MZ silicon optical modulator phase bias point adjusting method, electronic equipment, medium and program product thereof

Abstract

The invention discloses an MZ silicon optical modulator phase bias point adjusting method, electronic equipment, a medium and a program product thereof, and belongs to the technical field of optical communication. The minimum value and the maximum value of the sampling voltage of a photoelectric detector in any period and the current value range of a Heater corresponding to a monotone increasing interval or a monotone decreasing interval are searched; and then a set phase offset point is indexed in the current value range of the Heater. According to the invention, ADC sampling I / O port resources of a pair of differential photoelectric detectors and a micro control unit (MCU) of an MZ silicon optical chip are utilized, and the detection voltage of a photoelectric detector (MPD) of the MZ modulator is periodically changed in a sine rule along with the current change of a thermo-optic phase shifter (Heater); and the phase offset point locking value only needs to select one working point of any period as the modulation locking point of the optical module.

Description

Technical Field

[0001] The present invention belongs to the technical field of optical communication, and in particular relates to a method for adjusting a phase bias point of an MZ silicon optical modulator, electronic equipment, a medium and a program product thereof. Background Art

[0002] Highly integrated high-speed optoelectronic devices are the core optical components for the next generation of on-chip information communication and processing. Transmitting optical devices and receiving optical devices are two key optoelectronic devices for realizing the transceiver conversion of optical signals. With the explosive growth of information capacity, data centers have increasingly stringent requirements on the bandwidth, size and power consumption of optical modules. Transceiver integrated optical devices of the full silicon photonic solution are regarded as the core optical devices to meet this challenge. Among them, the Mach-Zehnder (MZ) structured silicon optical modulator, as the core optical device in the silicon photonics ecosystem, can realize high-speed electro-optical modulation of signals. Usually, the phase bias point of all external modulators will drift randomly with changes in temperature and environment. When the bias point of the external modulator deviates from the optimal operating point, the modulation performance of the modulator will decrease, causing serious degradation of the quality of the optical transmission signal, resulting in the adverse consequences of service interruption caused by post-correction flash errors, so realizing automatic closed-loop locking of the modulator bias point is the key technology for the practical application of external modulators.

[0003] At present, there are two main MZ automatic bias working point stability control technologies. The first is a harmonic analysis method based on an external low-frequency pilot signal. This method is complex to implement and requires hardware circuits such as a signal generator, a multi-stage AC amplifier circuit, a high-order analog bandpass filter, and a co-frequency signal detector. It is difficult to apply to optical module products with small packages such as QSFP-DD, QSFP, and OSFP. The other is an analysis method based on optical power ratio. However, the traditional optical power ratio algorithm requires external digital-to-analog conversion circuits, transimpedance amplifiers, power detectors, sampling and holding circuits, comparators, and digital controllers. The peripheral circuits are complex, costly, and large in size. In addition to the complexity of the hardware circuit, it also requires very complex MCU algorithm processing, including coarse scanning of the phase bias point and fine adjustment of the phase bias point, and a PID control algorithm. Therefore, it is of great significance to find a method for adjusting the phase bias point of an MZ silicon optical modulator that has a simple control algorithm and does not require external hardware circuits. Summary of the invention

[0004] In order to solve the problems in the prior art, the present invention provides a phase bias point adjustment method, electronic device, medium and program product of an MZ silicon optical modulator, which utilizes a pair of differential photodetectors of the MZ silicon optical chip itself and the ADC sampling I / O port resources of a microcontroller unit (MCU), and the detection voltage of the photodetector (MPD) of the MZ modulator changes with the current of the thermo-optical phase shifter (Heater) in a periodic sinusoidal manner, while the phase bias point locking value only needs to select one of the working points in any period as the modulation locking point of the optical module.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] One aspect of the present invention provides a method for adjusting the phase bias point of an MZ silicon optical modulator, by finding the minimum and maximum values ​​of the sampling voltage of one of the photodetectors in any period and the current value range of the heater corresponding to the monotonically increasing interval or decreasing interval, and then indexing to the set phase bias point within the current value range of the heater.

