characterized in that The first bias electrical signal is the first bias voltage signal; the processing unit optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain the half-wave RF optical signal, specifically for: The full-wave radio frequency electrical signal superimposed with the first bias voltage signal is optically modulated by an electro-absorption modulated laser to obtain the half-wave radio frequency optical signal.

74. The device according to claim 73, characterized in that The electro-absorption modulated laser includes a laser diode and an electro-absorption modulator; the processing unit optically modulates the full-wave radio frequency electrical signal superimposed with the first bias voltage signal through the electro-absorption modulated laser to obtain the half-wave radio frequency optical signal, specifically for: generating a continuous light wave signal through the laser diode; The full-wave radio frequency electrical signal superimposed with the first bias voltage signal is modulated onto the continuous light wave signal by the electro-absorption modulator to obtain the half-wave radio frequency optical signal.

75. The device according to claim 72, characterized in that The first bias electrical signal is the first bias current signal; the processing unit optically modulates the full-wave RF electrical signal superimposed with the first bias electrical signal to obtain the half-wave RF optical signal, specifically for: Optically modulating the full-wave radio frequency electrical signal superimposed with the first bias current signal through a direct modulation laser to obtain the half-wave radio frequency optical signal; The current corresponding to the first bias current signal is greater than or equal to the threshold current of the directly modulated laser, and the difference between the current corresponding to the first bias current signal and the threshold current is within a first range.

76. The device according to any one of claims 72 to 75, characterized in that The first bias electrical signal satisfies: the coefficient ratio between the multiple spectral components corresponding to the electrical signal obtained by photoelectric conversion of the first optical signal satisfies a first ratio; the first optical signal is the bias signal after superimposing the first bias electrical signal. The optical signal is obtained by optically modulating the electrical signal detected by the point.

77. The device according to claim 76, characterized in that The bias point detection electrical signal is a low-frequency sine wave signal; The error between the ratio of the coefficient corresponding to the DC component, the coefficient corresponding to the first-order harmonic component, the coefficient corresponding to the second-order harmonic component, and the coefficient corresponding to the third-order harmonic component of the electrical signal obtained by photoelectric conversion of the first optical signal and 0.32:0.5:0.21:0 is within the second range.

78. The device according to any one of claims 72 to 77, characterized in that The processing unit is further configured to generate a bias point detection electrical signal; The processing unit is further configured to superimpose a second bias electrical signal on the bias point detection electrical signal; The processing unit is further configured to optically modulate the bias point detection electrical signal superimposed with the second bias electrical signal to obtain a second optical signal; The processing unit is further configured to: determine that the first bias electrical signal is the second bias electrical signal if a coefficient ratio between a plurality of spectral components corresponding to an electrical signal obtained by performing photoelectric conversion on the second optical signal satisfies a first ratio; Otherwise, the second bias electrical signal is adjusted, and the adjusted second bias electrical signal is superimposed on the bias point detection electrical signal.

79. The device according to claim 70 or 71, characterized in that The processing unit converts the full-wave radio frequency electrical signal into a half-wave radio frequency optical signal, specifically for: Converting the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal; wherein the first half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the analog domain; By modulating the laser, a third bias electrical signal is superimposed on the first half-wave radio frequency electrical signal, and the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

80. The device according to claim 79, characterized in that The first half-wave RF electrical signal is the positive half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component, or the first half-wave RF electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave RF electrical signal in the analog domain relative to the DC component.

81. The device according to claim 79 or 80, characterized in that The full-wave radio frequency electrical signal is an analog signal; the processing unit converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, specifically for: converting the full-wave radio frequency electrical signal into the first half-wave radio frequency electrical signal through a low-noise power amplifier; The low noise power amplifier is a class B low noise power amplifier, a class C low noise power amplifier, or a class AB low noise power amplifier.

82. The device according to claim 79 or 80, characterized in that The full-wave radio frequency electrical signal is a digital signal; the processing unit converts the full-wave radio frequency electrical signal into a first half-wave radio frequency electrical signal, specifically for: Converting the full-wave radio frequency electrical signal into a second half-wave radio frequency electrical signal; wherein the second half-wave radio frequency electrical signal is a radio frequency electrical signal having the positive half amplitude or the negative half amplitude of the full-wave radio frequency electrical signal in the digital domain; Perform digital-to-analog conversion on the second half-wave radio frequency electrical signal to obtain the first half-wave radio frequency electrical signal.

83. The device according to claim 82, characterized in that The second half-wave radio frequency electrical signal is the positive half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component, or the second half-wave radio frequency electrical signal is obtained by inverting the negative half-amplitude signal of the full-wave radio frequency electrical signal in the digital domain relative to the DC component.

