Polarization equalization emission assembly based on coherent light silicon optical chip

Abstract

The utility model relates to the technical field of optical fiber communication, and discloses a polarization equalization transmitting assembly based on a coherent light silicon optical chip, which adopts a second optical splitter with an adjustable splitting ratio to split input continuous light and equalizes output light power of two paths of coherent light of X polarized light and Y polarized light. The two paths of coherent light of X polarized light and Y polarized light can be pre-adjusted only by adjusting the splitting ratio of the second optical splitter, optical power balance is achieved, high-speed electro-optical modulators in the two paths of coherent light do not need to be adjusted, the high-speed electro-optical modulators can be kept in the optimal state, an adjustable optical attenuator does not need to be additionally arranged in the two paths of coherent light, and the optical power balance is achieved. The utility model has the effects of improving the output power of the transmitting assembly, reducing the self power consumption of the transmitting assembly and improving the utilization efficiency of the high-speed photoelectric driver, and is more suitable for a small-sized packaged coherent optical module based on a coherent optical silicon optical chip.

Description

Technical Field

[0001] This utility model relates to the field of optical fiber communication technology, specifically, it is a polarization equalization transmission component based on a coherent silicon photonic chip. Background Technology

[0002] Coherent optical communication technology has become the mainstream technology for high-speed, high-capacity, and long-distance optical fiber communication and is widely used. Among them, coherent silicon photonics chips, with their advantages of small size, high integration, and low cost, have been widely used in coherent optical fiber transmission systems and devices, especially small-packaged coherent optical modules, such as the industry-standard OSFP and QSFP-DD coherent optical modules.

[0003] Industry-standard coherent optical signals employ polarization multiplexing (PM), which involves splitting the single-polarized light emitted from the signal source into X- and Y-polarized light, modulating them separately, and then combining the X- and Y-polarized light using the principle that orthogonally polarized light does not interfere with each other, thereby doubling the bit rate of light transmission at the same wavelength.

[0004] Coherent optical silicon photonics chips utilize silicon-based semiconductor technology to integrate and fabricate on a silicon wafer the components needed to generate coherent optical signals, including beam splitters, high-speed electro-optic modulators, optical phase controllers, X / Y polarization combiners, and various components used in coherent receivers.

[0005] Figure 1This diagram illustrates the principle of a conventional coherent silicon photonics chip transmitter. This conventional transmitter includes a first beam splitter, a second beam splitter, a high-speed electro-optic modulator, a polarization rotator, and a polarization combiner. Continuous wave (CW) light emitted from the local oscillator laser enters through the chip's input port. The first beam splitter splits a small portion of the light to the receiver for coherent reception. The remaining light is input to the second beam splitter and split into two beams at a fixed splitting ratio. The two optical signals pass through high-speed electro-optic modulators on their respective paths to form X-polarized and Y-polarized coherent light. The Y-polarized light is rotated by the polarization rotator to be orthogonal to the X-polarized light and then combined with the X-polarized light in the polarization combiner to output a polarization-multiplexed coherent optical signal. Ideally, the performance is best when the X-polarized and Y-polarized signals of the transmitter are perfectly balanced; therefore, the fixed splitting ratio of the second beam splitter is typically set to 50:50 (i.e., 50% to 50%). However, due to the inherent randomness in the fabrication process of coherent silicon photonics chips, even if the optical devices and optical path designs for X-polarized and Y-polarized signals are the same, the actual power of the obtained X-polarized optical signal and Y-polarized optical signal will still differ. Furthermore, the Y-polarized optical signal requires an additional polarization rotator, and the final polarization combiner results in greater losses for the Y-polarized optical signal than for the X-polarized optical signal.

[0006] Considering the above factors, when using a second beam splitter with a fixed splitting ratio (typically 50:50) for X-polarized and Y-polarized beam splitting, the X-polarized and Y-polarized light signals will exhibit different insertion losses (IL). Existing coherent silicon photonic chips primarily employ two methods to achieve equalization of X-polarized and Y-polarized light signals at the output port of the transmitting component.

