Silicon photonics coherent optical module transmitter performance optimization method and silicon photonics coherent optical module

Abstract

The present invention provides a method for optimizing the transmitting end performance of a silicon photonic coherent optical module and a silicon photonic coherent optical module. The method comprises: adjusting the gain of a driver until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value; adjusting the voltage value of a driving circuit for controlling the splitting ratio until the polarization-related loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value; if the splitting ratio is within a first preset range and the current value of the driving circuit is within a second preset range, setting the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value, the first voltage value being the voltage value obtained by the last adjustment; otherwise, returning to adjusting the voltage value of the driving circuit. Through the present invention, the problem of poor consistency of optical modulation-related loss and polarization-related loss of silicon photonic IQ modulators during mass production due to process can be effectively eliminated.

Description

Technical Field

[0001] The present invention relates to the field of optical communication technology, and in particular to a method for optimizing the transmitting end performance of a silicon photonic coherent optical module and a silicon photonic coherent optical module. Background Art

[0002] Silicon photonics technology uses silicon and silicon-based substrate materials (such as SiGe / Si and SOI) as optical media, leveraging existing CMOS manufacturing processes to develop and integrate optical devices on extremely small silicon wafers with thin-film on insulators. After 40 years of technological exploration and rapid development in recent years, silicon photonics has brought significant technological innovations to many industries, particularly in optical communications. In today's digital age, with the massive amounts of data flowing into it, big data transmission and artificial intelligence applications are placing higher demands on data throughput and latency. Optical modules integrated with silicon photonics are more capable of meeting the high-speed, low-cost performance requirements of current network transmission than traditional discrete optical modules. However, silicon photonics cannot directly reuse existing mature CMOS processes and fab production lines. Although both silicon photonics and microelectronics are based on silicon semiconductor processes, high-performance silicon photonic devices cannot be produced using unmodified microelectronics process platforms, requiring customized silicon photonics processes. The current level of silicon photonics technology is comparable to that of microelectronics in the early 1980s, with significant gaps in automation, systematization, and scalability. Silicon photonics technology has always been well-received but not commercially successful. The main problem currently hindering the development of silicon photonics technology is the lack of production capacity and yield rate.

[0003] Silicon photonics integrated optical devices have been widely used in coherent optical modules. However, due to the material properties of silicon photonics processes, even if the upper and lower arms of the MZI are designed identically, the associated losses of silicon photonics IQ modulators are higher than those of traditional processes. These losses include modulation-dependent loss (MDL) and polarization-dependent loss (PDL).

[0004] Excessive or poorly consistent modulation-dependent loss (MDL) can affect the subsequent transmission and reception of modulated signals. Conventional amplification techniques can typically be used to amplify modulated signals, but this amplification can distort the signal indicating the optically modulated data being transmitted. Therefore, silicon photonics IQ modulators must have relatively low MDL to improve the signal quality and consistency of the modulated signal at the transmitting end.

[0005] Polarization-dependent loss (PDL) is the ratio of the maximum to minimum transmission of an optical device or system under all polarization states. PDL is crucial for characterizing silicon photonics IQ modulators. Virtually every device exhibits polarization-dependent transmission, so the insertion loss (MDL) of a silicon photonics IQ modulator varies with the polarization state. This effect can grow uncontrollably along the transmission link, severely impacting transmission quality. The PDL of individual devices can cause large power fluctuations within the system, increasing the system's bit error rate and even leading to network failures.

[0006] Silicon photonics IQ modulators are sensitive to process technology, and the optical correlation loss (MDL and PDL) of the X / Y polarization states of mass-produced silicon photonics IQ modulators is very inconsistent, which has a significant impact on the transmitting end performance of coherent optical modules. The common practice is to require silicon photonics manufacturers to use optical modulation analyzers (OMAs) for manual calibration and performance screening before the devices leave the factory, which greatly reduces production efficiency and increases manufacturing costs. Summary of the Invention

[0007] The main purpose of the present invention is to provide a method for optimizing the transmitting end performance of a silicon photonic coherent optical module and a silicon photonic coherent optical module. The purpose is to address the technical problems in the prior art that the optical correlation loss of silicon photonic IQ modulators is larger than the loss of traditional process devices, and because it is sensitive to the process, the consistency of the optical correlation loss of the X / Y polarization states in mass production is very poor, resulting in large differences in the transmitting end performance of coherent optical modules, low yield and low production efficiency.

