Method, device and equipment for processing transmitted optical signal of optical signal transmitting circuit

Abstract

The embodiments of the present application provide a method, device and equipment for processing transmitted optical signals of an optical signal transmitting circuit, which relates to the field of optical communication technology and can realize real-time monitoring of each modulated optical signal. The method includes: dividing the transmitted optical signal output by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the transmitted optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optical modulation of a carrier optical signal according to a predetermined modulation format; sending the first optical signal to an optical signal receiving circuit; obtaining the low-frequency component of each modulated optical signal in the second optical signal; adjusting the bias voltage of the modulated optical signal according to a predetermined step length, and obtaining the power change value of the low-frequency component with the predetermined step length.

Description

Technical Field

[0001] The present application relates to the field of optical communication technology, and in particular to a method, device and equipment for processing transmitted optical signals of an optical signal transmitting circuit. Background Art

[0002] The application of the Internet in our daily life is becoming more and more extensive, such as augmented reality (AR), virtual reality (VR), live webcasting and 8K ultra-clear video. The commercial single-wave 100G / 200G rate cannot meet people's growing demand for Internet access. Therefore, in the future, the single-wave rate will gradually increase to 400G / 800G, or even 1.2T. Generally, increasing the signal baud rate or modulation format is an effective means to increase the single-wave rate. Since the signal baud rate increase range is limited by the bandwidth of electrical devices, it cannot support ultra-high-speed signal transmission alone, and it is necessary to use 64 quadrature amplitude modulation (QAM) and higher-order modulation formats. However, the application of high modulation formats will further compress the Euclidean distance between each constellation point, so that the slight imbalance of power between the I (in-phase) and Q (quadrature) signals in the modulated optical signal may cause serious degradation of system performance. Therefore, it is necessary to monitor the power of each modulated optical signal in real time and compensate for the power difference between them. Summary of the invention

[0003] The embodiments of the present application provide a method, device and equipment for processing transmitted optical signals of an optical signal transmitting circuit, which can realize real-time monitoring of each modulated optical signal.

[0004] In a first aspect, a method for processing a transmitted optical signal of an optical signal transmitting circuit is provided. The method for processing a transmitted optical signal of an optical signal transmitting circuit is used for a transmitted optical signal processing device of an optical signal transmitting circuit. The method comprises: dividing a transmitted optical signal output by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the transmitted optical signal comprises at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating a carrier optical signal according to a predetermined modulation format; sending the first optical signal to an optical signal receiving circuit; obtaining a low-frequency component of each modulated optical signal in the second optical signal; adjusting a bias voltage of the modulated optical signal according to a predetermined step length; and obtaining a change value of the power of the low-frequency component with a predetermined step length. Because in the above scheme, the transmitted optical signal processing device of the optical signal transmitting circuit can divide the transmitted optical signal output by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the transmitted optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating the carrier optical signal according to a predetermined modulation format; the first optical signal is sent to the optical signal receiving circuit; and then the low-frequency component of each modulated optical signal in the second optical signal is obtained; and the bias voltage of the modulated optical signal is adjusted according to a predetermined step length, and the power change value of the low-frequency component with the predetermined step length is obtained, thereby realizing real-time monitoring of each modulated optical signal of the transmitted optical signal.

[0005] In a possible implementation, the method further includes: when it is determined that the difference in the change values ​​corresponding to any two modulated optical signals is greater than or equal to a first threshold, adjusting the amplitudes of at least two modulated optical signals until the difference in the change values ​​corresponding to any two modulated optical signals in the at least two modulated optical signals is less than the first threshold. The setting of the first threshold is mainly based on the parameter setting of the modulator. In this implementation, power balance of each modulated optical signal is achieved.

[0006] In a possible implementation, it also includes: obtaining the slope of the power of the low-frequency component changing with the predetermined step size, the slope S = △P / δ, wherein δ is the predetermined step size; P is the power of the low-frequency component; △P is the change value of the power of the low-frequency component when the bias voltage changes by δ; when it is determined that the difference in the slopes corresponding to any two modulated optical signals is greater than or equal to the second threshold, adjusting the amplitudes of at least two modulated optical signals until the difference in the slopes corresponding to any two modulated optical signals in at least two modulated optical signals is less than the second threshold. In this implementation, power balancing of each modulated optical signal is achieved. In addition, since the change value of the power of the low-frequency component is not obvious when the adjustment step size of the bias voltage is small, and the predetermined step size δ is also a small value, taking the ratio of △P / δ can amplify the difference between △P and improve the accuracy of power balancing control.

[0007] In a possible implementation, the method further includes: adjusting the amplitude of at least two of the modulated optical signals, including: controlling the amplitude of any modulated optical signal to remain constant and adjusting the amplitude of the other modulated optical signals. Specifically, the method further includes: adjusting the amplitude of the modulated optical signal to adjust the amplitude of the modulated optical signal.

[0008] In a possible implementation manner, the method further includes: adjusting the bias voltage to an initial value.

[0009] In a possible implementation, among the at least two modulated optical signals, any two modulated optical signals with the same polarization state have different phases; or any two modulated signals with the same phase have different polarization states.