[0007] The first method, such as Figure 1 As shown, tunable optical attenuators are added to the X-polarized and Y-polarized optical paths. The amount of optical attenuation in the X-polarized and Y-polarized optical paths is controlled by adjusting the current applied to the optical attenuators, thereby achieving equalization of X-polarized and Y-polarized optical signals. This method has three main drawbacks: First, the optical attenuators introduce additional losses to the optical signal, wasting hard-won optical power and leading to a decrease in the final output optical power of the transmitting component; second, additional optical attenuation devices need to be added to the coherent silicon photonics chip; and third, the current applied to the tunable optical attenuators increases the power consumption of the coherent silicon photonics chip.

[0008] The second method achieves equalization of X-polarized and Y-polarized optical signals by adjusting the amplitude of the high-speed electro-modulation signal applied to the high-speed electro-optic modulators of the X-polarized and Y-polarized optical signals. The drawback of this method is that it reduces the utilization efficiency of the high-speed photoelectric driver that generates the high-speed electro-modulation signal, thereby leading to a decrease in the final output optical power of the transmitting component.

[0009] Therefore, in order to reduce power consumption and improve the utilization rate of high-speed optoelectronic drivers, it is necessary to improve the coherent light polarization equalization emission component. Utility Model Content

[0010] The purpose of this invention is to provide a polarization equalization emission component based on a coherent silicon photonic chip. At the front end of the two coherent light beams, the original fixed-ratio beam splitter is replaced with an adjustable-ratio beam splitter. Equalization of the X-polarized and Y-polarized coherent light beams is achieved by adjusting the pre-split ratio. This invention only requires adjusting the splitting ratio of the second beam splitter to achieve equalization, eliminating the need to adjust the high-speed electro-optic modulator in the two coherent light beams. This allows the high-speed electro-optic modulator to maintain optimal performance. Furthermore, it eliminates the need for additional adjustable optical attenuators in the two coherent light beams. This results in increased output power of the emission component, reduced power consumption of the emission component itself, and improved utilization efficiency of the high-speed photoelectric driver. It is particularly suitable for small-packaged coherent optical modules based on coherent silicon photonic chips.

[0011] This utility model is achieved through the following technical solution.

[0012] A polarization-equalized emission component based on a coherent silicon photonic chip includes a first beam splitter, a second beam splitter, a high-speed electro-optic modulator, a polarization rotator, and a polarization combiner. A continuous beam of light is split into two beams after passing through the first and second beam splitters. The two optical signals are respectively converted into X-polarized light and Y-polarized light coherent optical signals by the high-speed electro-optic modulators on their respective optical paths. The Y-polarized light is rotated by the polarization rotator to be orthogonal to the X-polarized light, and then combined with the X-polarized light in the polarization combiner to form a polarization-multiplexed coherent optical signal and output. The second beam splitter is an adjustable beam splitter used to adjust the splitting ratio of the two coherent beams to make the output optical power of the X-polarized light and Y-polarized light coherent beams equal.

[0013] To further implement this utility model, the second beam splitter includes a first beam splitting unit, a phase control unit, and a multiplexing unit;

[0014] The first beam splitting unit uses a fixed beam splitter with a splitting ratio of 50:50 to split one continuous light input from the first beam splitter into two optical signals with equal power in a 50:50 ratio.

[0015] The phase control unit comprises two units, which are respectively located on the two optical paths output by the first beam splitter. They are used to change the beam splitting ratio by generating a phase difference between the two optical signals through phase modulation, and then send the two phase-modulated optical signals to the multiplexing unit.

[0016] The multiplexing unit uses a 4-port 50:50 multiplexer to combine two phase-modulated optical signals into two output optical signals.

[0017] The aforementioned first beam splitting unit, phase control unit, and combiner unit constitute an MZ interferometer. According to the principle of the MZ interferometer, the optical power ratio of the two optical signals output by the combining unit changes with the phase difference generated by the phase control unit, thereby realizing a beam splitter with adjustable beam splitting ratio.