[0007] Preferably, the MZ silicon optical modulator comprises a high-power laser, an MZM silicon optical modulator, a coupler, a main photodetector, an auxiliary photodetector and a microcontroller unit connected in sequence, the main photodetector and the auxiliary photodetector are arranged in parallel, and the MZM silicon optical modulator is connected to an IDAC controller.

[0008] Preferably, the method comprises the following steps:

[0009] Step 1: Turn off the enable switch of the automatic control of the phase bias point of the MZ silicon optical modulator;

[0010] Step 2: The host computer scans the ADC value waveform of TXSUB and TXMAIN as the Heater DAC value changes;

[0011] Step 3. Find HT_min, HT_max and HT_Initial of the TXSUB ADC waveform and write them into the corresponding registers;

[0012] Step 4: Turn on the enable switch of the automatic control of the phase bias point;

[0013] Step 5: Heater DAC starts with HT_Initial as the initial value, and adjusts the DAC value of Heater in the range of HT_min and HT_Initial with a step of 1;

[0014] Step 6. When the ratio of TXMAIN to TXSUB is greater than Ratio+Delta, the Heater DAC value is increased by 1. When the ratio of TXMAIN to TXSUB is less than Ratio-Delta, the Heater DAC value is reduced by 1. When the ratio of TXMAIN to TXSUB is within the range of Ratio-Delta to Ratio+Delta, the Heater DAC remains unchanged.

[0015] Preferably, in the step 2,

[0016] Preferably, in step 3, HT_Initial is the Heater current DAC value corresponding to making the ADC values ​​of TXSUB and TXMAIN equal.

[0017] Preferably, in step six, Ratio is the ADC ratio of TXMAIN and TXSUB.

[0018] Preferably, N samples are used to sample the ADC ratio of TXMAIN and TXSUB at 25°C, 0°C and 70°C within 10 minutes, and then the difference between the average value of the ADC ratio and the minimum and maximum values ​​is taken as Delta, and the largest Delta value is selected as the default value configuration for all samples, where N>5.

[0019] Preferably, N samples are used to calculate the Ratio values ​​at 25°C, 0°C and 70°C, and the average Ratio values ​​of the N samples at 25°C, 0°C and 70°C are calculated. The Ratio value at 70°C and 25°C is used as the KH parameter, and the Ratio value at 0°C and 25°C is used as the KL parameter, wherein N>5;

[0020] When Temp_Real>25℃, Ratio=Ratio_RT+(Temp_Real-25℃) / (70℃-25℃)*KH;

[0021] On the contrary, Ratio=Ratio_RT+(Temp_Real-25°C) / (0°C-25°C)*KL, where Temp_Real is the real-time shell temperature of the optical module, Ratio_RT is the Ratio value at 25°C, Ratio_HT is the Ratio value at 70°C, and Ratio_LT is the Ratio value at 0°C.

[0022] Preferably, it is also applicable to lithium niobate MZ external modulator and indium phosphide MZ external modulator.

[0023] Another aspect of the present invention provides an electronic device, comprising: one or more processors; one or more memories for storing executable instructions, wherein when the executable instructions are executed by the processors, the method as described above is implemented.

[0024] Another aspect of the present invention provides a computer-readable storage medium, on which executable instructions are stored. When the instructions are executed by a processor, the method described above is implemented.

[0025] Another aspect of the present invention provides a computer program product, comprising a computer program, wherein the computer program comprises one or more executable instructions, and when the executable instructions are executed by a processor, the method as described above is implemented.

[0026] The beneficial effects of this technical solution are as follows:

[0027] 1. The present invention provides a method for adjusting the phase bias point of an MZ silicon optical modulator, which no longer requires the traditional hardware circuit construction or the use of a complex MCU algorithm, thereby reducing costs, simplifying the algorithm, and being able to fine-tune parameters according to the performance of each optical module, and having strong practicality.

[0028] 2. A method for adjusting the phase bias point of an MZ silicon optical modulator provided by the present invention utilizes the monotonicity of the sampling voltage ADC value of the photodetector in combination with the maximum and minimum values ​​to determine the debugging range of the phase bias point of the MZ silicon optical modulator, covering the fluctuation range of the phase bias point locking value within the operating temperature of the MZ silicon optical chip, and also determining the polarity of the optical module transmitting end, greatly reducing the difficulty of MCU algorithm processing and improving the fault tolerance rate.