[0008] In a first aspect, the present invention provides a method for optimizing the transmitting end performance of a silicon photonics coherent optical module, the method comprising:

[0009] Adjusting the gain of the driver until the difference between the modulation-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-dependent loss is less than a first preset value;

[0010] Adjust the voltage of the driving circuit that controls the splitting ratio until the polarization-dependent loss of the silicon photonics IQ modulator in the X and Y polarization states is minimized.

[0011] detecting whether the splitting ratio is within a first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within a second preset range;

[0012] If yes, setting the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value, wherein the first voltage value is the voltage value obtained by the last adjustment;

[0013] If not, the process returns to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent losses of the two polarization states X and Y of the silicon photonic IQ modulator are minimized.

[0014] Optionally, the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized includes:

[0015] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y value;

[0016] Detection Q x With Q y whether the absolute value of the difference is less than or equal to a second preset value;

[0017] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit that controls the splitting ratio is adjusted, and the error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is returned. x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y Value steps;

[0018] If Q x With Q y If the absolute value of the difference is less than or equal to the second preset value, it is determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

[0019] Optionally, the bit error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is obtained. x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y The steps for value include:

[0020] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y, set Pre-FEC_BER x Substitute the conversion formula of bit error rate and Q value before the first error correction into the Q value of the X polarization state. x value, set Pre-FEC_BER y Substitute the conversion formula of bit error rate and Q value before the second error correction into the Q value of the Y polarization state. y The conversion formula between the bit error rate and Q value before the first error correction is:

[0021]

[0022] The conversion formula between the bit error rate and the Q value before the second error correction is:

[0023]

[0024] Where erfcinv is the inverse function of the complementary error function.

[0025] Optionally, if Q x With Q y If the absolute value of the difference is greater than a second preset value, the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio includes:

[0026] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted according to the voltage adjustment formula. The voltage adjustment formula is:

[0027] txpow xy =txpow xy '+abs(Q x -Q y )*c

[0028] Among them, abs() means to find the absolute value of the value in the brackets, txpow xy is the adjusted voltage value, txpow xy ' is the voltage value before adjustment, and c is the preset constant.

[0029] Optionally, before the step of detecting whether the splitting ratio is within the first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within the second preset range, the method further includes:

[0030] Obtain the optical power value txpdx_adc obtained by photoelectric conversion of the monitor-PD in the X polarization state and the optical power value txpdy_adc obtained by photoelectric conversion of the monitor-PD in the Y polarization state and the ADC;

[0031] Substitute txpdx_adc and txpdy_adc into the splitting ratio calculation formula to obtain the splitting ratio. The splitting ratio calculation formula is:

[0032] txpdx_ratio=txpdx_adc / txpdy_adc

[0033] Among them, txpdx_ratio is the splitting ratio.

[0034] Optionally, if so, the step of setting the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value includes:

[0035] If yes, then setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, and recording the operating temperature of the silicon photonic IQ modulator;

[0036] After the step of setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, the following step further comprises:

[0037] When the operating temperature of the silicon photonics IQ modulator changes, the adjustment coefficient is determined based on the temperature change value and the corresponding relationship between temperature and voltage;

[0038] The first voltage value is adjusted according to the adjustment coefficient to obtain a second voltage value, and the voltage value of the driving circuit for controlling the splitting ratio is set to the second voltage value.

[0039] In a second aspect, the present invention further provides a silicon photonics coherent optical module, comprising:

[0040] A first adjustment module is configured to adjust the gain of the driver until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value;

[0041] The second adjustment module is used to adjust the voltage value of the driving circuit that controls the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized;

[0042] a detection module, configured to detect whether the splitting ratio is within a first preset range and whether a current value of a driving circuit for controlling the splitting ratio is within a second preset range;

[0043] A setting module, configured to set the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value if yes, wherein the first voltage value is the voltage value obtained by the last adjustment;

[0044] The return module is used to return to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized if no.

[0045] Optionally, the second adjustment module is used to:

[0046] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y value;

[0047] Detection Q x With Q y whether the absolute value of the difference is less than or equal to a second preset value;

[0048] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit that controls the splitting ratio is adjusted, and the error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is returned. x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y Value steps;

[0049] If Q x With Q y If the absolute value of the difference is less than or equal to the second preset value, it is determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

[0050] Optionally, the second adjustment module is used to:

[0051] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , set Pre-FEC_BER x Substitute the conversion formula of bit error rate and Q value before the first error correction into the Q value of the X polarization state. x value, set Pre-FEC_BER y Substitute the conversion formula of bit error rate and Q value before the second error correction into the Q value of the Y polarization state. y The conversion formula between the bit error rate and Q value before the first error correction is:

[0052]

[0053] The conversion formula between the bit error rate and the Q value before the second error correction is:

[0054]

[0055] Where erfcinv is the inverse function of the complementary error function.