[0018] To better realize this utility model, the second beam splitter further includes two beam splitting detection units; the two beam splitting detection units are respectively set on the two optical paths output by the beam combiner unit, and are used to sample and detect the output light of each optical path and then feed back the optical power ratio of the two output lights to the phase control unit.

[0019] To better realize this utility model, the spectral detection unit further includes a sampling beam splitter and a sampling light detector; the sampling beam splitter splits the sampling light and sends it to the sampling light detector for detection.

[0020] To better realize this utility model, the splitting ratio of the sampling beam splitter is 99:1 or 98:2, and the sampling beam splitter sends the sampling light with lower power to the sampling light detector for detection.

[0021] To better realize this utility model, the two phase control units are further referred to as: a first phase controller and a second phase controller; the first phase controller independently modulates one optical signal split by the first beam splitter through a first control signal; the second phase controller independently modulates the other optical signal split by the first beam splitter through a second control signal.

[0022] To better realize this utility model, the first phase controller and the second phase controller further modulate the two optical signals with the same amplitude and opposite direction.

[0023] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0024] Since the pre-adjustment can be performed through the second beam splitter with adjustable splitting ratio, when equalizing the X-polarized and Y-polarized optical signals, there is no need to adjust the high-speed electro-modulation signal in the X-polarized XI / XQ modulator or the Y-polarized YI / YQ modulator. This allows the high-speed electro-optic modulator to be maintained in the optimal state, avoiding damage to the optical power output of the transmitting component, and thus improving the performance of the output optical signal of the transmitting component.

[0025] There is no need to add an adjustable optical attenuator to the transmitting component, which can reduce the power consumption of the transmitting component itself and avoid damage to the optical power output of the transmitting component, thereby improving the performance of the output optical signal of the transmitting component. Attached Figure Description

[0026] This utility model will be further described in conjunction with the following drawings and embodiments. All inventive concepts of this utility model should be considered as the disclosed content and the scope of protection of this utility model.

[0027] Figure 1 This is a schematic diagram of an existing coherent silicon photonic chip emission assembly.

[0028] Figure 2 This is a schematic diagram of Embodiment 1 of the polarization equalization emission component based on coherent silicon photonics chip in this application.

[0029] Figure 3 for Figure 2 A schematic diagram of the second beam splitter.

[0030] Figure 4 This is a schematic diagram of the second beam splitter in Embodiment 2 of the polarization equalization emission component based on coherent silicon photonics chip in this application.

[0031] Figure 5 For adopted Figure 1 A schematic diagram showing the variation of the output optical power of the coherent silicon photonic chip in the transmitting component with the amplitude of the high-speed electrical modulation signal.

[0032] Figure 6 This is a schematic diagram showing the change in output optical power of a coherent silicon photonic chip using Embodiment 4 of this application as the transmitting component as a function of a high-speed electrical modulation signal. Detailed Implementation

[0033] Example 1:

[0034] This embodiment provides a polarization-equalized emission component based on a coherent silicon photonic chip, such as... Figure 2 As shown, the system includes a first beam splitter, a second beam splitter, a high-speed electro-optic modulator, a polarization rotator, and a polarization combiner. A continuous beam of light is split into two beams after passing through the first and second beam splitters. The two beams are then converted into X-polarized and Y-polarized coherent optical signals by high-speed electro-optic modulators on their respective paths. The Y-polarized light is rotated by a polarization rotator to be orthogonal to the X-polarized light and then combined with the X-polarized light in the polarization combiner to form a polarization-multiplexed coherent optical signal, which is then output. The second beam splitter is an adjustable splitter, used to adjust the splitting ratio of the two coherent beams, ensuring balanced output power for both the X-polarized and Y-polarized beams. The four high-speed electro-optic modulators are an X-polarized XI / XQ modulator and a Y-polarized YI / YQ modulator.

[0035] The transmitting component described in this embodiment only needs to adjust the splitting ratio of the second beam splitter to achieve balanced adjustment of the output optical power of the two coherent beams, X-polarized light and Y-polarized light, without adjusting the high-speed electro-optic modulator in the two coherent beams;

[0036] The transmitting component described in this embodiment does not require adjustment of the high-speed electro-optic modulator in the two coherent beams, so that the high-speed electro-optic modulator can be maintained in the optimal state, thereby improving the output power of the transmitting component, reducing the power consumption of the transmitting component itself, and improving the utilization efficiency of the high-speed photoelectric driver.