[0029] 3. The present invention provides a method for adjusting the phase bias point of an MZ silicon optical modulator, which opens the registers of the voltage ADC ratio and fluctuation range of the two photodetectors and the high and low temperature compensation coefficients, and can fine-tune the parameters according to the optical eye diagram performance of each optical module, which is highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of the present invention;

[0031] Figure 2 is a model diagram of the MZ silicon optical modulator in the present invention;

[0032] Figure 3 It is a curve diagram of Heater_DAC VSTXMAIN and TXSUB of the host computer scanning 4 channels of 400G DR4 in Example 3 of the present invention. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0034] Example 1

[0035] like Figure 1 As shown, a method for adjusting the phase bias point of an MZ silicon optical modulator is provided, by finding the minimum and maximum values ​​of the sampling voltage of one of the photodetectors in any period and the current value range of the heater corresponding to the monotonically increasing interval or decreasing interval, and then indexing to the set phase bias point within the current value range of the heater.

[0036] Example 2

[0037] A method for adjusting the phase bias point of an MZ silicon optical modulator is disclosed. The method finds the minimum and maximum values ​​of the sampling voltage of one of the photodetectors in any period and the current value range of the heater corresponding to the monotonically increasing or decreasing interval, and then indexes to the set phase bias point within the current value range of the heater.

[0038] like Figure 2 As shown, the MZ silicon optical modulator includes a high-power laser, an MZM silicon optical modulator, a coupler, a main photodetector, an auxiliary photodetector and a microcontroller unit connected in sequence, the main photodetector and the auxiliary photodetector are arranged in parallel, and the MZM silicon optical modulator is connected to the IDAC controller.

[0039] The steps include:

[0040] Step 1: Turn off the enable switch of the automatic control of the phase bias point of the MZ silicon optical modulator;

[0041] Step 2: The host computer scans the ADC value waveform of TXSUB and TXMAIN as the Heater DAC value changes;

[0042] Step 3. Find HT_min, HT_max and HT_Initial of the TXSUB ADC waveform and write them into the corresponding registers;

[0043] Step 4: Turn on the enable switch of the automatic control of the phase bias point;

[0044] Step 5: Heater DAC starts with HT_Initial as the initial value, and adjusts the DAC value of Heater in the range of HT_min and HT_Initial with a step of 1;

[0045] Step 6. When the ratio of TXMAIN to TXSUB is greater than Ratio+Delta, the Heater DAC value is increased by 1. When the ratio of TXMAIN to TXSUB is less than Ratio-Delta, the Heater DAC value is reduced by 1. When the ratio of TXMAIN to TXSUB is within the range of Ratio-Delta to Ratio+Delta, the Heater DAC remains unchanged.

[0046] Wherein, in the step 3, HT_Initial is the Heater current DAC value corresponding to the ADC values ​​of TXSUB and TXMAIN being equal.

[0047] Wherein, in step six, Ratio is the ADC ratio of TXMAIN and TXSUB.

[0048] Among them, use N samples to sample the ADC ratio of TXMAIN and TXSUB within 10 minutes at 25℃, 0℃ and 70℃, then take the difference between the average value of the ADC ratio and the minimum and maximum values ​​as Delta, and select the largest Delta value as the default value configuration for all samples, where N>5.

[0049] Among them, use N samples to calculate the Ratio values ​​under the conditions of 25℃, 0℃ and 70℃, find the average Ratio of N samples under the conditions of 25℃, 0℃ and 70℃, use the Ratio ratio under the conditions of 70℃ and 25℃ as the KH parameter, and use the Ratio ratio under the conditions of 0℃ and 25℃ as the KL parameter, where N>5;

[0050] That is: KH=Ratio_HT / Ratio_RT; KL=Ratio_LT / Ratio_RT;

[0051] When Temp_Real>25℃, Ratio=Ratio_RT+(Temp_Real-25℃) / (70℃-25℃)*KH;

[0052] On the contrary, Ratio=Ratio_RT+(Temp_Real-25°C) / (0°C-25°C)*KL, where Temp_Real is the real-time shell temperature of the optical module, Ratio_RT is the Ratio value at 25°C, Ratio_HT is the Ratio value at 70°C, and Ratio_LT is the Ratio value at 0°C.

