Coupling sampling circuit and method adaptive to strong and weak incident light intensity

Abstract

The invention provides a coupling sampling circuit and method adapting to strong and weak incident light intensity. The coupling sampling circuit comprises a control module, a sampling switching module and a sampling assembly which are connected in sequence. The sampling assembly at least comprises a first sampling module and a second sampling module; the first sampling module and the second sampling module are respectively used for collecting backlight current output by the silicon optical chip and converting the backlight current into sampling voltage within a preset range; the control module is used for judging whether the sampling voltage reaches a set threshold value or not and generating a corresponding switching signal, if yes, collecting through a second coupling mode, and if not, continuously collecting through the first coupling mode so as to adapt to high-precision coupling of strong current and weak current; and the sampling switching module is used for determining whether to start the second sampling module to participate in acquisition or not according to the switching signal. According to the invention, the precision and efficiency of the coupling process are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical communication technology, in particular to a coupling sampling circuit and method suitable for strong and weak input light intensity. BACKGROUND

[0002] With the rapid growth of data center interconnection applications, the demand for high-speed optical modules is increasing day by day. Coupling process is the core process of optical module manufacturing, and the effect of coupling process directly affects the transmission efficiency of signal light in optical module and determines the performance of optical module.

[0003] In the coupling process of the high-speed optical module emission end based on a silicon optical chip, the signal light emitted by the laser needs to be precisely converged at the light-in waveguide of the silicon optical chip to complete the mode field matching. The light-in waveguide mode field diameter of the silicon optical chip is usually only about 500 nm, and the SSC (Spot Size Converter) structure can only expand the optical mode field to more than 3 um, which puts higher requirements on the coupling process. In order to meet the needs of strong input light intensity, the conventional coupling sampling circuit often uses a sampling circuit with a small sampling resistance value to ensure that the sampling voltage generated by the sampling resistance does not exceed the receiving range of the control module under the condition of strong input light intensity. However, such a coupling sampling circuit is difficult to capture weak input light intensity (since the input light intensity is weak and the sampling resistance value is small, the sampling voltage generated is also very weak and is easily submerged in circuit noise, making it difficult to be captured), which leads to a long time required to find the initial signal light (i.e. to find the coupling position with the best input light intensity), and the coupling process is inefficient. SUMMARY

[0004] The purpose of the present application is to provide a coupling sampling circuit and method suitable for strong and weak input light intensity to improve the coupling efficiency of the silicon optical chip.

[0005] To solve the above technical problems, the present application provides a coupling sampling circuit suitable for strong and weak input light intensity, which comprises a control module, a sampling switching module and a sampling component connected in sequence; the sampling component comprises at least a first sampling module and a second sampling module; The first sampling module and the second sampling module are respectively used for collecting the backlight current output by the silicon optical chip and converting the backlight current into a sampling voltage within a preset range; the backlight current is converted from the input light intensity of the backlight based on the photodetector of the silicon optical chip; The control module judges whether the sampling voltage reaches a set threshold value and generates a corresponding switching signal, if yes, the second coupling mode is used for collection, and if not, the first coupling mode is used for collection; the first coupling mode is the collection by the first sampling module, and the second coupling mode is the simultaneous collection by the first sampling module and the second sampling module arranged in parallel; The sampling switching module is configured to determine whether to enable the second sampling module to participate in the collection according to the switching signal.

[0006] According to the above scheme, the sampling resistance of the first sampling module is greater than the sampling resistance of the second sampling module.

[0007] According to the above scheme, the control module comprises a monitoring signal interface and a logic control interface; the monitoring signal interface inputs the sampling voltage generated in the first coupling mode or the second coupling mode, and the logic control interface outputs the switching signal of the sampling switching module.

[0008] According to the above scheme, the first sampling module is connected to the silicon optical chip and the sampling point respectively at two ends; and the monitoring signal interface is connected to the sampling point.

[0009] According to the above scheme, the second sampling module is connected to the sampling switching module and the sampling point respectively at two ends.

[0010] According to the above scheme, the sampling switching module comprises a MOS tube.

[0011] According to the above scheme, the heating control module comprises a heater control interface; the silicon optical chip comprises a heater, the heater control interface is connected to the heater, and the heating control module is connected to the control module. The control module controls the temperature of the heater through the heating control module based on the sampling voltage.

[0012] According to the above scheme, the heating control module is an AFE chip, and the AFE chip is connected to the heater control interface through an SPI bus.