[0037] The transmitting component described in this embodiment is relative to, for example, Figure 1 The prior art shown sets the second beam splitter used for coherent light splitting as a beam splitter with an adjustable splitting ratio, and there is no need to set up an adjustable light attenuator.

[0038] Therefore, the transmitting component described in this embodiment is more suitable for small-packaged coherent optical modules based on coherent silicon photonic chips.

[0039] Example 2:

[0040] This embodiment describes the second beam splitter in detail, based on Embodiment 1.

[0041] like Figure 3 As shown, in this embodiment, the second beam splitter with adjustable splitting ratio is based on the Mach-Zehnder interferometer principle and includes a first beam splitting unit, a phase control unit, and a beam combining unit. The two phase control units are a first phase controller and a second phase controller; the Mach-Zehnder interferometer is an interferometer.

[0042] The first beam splitting unit uses a fixed beam splitter with a splitting ratio of 50:50 to split one continuous light input from the first beam splitter into two optical signals with the same optical power at a fixed splitting ratio of 50:50.

[0043] The phase control unit comprises two units, which are respectively located on the two optical paths output by the first beam splitter. They are used to change the beam splitting ratio by generating a phase difference between the two optical signals through phase modulation, and then send the two phase-modulated optical signals to the multiplexing unit.

[0044] The beam combiner unit uses a 4-port 50:50 beam combiner to combine two phase-modulated beams into two output beams and output them to their respective optical paths via high-speed electro-optic modulators.

[0045] The aforementioned first beam splitting unit, phase control unit, and combiner unit constitute an MZ interferometer. According to the principle of the MZ interferometer, the optical power ratio of the two optical signals output by the combining unit changes with the phase difference generated by the phase control unit, thereby realizing a beam splitter with adjustable beam splitting ratio.

[0046] In this embodiment, when it is necessary to equalize the two polarized beams output by the transmitting component, the phase difference between the two polarized beams is created by adjusting the control signals of the first phase controller and the second phase controller in the second beam splitter, so as to adjust the phase change of the two phase control units, thereby achieving equalization of the two polarized beams while maintaining the output power of the transmitting component.

[0047] Further optionally, in this embodiment, the second beam splitter further includes two beam splitter detection units; the two beam splitter detection units are respectively disposed on the two optical paths output by the beam combiner unit, and are used to sample and detect the output light of each optical path and then feed back the optical power ratio of the two output lights to the phase control unit.

[0048] Using this embodiment, the optical power ratio of X-polarized light and Y-polarized light can be detected. This ratio can be used to further adjust the splitting ratio of the second beam splitter to compensate and correct it. When the splitting ratio of the second beam splitter changes due to factors such as changes in the wavelength of the optical signal or changes in the ambient temperature of the transmitting component, the X-polarized and Y-polarized light signals can be balanced.

[0049] Further optional, in this embodiment, such as Figure 4 As shown, the beam splitting detection unit includes a sampling beam splitter and a sampling light detector; the sampling beam splitter splits the sampling light and sends it to the sampling light detector for detection.

[0050] Using this embodiment, only a portion of the optical power needs to be separated to obtain the ratio of X-polarized light to Y-polarized light power. Based on this ratio, the splitting ratio of the second beam splitter can be further compensated and corrected.

[0051] Alternatively, in this embodiment, the splitting ratio of the sampling beam splitter is 99:1 or 98:2, and the sampling beam splitter sends the lower-power sampling light to the sampling light detector for detection.

[0052] Using this embodiment, only a small amount of optical power needs to be separated to obtain the optical power ratio of X-polarized light and Y-polarized light. Based on this ratio, the splitting ratio of the second beam splitter can be further compensated and corrected.

[0053] Further optionally, in this embodiment, the first phase controller and the second phase controller perform phase modulation on the two optical signals with the same amplitude and opposite directions.

