Dither signal generation and feedback acquisition circuit and method and coherent optical module

Abstract

The invention relates to the technical field of coherent optical communication, in particular to a Dither signal generation and feedback acquisition circuit and method and a coherent optical module, and the circuit comprises an MCU and a DAC chip. The MCU comprises a disturbance generator, an SPI (Serial Peripheral Interface), an on-chip ADC (Analog to Digital Converter), an automatic bias controller and two DMA channels; the first DMA channel, the SPI interface and the DAC chip are connected in sequence, the disturbance generator is connected with the SPI interface, and the DAC chip is connected to a laser and used for sending Dither signals to the laser; the on-chip ADC is connected with the second DMA channel and the laser and used for collecting feedback signals under driving of the second DMA channel, and the on-chip ADC is sequentially connected with the automatic bias controller and the disturbance generator and used for sending optimized and adjusted Dither signal parameters to the disturbance generator. The running efficiency of the MCU can be improved, and the internal resource utilization rate of the MCU is also improved.

Description

Technical Field

[0001] The present invention relates to the technical field of coherent optical communications, and in particular to a dither signal generation and feedback acquisition circuit, method and coherent optical module. Background Art

[0002] In coherent optical communication systems, in order to reduce the frequency drift of the laser and the nonlinear effect of the optical link, it is usually necessary to introduce a dither signal and perform closed-loop control. Traditional methods mainly rely on analog circuits, which have problems such as large signal noise and poor stability.

[0003] During the entire working time of the coherent optical module, the output of the dither signal and the collection of the feedback signal will run continuously. If MCU is used for control, a large amount of MCU processing time will be required, which will seriously affect the working efficiency of the MCU and reduce the timeliness of other functions of the coherent optical module. In addition, the demand for hardware resources is high, which increases the overall cost of the coherent optical module. Summary of the invention

[0004] The purpose of the present invention is to provide a dither signal generation and feedback collection circuit, method and coherent optical module, in which the control is handed over to the DMA channel of the MCU, and the DMA channel does not need the participation of the MCU when running. This not only improves the operating efficiency of the MCU, but also makes full use of the internal resources of the MCU. The generation of dither signals and the collection of feedback signals, as well as the subsequent optimization and adjustment of the automatic bias voltage control algorithm, can be completed by using one MCU and one DAC chip. The entire closed-loop control is realized with less hardware resources, which helps to reduce the cost of the coherent optical module.

[0005] The present invention is implemented by the following technical solutions: a dither signal generation and feedback acquisition circuit, the dither signal generation and feedback acquisition circuit is applied to a coherent optical module, and the circuit includes a first micro control unit and a DAC chip;

[0006] The first microcontroller unit includes a disturbance generator, an SPI interface, an on-chip ADC, an automatic bias controller, and two direct memory access DMA channels operating simultaneously;

[0007] The signal output end of the first DMA channel is connected to the first signal input end of the SPI interface, the signal output end of the disturbance generator is connected to the second signal input end of the SPI interface, and the signal output end of the SPI interface is connected to the signal input end of the DAC chip, and is used to send a preset data stream to the DAC chip according to a preset rule under the drive of the first DMA channel, and the signal output end of the DAC chip is connected to the laser in the coherent optical module, and is used to send a dither signal to the laser;

[0008] The signal input end of the on-chip ADC is connected to the signal output end of the second DMA channel, the signal acquisition end of the on-chip ADC is connected to the laser, and is used to collect feedback signals under the drive of the second DMA channel, the signal output end of the on-chip ADC is connected to the signal input end of the automatic bias controller, and the signal output end of the automatic bias controller is connected to the signal input end of the disturbance generator, and is used to send the Dither signal parameters optimized and adjusted by the automatic bias voltage control algorithm to the disturbance generator.

[0009] According to a preferred embodiment, the DAC chip includes a first DAC channel and a second DAC channel, and the first DAC channel and the second DAC channel are respectively connected to two arms of the laser to provide two dither signals of different frequencies to the laser.

[0010] According to a preferred embodiment, the preset data stream is composed of a first data stream and a second data stream, and the first data stream and the second data stream contain different DAC channel information and preset value information.

[0011] According to a preferred embodiment, the preset data stream is composed of a first data stream and a second data stream arranged in an alternating manner.

[0012] According to a preferred embodiment, the first micro control unit also includes a first timer and a second timer, the signal output end of the first timer is connected to the signal input end of the first DMA channel, and the signal output end of the second timer is connected to the signal input end of the second DMA channel.

[0013] According to a preferred embodiment, the circuit further comprises a second micro control unit, which is communicatively connected with the first micro control unit and is used to control the first micro control unit through internal instructions and read information in the first micro control unit.