[0010] In a second aspect, a transmission optical signal processing device of an optical signal transmission circuit is provided, comprising: a splitter, used to split the transmission optical signal output by the optical signal transmission circuit into a first optical signal and a second optical signal, wherein the transmission optical signal comprises at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating a carrier optical signal according to a predetermined modulation format; sending the first optical signal to an optical signal receiving circuit; a filter, used to obtain a low-frequency component of each modulated optical signal in the second optical signal; the processor, used to adjust the bias voltage of the modulated optical signal according to a predetermined step size; the processor is also used to obtain a change value of the power of the low-frequency component with the predetermined step size.

[0011] In a possible implementation, the processor is further configured to adjust the amplitudes of at least two of the modulated optical signals when it is determined that the difference in change values ​​corresponding to any two of the modulated optical signals is greater than or equal to a first threshold, until the difference in change values ​​corresponding to any two of the at least two modulated optical signals is less than the first threshold.

[0012] In a possible implementation, the processor is further configured to obtain a slope of the power of the low-frequency component changing with the predetermined step size, the slope S=△P / δ, wherein δ is the predetermined step size, P is the power of the low-frequency component, and △P is a change in the power of the low-frequency component when the bias voltage changes by δ; the processor is further configured to adjust the amplitudes of any two of the at least two modulated optical signals when it is determined that the difference in the slopes corresponding to any two of the modulated optical signals is greater than or equal to a second threshold, until the difference in the slopes corresponding to the at least two modulated optical signals is less than the second threshold.

[0013] In a possible implementation manner, the processor is specifically configured to control the amplitude of any one of the modulated optical signals to remain constant, and adjust the amplitudes of other modulated optical signals.

[0014] In a possible implementation manner, the processor is specifically configured to adjust an amplitude of a modulation signal of the modulated optical signal to adjust the amplitude of the modulated optical signal.

[0015] In a possible implementation, the processor is further configured to adjust the bias voltage to an initial value.

[0016] In a possible implementation, among the at least two modulated optical signals, any two modulated optical signals with the same polarization state have different phases; or any two modulated optical signals with the same phase have the same polarization state.

[0017] According to a third aspect, an optical signal transmitter is provided, comprising: an optical signal transmitting circuit and a transmitted optical signal processing device of the optical signal transmitting circuit.

[0018] In a fourth aspect, a communication device is provided, comprising the above-mentioned optical signal transmitter and a signal source, wherein the signal source is used to output an electrical signal to the optical signal transmitter, and the optical signal transmitting circuit in the optical signal transmitter is used to convert the electrical signal into the transmitted optical signal.

[0019] Among them, the technical effects brought about by any possible implementation method in the second to fourth aspects can refer to the technical effects brought about by different implementation methods in the above-mentioned first aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of the structure of an optical module provided in an embodiment of the present application;

[0021] Figure 2 A schematic diagram of the structure of an optical signal transmission circuit provided in an embodiment of the present application;

[0022] Figure 3 A schematic diagram of the structure of an optical signal transmitting circuit provided in another embodiment of the present application;

[0023] Figure 4 A schematic diagram of the structure of a modulator provided in an embodiment of the present application;

[0024] Figure 5 A schematic structural diagram of a modulator provided in another embodiment of the present application;

[0025] Figure 6 A schematic structural diagram of a modulator provided in yet another embodiment of the present application;

[0026] Figure 7 A schematic diagram of a modulation principle of a carrier optical signal provided in an embodiment of the present application;

[0027] Figure 8A schematic diagram of the structure of a transmitted optical signal processing device of an optical signal transmitting circuit is provided for an embodiment of the present application;

[0028] Fig. 9 A schematic diagram of a filtering principle is provided for an embodiment of the present application;

[0029] Fig.10 A curve diagram of a voltage difference δ between a bias voltage and a quad point and a power change ΔP of a signal is provided for an embodiment of the present application;

[0030] Fig.11 A schematic flow chart of a method for processing a transmitted optical signal of an optical signal transmitting circuit is provided for an embodiment of the present application;

[0031] Fig.12 A schematic flow chart of a method for processing a transmitted optical signal of an optical signal transmitting circuit is provided for another embodiment of the present application;

[0032] Fig.13 A schematic flow chart of a method for processing a transmitted optical signal of an optical signal transmitting circuit is provided for yet another embodiment of the present application. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0034] The embodiments of the present application are applied to an optical signal transmitter, which includes an optical signal transmitting circuit. The function of the optical signal transmitting circuit is to convert an electrical signal into an optical signal, and input the optical fiber for transmission to an optical signal receiving circuit. In addition, the embodiments of the present application can also be applied to an optical module, which is used for photoelectric conversion. The optical module is also called an optical transmission module. Figure 1 As shown, the optical module includes an optical signal transmitting circuit 11 and an optical signal receiving circuit 12. The function of the optical signal transmitting circuit 11 is to convert an electrical signal into an optical signal and input it into an optical fiber 13 for transmission. The function of the optical signal receiving circuit 12 is to receive the optical signal transmitted by the optical fiber 13 and convert it into an electrical signal. Figure 1 The optical signal transmitting circuit 11 and the optical signal receiving circuit 12 can multiplex the optical fiber 13. Of course, the optical signals of the optical signal transmitting circuit 11 and the optical signal receiving circuit 12 can also be transmitted in two optical fibers respectively. Usually, the optical module at the transmitting end converts the electrical signal into an optical signal, and after transmitting through the optical fiber, the optical module at the receiving end converts the optical signal into an electrical signal.