[0054] In this embodiment, when two phase controllers simultaneously adjust their respective optical paths, if the modulation voltage ΔV produces a phase change of Φ in one optical path, then by simultaneously modulating the two optical signals with the differential modulation voltage ±ΔV, a phase difference of 2Φ can be generated between the two optical signals, thus doubling the modulation efficiency. Alternatively, as needed, the first and second control signals can be adjusted to modulate only one optical signal, flexibly controlling the two phase control units to better adjust the splitting ratio of the second beam splitter. The construction of the MZ interferometer is prior art and not an improvement of this embodiment, therefore it will not be described further.

[0055] In this embodiment, the splitting ratio of the first beam splitting unit is 50:50, the splitting ratio of the wave combiner unit is 50:50, and according to the principle of coherent light being added in phase, under the initial conditions, when the phase difference between the two beams is controlled at 90 degrees, the splitting ratio of the second beam splitter is 50:50.

[0056] Therefore, the working principle and beneficial effects of this embodiment are as follows:

[0057] When equalizing the output optical power of coherent X-polarized light and Y-polarized light, the phase difference between the two polarized lights is created by adjusting the control signals of the first phase controller and the second phase controller in the second beam splitter. This adjusts the input of the two phase control units, thereby adjusting the splitting ratio of the second beam splitter and achieving equalization while maintaining the output power of the transmitting component.

[0058] By transmitting a small amount of optical power from the sampling beam splitter to the sampling photodetector, the ratio of the optical power of X-polarized light to Y-polarized light can be obtained. Based on this ratio, the splitting ratio of the second beam splitter can be further compensated and corrected.

[0059] When two phase controllers simultaneously adjust their respective optical paths, if the modulation voltage ΔV produces a phase change of Φ on one optical path, then when the differential modulation voltage ±ΔV is used to modulate the two optical signals simultaneously, a phase difference of 2Φ can be generated between the two optical signals, thus doubling the modulation efficiency.

[0060] Example 3:

[0061] In this embodiment, the two phase control units are referred to as: the first phase controller and the second phase controller;

[0062] The sampling beam splitters in the two sets of beam splitting detection units are denoted as: the first sampling beam splitter and the second sampling beam splitter;

[0063] The sampling photodetectors in the two sets of spectral detection units are denoted as: the first sampling photodetector and the second sampling photodetector;

[0064] The four high-speed electro-optic modulators are denoted as: X-polarized XI and XQ modulators, and Y-polarized YI and YQ modulators; the XI and XQ modulators are set in the optical path corresponding to the X-polarized light, and the YI and YQ modulators are set in the optical path corresponding to the Y-polarized light.

[0065] This embodiment presents a polarization-equalized emission component based on a coherent silicon photonic chip, such as... Figure 2 As shown, it includes a first beam splitter, a second beam splitter, X-polarized XI and XQ modulators, Y-polarized YI and YQ modulators, a polarization rotator, and a polarization combiner, as follows. Figure 3 As shown, the second beam splitter includes a first beam splitting unit, a first phase controller, a second phase controller, a multiplexing unit, a first sampling beam splitter, a second sampling beam splitter, a first sampling photodetector, and a second sampling photodetector;

[0066] One output of the beam combiner unit is connected to the X-polarization XI / XQ modulator through the first sampling beam splitter, and the other output is connected to the Y-polarization YI / YQ modulator through the second sampling beam splitter.

[0067] The input of the first sampling photodetector is connected to the first sampling beam splitter, and the input of the second sampling photodetector is connected to the second sampling beam splitter;

[0068] The input of the first beam splitter is a local oscillator laser, one output of the first beam splitter is connected to the receiving component, and the other output of the first beam splitter is connected to the first beam splitting unit;

[0069] One output of the first beam splitter transmits a first optical signal to the multiplexing unit through the first phase controller, and the other output of the first beam splitter transmits a second optical signal to the multiplexing unit through the second phase controller.

[0070] Among them, the X-polarized XI and XQ modulators and the Y-polarized YI and YQ modulators are four high-speed electro-optic modulators.