[0014] The present invention also provides a dither signal generation and feedback collection control method, which is applied to the dither signal generation and feedback collection circuit as described above, and the method comprises the following steps:

[0015] Step S1, initializing DMA channel;

[0016] Step S2, triggering the first DMA channel, controlling the SPI interface to transmit the preset data stream to the DAC chip, and sending a Dither signal to the laser through the DAC chip;

[0017] Step S3, triggering the second DMA channel to control the on-chip ADC to collect feedback signals;

[0018] Step S4, determine whether the signal generation and feedback collection process is completed, if so, the program ends;

[0019] If not, go to step S5;

[0020] Step S5: Analyze the feedback signal using the automatic bias controller, optimize and adjust the Dither signal parameters according to the analysis results and send them to the disturbance generator, adjust the preset data stream in real time, and go to step S2.

[0021] According to a preferred embodiment, sending a Dither signal to a laser through a DAC chip specifically includes:

[0022] Based on the preset data stream, two Dither signals with different frequencies are respectively set to the first DAC channel and the second DAC channel, and the Dither signals are respectively sent to the two arms of the laser through the first DAC channel and the second DAC channel.

[0023] According to a preferred embodiment, step S1 further includes configuring a timer;

[0024] Step S2 also includes enabling a first timer, and triggering a first DMA channel through the first timer;

[0025] Step S4 also includes enabling a second timer, and triggering a second DMA channel through the second timer.

[0026] The present invention also provides a coherent optical module, comprising the Dither signal generation and feedback acquisition circuit as described above.

[0027] The technical solution of a dither signal generation and feedback acquisition circuit, method and coherent optical module provided by the present invention has at least the following advantages and beneficial effects: (1) The coherent optical module MCU controls the DAC chip through the DMA channel to generate a high-precision dither signal, and uses the DMA channel to control the on-chip ADC to synchronously collect the feedback signal, thereby realizing closed-loop control; the automatic bias controller is used to optimize the dither signal parameters, which can effectively reduce the nonlinear effect and frequency drift in the coherent optical communication, and effectively improve the performance and stability of the coherent optical module; (2) The present invention transfers the control to the DMA channel of the MCU, and the DMA channel does not require the participation of the MCU when running, which not only improves the operating efficiency of the MCU, but also makes full use of the internal resources of the MCU. The generation of the dither signal and the collection of the feedback signal, as well as the subsequent optimization and adjustment of the automatic bias voltage control algorithm, can be completed by using one MCU and one DAC chip; (3) The use of one MCU eliminates the need for communication interaction between MCUs, and uses fewer hardware resources to realize the entire closed-loop control, making the entire control more concise in software implementation, which helps to reduce the cost of the coherent optical module. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of the principle of a dither signal generation and feedback acquisition circuit provided in Example 1 of the present invention;

[0029] Figure 2 A flowchart of a dither signal generation and feedback acquisition control method provided in Example 5 of the present invention;

[0030] Figure 3 A timing diagram of synchronous processing of a dither signal and a feedback signal provided in Embodiment 5 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0032] Example 1

[0033] Figure 1 The schematic diagram of the principle of a dither signal generation and feedback acquisition circuit provided by an embodiment of the present invention is shown in FIG. The dither signal generation and feedback acquisition circuit is applied to a coherent optical module; see Figure 1 As shown, the Dither signal generation and feedback acquisition circuit includes a first micro control unit and a DAC chip.

[0034] The first microcontroller unit, hereinafter referred to as the secondary MCU, includes a disturbance generator, an SPI interface, an on-chip ADC, an automatic bias controller, and two direct memory access DMA channels working simultaneously.

[0035] In this embodiment, the control logic of the DMA channel is preconfigured, and the DAC chip is controlled by the DMA channel to generate a high-precision dither signal. The DMA channel does not require the participation of the secondary MCU when running, so as to improve the operating efficiency of the secondary MCU and make full use of the internal resources of the secondary MCU. The specific configuration of the circuit is as follows:

[0036] The DMA channel transmits data between the secondary MCU and the DAC chip to realize synchronous high-speed processing of signals; the signal output end of the first DMA channel is connected to the first signal input end of the SPI interface, the signal output end of the disturbance generator is connected to the second signal input end of the SPI interface, and the signal output end of the SPI interface is connected to the signal input end of the DAC chip, which is used to send a preset data stream to the DAC chip according to a preset rule under the drive of the first DMA channel; the DAC chip converts the digital signal into an analog disturbance signal, and the signal output end of the DAC chip is connected to the laser in the coherent optical module, which is used to send a dither signal to the laser at a preset frequency.