[0035] Among them, optical signal transmitters or optical modules are mainly used in Ethernet, fiber to the home (FTTH), optical transport network (OTN), network storage, data center and other fields. Based on the above application fields, optical signal transmitters or optical modules are mainly used in the above fields such as: optical line terminal (OLT), optical network unit (ONU), switch, fiber router, video optical terminal, fiber transceiver, fiber network card and other equipment. The communication equipment may also include a signal source for generating an electrical signal and inputting the electrical signal into the optical signal transmitter (or optical module). The optical signal transmitter converts the electrical signal into an optical signal and transmits it through an optical fiber. Among them, the optical signal transmitter and optical module support different rate classifications, such as: 1G~10G low rate, 25G, 40G, 50G, 100G, 200G / 400G, etc.

[0036] In order to realize the conversion of electrical signals into optical signals, an optical signal transmitting circuit is provided in the example of the present application. Figure 2 , Figure 3 As shown, it includes: a light source 21, a driver 23, and a modulator 24. The light source 21 is connected to the optical input port of the modulator 24, and the signal source 22 is connected to the electrical signal input port of the modulator 24 through the driver 23; the optical output port of the modulator 24 is connected to the output end out of the optical signal transmitting circuit. The light source 21 can be a laser (laser diode, LD, also known as a laser diode) for generating a carrier optical signal, and the signal source 22 is used to generate a transmitting electrical signal; the driver 23 is used to amplify the transmitting electrical signal to generate a modulation signal; and the modulator 24 is used to modulate the modulation signal onto the carrier optical signal to generate a modulated optical signal.

[0037] In addition, in order to realize multi-channel modulated optical signals, that is, multiplexing multiple modulated optical signals into the same transmission optical fiber, the embodiments of the present application can form modulated optical signals in different modulation modes. In this case, the optical signal transmission circuit can include multiple modulators 24 (such as Figure 2 The modulators 24-1 and 24-2 in Figure 3 Modulators 24-1, 24-2, 24-3, 24-4), wherein each modulator 24 is used to modulate a modulated optical signal; the signal source 22 can generate a transmission electrical signal corresponding to each modulator 24, and each modulator 24 supports a modulated optical signal. For example: any two modulated optical signals with the same polarization state have different phases; any two modulated signals with the same phase have different polarization states. Figure 3As shown, the optical signal transmission circuit may further include a polarizing beam splitter (PBS) 26 located between the light source 21 and the modulator 24, and a polarization beam combiner (PBC) 27 disposed at the output end of the modulator 24; wherein the PBS may split the carrier optical signal into optical signals with different polarization states and input the signals into the corresponding modulators 24. The PBC 27 is used to combine the modulated optical signals output by different modulators 24 into the same transmission optical fiber. In order to achieve different modulated optical signals having different phases, as shown in FIG. Figure 2 As shown, the optical output port of the modulator 24 - 2 is connected to the phase shifter 25 for performing phase shift on the modulated optical signal output by the modulator 24 - 2 .

[0038] Take quadrature amplitude modulation (QAM) as an example. Figure 2 As shown, the optical signal transmission circuit may include at least two modulators 24, wherein the optical output port of one modulator 24-1 is directly connected to the output end out of the transmission circuit, and the optical output port of the other modulator 24-2 is connected to the output port out of the transmission circuit through a phase shifter 25 (wherein the phase shifter 25 is a π / 2 phase shifter, which is used to perform a π / 2 phase shift on the optical signal output by the modulator 24-2), so that the modulated optical signal XI formed by the carrier optical signal output by the light source 21 after passing through the branch of the modulator 24-1 has a phase difference of π / 2 with the modulated optical signal XQ formed by the carrier optical signal output by the light source 21 after passing through the branch of the modulator 24-2, thereby realizing QAM modulation. Specifically, Figure 2Take the realization of two channels of modulated optical signals (XI, XQ) as an example, where XI and XQ differ in phase by 90°; wherein the carrier optical signal generated by the light source 21 is output to the modulator 24-1 and the modulator 24-2 respectively, and the signal source 22 is used to generate two transmission electrical signals XI-Amp and XQ-AMP; the driver 23 is used to amplify the transmission electrical signals XI-Amp and XQ-AMP respectively to generate modulated signals XI-Urf(t) and XQ-Urf(t); wherein the driver 23 independently amplifies the transmission electrical signals XI-Amp and XQ-AMP in the present application, that is, each transmission electrical signal can be amplified with a different gain multiple. In the embodiment of the present application, in order to implement the monitoring and balancing of each modulated optical signal, the driver amplifies each transmission electrical signal with a constant gain multiple, and each transmission electrical signal can be amplified with the same gain multiple. The modulator 24-1 modulates the modulation signal XI-Urf(t) onto the carrier optical signal to generate the modulated optical signal XI; the modulator 24-1 modulates the modulation signal XQ-Urf(t) onto the carrier optical signal and generates the modulated optical signal XQ after the phase is shifted by 90° through the π / 2 phase shifter 25.