[0013] The application also provides a coupling sampling method suitable for strong and weak input light intensity, comprising: S1, when starting coupling, it is the first coupling stage, and a first coupling mode is adopted; the first coupling mode is collected by the first sampling module; S2, the first sampling module converts the backlight current into the sampling voltage of the first coupling stage; the backlight current is converted by the photodetector of the silicon optical chip based on the input backlight intensity; S3, after the sampling voltage of the first coupling stage reaches a set threshold, the second coupling stage is entered and a second coupling mode is adopted; the second coupling mode is that the first sampling module and the second sampling module are simultaneously collected in parallel; S4, the first sampling module and the second sampling module convert the backlight current into the sampling voltage of the second coupling stage.

[0014] According to the above scheme, comprising: adjusting the voltage signal applied to the heater according to the sampling voltage.

[0015] Advantages The application adjusts the strong and weak input light intensity by setting the first sampling module and the second sampling module, and switching the coupling mode by the control module to adapt to different input light intensity, which ensures that the weak input light intensity can be effectively detected, and the strong input light intensity will not cause the sampling voltage saturation, avoids that when the sampling voltage is saturated, the coupling curve produces a large flat area (see Figure 6 ), the control module cannot continue to track the further change of the input light intensity, and then the strong and weak input light intensity is adapted; compared with the conventional coupling sampling circuit using a single sampling path, the coupling sampling circuit of the application significantly improves the efficiency of the coupling process.

[0016] Further, the application controls the heater of the silicon optical chip in real time based on the backlight intensity by the heating control module, realizes the locking of the silicon optical chip operating point control loop after the coupling is completed, and reduces the power difference between the output light of the silicon optical chip and the input backlight. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a system schematic diagram of the coupling sampling circuit for adapting to strong and weak input light intensity of the embodiment one of the application; Figure 2 is a structure schematic diagram of the coupling sampling circuit for adapting to strong and weak input light intensity of the embodiment one of the application; Figure 3 is a structure schematic diagram of the coupling sampling circuit for adapting to strong and weak input light intensity of the embodiment two of the application; Figure 4 is a circuit structure schematic diagram of the first sampling module provided by the embodiment of the application; Figure 5 is a circuit structure schematic diagram of the second sampling module provided by the embodiment of the application; Figure 6 is a coupling flat area change schematic diagram of the embodiment of the application; Figure 7 is a coupling sampling method flowchart schematic diagram for adapting to strong and weak input light intensity of the embodiment one of the application.

[0018] In the figure: 1-silicon optical chip, 101-optoelectronic detector, 102-heater, 2-first sampling module, 3-second sampling module, 4-sampling switching module, 5-control module, 501-logic control interface, 502-monitoring signal interface, 6-heating control module, 601-heater control interface, 7-SPI bus, 8-sampling point. DETAILED DESCRIPTION

[0019] To make the objects, technical solutions and advantages of the embodiments of the present disclosure clearer, the following will be combined with the drawings of the embodiments of the present disclosure to make a clear and complete description of the technical solutions of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by a person of ordinary skill in the art without any inventive effort fall within the protection scope of the present disclosure.

[0020] Embodiment one: Referring to Figure 1 , Figure 2 The embodiment provides a coupling sampling circuit suitable for strong and weak incoming light intensity, which comprises a control module 5 (i.e. MCU: MicroController Unit) connected in sequence, a sampling switching module 4 and a sampling component; the sampling component at least comprises a first sampling module 2 and a second sampling module 3. The first sampling module 2 and the second sampling module 3 are respectively used for collecting the backlight current output by a silicon optical chip 1 (Photonic Integrated Circuits) and converting the backlight current into a sampling voltage in a preset range; the backlight current is converted by a photodetector 101 (MPD, Monitor PD) of the silicon optical chip 1 based on the incoming light intensity of the input backlight. The control module 20 is used for judging whether the sampling voltage reaches a set threshold value and generating a corresponding switching signal, if yes, collecting through a second coupling mode, otherwise, continuing to collect through a first coupling mode. The first coupling mode is the first sampling module collecting, and the second coupling mode is the first sampling module and the second sampling module collecting simultaneously in parallel.

[0021] The sampling switching module 4 is used for determining whether to enable the second sampling module 3 to participate in collecting according to the switching signal.

[0022] Further, the sampling resistance of the first sampling module 2 is greater than the sampling resistance of the second sampling module 3.