[0056] Optionally, the second adjustment module is used to:

[0057] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted according to the voltage adjustment formula. The voltage adjustment formula is:

[0058] txpow xy =txpow xy '+abs(Q x -Q y )*c

[0059] Among them, abs() means to find the absolute value of the value in the brackets, txpow xy is the adjusted voltage value, txpow xy ' is the voltage value before adjustment, and c is the preset constant.

[0060] In the present invention, the gain of the driver is adjusted until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value; the voltage value of the driving circuit for controlling the splitting ratio is adjusted until the polarization-related loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized; it is detected whether the splitting ratio is within the first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within the second preset range; if so, the voltage value of the driving circuit for controlling the splitting ratio is set to a first voltage value, wherein the first voltage value is the voltage value obtained by the last adjustment; if not, the voltage value of the driving circuit for adjusting the splitting ratio is returned to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-related loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized. Through the present invention, the problem of poor consistency of optical modulation-related loss and polarization-related loss of the silicon photonic IQ modulator caused by the process in the mass production process can be effectively eliminated, thereby improving the signal quality and consistency of the transmitting end of the silicon photonic coherent optical module and optimizing the transmitting end performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a flow chart of an embodiment of a method for optimizing the transmitting-end performance of a silicon photonics coherent optical module according to the present invention;

[0062] Figure 2 This is a basic block diagram of the internal structure of a silicon photonics transceiver integrated device COSA in one embodiment;

[0063] Figure 3 A detailed block diagram of the internal structure of a silicon photonics transceiver integrated device COSA in one embodiment;

[0064] Figure 4 Schematic diagram of the architecture of a super 100G silicon photonics coherent optical module in one embodiment;

[0065] Figure 5 Schematic diagram of the architecture of the COSA, the main control unit, and the current source driving unit for controlling the splitting ratio in one embodiment;

[0066] Figure 6 is a schematic diagram of a driving circuit for controlling the splitting ratio in one embodiment;

[0067] Figure 7 FIG. 1 is a schematic diagram of functional modules of an embodiment of a silicon photonics coherent optical module according to the present invention.

[0068] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0069] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0070] In a first aspect, an embodiment of the present invention provides a method for optimizing the transmitting end performance of a silicon photonics coherent optical module.

[0071] In one embodiment, referring to Figure 1 , Figure 1 FIG. 1 is a flow chart of an embodiment of a method for optimizing the performance of a silicon photonic coherent optical module transmitting end according to the present invention. Figure 1 As shown in the figure, the performance optimization method for the silicon photonics coherent optical module transmitter includes:

[0072] Step S10, adjusting the gain of the driver until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value;

[0073] In this embodiment, refer to Figure 2 , Figure 2 This is a basic block diagram of the internal structure of the silicon photonics transceiver integrated device COSA in one embodiment. Figure 2As shown, the COSA integrates a silicon photonics IQ modulator (DP-IQ Modulator), a coherent receiver (ICR), a beam splitter (BS), a high-bandwidth linear driver (Driver), and a high-bandwidth linear transimpedance amplifier (TIA). The beam splitter (BS) splits the optical signal output by the external integrated adjustable narrow linewidth light source (ITLA) into two paths: one path is fed into the silicon photonics IQ modulator at the transmitter, and the other path is fed into the coherent receiver at the receiver. The driver amplifies the high-speed analog electrical signal output by the DSP and feeds it into the silicon photonics IQ modulator. The silicon photonics IQ modulator modulates the optical signal at the transmitter. The coherent receiver performs the optical-to-electrical conversion of the optical signal input on the line side. The TIA amplifies the analog electrical signal and feeds it into the DSP for processing.

[0074] Among them, the silicon photonics IQ modulator needs to be driven by an RF voltage, and adjusting the OA value of the high-bandwidth linear driver, that is, the gain size (actually changing the size of the electrical signal amplitude signal output by the high-bandwidth linear driver Driver), can change the modulation-related loss of the silicon photonics IQ modulator's X and Y polarization states.