[0039] In addition, refer to Figure 3 As shown, the embodiment of the present application can also realize modulated optical signals (XI, XQ, YI, YQ) of four channels, wherein the optical signal transmitting circuit also includes: PBS26, and PBC27, wherein PBS26 is arranged between the light source 21 and the modulator 24, and can split the carrier optical signal into two carrier optical signals X and Y with different polarization states, for example, the polarization directions of the carrier optical signals X and Y are perpendicular to each other. Then, the carrier optical signal X is transmitted to the corresponding modulator 24-1 and modulator 24-2 for modulation, forming modulated optical signals XI and XQ; the carrier optical signal Y is transmitted to the corresponding modulator 24-3 and modulator 24-4 for modulation, forming modulated optical signals YI and YQ. Finally, the polarization combiner 27 combines the optical signals to the output end out of the optical signal transmitting circuit.

[0040] The above embodiments describe in detail the modulation methods of two-channel and four-channel modulated optical signals. When more channels of modulated optical signals are required, the carrier optical signal of the light source 21 can be split into optical signals of more polarization states through PBS.

[0041] For the modulator 24, a Mach-Zehnder (MZ) modulator may be used, wherein the MZ modulator may be silicon photonics, lithium niobate LiNbO 3 , Indium Phosphide INP and other MZ modulators. Figure 4 , Figure 5 , Figure 6 As shown, the MZ modulator can be made of LiNbO 3The interferometer is formed by connecting waveguides A and B in parallel, which are formed by titanium diffusion on the surface of the crystal. The carrier optical signal Ein(t) is input into waveguides A and B through the input port C, and two polarized light waves with the same frequency but different phases are formed in waveguides A and B, and interfere at the output port D of waveguides A and B to obtain the modulated optical signal Eout(t). The applied voltage (i.e., modulation signal) Urf(t) to A and / or B can introduce phase changes that can be converted into amplitude changes. Figure 4 , Figure 5 , Figure 6 As shown, the modulation signal Urf(t) can be applied to either or both of waveguides A or B. In addition, the modulator needs to perform signal modulation at a stable DC bias operating point (quad point), so Figure 4 , Figure 5 , Figure 6 Also shown is the DC bias voltage Udc(t) applied by A and / or B, whose function is to adjust the DC bias operating point of the modulator. Figure 4 The Urf(t) inputted on waveguides A and B is in differential form, so the modulator works in push-pull mode to realize intensity modulation of the signals inputted on waveguides A and B. Figure 7 As shown, the modulation principle of the carrier optical signal is that the carrier optical signal changes its waveform (amplitude and phase) under the action of the input electrical signal Es (ie Urf(t)+Udc(t)) to generate a modulated optical signal Os.

[0042] Based on the above optical signal transmitting circuit, Figure 8 As shown, a schematic diagram of the structure of a transmitted optical signal processing device of an optical signal transmitting circuit is provided, including: a splitter 81, a filter 82 and a processor 83.

[0043] The optical splitter 81 is used to divide the transmitted optical signal output by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the transmitted optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optical modulation of the carrier optical signal according to a predetermined modulation format; and the first optical signal is sent to the optical signal receiver. The predetermined modulation format in the embodiment of the present application can be any one of the following modulation formats: quadrature phase shift keying (QPSK), 8QAM (quadrature amplitude modulation), 16QAM, 32QAM, 64QAM, 128QAM, 256QAM.

[0044] Filter 82 is used to obtain the low-frequency components of each modulated optical signal in the second optical signal. Wherein, filter 82 is a low-pass filter, that is, filter 82 has the characteristics of passing low frequencies and blocking high frequencies, so that the low-frequency components in the modulated optical signal pass through filter 82 through the filter, and the high-frequency AC components are filtered out. Wherein, the frequency range of the modulated optical signal is usually 0 to 80GHZ, which will be further increased with the upper limit of 80GHZ. The low-frequency component provided in the embodiment of the present application refers to the frequency range relative to the modulated optical signal, and the low-frequency component is the low-frequency part in the communication optical signal, for example, 0 to 1GHZ. In the simulation process of the following example, the frequency range of the low-frequency component is illustrated by taking 0 to 100KHZ as an example.

[0045] The processor 83 is used to adjust the bias voltage of the modulated optical signal according to a predetermined step length; the processor 83 is also used to obtain the change value of the power of the low-frequency component with the predetermined step length.

[0046] The bias voltage is the above-mentioned Udc(t), and the bias voltage Udc(t) is usually a fixed DC value Udc, and its value mainly depends on the curve of the modulation signal (that is, the amplitude of the transmitted electrical signal output by the above-mentioned signal source). The processor 83 can change the initial value Udc of the bias voltage according to a predetermined step length δu, for example, the bias voltage can be gradually reduced according to a predetermined step length δu, or the bias voltage can be gradually increased according to a predetermined step length; the processor 83 can use a photodiode to monitor the power of the low-frequency component of the modulated optical signal, for example, after the bias voltage of the modulated optical signal XI is reduced by a predetermined step length δu, the bias voltage is Udc-δu; the power P1 of the low-frequency component of the modulated optical signal XI when the bias voltage is Udc can be detected by the photodiode. XI , and the power P2 of the low-frequency component of the modulated optical signal XI when the bias voltage is Udc-δu XI , and the difference between the two is the change value δP XI .