[0037] Furthermore, the on-chip ADC is controlled by the DMA channel to synchronously collect feedback signals. After the feedback signal collection is completed, the data is transmitted to the secondary MCU for processing, thereby realizing closed-loop control. The specific configuration of the circuit is as follows:

[0038] The DMA channel transmits data between the secondary MCU and the on-chip ADC to achieve synchronous high-speed processing of signals; the signal input end of the on-chip ADC is connected to the signal output end of the second DMA channel, the on-chip ADC converts the analog signal into a digital signal, and the signal acquisition end of the on-chip ADC is connected to the laser to collect feedback signals at a preset frequency under the drive of the second DMA channel.

[0039] Furthermore, the automatic bias voltage control ABC algorithm is used to optimize the Dither signal parameters to reduce the nonlinear effect and frequency drift in coherent optical communication and improve the performance and stability of the coherent optical module. The specific circuit configuration is as follows:

[0040] The automatic bias controller optimizes and adjusts the Dither signal parameters, such as the amplitude of the Dither signal, according to the feedback signal; the signal output end of the on-chip ADC is connected to the signal input end of the automatic bias controller, and the signal output end of the automatic bias controller is connected to the signal input end of the disturbance generator, so as to send the Dither signal parameters optimized and adjusted by the automatic bias voltage control algorithm to the disturbance generator.

[0041] In summary, this embodiment uses one MCU, eliminates the communication interaction between MCUs, uses fewer hardware resources to implement the entire closed-loop control, makes the entire control more concise in software implementation, and helps to reduce the cost of coherent optical modules.

[0042] Example 2

[0043] This embodiment is based on the technical solution provided in Example 1, and further describes the DAC chip:

[0044] In this embodiment, the preset data stream is composed of an alternating arrangement of a first data stream and a second data stream, and the first data stream and the second data stream contain different DAC channel information and preset numerical information, so as to ensure that the DAC chip can correctly identify and set the correct Dither data point; the DAC channel information is used to instruct the DAC chip to allocate the corresponding data stream to the corresponding DAC channel; the DAC chip includes a first DAC channel and a second DAC channel, and the first DAC channel and the second DAC channel are respectively connected to the two arms of the laser, so as to provide two Dither signals of different frequencies to the laser.

[0045] Through the above method, it is possible to implement two Dither signals with different frequencies on one laser at the same time.

[0046] Example 3

[0047] This embodiment is based on the technical solution provided in Embodiment 2, and further explains the triggering method of the DMA channel:

[0048] In this embodiment, the first micro control unit also includes a first timer and a second timer, the signal output end of the first timer is connected to the signal input end of the first DMA channel, and the signal output end of the second timer is connected to the signal input end of the second DMA channel; in this embodiment, the first timer periodically triggers the first DMA channel to control the SPI interface to transmit a preset data stream to the DAC chip, thereby ensuring that the time interval between each data point of the output Dither signal is accurate and consistent; in addition, the second timer also periodically triggers the second DMA channel to control the on-chip ADC to complete the collection of the feedback signal, and maintains a stable frequency when collecting the feedback signal, thereby ensuring that the collected feedback signal is complete and accurate.

[0049] Example 4

[0050] This embodiment is based on the technical solution provided in Embodiment 3, and configures a second microcontroller unit as a main MCU. The main MCU is communicatively connected with the secondary MCU to control the secondary MCU through internal instructions and read information in the secondary MCU.

[0051] Example 5

[0052] This embodiment provides a dither signal generation and feedback acquisition control method based on the technical solution provided in any one of embodiments 3 to 4. The method is applied to the dither signal generation and feedback acquisition circuit as in any one of embodiments 3 to 4. Figure 2 and Figure 3 As shown, the method comprises the following steps:

[0053] Step S1, initialize the DMA channel and timer, configure the DMA channel in the secondary MCU, one DMA channel sends commands and preset data streams to the DAC chip according to preset rules, and another DMA channel controls the on-chip ADC of the secondary MCU to synchronously collect feedback signals.

[0054] Step S2, enabling the first timer, triggering the first DMA channel through the first timer, controlling the SPI interface to transmit the preset data stream to the DAC chip, and sending a Dither signal to the laser through the DAC chip;

[0055] In this embodiment, a Dither signal is sent to the laser through a DAC chip, specifically including: setting two Dither signals of different frequencies to a first DAC channel and a second DAC channel respectively based on a preset data stream, and sending the Dither signal to two arms of the laser through the first DAC channel and the second DAC channel respectively.

[0056] Step S3, enabling the second timer, triggering the second DMA channel through the second timer, and controlling the on-chip ADC to collect the feedback signal.