[0075] Reference Figure 3 , Figure 3 FIG. 1 is a detailed block diagram of the internal structure of a silicon photonic transceiver integrated device COSA in one embodiment. Figure 3 As shown in the figure, the dotted box is the structure block diagram of the silicon photonics IQ modulator and driver at the transmitting end. The basic design principle of the silicon photonics IQ modulator is to split the incident light into two paths, X and Y, through the beam splitter BS. Figure 3 The currents (PHASE_XI, PHASE_XQ, PHASE_YI, PHASE_YQ, PHASE_X, and PHASE_Y) in the modulators (electro-optical effect) change the phase difference between the two optical paths. These paths are then superimposed at the modulator output by the MMI_2x2 combiner. Silicon photonics IQ modulators typically use the VOA design to control the output power of each MZM (for example, the splitting ratio control parameter TXPOWXY is designed for the VOA). Monitor-PD (MPD) is also designed to monitor the output power of each MZM. Figure 3 The six monitor-PDs shown are: TX_MPD_X, TX_MPD_Y, TX_MPD_XI, TX_MPD_XQ, TX_MPD_YI, and TX_MPD_YQ, ​​which are abbreviated as TXPDX, TXPDY, TXPDXI, TXPDXQ, TXPDYI, and TXPDYQ, respectively.

[0076] Reference Figure 4 , Figure 4 FIG. 1 is a schematic diagram of the architecture of a super 100G silicon photonics coherent optical module in one embodiment. Figure 4 As shown in the figure, the main components of the ultra-100G silicon photonics coherent optical module are: DSP, integrated silicon photonics transceiver (COSA), optical amplifier (OA), integrated tunable narrow linewidth light source (ITLA), module controller, and other blocks. The ATT is an adjustable optical attenuator; the integrated silicon photonics transceiver (COSA) includes a driver, transimpedance amplifier (TIA), coherent receiver (ICR), silicon photonics IQ modulator (DP-IQ modulator), and beam splitter (BS).

[0077] Reference Figure 5 , Figure 5 FIG. 1 is a schematic diagram of the structure of the COSA, the main control unit, and the current source driving unit for controlling the splitting ratio in one embodiment. Figure 5 As shown, COSA (i.e. Figure 2 The mother MZM and child MZM of the DP-IQ Modulator in the TXPD are both equipped with built-in monitoring PDs, namely monitor-PDs. x and TXPD y Monitor-PD, TXPD of the mother MZM xI TXPD xQ TXPD yI and TXPD yQ This is the monitor-PD for the sub-MZM. After the analog unit undergoes photoelectric conversion, signal amplification, and A / D conversion processing, the monitor-PD is sent to the main control unit, the module controller, for digital processing and reporting. TXPOWXY is the X / Y polarization splitting control pin of the silicon photonics IQ modulator and is driven by an external current source.

[0078] Specifically, first obtain the modulation-related losses of the two polarization states X and Y of the silicon photonics IQ modulator, for example:

[0079] Modulation-dependent loss (MDL) of silicon photonics IQ modulator X x The way to obtain is:

[0080]

[0081] Modulation-dependent loss (MDL) of silicon photonics IQ modulator Y y The way to obtain is:

[0082]

[0083] Among them, TXPD x TXPD xI TXPD xQ TXPD y TXPDyI and TXPD yQ The monitor-PD is a built-in monitoring PD in the silicon photonics IQ modulator. The value is obtained by the MCU through ADC sampling after passing through the photoelectric conversion circuit.

[0084] Then, check whether condition 1 is met:

[0085] Modulation-dependent loss (MDL) of silicon photonics IQ modulator X x The difference between the target modulation-related loss and the target modulation-related loss is less than the first preset value, and the modulation-related loss MDL of the silicon photonic IQ modulator Y is y The difference between the target modulation related loss and the target modulation related loss is smaller than a first preset value.

[0086] Among them, the target modulation related loss and the first preset value are set according to actual needs. For example, the target modulation related loss is set to 18db and the first preset value is set to 0.25db. This is only for schematic explanation and does not constitute a restriction on the target modulation related loss and the first preset value.

[0087] If the above condition 1 is not met, adjust the gain of the driver until the above condition 1 is met.

[0088] Step S20, adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator reaches a minimum value;

[0089] In this embodiment, the voltage value of the driving circuit for controlling the splitting ratio is adjusted so that the polarization-dependent losses of the X and Y polarization states of the silicon photonics IQ modulator mother MZM are minimized.