[0047] Specifically, after the bias voltage of any modulated optical signal is adjusted, the specific description of obtaining the power change value of the low-frequency component of the modulated optical signal along with the predetermined step length is as follows:

[0048] Take the modulated optical signal XI as an example to illustrate, the power P of the low-frequency component of the modulated optical signal XI XI It can be expressed as:

[0049] P XI =(XI_Amp*GXI*AttXI) 2 *F_f+DC(Udc)(Formula 1).

[0050] XI_Amp: The amplitude of the transmitted electrical signal XI-Amp, expressed in Figure 3Taking the optical signal transmitting circuit shown as an example, the initial values ​​of the four-way transmitting electrical signal are set to be consistent, that is, (XI-Amp) = (XQ-Amp) = (YI-Amp) = (YQ-Amp); GXI: is the gain of the transmitting electrical signal XI-Amp. In the embodiment of the present application, the four-way gain is set to be consistent; AttXI: is the insertion loss of the modulated optical signal XI. For the modulated optical signal XI, it is a fixed value. Since the devices passed by each optical signal are different, the insertion losses between the four paths are inconsistent; the square of the product of the above three items XI_Amp, GXI and AttXI is the total power of the modulated optical signal XI. F_f is the filter power conversion coefficient, which is a constant, where F is the bandwidth of the modulated optical signal, and f is the bandwidth of the low-frequency component output by the filter 82. DC (Udc): is a function of the DC bias voltage Udc, which depends on the curve of the modulation signal, and the bias voltage is changed by adjusting Udc. Among them, the power P of the low-frequency component of the modulated optical signal XQ XQ , the power P of the low-frequency component of YI YI And the power P of the low-frequency component of YQ YQ The calculation method is similar to P XI similar.

[0051] Combined with the above description, the total power P of the modulated optical signal is related to the amplitude Amp of the transmitted electrical signal, the gain multiple G of the driver, and the insertion loss Att. Fig. 9 As shown in FIG. 8 , after low-pass filtering by filter 82, the power of the low-frequency component of the modulated optical signal is P', P / P'=F / f, F is the bandwidth of the modulated optical signal, and f is the bandwidth of the optical signal with low-frequency components after filtering. When the modulator bias voltage Udc changes slightly around the quad point, the electro-optical conversion curve (or modulation curve) can be regarded as linear. At this time, changing the bias voltage Udc will only change the DC power in the modulated optical signal, and will have no effect on the non-DC components. The simulation results are shown in FIG. Fig.10 As shown, Fig.10 The horizontal axis x in the figure represents the voltage difference δ between the bias voltage and the quad point, and the vertical axis y represents the power change △P of the signal when the bias voltage is changed. Fig.10 It can be seen that when the bias voltage Udc is changed, the change values ​​of the total signal power P and the total low-frequency component power P' are exactly the same, that is, a slight change of Udc around the quad point will only change the DC component in the modulated optical signal, but has little effect on the non-DC component.

[0052] When the bias voltages of the four channels are all Udc, the total power of the low-frequency components of the four-channel modulated optical signals is P'=P XI (Udc)+P XQ (Udc)+P YI (Udc)+P YQ(Udc); When the bias voltage of the modulated optical signal XI is set to Udc + δ, the bias voltages of the other three modulated optical signals remain unchanged. At this time, the total power of the low-frequency components of the four modulated optical signals is P XI (Udc+δ)+P XQ (Udc)+P YI (Udc)+P YQ (Udc), subtracting the two to obtain the power change value △P of the low-frequency component of the modulated optical signal XI with the predetermined step length XI =P XI (Udc+δ)-P XI (Udc), △P can be obtained by the same method XQ , △P YI , △P YQ In this way, by detecting the four modulated optical signals respectively through a photodiode, the power change value of the low-frequency component of each modulated optical signal with the predetermined step length can be detected.

[0053] Usually, the bias voltage is a fixed value, but the DC bias point of the modulator will "drift" as the ambient temperature changes, causing the performance of the transmission system to deteriorate. Therefore, a low-frequency perturbation signal (that is, dither) is usually added to the bias voltage Udc of the modulator to monitor and adjust the DC bias operating point of the modulator (referred to as the bias point) so that the modulator always works in the correct state, that is, the quad point, such as Figure 7 The DC bias operating point shown. Assuming that the bias voltage Udc of the modulator is 3.5V, the dither amplitude is 0.1V, and the frequency is 1KHz of a sine or square wave signal, then Udc will swing around the quad point at a frequency of 1KHz. In the embodiments of the present application, the perturbation signal can be reused, and the frequency and amplitude of the dither signal can be adjusted to form a predetermined step length to adjust the bias voltage. Alternatively, a separate circuit can be added to generate the predetermined step length to adjust the bias voltage. It should be noted that when implementing the solution provided in the embodiments of the present application, the existing perturbation signal dither needs to be suspended.