[0053] The above method is also applicable to lithium niobate MZ external modulator and indium phosphide MZ external modulator. The Ratio value and Delta value of the lithium niobate MZ external modulator and indium phosphide MZ external modulator are corrected according to the actual optical eye diagram performance. Correction according to the actual optical eye diagram performance is a prior art and is not described in detail here.

[0054] The electronic device according to an embodiment of the present invention includes a processor, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) or a program loaded from a storage portion into a random access memory (RAM). The processor may, for example, include a general-purpose microprocessor (e.g., CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor may also include an onboard memory for caching purposes. The processor may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0055] In RAM, various programs and data required for the operation of the electronic device are stored. The processor, ROM and RAM are connected to each other through a bus. The processor performs various operations of the method flow according to the embodiment of the present invention by executing the program in ROM and / or RAM. It should be noted that the program can also be stored in one or more memories other than ROM and RAM. The processor can also perform various operations of the method flow according to the embodiment of the present invention by executing the program stored in the one or more memories.

[0056] According to an embodiment of the present invention, the electronic device may further include an input / output (I / O) interface, which is also connected to the bus. The electronic device may also include one or more of the following components connected to the input / output (I / O) interface: an input part including a keyboard, a mouse, etc.; an output part including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage part including a hard disk, etc.; and a communication part including a network interface card such as a LAN card, a modem, etc. The communication part performs communication processing via a network such as the Internet. The drive is also connected to the input / output (I / O) interface as needed. Removable media, such as magnetic disks, optical disks, magneto-optical disks, semiconductor memories, etc., are installed on the drive as needed so that the computer program read therefrom is installed into the storage part as needed.

[0057] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiment; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present invention is implemented.

[0058] According to an embodiment of the present invention, a computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus or a device. For example, according to an embodiment of the present invention, a computer-readable storage medium may include the ROM and / or RAM described above and / or one or more memories other than ROM and RAM.

[0059] The embodiment of the present invention also includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method shown in the flowchart. When the computer program product is run in a computer system, the program code is used to enable the computer system to implement the method of the embodiment of the present invention.

[0060] When the computer program is executed by the processor, the above functions defined in the system / device of the embodiment of the present invention are performed. According to the embodiment of the present invention, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0061] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device, a magnetic storage device, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of a signal on a network medium, and downloaded and installed through a communication part, and / or installed from a removable medium. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0062] In such an embodiment, the computer program can be downloaded and installed from a network through a communication part, and / or installed from a removable medium. When the computer program is executed by a processor, the above-mentioned functions defined in the system of an embodiment of the present invention are performed. According to an embodiment of the present invention, the system, device, means, module, unit, etc. described above can be implemented by a computer program module.

[0063] According to an embodiment of the present invention, the program code for executing the computer program provided by the embodiment of the present invention can be written in any combination of one or more programming languages, specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, such as Java, C++, python, "C" language or similar programming languages. The program code can be executed completely on the user computing device, partially on the user device, partially on the remote computing device, or completely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0064] Example 3

[0065] This embodiment adopts the method described in Embodiment 2. Taking 400G DR4 as an example, the ADC change curves of TXMAIN and TXSUB of the main and auxiliary photodetectors obtained by scanning the Heater_DAC changes of 4 channels with the host computer are as follows: Figure 3 As shown, find the minimum and maximum values ​​of the ADC voltage of TXSUB and the minimum and maximum values ​​of the heater current DAC corresponding to the monotonically increasing range, record them as HT_min and HT_max, and use the heater current DAC value corresponding to the equal ADC values ​​of TXSUB and TXMAIN as the initial value of the heater when the optical module is powered on, record them as HT_Initial, and write HT_min, HT_max and HT_Initial into the registers opened by the MCU. In order to adapt to the differences in the optical eye diagrams between different MZ silicon optical modulators and modules, the MCU also needs to open the corresponding registers for configuration of the ADC ratio of TXMAIN and TXSUB, record them as Ratio, and the fluctuation value Delta of Ratio and the high and low temperature compensation coefficients KH and KL.