[0090] Reference Figure 6 , Figure 6 FIG. 1 is a schematic diagram of a driving circuit for controlling the splitting ratio in an embodiment. Figure 6 As shown in the figure, the driving circuit for controlling the splitting ratio is based on an op amp + MOSFET tube. The sampling resistor Rsense is at the bottom, and the load inside the silicon photonic IQ modulator is at the top. That is, the splitting ratio control pin TXPOWXY is driven by a current source. The current flowing through the sampling resistor is the current of TXPOWXY. The current I TXPOWXY =I Rs =V DAC_TXPOWXY / R S The working principle of this driving circuit is as follows: adjusting the DAC voltage value can change the current of the splitting ratio TXPOWXY. By adjusting the voltage value of the driving circuit that controls the splitting ratio, the polarization-dependent loss of the X and Y polarization states can be adjusted.

[0091] Furthermore, in one embodiment, step S20 includes:

[0092] Step S201: Obtain the pre-error correction bit error rate Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y value;

[0093] In this embodiment, the DSP monitors and reads the pre-error correction bit error rate Pre-FEC_BER of the X polarization state. x And the bit error rate before correction Pre-FEC_BER of the Y polarization state y , and then further based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y value.

[0094] Furthermore, in one embodiment, step S201 includes:

[0095] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , set Pre-FEC_BER x Substitute the conversion formula of bit error rate and Q value before the first error correction into the Q value of the X polarization state. x value, set Pre-FEC_BER y Substitute the conversion formula of bit error rate and Q value before the second error correction into the Q value of the Y polarization state. y The conversion formula between the bit error rate and Q value before the first error correction is:

[0096]

[0097] The conversion formula between the bit error rate and the Q value before the second error correction is:

[0098]

[0099] Where erfcinv is the inverse function of the complementary error function.

[0100] In a phase-modulated coherent optical transmission system, the approximate relationship between the bit error rate (BER) before correction and Q (Linear) is as follows:

[0101]

[0102] Therefore, we can infer:

[0103]

[0104] Thus, the first conversion formula between the bit error rate before error correction and the Q value and the second conversion formula between the bit error rate before error correction and the Q value are obtained.

[0105] Step S202, detect Q x With Q y whether the absolute value of the difference is less than or equal to a second preset value;

[0106] In this embodiment, Q x With Q y Whether the absolute value of the difference is less than or equal to the second preset value, the second preset value is set according to actual needs, for example, 0.1dB. It should be noted that this is only an illustrative description and does not constitute a limitation on the second preset value.

[0107] Step S203, if Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted, and the process returns to step S201;

[0108] In this embodiment, if Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted, and the process returns to step S201.

[0109] Furthermore, in one embodiment, if Q x With Q y If the absolute value of the difference is greater than a second preset value, the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio includes:

[0110] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted according to the voltage adjustment formula. The voltage adjustment formula is:

[0111] txpow xy =txpow xy '+abs(Q x -Q y )*c

[0112] Among them, abs() means to find the absolute value of the value in the brackets, txpow xy is the adjusted voltage value, txpow xy ' is the voltage value before adjustment, and c is the preset constant.

[0113] Step S204, if Q x With Q yIf the absolute value of the difference is less than or equal to the second preset value, it is determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

[0114] In this embodiment, when Q x With Q y When the absolute value of the difference is less than or equal to the second preset value, it can be determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

[0115] Step S30, detecting whether the splitting ratio is within a first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within a second preset range;

[0116] In this embodiment, when the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonics IQ modulator and the target modulation-related loss is less than the first preset value, and the polarization-related loss of the two polarization states X and Y of the silicon photonics IQ modulator is a minimum value, the splitting ratio is calculated, the current value of the driving circuit that controls the splitting ratio is read, and it is detected whether the splitting ratio is within the first preset range and whether the current value of the driving circuit that controls the splitting ratio is within the second preset range.

[0117] Furthermore, before step S30, the method further includes:

[0118] Obtain the optical power value txpdx_adc obtained by photoelectric conversion of the monitor-PD in the X polarization state and the optical power value txpdy_adc obtained by photoelectric conversion of the monitor-PD in the Y polarization state and the ADC;

[0119] Substitute txpdx_adc and txpdy_adc into the splitting ratio calculation formula to obtain the splitting ratio. The splitting ratio calculation formula is:

[0120] txpdx_ratio=txpdx_adc / txpdy_adc

[0121] Among them, txpdx_ratio is the splitting ratio.