[0054] In the embodiment of the present application, the optical splitter in the optical signal processing device of the optical signal transmitting circuit can divide the optical signal transmitted by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the optical signal transmitted includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optical modulation of the carrier optical signal according to a predetermined modulation format; the first optical signal is sent to the optical signal receiving circuit; the filter can obtain the low-frequency component of each modulated optical signal in the second optical signal; the processor can adjust the bias voltage of the modulated optical signal according to a predetermined step length, and obtain the power change value of the low-frequency component with the predetermined step length. Thus, real-time monitoring of each modulated optical signal of the transmitted optical signal is realized.

[0055] Since the insertion loss of each modulated optical signal is not consistent, the △P calculated by formula 1 is XI , △P XQ , △P YI , △P YQ The power of the modulated optical signal is not equal to that of the modulated optical signal due to the inconsistent insertion loss. Figure 8 As shown, in order to achieve power balance of each modulated optical signal: the processor 83 is used to determine that when the difference in the change values ​​corresponding to any two modulated optical signals is greater than or equal to the first threshold, adjust the amplitudes of at least two modulated optical signals until the difference in the change values ​​corresponding to any two modulated optical signals in at least two modulated optical signals is less than the first threshold. The setting of the first threshold is mainly based on the parameter setting of the modulator. Specifically, the processor 83 is specifically used to control the amplitude of any modulated optical signal to remain constant and adjust the amplitudes of other modulated optical signals. The processor 83 is specifically used to adjust the amplitude of the modulated signal of the modulated optical signal to adjust the amplitude of the modulated optical signal. For example, the amplitude of the modulated optical signal XI is kept constant, that is, the amplitude of the modulated signal of the modulated optical signal XI is not adjusted, and the amplitudes of the modulated signals of the modulated optical signals XQ, YI, and YQ are adjusted in turn until △P XI , △P XQ , △P YI , △P YQ The difference between the two values ​​is less than the first threshold (for example, △P XI , △P XQ , △P YI , △P YQ All are equal), thereby achieving power balance of each modulated optical signal. Wherein, the modulated signal is the signal after the transmission electrical signal emitted by the signal source is amplified by the driver, so the processor can adjust the amplitude of the modulated optical signal by adjusting the amplitude of the transmission electrical signal through the signal source.

[0056] In addition, since the change in the power of the low-frequency component is not obvious when the adjustment step size of the bias voltage is small, in order to improve the accuracy of power balancing control, in an embodiment of the present application, the processor 83 is also used to obtain the slope of the power of the low-frequency component changing with the predetermined step size, the slope S = △P / δ, wherein δ is the predetermined step size, P is the power of the low-frequency component, and △P is the change in the power of the low-frequency component when the bias voltage changes by δ.

[0057] Combined with the above formula 1, formula 1 can be transformed into: P XI =S(XI_Amp,AttXI)+DC(Udc) (Formula 2).

[0058] Then P XI Considered as a linear function of Udc, S(XI_Amp, AttXI) is a function of the insertion loss and the amplitude of the transmitted electrical signal XI-Amp. For the modulated optical signal XI, S(XI_Amp, AttXI) = S XI is a constant, and S can be changed by adjusting the amplitude of the transmitting electrical signal XI-Amp. XI . Since the △P difference between the four modulated optical signals may be very small, the change in the power of the low-frequency component is not obvious enough, which will affect the accuracy of power balancing control. The predetermined step size δ is also a small value, so taking the ratio of the two can amplify the difference between △P, that is, △P / δ. Processor 83 is used to adjust the amplitude of at least two modulated optical signals when it is determined that the difference in the slopes corresponding to any two modulated optical signals is greater than or equal to the second threshold, until the difference in the slopes corresponding to at least two of the modulated optical signals is less than the second threshold. In this way, since δ is small enough, the slope S=△P / δ can be amplified. Processor 83 is specifically used to control the amplitude of any modulated optical signal to remain constant and adjust the amplitudes of other modulated optical signals. Processor 83 is specifically used to adjust the modulation voltage of the modulated optical signal to adjust the amplitude of the modulated optical signal. For example, the amplitude of the modulated optical signal XI is kept constant, that is, the amplitude of the modulated signal of the modulated optical signal XI is not adjusted, and the amplitudes of the modulated signals of the modulated optical signals XQ, YI, and YQ are adjusted in turn until S XI , S XQ , S YI , S YQ The difference between the two is less than the second threshold (for example, S XI , S XQ , S YI , S YQ all equal).

[0059] Based on the above optical signal transmission circuit, refer to Fig.11 As shown, an embodiment of the present application provides a method for processing a transmitted optical signal of an optical signal transmitting circuit, comprising the following steps:

[0060] 101. Divide a transmission optical signal output by an optical signal transmission circuit into a first optical signal and a second optical signal, wherein the transmission optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating a carrier optical signal according to a predetermined modulation format.

[0061] 102. Send a first optical signal to an optical signal receiving circuit.

[0062] 103. Obtain a low-frequency component of each modulated optical signal in the second optical signal.

[0063] 104. Adjust the bias voltage of the modulated optical signal according to a predetermined step size.

[0064] 105. Obtain a change value of the power of the low-frequency component with a predetermined step length.