[0071] The first phase controller and the second phase controller are two phase control units.

[0072] In this embodiment, the splitting ratio of the first beam splitting unit is 50:50, and the splitting ratio of the beam combining unit is 50:50.

[0073] One output of the multiplexing unit is connected to the polarization multiplexer via the X-polarized XI / XQ modulator, and the other output is connected to the polarization rotator and the polarization multiplexer in sequence via the Y-polarized YI / YQ modulator.

[0074] The polarization combiner is used to output polarization-multiplexed coherent optical signals;

[0075] The first phase controller is used to control the phase of the first optical signal, and the second phase controller is used to control the phase of the second optical signal, so that the splitting ratio of the second beam splitter is adjustable;

[0076] In this embodiment, the initial splitting ratio of the second beam splitter is 50:50.

[0077] In this embodiment, both the X-polarized XI / XQ modulator and the Y-polarized YI / YQ modulator are composed of high-speed silicon photonic modulators.

[0078] The working principle of this embodiment is as follows:

[0079] The continuous light emitted by the local oscillator laser is split into a small portion by a first beam splitter and sent to the receiver for coherent reception. The majority of the light used by the transmitting component is split by a second beam splitter into X-polarized and Y-polarized light, which are then modulated by an X-polarized XI / XQ modulator and a Y-polarized YI / YQ modulator, respectively. The modulated Y-polarized light is then rotated by a polarization rotator to make it orthogonal to the X-polarized light. Finally, the X-polarized and Y-polarized light are combined by a polarization combiner to form a polarization-multiplexed coherent optical signal, which is then output. When it is necessary to equalize the X-polarized and Y-polarized light signals at the output port of the transmitting component, the control signals of the first and second phase controllers in the second beam splitter are adjusted to create a phase difference between the two beams, thereby adjusting the splitting ratio of the second beam splitter and achieving equalization of the X-polarized and Y-polarized light signals at the output port of the transmitting component.

[0080] Example 4:

[0081] This embodiment is a further optimization based on embodiment 3. In this embodiment, the splitting ratio of the first beam splitting unit is 50:50, and the splitting ratio of the beam combining unit is 50:50.

[0082] In this embodiment, the first phase controller controls the phase of the first optical signal through a first control signal, and the second phase controller controls the phase of the second optical signal through a second control signal.

[0083] In this embodiment, the first control signal and the second control signal have the same amplitude but opposite directions.

[0084] Specifically, such as Figure 4As shown, the first control signal and the second control signal are differential phase control electrical signals. That is, when the first control signal with a modulation voltage of ΔV is applied to the first phase controller to cause the optical signal passing through the first phase controller to generate a phase displacement of Φ, the second control signal with a modulation voltage of -ΔV is applied to the second phase controller to cause the optical signal passing through the second phase controller to generate a phase displacement of -Φ. In this way, only a differential modulation voltage of ±ΔV is needed to generate a phase difference of 2Φ between the two optical signals.

[0085] In this embodiment, the splitting ratio of the first sampling beam splitter is 99:1 or 98:2, and the splitting ratio of the second sampling beam splitter is 99:1 or 98:2; the lower power output of the first sampling beam splitter is connected to the first sampling photodetector, and the lower power output of the second sampling beam splitter is connected to the second sampling photodetector.

[0086] The other parts of this embodiment are the same as those in Embodiment 1, so they will not be described again.

[0087] The working principle of this embodiment is as follows:

[0088] The continuous light emitted by the local oscillator laser is split into a small portion by the first beam splitter and sent to the receiver for coherent reception. The majority of the light used for the transmitting components is split by the second beam splitter. In the second beam splitter, the input is first split into two beams in a 50:50 ratio. Different phase modulations are performed on the two beams after splitting, or only one beam is modulated. Then, the two modulated beams are combined into two output beams, namely X-polarized light and Y-polarized light, by a 4-port 50:50 combiner. The X-polarized light is modulated by an X-polarized XI / XQ modulator and the Y-polarized light is modulated by a YI / YQ modulator, respectively. The modulated Y-polarized light is then rotated by a polarization rotator. Finally, the X-polarized light and Y-polarized light are combined by a polarization combiner to form a polarization-multiplexed coherent optical signal output.