[0057] Step S4, determine whether the signal generation and feedback collection process is completed, if so, the program ends; if not, go to step S5.

[0058] Step S5, using the automatic bias controller to analyze the feedback signal, optimizing and adjusting the Dither signal parameters according to the analysis results and sending them to the disturbance generator, adjusting the preset data stream in real time, improving the control accuracy and response speed of the Dither signal, and then going to step S2.

[0059] Example 6

[0060] This embodiment provides a coherent optical module based on the technical solution provided in any one of Embodiments 3 to 4. The coherent optical module includes a dither signal generation and feedback acquisition circuit as in any one of Embodiments 3 to 4.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A dither signal generation and feedback acquisition circuit, characterized in that: The Dither signal generation and feedback acquisition circuit is applied to a coherent optical module, and the circuit includes a first micro control unit and a DAC chip; The first microcontroller unit includes a disturbance generator, an SPI interface, an on-chip ADC, an automatic bias controller, and two direct memory access DMA channels operating simultaneously; The signal output end of the first DMA channel is connected to the first signal input end of the SPI interface, the signal output end of the disturbance generator is connected to the second signal input end of the SPI interface, and the signal output end of the SPI interface is connected to the signal input end of the DAC chip, and is used to send a preset data stream to the DAC chip according to a preset rule under the drive of the first DMA channel, and the signal output end of the DAC chip is connected to the laser in the coherent optical module, and is used to send a dither signal to the laser; The signal input end of the on-chip ADC is connected to the signal output end of the second DMA channel, the signal acquisition end of the on-chip ADC is connected to the laser, and is used to collect feedback signals under the drive of the second DMA channel, the signal output end of the on-chip ADC is connected to the signal input end of the automatic bias controller, and the signal output end of the automatic bias controller is connected to the signal input end of the disturbance generator, and is used to send the Dither signal parameters optimized and adjusted by the automatic bias voltage control algorithm to the disturbance generator.

2. The Dither signal generation and feedback acquisition circuit according to claim 1, characterized in that: The DAC chip includes a first DAC channel and a second DAC channel, wherein the first DAC channel and the second DAC channel are respectively connected to two arms of the laser and are used to provide two dither signals of different frequencies to the laser.

3. The Dither signal generation and feedback acquisition circuit according to claim 2, characterized in that: The preset data stream is composed of a first data stream and a second data stream, and the first data stream and the second data stream contain different DAC channel information and preset value information.

4. The Dither signal generation and feedback acquisition circuit according to claim 3, characterized in that: The preset data stream is composed of a first data stream and a second data stream arranged alternately.

5. The dither signal generation and feedback acquisition circuit according to any one of claims 1 to 4, characterized in that: The first micro control unit also includes a first timer and a second timer. The signal output end of the first timer is connected to the signal input end of the first DMA channel, and the signal output end of the second timer is connected to the signal input end of the second DMA channel.

6. The Dither signal generation and feedback acquisition circuit according to claim 5, characterized in that: The circuit also includes a second micro control unit, which is communicatively connected to the first micro control unit and is used to control the first micro control unit through internal instructions and read information in the first micro control unit.

7. A dither signal generation and feedback acquisition control method, characterized in that: Applied to the dither signal generation and feedback acquisition circuit as claimed in any one of claims 5 to 6, the method comprises the following steps: Step S1, initializing DMA channel; Step S2, triggering the first DMA channel, controlling the SPI interface to transmit the preset data stream to the DAC chip, and sending a Dither signal to the laser through the DAC chip; Step S3, triggering the second DMA channel to control the on-chip ADC to collect feedback signals; Step S4: determine whether the signal generation and feedback collection process is completed, if so, the program ends; If not, go to step S5; Step S5: Analyze the feedback signal using the automatic bias controller, optimize and adjust the Dither signal parameters according to the analysis results and send them to the disturbance generator, adjust the preset data stream in real time, and go to step S2.

8. The dither signal generation and feedback acquisition control method according to claim 7, characterized in that: The sending of the Dither signal to the laser through the DAC chip specifically includes: Based on the preset data stream, two Dither signals with different frequencies are respectively set to the first DAC channel and the second DAC channel, and the Dither signals are respectively sent to the two arms of the laser through the first DAC channel and the second DAC channel.

9. The dither signal generation and feedback acquisition control method according to claim 8, characterized in that: Step S1 also includes configuring a timer; Step S2 also includes enabling a first timer, and triggering a first DMA channel through the first timer; Step S4 also includes enabling a second timer, and triggering a second DMA channel through the second timer.

10. A coherent optical module, characterized in that: It comprises the Dither signal generating and feedback collecting circuit as described in any one of claims 1 to 6.

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