[0023] Further, the control module 5 comprises a monitoring signal interface 502 and a logic control interface 501; the monitoring signal interface 502 inputs the sampling voltage generated in the first sampling mode or the second sampling mode, and the logic control interface 501 outputs the switching signal of the sampling switching module 4.

[0024] Further, the first sampling module 2 is connected with the silicon optical chip 1 and a sampling point 8 at two ends (i.e. input end and output end) respectively; and the monitoring signal interface 502 is connected to the sampling point 8.

[0025] Further, the second sampling module 3 is connected with the sampling switching module 4 and the sampling point 8 at both ends (i.e. input end and output end) respectively, and the monitoring signal pin is connected to the sampling point. In the embodiment, the resistance of the first sampling module 2 is greater than the resistance when the first sampling module 2 and the second sampling module 3 are connected in parallel, and thus the two coupling modes are adapted to the weak backlight current and the strong backlight current in the coupling process respectively.

[0026] The embodiment also provides specific circuit structures of the first sampling module 2 (see Figure 4 ) and the second sampling module 3 (see Figure 5 ); in the figure, is the backlight current, is the reference voltage input from outside, is the sampling voltage.

[0027] Further, the sampling switching module 4 comprises a MOS tube (MOSFET, Metal Oxide Semiconductor Field Effect Transistor), the gate of the MOS tube is connected with the logic control interface 501, and the drain and the source of the MOS tube are connected with the second sampling module 3 and the photodetector 101 respectively.

[0028] Referring to Figure 7 , the embodiment also provides a coupling sampling method adapted to the strong and weak input light intensity, comprising: S1, when starting coupling, the first coupling mode is adopted in the first coupling stage; the first coupling mode is that the first sampling module 2 collects; S2, the first sampling module 2 converts the backlight current into the sampling voltage in the first coupling stage; the backlight current is converted by the photodetector 101 of the silicon optical chip 1 based on the input backlight intensity; S3, after the sampling voltage in the first coupling stage reaches the set threshold value, the second coupling mode is adopted in the second coupling stage; the second coupling mode is that the first sampling module 2 and the second sampling module 3 which are connected in parallel collect simultaneously; S4, the first sampling module 2 and the second sampling module 3 convert the backlight current into the sampling voltage in the second coupling stage; In the second coupling stage, the coupling position is found by continuously adjusting, and thus the coupling process is completed.

[0029] The working principle of the coupling sampling circuit of the embodiment is as follows: In the initial stage of the coupling process, the system is in the first coupling mode. The signal sent by the logic control interface 501 of the control module 5 turns off the MOS transistor, and the branch where the first sampling module 2 is located is always in the on state. When the signal light emitted from the laser is coupled into the input waveguide of the silicon photonic chip 1, the photodetector 101 integrated in the silicon photonic chip 1 receives a weak backlight signal. The converted weak backlight current signal is received by the first sampling module 2 and converted into a sampling voltage for the first coupling stage. The control module 5 obtains the sampling voltage of the first coupling stage through the monitoring signal interface 502. The ADC (analog-to-digital converter) in the control module 5 samples the sampling voltage of the first coupling stage and converts it into a first-stage digital signal, which corresponds to the sampling value stored in the control module 5. When the first sampling module 2 is selected for acquisition, the coupling sampling circuit has high sensitivity and can convert the weak backlight current signal into a detectable sampling voltage.

[0030] After receiving the signal light, the photodetector 101 finely couples the signal light with the incident waveguide of the silicon photonic chip 1. During the process, the control module 5 monitors the incident light intensity in real time through the monitoring signal interface 502.

[0031] When the sampling voltage received by the ADC reaches the threshold, it indicates that the photodetector 101 generates a strong backlight current signal, such as... Figure 6 As shown, the coupling curve enters a large flat region, making finer coupling impossible to find a larger target optical power. To control the sampling voltage and prevent it from becoming too large, the control module 5 outputs a logic signal to turn on the MOS transistor on the branch where the second sampling module 3 is located. At this time, it switches to the second coupling mode, and the first sampling module 2 and the second sampling module 3, which are connected in parallel, work simultaneously. After switching to the second coupling mode, the flat region of the coupling process is narrowed, allowing for finer coupling to find the optimal coupling position and achieve the best coupled optical power. The ADC in the control module 5 samples the sampling voltage of the first coupling stage and converts it into a second-stage digital signal, which corresponds to the sampled value within the control module 5. When the second sampling module 3 is used for acquisition, the coupling sampling circuit has low sensitivity, which can prevent the sampling voltage from saturating due to strong incident light intensity.