[0066] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for adjusting the phase bias point of an MZ silicon optical modulator, characterized in that: The following steps are involved: By finding the minimum and maximum values ​​of the sampling voltage of one of the photodetectors in any period and the current value range of the heater corresponding to the monotonically increasing or decreasing interval, the set phase bias point is indexed within the current value range of the heater.

2. The method for adjusting the phase bias point of a MZ silicon optical modulator according to claim 1, characterized in that: The MZ silicon optical modulator comprises a high-power laser, an MZM silicon optical modulator, a coupler, a main photodetector, an auxiliary photodetector and a microcontroller unit which are connected in sequence. The main photodetector and the auxiliary photodetector are arranged in parallel. The MZM silicon optical modulator is connected to an IDAC controller.

3. The method for adjusting the phase bias point of a MZ silicon optical modulator according to claim 2, characterized in that: The following steps are involved: Step 1: Turn off the enable switch of the automatic control of the phase bias point of the MZ silicon optical modulator; Step 2: The host computer scans the ADC value waveform of TXSUB and TXMAIN as the Heater DAC value changes; Step 3. Find HT_min, HT_max and HT_Initial of the TXSUB ADC waveform and write them into the corresponding registers; Step 4: Turn on the enable switch of the automatic control of the phase bias point; Step 5: Heater DAC starts with HT_Initial as the initial value, and adjusts the DAC value of Heater in the range of HT_min and HT_Initial with a step of 1; Step 6. When the ratio of TXMAIN to TXSUB is greater than Ratio+Delta, the Heater DAC value is increased by 1. When the ratio of TXMAIN to TXSUB is less than Ratio-Delta, the Heater DAC value is reduced by 1. When the ratio of TXMAIN to TXSUB is within the range of Ratio-Delta to Ratio+Delta, the Heater DAC remains unchanged.

4. The method for adjusting the phase bias point of a MZ silicon optical modulator according to claim 3, characterized in that: In the step 3, HT_Initial is the Heater current DAC value corresponding to the ADC values ​​of TXSUB and TXMAIN being equal; in the step 6, Ratio is the ADC ratio of TXMAIN and TXSUB.

5. The method for adjusting the phase bias point of a MZ silicon optical modulator according to claim 4, characterized in that: In step 6, N samples are used to sample the ADC ratio of TXMAIN and TXSUB at 25°C, 0°C and 70°C within 10 minutes, and then the difference between the average value of the ADC ratio and the minimum and maximum values ​​is taken as Delta, and the largest Delta value is selected as the default value configuration for all samples, where N>5.

6. The method for adjusting the phase bias point of a MZ silicon optical modulator according to claim 5, characterized in that: Calculate the Ratio values ​​at 25℃, 0℃ and 70℃ using N samples, find the average Ratio of N samples at 25℃, 0℃ and 70℃, use the Ratio ratio at 70℃ and 25℃ as the KH parameter, and use the Ratio ratio at 0℃ and 25℃ as the KL parameter, where N>5; When Temp_Real>25℃, Ratio=Ratio_RT+(Temp_Real-25℃) / (70℃-25℃)*KH; On the contrary, Ratio=Ratio_RT+(Temp_Real-25°C) / (0°C-25°C)*KL, where Temp_Real is the real-time shell temperature of the optical module, Ratio_RT is the Ratio value at 25°C, Ratio_HT is the Ratio value at 70°C, and Ratio_LT is the Ratio value at 0°C.

7. The method for adjusting the phase bias point of a MZ silicon optical modulator according to claim 6, characterized in that: It is also applicable to lithium niobate MZ external modulators and indium phosphide MZ external modulators.

8. An electronic device, characterized in that: include: One or more processors; one or more memories for storing executable instructions, wherein when the executable instructions are executed by the processors, the method according to any one of claims 1 to 7 is implemented.

9. A computer-readable storage medium, characterized in that: The storage medium stores executable instructions, which, when executed by a processor, implement the method according to any one of claims 1 to 7.

10. A computer program product, characterized in that The method comprises a computer program, wherein the computer program comprises one or more executable instructions, and when the executable instructions are executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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