[0089] In the initial state, the phase difference between the first optical signal and the second optical signal is set to 90 degrees. When adjusting the two optical signals simultaneously, the modulation efficiency is doubled by applying a differential phase control electrical signal.

[0090] When the wavelength of the optical signal or the ambient temperature at which the coherent silicon photonic chip operates changes, the splitting ratio of the beam splitter may change even if the voltage value of the control signal remains unchanged. In this case, the first sampling beam splitter, the second sampling beam splitter, the first sampling photodetector, and the second sampling photodetector can be used to collect the optical power ratio of X-polarized light and Y-polarized light in order to further compensate and correct the splitting ratio of the second beam splitter.

[0091] The following is a comparison between this embodiment and the prior art:

[0092] like Figure 5 As shown, it adopted Figure 1 A schematic diagram showing the change in output optical power of the coherent optical silicon photonic chip of the transmitting component with the amplitude of the high-speed electrical modulation signal, wherein the splitting ratio of the beam splitter 2 is fixed at 50:50;

[0093] The output optical power in the figure is labeled as "relative output optical power". That is, a base number is added to the actual optical power value to make it relative optical power. In this way, the change in actual optical power and relative optical power are exactly the same. Since the amplitude of high-speed electrical modulation signal itself is difficult to measure, the high-speed electrical modulation signal amplitude monitoring voltage on the horizontal axis is a measurable signal that is proportional to the amplitude of high-speed electrical modulation signal.

[0094] The units for optical power are dBm, relative optical power is dB, the change in optical power and relative optical power is dB, and the voltage for monitoring the amplitude of the high-speed electronic modulation signal is V.

[0095] Because the optical path loss of the Y-polarized signal is relatively large, when beam splitter 2 has the same splitting ratio for the X-polarized and Y-polarized signals, and the amplitude of the high-speed electrical modulation signal applied to the X-polarized signal is the same as that applied to the Y-polarized signal, such as Figure 5 When the amplitude monitoring voltage of the modulation signal is 2.3V, the relative optical power of the X-polarized signal at the output end is about 5.3dB, which is about 1.6dB higher than that of the Y-polarized signal at the output end, which is about 3.7dB.

[0096] Among them, the Y-polarized signal includes YI and YQ signals, and the X-polarized signal includes XI and XQ signals.

[0097] In this case, in order to balance the optical power of the X-polarized and Y-polarized signals at the output, the amplitude of the high-speed electrical modulation signal of the X-polarized signal needs to be reduced to about 1.87V, corresponding to the monitoring voltage. The final output relative optical signal is also at the 3.7dB level, so as to achieve balance with the Y-polarized signal.

[0098] like Figure 6 The diagram shows the output optical power of the coherent optical silicon photonics chip, which uses this embodiment as the transmitting component, as a function of the amplitude of the high-speed electrical modulation signal.

[0099] Similarly, the output optical power in the figure is labeled as "relative output optical power", which means that a base number is uniformly added to the actual optical power value to become the relative optical power. In this way, the change in actual optical power and relative optical power is exactly the same. Since the amplitude of the high-speed electrical modulation signal itself is difficult to measure, the high-speed electrical modulation signal amplitude monitoring voltage on the horizontal axis is a measurable signal that is proportional to the amplitude of the high-speed electrical modulation signal.

[0100] exist Figure 6Although the optical path loss of the Y-polarized signal is relatively large, the splitting ratio of the second beam splitter can be adjusted so that when the amplitude of the high-speed electrical modulation signal applied to the X-polarized signal is the same as that applied to the Y-polarized signal, the relative optical power of the X-polarized signal at the output end is similar to that of the Y-polarized signal at the output end.

[0101] When the amplitude of the high-speed electrical modulation signal of XI is set to correspond to the monitoring voltage of 2.2V, and the amplitudes of the high-speed electrical modulation signals of XQ, YI, and YQ are set to correspond to the monitoring voltage of 2.3V, an optical signal with a relative optical power of approximately 5.35dB with balanced X-polarized and Y-polarized signals at the output end can be obtained.