[0065] In the embodiment of the present application, the optical splitter in the optical signal processing device of the optical signal transmitting circuit can divide the optical signal transmitted by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the optical signal transmitted includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optical modulation of the carrier optical signal according to a predetermined modulation format; the first optical signal is sent to the optical signal receiving circuit; the filter can obtain the low-frequency component of each modulated optical signal in the second optical signal; the processor can adjust the bias voltage of the modulated optical signal according to a predetermined step length, and obtain the power change value of the low-frequency component with the predetermined step length. Thus, real-time monitoring of each modulated optical signal of the transmitted optical signal is realized.

[0066] In one embodiment, referring to Fig.12 As shown, Fig.11 The corresponding solutions are different in that the optical signal transmission circuit provided in the embodiment provides a method for processing a transmitted optical signal, and further includes power compensation for the modulated optical signal, which specifically includes the following steps:

[0067] 201. Split a transmission optical signal output by an optical signal transmission circuit into a first optical signal and a second optical signal.

[0068] The transmitted optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating a carrier optical signal according to a predetermined modulation format.

[0069] 202. Send a first optical signal to an optical signal receiving circuit.

[0070] 203. Obtain a low-frequency component of each modulated optical signal in the second optical signal.

[0071] 204. Adjust the bias voltage of the modulated optical signal according to a predetermined step size.

[0072] 205. Obtain a change value of the power of the low-frequency component with a predetermined step length.

[0073] 206. When it is determined that the difference between the change values ​​corresponding to any two modulated optical signals is greater than or equal to the first threshold, adjust the amplitudes of at least two modulated optical signals until the difference between the change values ​​corresponding to any two of the at least two modulated optical signals is less than the first threshold.

[0074] Wherein, step 206 specifically includes controlling the amplitude of any modulated optical signal to remain constant and adjusting the amplitude of other modulated optical signals. Furthermore, the amplitude of the modulated optical signal is adjusted by adjusting the amplitude of the modulated signal of the modulated optical signal.

[0075] 207. Adjust the bias voltage to an initial value.

[0076] For example, adjust the bias voltage to Quad, or when the dither signal is multiplexed to adjust the bias voltage, switch the dither signal back to monitor and adjust the DC bias operating point of the modulator.

[0077] In this way, after steps 201-206, the balanced control of the modulated optical signal is realized, and then the bias voltage is restored to the initial value, that is, the DC bias operating point of the modulator, and the next monitoring and power balancing are started.

[0078] In one embodiment, referring to Fig.13 As shown, Fig.11 The corresponding solutions are different in that the optical signal transmission circuit provided in the embodiment provides a method for processing a transmitted optical signal, and further includes power compensation for the modulated optical signal, which specifically includes the following steps:

[0079] 301. Divide a transmission optical signal output by an optical signal transmission circuit into a first optical signal and a second optical signal, wherein the transmission optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating a carrier optical signal according to a predetermined modulation format.

[0080] 302. Send the first optical signal to an optical signal receiving circuit.

[0081] 303. Obtain a low-frequency component of each modulated optical signal in the second optical signal.

[0082] 304. Adjust the bias voltage of the modulated optical signal according to a predetermined step size.

[0083] 305. Obtain a change value of the power of the low-frequency component with a predetermined step length.

[0084] 306. Obtain a slope of the power of the low-frequency component changing with a predetermined step length.

[0085] Slope S=δP / δVb, wherein δVb is the predetermined step length, Vb is the bias voltage, P is the power of the low-frequency component, and δP is the change value of the power of the low-frequency component when the bias voltage changes by δVb;

[0086] 307. When it is determined that the difference between the slopes corresponding to the at least two modulated optical signals is greater than or equal to the second threshold, adjust the amplitudes of the at least two modulated optical signals until the difference between the slopes corresponding to any two of the at least two modulated optical signals is less than the second threshold.

[0087] Wherein, step 307 specifically includes controlling the amplitude of any modulated optical signal to remain constant and adjusting the amplitude of other modulated optical signals. Furthermore, the amplitude of the modulated optical signal is adjusted by adjusting the amplitude of the modulated signal of the modulated optical signal.

[0088] 308. Adjust the bias voltage to an initial value.

[0089] For example, adjust the bias voltage to Quad, or when the dither signal is multiplexed to adjust the bias voltage, switch the dither signal back to monitor and adjust the DC bias operating point of the modulator.

[0090] In this way, after steps 301-307, the balanced control of the modulated optical signal is realized, and then the bias voltage is restored to the initial value, that is, the DC bias operating point of the modulator, and the next monitoring and power balancing are started.

[0091] Among them, due to the above Figure 8 The optical signal transmitting circuit of the optical signal transmitting device is used to implement the above Figure 11-13 The optical signal transmitting circuit of the provided optical signal transmitting signal processing method, therefore, Figure 11-13 The specific description of each step of the method for processing the transmitted optical signal of the provided optical signal transmitting circuit can refer to the description of the functions of each unit or module in the transmitted optical signal processing device of the above-mentioned optical signal transmitting circuit, and the technical effects achieved can also refer to the corresponding description in the transmitted optical signal processing device of the above-mentioned optical signal transmitting circuit.