[0122] In this embodiment, by reading the optical power values ​​of the mother MZM, i.e., the two polarization state monitoring PDs, i.e., monitor-PD, after being sampled by the photoelectric conversion ADC, the code values ​​of ADC_TXPDX and ADC_TXPDY, i.e., txpdx_adc and txpdy_adc, can be obtained, thereby calculating the splitting ratio txpd_ratio = txpdx_adc / txpdy_adc.

[0123] Step S40: If yes, then set the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value, wherein the first voltage value is the voltage value obtained by the last adjustment;

[0124] In this embodiment, if the splitting ratio is within the first preset range and the current value of the driving circuit for controlling the splitting ratio is within the second preset range, the voltage value of the driving circuit for controlling the splitting ratio is set to the voltage value obtained by the last adjustment.

[0125] Step S50: If not, return to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator reaches a minimum.

[0126] In this embodiment, if the splitting ratio is not within the first preset range and / or the current value of the driving circuit for controlling the splitting ratio is not within the second preset range, the process returns to step S20.

[0127] In this embodiment, the gain of the driver is adjusted until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value; the voltage value of the driving circuit for controlling the splitting ratio is adjusted until the polarization-related loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized; it is detected whether the splitting ratio is within the first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within the second preset range; if so, the voltage value of the driving circuit for controlling the splitting ratio is set to a first voltage value, wherein the first voltage value is the voltage value obtained by the last adjustment; if not, the process returns to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-related loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized. Through this embodiment, the problem of poor consistency of optical modulation-related loss and polarization-related loss of silicon photonics IQ modulators caused by the process in mass production can be effectively eliminated, thereby improving the quality and consistency of the transmitting signal of the silicon photonics coherent optical module and optimizing the transmitting performance. Without the need to use expensive instruments, the control characteristics of the coherent optical module itself are fully utilized, and there is no need to change the existing optical module hardware circuit, which is low cost and high efficiency.

[0128] Furthermore, in one embodiment, if yes, the step of setting the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value includes:

[0129] If yes, then setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, and recording the operating temperature of the silicon photonic IQ modulator;

[0130] After the step of setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, the following step further comprises:

[0131] When the operating temperature of the silicon photonics IQ modulator changes, the adjustment coefficient is determined based on the temperature change value and the corresponding relationship between temperature and voltage;

[0132] The first voltage value is adjusted according to the adjustment coefficient to obtain a second voltage value, and the voltage value of the driving circuit for controlling the splitting ratio is set to the second voltage value.

[0133] In this embodiment, the voltage value of the driving circuit that controls the splitting ratio is set to a first voltage value, and the operating temperature of the silicon photonics IQ modulator is recorded; subsequently, if it is detected that the operating temperature of the silicon photonics IQ modulator has changed, the adjustment coefficient is determined based on the temperature change value and the correspondence between temperature and voltage; thereby, the first voltage value is adjusted according to the adjustment coefficient to obtain a second voltage value, and the voltage value of the driving circuit that controls the splitting ratio is set to the second voltage value.

[0134] In a second aspect, an embodiment of the present invention further provides a silicon photonic coherent optical module.

[0135] In one embodiment, referring to Figure 7 , Figure 7 FIG1 is a functional module diagram of an embodiment of a silicon photonic coherent optical module of the present invention. Figure 7 As shown in the figure, the silicon photonics coherent optical module includes:

[0136] A first adjustment module 10 is configured to adjust the gain of the driver until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value;

[0137] The second adjustment module 20 is used to adjust the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized;

[0138] A detection module 30 is used to detect whether the splitting ratio is within a first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within a second preset range;

[0139] A setting module 40 is configured to set the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value if yes, wherein the first voltage value is the voltage value obtained by the last adjustment;

[0140] Return module 50 is used to, if not, return to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized.

[0141] Furthermore, in one embodiment, the second adjustment module 20 is configured to:

[0142] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculatedx Value and Q of Y polarization state y value;

[0143] Detection Q x With Q y whether the absolute value of the difference is less than or equal to a second preset value;

[0144] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit that controls the splitting ratio is adjusted, and the error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is returned. x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y Value steps;

[0145] If Q x With Q y If the absolute value of the difference is less than or equal to the second preset value, it is determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

[0146] Furthermore, in one embodiment, the second adjustment module 20 is configured to:

[0147] Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , set Pre-FEC_BER x Substitute the conversion formula of bit error rate and Q value before the first error correction into the Q value of the X polarization state. x value, set Pre-FEC_BER y Substitute the conversion formula of bit error rate and Q value before the second error correction into the Q value of the Y polarization state. y The conversion formula between the bit error rate and Q value before the first error correction is:

[0148]

[0149] The conversion formula between the bit error rate and the Q value before the second error correction is:

[0150]

[0151] Where erfcinv is the inverse function of the complementary error function.

