Control system of adjustable optical filter

Abstract

The utility model discloses a control system of an adjustable optical filter, which relates to the technical field of optical fiber communication and comprises an input acquisition channel connected with an input end of the adjustable optical filter, an output acquisition channel connected with an output end of the adjustable optical filter and a voltage amplification circuit connected with a control end group of the adjustable optical filter. The input acquisition channel is connected with a first signal acquisition end of the main controller, the output acquisition channel is connected with a second signal acquisition end of the main controller, and an input end of the voltage amplification circuit is connected with a control voltage output end group of the main controller; the input acquisition channel is used for acquiring an input optical power signal, and the output acquisition channel is used for acquiring an output optical power signal. The system can carry out closed-loop control on the filtering frequency of the adjustable optical filter, so that the deviation between the input light frequency and the output light frequency of the adjustable optical filter is kept within a reasonable threshold range.

Description

Technical Field

[0001] The utility model relates to the technical field of optical fiber communication, in particular to a control system of an adjustable optical filter. Background Art

[0002] The primary operating mode of an adjustable optical filter is open-loop control, where the filter frequency of the input light is altered by changing its control voltage. However, when operating in open-loop control mode, if the adjustable optical filter controller operates for too long or the ambient temperature changes, the filter frequency may deviate from the set frequency. Therefore, in the prior art, the relationship between the filter frequency and the control voltage of the adjustable optical filter is calibrated before shipment. In open-loop control mode, the operating voltage of the adjustable optical filter is adjusted according to the ambient operating temperature. However, since the accuracy of the adjustable optical filter is also affected by operating time and other environmental factors, the correspondence between the control voltage and the filter frequency may still deviate in actual applications. This can result in an excessively large filter frequency error, causing a significant deviation between the input and output light frequencies of the adjustable optical filter, thus affecting the normal operation of the adjustable optical filter. Utility Model Content

[0003] In response to the above problems and technical requirements, the applicant has proposed a control system for a tunable optical filter.

[0004] The technical solution of the utility model is as follows:

[0005] A control system for an adjustable optical filter, comprising an input acquisition channel connected to an input end of the adjustable optical filter, an output acquisition channel connected to an output end of the adjustable optical filter, and a voltage amplifying circuit connected to a control end group of the adjustable optical filter;

[0006] The input acquisition channel is connected to the first signal acquisition terminal of the main controller, the output acquisition channel is connected to the second signal acquisition terminal of the main controller, and the input terminal of the voltage amplification circuit is connected to the control voltage output terminal group of the main controller;

[0007] The input acquisition channel is used to acquire input optical power signals, and the output acquisition channel is used to acquire output optical power signals;

[0008] The main controller is used to control the output voltage of the voltage amplifier circuit so that the tunable optical filter operates at a preset filtering frequency. The main controller is also used to adjust the output voltage of the voltage amplifier circuit according to the output optical power signal after the tunable optical filter operates at the preset filtering frequency, so as to adjust the filtering frequency of the tunable optical filter.

[0009] A further technical solution is that the input acquisition channel includes a first optical splitter and a first photodetector, wherein:

[0010] The main splitting end of the first splitter is connected to the input end of the tunable optical filter, the auxiliary splitting end of the first splitter is connected to the input end of the first photodetector, and the output end of the first photodetector is connected to the first signal acquisition end of the main controller.

[0011] A further technical solution is that the output collection channel includes a second spectrometer and a second photodetector, wherein:

[0012] The input end of the second optical splitter is connected to the output end of the tunable optical filter, the auxiliary optical splitting end of the second optical splitter is connected to the input end of the second photodetector, and the output end of the second photodetector is connected to the second signal acquisition end of the main controller.

[0013] A further technical solution is that the input acquisition channel further includes a first signal amplifier, and the output acquisition channel further includes a second signal amplifier;

[0014] The output end of the first photodetector is connected to the first signal acquisition end of the main controller through a first signal amplifier;

[0015] The output end of the second photodetector is connected to the second signal collection end of the main controller through a second signal amplifier.