84. The device according to any one of claims 79 to 83, characterized in that The processing unit is further configured to perform spectrum adjustment on the first half-wave radio frequency electrical signal using a filter function; The processing unit superimposes a third bias electrical signal on the first half-wave radio frequency electrical signal, and optically modulates the first half-wave radio frequency electrical signal superimposed with the third bias electrical signal to obtain the half-wave radio frequency optical signal, specifically for: The first half-wave radio frequency electrical signal after spectrum adjustment is superimposed with the third bias electrical signal, and the first half-wave radio frequency electrical signal after spectrum adjustment and superimposition of the third bias electrical signal is optically modulated to obtain the half-wave radio frequency optical signal.

85. The device according to any one of claims 79 to 84, characterized in that The modulated laser is a directly modulated laser, the third bias electrical signal is a second bias current signal, and the current corresponding to the second bias current signal is greater than or equal to the threshold current of the directly modulated laser; or, The modulated laser is an electro-absorption modulated laser, the third bias electrical signal is a second bias voltage signal, and the voltage corresponding to the second bias voltage signal is greater than the first voltage.

86. The device according to claim 85, characterized in that The second bias current signal is a third bias current signal corresponding to a third optical signal having a maximum signal-to-noise ratio among the plurality of third optical signals; The plurality of third optical signals correspond one-to-one to the plurality of third bias current signals; each of the plurality of third optical signals is obtained by optically modulating the first half-wave RF electrical signal superimposed with the third bias current signal corresponding to the third optical signal by the processing unit; The currents corresponding to the plurality of third bias current signals are different from each other, and the currents corresponding to the plurality of third bias current signals are all greater than or equal to the threshold current.

87. The device according to claim 85, characterized in that The second bias voltage signal is a third bias voltage signal corresponding to a fourth optical signal having the smallest adjacent channel leakage power ratio among the plurality of fourth optical signals; The plurality of fourth optical signals correspond one-to-one to the plurality of third bias voltage signals; each of the plurality of fourth optical signals is obtained by optically modulating the first half-wave radio frequency electrical signal superimposed with the third bias voltage signal corresponding to the fourth optical signal; The voltages corresponding to the plurality of third bias voltage signals are different from each other, and the voltages corresponding to the plurality of third bias voltage signals are all greater than or equal to the first voltage.

88. The device according to any one of claims 70 to 87, characterized in that The full-wave radio frequency electrical signal is a signal that has been subjected to digital predistortion processing.

89. A communication device, characterized in that The device comprises: A communication unit, configured to receive a half-wave radio frequency optical signal; the half-wave radio frequency optical signal is a radio frequency optical signal having a positive half amplitude or a negative half amplitude of a full-wave radio frequency electrical signal; A processing unit is used to convert the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal.

90. The device according to claim 89, characterized in that The half-wave radio frequency optical signal is obtained by optically modulating the positive half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component, or the half-wave radio frequency optical signal is obtained by optically modulating the inverted negative half-amplitude signal of the full-wave radio frequency electrical signal relative to the DC component.

91. The device according to claim 89 or 90, characterized in that The full-wave radio frequency electrical signal obtained by converting the half-wave radio frequency optical signal is: a baseband signal in the electrical signal obtained by performing photoelectric conversion on the half-wave radio frequency optical signal.

92. The device according to claim 91, characterized in that The processing unit converts the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal, specifically for: Performing photoelectric conversion on the half-wave radio frequency optical signal through a photodetector to obtain a first electrical signal; the passband of the photodetector covers the spectrum of the baseband signal; Filtering the first electrical signal through a bandpass filter to obtain the full-wave radio frequency electrical signal; The passband of the bandpass filter only contains the frequency spectrum of the baseband signal.

93. The device according to claim 91, characterized in that The processing unit converts the half-wave radio frequency optical signal into the full-wave radio frequency electrical signal, specifically for: The half-wave radio frequency optical signal is photoelectrically converted by a photoelectric detector to obtain a first electrical signal, and the full-wave radio frequency electrical signal is determined from the first electrical signal; the passband of the photoelectric detector only contains the spectrum of the baseband signal.

94. A communication device, characterized in that including memory and processor; The memory is used to store instructions or computer programs; The processor is configured to execute the computer program or instructions stored in the memory, so that the communication device executes the method according to any one of claims 1 to 19, or so that the communication device executes the method according to any one of claims 20 to 24.

95. A communication system, the communication system comprising a first communication device and a second communication device; The first communication device is used to perform the method according to any one of claims 1 to 19; The second communication device is configured to execute the method according to any one of claims 20 to 24.

96. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed, the method according to any one of claims 1 to 19 is implemented, or the method according to any one of claims 20 to 24 is implemented.

97. A computer program product, comprising: Computer program code, when the computer program code is run, implements the method according to any one of claims 1 to 19, or implements the method according to any one of claims 20 to 24.

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