[0152] Furthermore, in one embodiment, the second adjustment module 20 is configured to:

[0153] If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted according to the voltage adjustment formula. The voltage adjustment formula is:

[0154] txpow xy =txpow xy '+abs(Q x -Q y )*c

[0155] Among them, abs() means to find the absolute value of the value in the brackets, txpow xy is the adjusted voltage value, txpow xy ' is the voltage value before adjustment, and c is the preset constant.

[0156] Furthermore, in one embodiment, the silicon photonics coherent optical module transmitting end performance optimization further includes a computing module for:

[0157] Obtain the optical power value txpdx_adc obtained by photoelectric conversion of the monitor-PD in the X polarization state and the optical power value txpdy_adc obtained by photoelectric conversion of the monitor-PD in the Y polarization state and the ADC;

[0158] Substitute txpdx_adc and txpdy_adc into the splitting ratio calculation formula to obtain the splitting ratio. The splitting ratio calculation formula is:

[0159] txpdx_ratio=txpdx_adc / txpdy_adc

[0160] Among them, txpdx_ratio is the splitting ratio.

[0161] Furthermore, in one embodiment, a module 40 is provided for:

[0162] If yes, then setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, and recording the operating temperature of the silicon photonic IQ modulator;

[0163] When the operating temperature of the silicon photonics IQ modulator changes, the adjustment coefficient is determined based on the temperature change value and the corresponding relationship between temperature and voltage;

[0164] The first voltage value is adjusted according to the adjustment coefficient to obtain a second voltage value, and the voltage value of the driving circuit for controlling the splitting ratio is set to the second voltage value.

[0165] Among them, the functional implementation of each module in the above-mentioned silicon photonic coherent optical module corresponds to the various steps in the embodiment of the above-mentioned silicon photonic coherent optical module transmitting end performance optimization method, and their functions and implementation processes are not repeated here one by one.

[0166] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0167] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

[0168] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, or of course by hardware, but in many cases the former is a better embodiment. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above and includes a number of instructions for enabling a terminal device to execute the methods described in various embodiments of the present invention.

[0169] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for optimizing the transmitting end performance of a silicon photonic coherent optical module, characterized in that: The method for optimizing the transmitting end performance of a silicon photonics coherent optical module includes: Adjusting the gain of the driver until the difference between the modulation-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-dependent loss is less than a first preset value; Adjust the voltage of the driving circuit that controls the splitting ratio until the polarization-dependent loss of the silicon photonics IQ modulator in the X and Y polarization states is minimized. detecting whether the splitting ratio is within a first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within a second preset range; If yes, setting the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value, wherein the first voltage value is the voltage value obtained by the last adjustment; If not, return to the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator reaches a minimum value; The step of adjusting the voltage value of the driving circuit for controlling the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator reaches a minimum value includes: Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y value; Detection Q x With Q y whether the absolute value of the difference is less than or equal to a second preset value; If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit that controls the splitting ratio is adjusted, and the error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is returned. x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y Value steps; If Q x With Q y If the absolute value of the difference is less than or equal to the second preset value, it is determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

2. The method for optimizing the transmitting end performance of a silicon photonics coherent optical module according to claim 1, wherein: The bit error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is obtained x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y The steps for value include: Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , set Pre-FEC_BER x Substitute the conversion formula of bit error rate and Q value before the first error correction into the Q value of the X polarization state. x value, set Pre-FEC_BER y Substitute the conversion formula of bit error rate and Q value before the second error correction into the Q value of the Y polarization state. y The conversion formula between the bit error rate and Q value before the first error correction is: （2* ） The conversion formula between the bit error rate and the Q value before the second error correction is: （2* ） Where erfcinv is the inverse function of the complementary error function.

3. The method for optimizing the transmitting end performance of a silicon photonics coherent optical module according to claim 1, wherein: If Q x With Q y If the absolute value of the difference is greater than a second preset value, the step of adjusting the voltage value of the driving circuit for controlling the splitting ratio includes: If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted according to the voltage adjustment formula. The voltage adjustment formula is: txpow xy =txpow xy '+abs(Q x -Q y )*c Among them, abs() means to find the absolute value of the value in the brackets, txpow xy is the adjusted voltage value, txpow xy ' is the voltage value before adjustment, and c is the preset constant.