[0016] A further technical solution is that the voltage amplifying circuit includes a long-wave control voltage amplifying circuit and a short-wave control voltage amplifying circuit;

[0017] The control end group of the tunable optical filter includes a long-wave control end and a short-wave control end, and the control voltage output end group of the main controller includes a long-wave control voltage output end and a short-wave control voltage output end;

[0018] The long-wave control voltage output terminal of the main controller is connected to the long-wave control terminal of the adjustable optical filter through the long-wave control voltage amplifier circuit, and the short-wave control voltage output terminal of the main controller is connected to the short-wave control terminal of the adjustable optical filter through the short-wave control voltage amplifier circuit.

[0019] A further technical solution is that the long-wave control voltage amplifying circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, an operational amplifier U1 and a capacitor C1, wherein:

[0020] The non-inverting input terminal of the operational amplifier U1 is connected to the long-wave control voltage output terminal through the resistor R1 for receiving the long-wave control voltage; the inverting input terminal of the operational amplifier U1 is grounded through the resistor R3 and connected to the output terminal of the operational amplifier U1 through the resistor R2;

[0021] The ground terminal of the operational amplifier U1 is grounded, and the power supply terminal of the operational amplifier U1 is connected to the power supply voltage VCC and is grounded through the capacitor C1.

[0022] A further technical solution is that the short-wave control voltage amplifying circuit includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, an operational amplifier U2 and a capacitor C2, wherein:

[0023] The non-inverting input terminal of the operational amplifier U2 is connected to the shortwave control voltage output terminal through a resistor R5 for receiving the shortwave control voltage; the inverting input terminal of the operational amplifier U2 is grounded through a resistor R7 and connected to the output terminal of the operational amplifier U2 through a resistor R6;

[0024] The ground terminal of the operational amplifier U2 is grounded, and the power supply terminal of the operational amplifier U2 is connected to the power supply voltage VCC and is grounded through the capacitor C2.

[0025] A further technical solution is that the output end of the operational amplifier U1 is connected to the first pin of the plug J1 through the resistor R4, and the first pin of the plug J1 is connected to the long-wave control voltage output end;

[0026] The output end of the operational amplifier U2 is connected to the third pin of the plug J1 through the resistor R8. The third pin of the plug J1 is connected to the shortwave control voltage output end. The second pin of the plug J1 is grounded.

[0027] A further technical solution is that the main controller is also used to store the corresponding relationship between the filter frequency and the long-wave control voltage and the short-wave control voltage.

[0028] A further technical solution is that the main controller is further used to determine the control state of the tunable optical filter according to the input optical power signal and the output optical power signal.

[0029] The beneficial technical effects of the utility model are:

[0030] This application adds input and output acquisition channels before and after the tunable optical filter, enabling the acquisition of the filter's input and output optical power signals during practical applications. Based on the real-time acquired output optical power signals, a main controller controls the output voltage of the voltage amplifier circuit to adjust the filter frequency of the tunable optical filter in real time. This enables closed-loop control of the filter frequency, ensuring that the deviation between the filter's input and output optical frequencies remains within a reasonable threshold. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic block diagram of an embodiment of the adjustable optical filter control system provided by the utility model.

[0032] Figure 2 This is a circuit principle diagram of an embodiment of a voltage amplifier circuit provided by the utility model.

[0033] Reference numerals: 1 - main controller, 2 - tunable optical filter, 3 - first optical splitter, 4 - first photodetector, 5 - second optical splitter, 6 - second photodetector. DETAILED DESCRIPTION

[0034] The specific implementation of the present utility model will be further described below with reference to the accompanying drawings.

[0035] The utility model provides a control system for an adjustable optical filter, such as Figure 1 As shown, it includes an input acquisition channel connected to the input end of the tunable optical filter 2, an output acquisition channel connected to the output end of the tunable optical filter 2, and a voltage amplifying circuit connected to the control end group of the tunable optical filter 2;

[0036] The input acquisition channel is connected to the first signal acquisition terminal of the main controller 1, the output acquisition channel is connected to the second signal acquisition terminal of the main controller 1, and the input end of the voltage amplification circuit is connected to the control voltage output terminal group of the main controller 1;

[0037] The input acquisition channel is used to acquire input optical power signals, and the output acquisition channel is used to acquire output optical power signals;

[0038] The main controller 1 is used to control the output voltage of the voltage amplifier circuit so that the tunable optical filter 2 operates at a preset filtering frequency. The main controller 11 is also used to adjust the output voltage of the voltage amplifier circuit according to the output optical power signal after the tunable optical filter 2 operates at the preset filtering frequency, so as to adjust the filtering frequency of the tunable optical filter.