[0092] Although the present application has been described in conjunction with specific features and embodiments thereof, it is obvious that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and the drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are deemed to have covered any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for processing a transmitted optical signal of an optical signal transmitting circuit, characterized in that: include: Splitting the transmitted optical signal output by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the transmitted optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating a carrier optical signal according to a predetermined modulation format; Sending the first optical signal to an optical signal receiving circuit; Acquire a low-frequency component of each of the modulated optical signals in the second optical signal; adjusting the bias voltage of the modulated optical signal according to a predetermined step size; Obtaining a change value of the power of the low-frequency component with the predetermined step length; When it is determined that the difference between the change values ​​corresponding to any two of the modulated optical signals is greater than or equal to the first threshold, the amplitudes of at least two of the modulated optical signals are adjusted until the difference between the change values ​​corresponding to any two of the at least two modulated optical signals is less than the first threshold; or, the slope of the power of the low-frequency component changing with the predetermined step size is obtained, the slope S=△P / δ, wherein δ is the predetermined step size; P is the power of the low-frequency component; △P is the change value of the power of the low-frequency component when the bias voltage changes by δ; when it is determined that the difference between the slopes corresponding to any two of the modulated optical signals is greater than or equal to the second threshold, the amplitudes of at least two of the modulated optical signals are adjusted until the difference between the slopes corresponding to any two of the at least two modulated optical signals is less than the second threshold.

2. The method for processing a transmitted optical signal of an optical signal transmitting circuit according to claim 1, characterized in that: The adjusting the amplitudes of at least two of the modulated optical signals comprises: The amplitude of any one of the modulated optical signals is controlled to remain constant, and the amplitudes of the other modulated optical signals are adjusted.

3. The method for processing a transmitted optical signal of an optical signal transmitting circuit according to claim 1, characterized in that: Also includes: The amplitude of the modulated signal of the modulated optical signal is adjusted to adjust the magnitude of the modulated optical signal.

4. The method for processing a transmitted optical signal of an optical signal transmitting circuit according to claim 1, characterized in that: Also includes: The bias voltage is adjusted to an initial value.

5. The method for processing a transmitted optical signal of an optical signal transmitting circuit according to claim 1, characterized in that: Among the at least two modulated optical signals, any two modulated optical signals with the same polarization state have different phases; or any two modulated optical signals with the same phase have different polarization states.

6. A transmission light signal processing device of an optical signal transmission circuit, characterized in that: include: An optical splitter is used to split the transmitted optical signal output by the optical signal transmitting circuit into a first optical signal and a second optical signal, wherein the transmitted optical signal includes at least two modulated optical signals, wherein the modulated optical signal is generated by electro-optically modulating the carrier optical signal according to a predetermined modulation format; and send the first optical signal to the optical signal receiving circuit; A filter, used for obtaining a low-frequency component of each of the modulated optical signals in the second optical signal; A processor, configured to adjust a bias voltage of the modulated optical signal according to a predetermined step size; The processor is further configured to obtain a change value of the power of the low-frequency component with respect to the predetermined step length; The processor is further configured to, when it is determined that the difference between the change values ​​corresponding to any two of the modulated optical signals is greater than or equal to a first threshold, adjust the amplitudes of at least two of the modulated optical signals until the difference between the change values ​​corresponding to any two of the at least two modulated optical signals is less than the first threshold; or, the processor is further configured to obtain a slope of the power of the low-frequency component changing with the predetermined step size, wherein the slope S=ΔP / δ, wherein δ is the predetermined step size, P is the power of the low-frequency component, and ΔP is a change value of the power of the low-frequency component when the bias voltage changes by δ; the processor is further configured to, when it is determined that the difference between the slopes corresponding to any two of the modulated optical signals is greater than or equal to a second threshold, adjust the amplitudes of any two of the at least two modulated optical signals until the difference between the slopes corresponding to the at least two of the modulated optical signals is less than the second threshold.

7. The transmission light signal processing device of the optical signal transmission circuit according to claim 6, characterized in that: The processor is specifically used to control the amplitude of any of the modulated optical signals to remain constant and adjust the amplitudes of other modulated optical signals.

8. The transmitted optical signal processing device of the optical signal transmitting circuit according to claim 6, characterized in that: The processor is specifically configured to adjust the amplitude of the modulated signal of the modulated optical signal to adjust the amplitude of the modulated optical signal.

9. The transmission light signal processing device of the optical signal transmission circuit according to claim 6, characterized in that: The processor is further configured to adjust the bias voltage to an initial value.

10. The transmission light signal processing device of the optical signal transmission circuit according to claim 6, characterized in that: Among the at least two modulated optical signals, any two modulated optical signals with the same polarization state have different phases; or any two modulated optical signals with the same phase have the same polarization state.

11. An optical signal transmitter, characterized in that: include: An optical signal transmitting circuit and a transmitted optical signal processing device of the optical signal transmitting circuit as claimed in any one of claims 6 to 10.

12. A communication device, characterized in that: It comprises the optical signal transmitter and a signal source as claimed in claim 11, wherein the signal source is used to output an electrical signal to the optical signal transmitter, and the optical signal transmitting circuit in the optical signal transmitter is used to convert the electrical signal into the transmitting optical signal.

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