4. The method for optimizing the transmitting end performance of a silicon photonics coherent optical module according to any one of claims 1 to 3, wherein: Before the step of detecting whether the splitting ratio is within the first preset range and whether the current value of the driving circuit for controlling the splitting ratio is within the second preset range, the method further includes: Obtain the optical power value txpdx_adc obtained by photoelectric conversion of the monitor-PD in the X polarization state and the optical power value txpdy_adc obtained by photoelectric conversion of the monitor-PD in the Y polarization state and the ADC; Substitute txpdx_adc and txpdy_adc into the splitting ratio calculation formula to obtain the splitting ratio. The splitting ratio calculation formula is: txpdx_ratio=txpdx_adc / txpdy_adc Among them, txpdx_ratio is the splitting ratio.

5. The method for optimizing the transmitting end performance of a silicon photonic coherent optical module according to any one of claims 1 to 3, characterized in that: If yes, the step of setting the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value includes: If yes, then setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, and recording the operating temperature of the silicon photonic IQ modulator; After the step of setting the voltage value of the driving circuit for controlling the splitting ratio to the first voltage value, the following step further comprises: When the operating temperature of the silicon photonics IQ modulator changes, the adjustment coefficient is determined based on the temperature change value and the corresponding relationship between temperature and voltage; The first voltage value is adjusted according to the adjustment coefficient to obtain a second voltage value, and the voltage value of the driving circuit for controlling the splitting ratio is set to the second voltage value.

6. A silicon photonic coherent optical module, characterized in that: The silicon photonics coherent optical module includes: A first adjustment module is configured to adjust the gain of the driver until the difference between the modulation-related loss of the two polarization states X and Y of the silicon photonic IQ modulator and the target modulation-related loss is less than a first preset value; The second adjustment module is used to adjust the voltage value of the driving circuit that controls the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is minimized; a detection module, configured to detect whether the splitting ratio is within a first preset range and whether a current value of a driving circuit for controlling the splitting ratio is within a second preset range; A setting module, configured to set the voltage value of the driving circuit for controlling the splitting ratio to a first voltage value if yes, wherein the first voltage value is the voltage value obtained by the last adjustment; a return module, configured to, if not, return the voltage value of the driving circuit for adjusting the splitting ratio until the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator reaches a minimum; The second adjustment module is used to: Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y value; Detection Q x With Q y whether the absolute value of the difference is less than or equal to a second preset value; If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit that controls the splitting ratio is adjusted, and the error rate before error correction Pre-FEC_BER of the X polarization state of the silicon photonic IQ modulator is returned. x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , and based on the conversion formula of bit error rate and Q value before error correction, the Q value of X polarization state is calculated x Value and Q of Y polarization state y Value steps; If Q x With Q y If the absolute value of the difference is less than or equal to the second preset value, it is determined that the polarization-dependent loss of the two polarization states X and Y of the silicon photonic IQ modulator is a minimum value.

7. The silicon photonics coherent optical module according to claim 6, wherein: The second adjustment module is used to: Obtain the Pre-FEC_BER of the silicon photonics IQ modulator in the X polarization state x And the Pre-FEC_BER of the Y polarization state of the silicon photonics IQ modulator y , set Pre-FEC_BER x Substitute the conversion formula of bit error rate and Q value before the first error correction into the Q value of the X polarization state. x value, set Pre-FEC_BER y Substitute the conversion formula of bit error rate and Q value before the second error correction into the Q value of the Y polarization state. y The conversion formula between the bit error rate and Q value before the first error correction is: （2* ） The conversion formula between the bit error rate and the Q value before the second error correction is: （2* ） Where erfcinv is the inverse function of the complementary error function.

8. The silicon photonics coherent optical module according to claim 6, wherein: The second adjustment module is used to: If Q x With Q y If the absolute value of the difference is greater than the second preset value, the voltage value of the driving circuit for controlling the splitting ratio is adjusted according to the voltage adjustment formula. The voltage adjustment formula is: txpow xy =txpow xy '+abs(Q x -Q y )*c Among them, abs() means to find the absolute value of the value in the brackets, txpow xy is the adjusted voltage value, txpow xy ' is the voltage value before adjustment, and c is the preset constant.

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