[0032] The coupling sampling circuit in this embodiment uses two sampling modules with different resistance values ​​connected in parallel. Combined with the sampling switching module, it forms two coupling modes to prevent the coupling curve from entering the flat region too early due to sampling voltage saturation, which would prevent further fine coupling. This significantly shortens the time for the photodetector 101 to find the initial signal light when the silicon photonic chip 1 is coupled, and improves the efficiency of the coupling process.

[0033] Example 2: See Figure 3The embodiment discloses a coupling sampling circuit suitable for strong and weak input light intensity, and the difference from the coupling sampling circuit in the first embodiment is that the coupling sampling circuit further comprises a heating control module 6, the heating control module 6 comprises a heater control interface 601; the silicon optical chip 1 comprises a heater 102, the heater control interface 601 is connected with the heater 102, and the heating control module 6 is connected with the control module 5. The control module 5 adjusts the voltage signal applied to the heater 102 through the heating control module 6 based on the sampling voltage.

[0034] Further, the heating control module 6 is an AFE chip (Analog Front End), and the AFE chip is connected with the heater control interface 601 through an SPI bus 7.

[0035] The embodiment further discloses a coupling sampling method suitable for strong and weak input light intensity, and the difference from the coupling sampling method suitable for strong and weak input light intensity in the first embodiment is that the coupling sampling method further comprises the following step: adjusting the voltage signal applied to the heater 102 in the silicon optical chip 1 through the heating control module 6 according to the sampling voltage. It should be noted that the step is continuously executed in the whole process of the coupling sampling method, that is, the step is executed in parallel with steps S1-S4 in the first embodiment.

[0036] The coupling sampling circuit in the embodiment adjusts the voltage signal loaded on the heater 102 in the silicon optical chip 1 according to the sampling value in the control module 5 through the AFE chip, effectively controls the photoelectric current jump of the silicon optical chip 1 caused by external factors such as temperature, provides a precise and stable monitoring reference for the working point control loop locking of the silicon optical chip 1, and reduces the light power difference between the output light and the input backlight.

[0037] It should be noted that, according to the needs of implementation, each step / component described in the present application can be split into more steps / components, or two or more steps / components or part of the operation of the steps / components can be combined into a new step / component, so as to realize the purpose of the present application.

[0038] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A coupling sampling circuit adapted to strong and weak incoming light intensity, characterized in that, The sampling device comprises a control module, a sampling switch module and a sampling assembly connected in sequence. The first sampling module and the second sampling module are respectively used for collecting the backlight current output by the silicon optical chip and converting the backlight current into a sampling voltage within a preset range. The control module is used for judging whether the sampling voltage reaches a set threshold value and generating a corresponding switching signal. The sampling switch module is used for determining whether to enable the second sampling module to participate in the collection according to the switching signal.

2. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 1, characterized in that, The sampling resistance of the first sampling module is greater than the sampling resistance of the second sampling module.

3. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 1, characterized in that, The control module comprises a monitoring signal interface and a logic control interface.

4. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 3, characterized in that, The monitoring signal interface inputs the sampling voltage generated in the first coupling mode or the second coupling mode, and the logic control interface outputs the switching signal of the sampling switch module.

5. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 4, characterized in that, The first sampling module is connected to the silicon optical chip and a sampling point at two ends respectively.

6. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 1, characterized in that, The monitoring signal interface is connected to the sampling point.

7. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 3, characterized in that, The second sampling module is connected to the sampling switch module and the sampling point at two ends respectively. The sampling switch module comprises a MOS tube.

8. The coupling and sampling circuit adaptive to strong and weak incident light intensity according to claim 7, characterized in that, The heating control module comprises a heater control interface.

9. A coupling sampling method suitable for adapting to strong and weak incoming light intensity, characterized in that, The control module controls the temperature of the heater through the heating control module based on the sampling voltage. The heating control module is an AFE chip connected to the heater control interface through an SPI bus. The method comprises the following steps: S1, a first coupling stage is adopted when starting coupling. The first coupling mode is used for collecting by the first sampling module. S2, the first sampling module converts the backlight current into a sampling voltage in the first coupling stage.

10. The method of claim 9, wherein the coupling sampling method is adapted to the strong and weak light intensity. S3, after the sampling voltage in the first coupling stage reaches a set threshold value, a second coupling stage is entered and a second coupling mode is adopted. S4, the first sampling module and the second sampling module convert the backlight current into a sampling voltage in the second coupling stage. According to the sampling voltage, the voltage signal applied to the heater is adjusted.

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