[0102] In this case, the capabilities of the high-speed electric driver are fully utilized. Specifically, the amplitudes of the high-speed electric modulation signals output by the high-speed electric drivers corresponding to XI, XQ, YI, and YQ are all set to around the monitoring voltages of 2.2V and 2.3V, and the output optical power of the X-polarized signal and the Y-polarized signal is also greatly improved.

[0103] In summary, the beneficial effects of this embodiment also include:

[0104] By using a first phase controller and a second phase controller, the phase of the optical signal can be adjusted without losing optical power, thereby adjusting the splitting ratio.

[0105] By using differential modulation voltage control with the first and second phase controllers of the MZ interferometer, the phase modulation efficiency is doubled.

[0106] By using the first sampling beam splitter, the second sampling beam splitter, the first sampling photodetector, and the second sampling photodetector, only a small amount of optical power needs to be split to obtain the optical power ratio of X-polarized light and Y-polarized light. Based on this ratio, the splitting ratio of the second beam splitter can be further compensated and corrected.

[0107] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A polarization-equalized emission component based on a coherent silicon photonic chip, comprising a first beam splitter, a second beam splitter, a high-speed electro-optic modulator, a polarization rotator, and a polarization combiner, wherein a continuous beam is split into two beams after passing through the first and second beam splitters, and the two optical signals are respectively converted into X-polarized light and Y-polarized light coherent optical signals by the high-speed electro-optic modulators on their respective optical paths. The Y-polarized light is rotated by the polarization rotator to be orthogonal to the X-polarized light, and then combined with the X-polarized light in the polarization combiner to form a polarization-multiplexed coherent optical signal and output; characterized in that: The second beam splitter is an adjustable beam splitter, used to adjust the splitting ratio of the two coherent beams to make the output optical power of the X-polarized and Y-polarized coherent beams balanced.

2. The polarization equalization emission component based on a coherent silicon photonic chip according to claim 1, characterized in that: The second beam splitter includes a first beam splitting unit, a phase control unit, and a multiplexing unit; The first beam splitting unit uses a fixed beam splitter with a splitting ratio of 50:50 to split one continuous light input from the first beam splitter into two optical signals with equal power in a 50:50 ratio. The phase control unit comprises two units, which are respectively located on the two optical paths output by the first beam splitter. They are used to change the beam splitting ratio by generating a phase difference between the two optical signals through phase modulation, and then send the two phase-modulated optical signals to the multiplexing unit. The multiplexing unit uses a 4-port 50:50 multiplexer to combine two phase-modulated optical signals into two output optical signals.

3. The polarization equalization emission component based on a coherent silicon photonic chip according to claim 2, characterized in that: The second beam splitter also includes two beam splitting detection units; the two beam splitting detection units are respectively set on the two optical paths output by the beam combiner unit, and are used to sample and detect the output light of each optical path and then feed back the optical power ratio of the two output lights to the phase control unit.

4. The polarization equalization emission component based on a coherent silicon photonic chip according to claim 3, characterized in that: The spectral detection unit includes a sampling beam splitter and a sampling light detector; the sampling beam splitter splits the sampling light and sends it to the sampling light detector for detection.

5. The polarization equalization emission component based on a coherent silicon photonic chip according to claim 4, characterized in that: The sampling beam splitter has a splitting ratio of 99:1 or 98:2, and sends the lower-power sampling light to the sampling light detector for detection.

6. The polarization equalization emission component based on a coherent silicon photonic chip according to claim 3, characterized in that: The two phase control units are respectively referred to as: a first phase controller and a second phase controller; the first phase controller independently modulates one optical signal split by the first beam splitter using a first control signal; the second phase controller independently modulates the other optical signal split by the first beam splitter using a second control signal.

7. A polarization-equalized emission component based on a coherent silicon photonic chip according to claim 6, characterized in that: The first phase controller and the second phase controller perform phase modulation on the two optical signals with the same amplitude but opposite directions.

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