[0039] Specifically, the output end of the voltage amplifier circuit is connected to the control end group of the tunable optical filter 2. The control end group of the tunable optical filter 2 includes a long-wave control end and a short-wave control end. The control voltage output end group of the main controller 1 includes a long-wave control voltage output end and a short-wave control voltage output end. The long-wave control voltage outputted from the long-wave control voltage output end of the main controller 1 is amplified by the voltage amplifier circuit and then inputted into the long-wave control end of the tunable optical filter 2. The short-wave control voltage outputted from the short-wave control voltage output end of the main controller 1 is amplified by the voltage amplifier circuit and then inputted into the short-wave control end of the tunable optical filter 2. The amplified long-wave control voltage and short-wave control voltage are used to jointly control the filtering frequency of the tunable optical filter 2. The output voltage of the voltage amplifier circuit is the amplified long-wave control voltage and short-wave control voltage.

[0040] The main controller 1 stores the correspondence between the filtering frequency of the tunable optical filter 2 and the long-wavelength control voltage and the short-wavelength control voltage. When the tunable optical filter 2 begins operation, the main controller 1 configures the long-wavelength control voltage and the short-wavelength control voltage according to this correspondence, enabling the tunable optical filter 2 to operate at the preset filtering frequency. After the tunable optical filter 2 enters operation, the main controller 1 adjusts the long-wavelength control voltage and the short-wavelength control voltage in real time based on the output optical power signal collected by the output acquisition channel and this correspondence, thereby adjusting the filtering frequency of the tunable optical filter 2 and achieving closed-loop control of the filtering frequency.

[0041] In this embodiment, during closed-loop control of the filtering frequency, the main controller 1 adjusts the filtering frequency of the tunable optical filter 2 according to the output optical power signal in accordance with the corresponding relationship, and detects the magnitude of the output optical power signal after each adjustment until the output optical power represented by the output optical power signal reaches maximum power. At this point, the frequency deviation between the filtering frequency of the tunable optical filter and the input optical frequency is minimized, and the deviation between the input optical frequency and the output optical frequency remains within a reasonable threshold range. This reasonable threshold range can generally be determined based on actual application requirements, such as ±15 GHz.

[0042] This application enables closed-loop control of the filtering frequency of the tunable optical filter 2, preventing errors in the filtering frequency of the tunable optical filter 2 due to factors such as changes in the external environment, thereby improving the stability and control accuracy of the application of the tunable optical filter 2. The specific structure and operating principle of the input acquisition channel, output acquisition channel, and voltage amplification circuit can be found in the following description.

[0043] Furthermore, the input acquisition channel includes a first spectrometer 3 and a first photodetector 4, wherein the main spectrometer end of the first spectrometer 3 is connected to the input end of the tunable optical filter 2, the auxiliary spectrometer end of the first spectrometer 3 is connected to the input end of the first photodetector 4, and the output end of the first photodetector 4 is connected to the first signal acquisition end of the main controller 1.

[0044] The output collection channel includes a second spectrometer 5 and a second photodetector 6, wherein the input end of the second spectrometer 5 is connected to the output end of the tunable optical filter 2, the auxiliary spectrometer end of the second spectrometer 5 is connected to the input end of the second photodetector 6, and the output end of the second photodetector 6 is connected to the second signal collection end of the main controller 1.

[0045] Preferably, the input acquisition channel further includes a first signal amplifier, and the output acquisition channel further includes a second signal amplifier; the output end of the first photodetector 4 is connected to the first signal acquisition end of the main controller 1 through the first signal amplifier; the output end of the second photodetector 6 is connected to the second signal acquisition end of the main controller 1 through the second signal amplifier. Figure 1 As shown in FIG, both the first signal amplifier and the second signal amplifier can adopt existing common forms.

[0046] Specifically, the input end of the first spectrometer 3 is connected to the input light as the input end of the input collection channel. After being split by the first spectrometer 3, the input light is respectively input to the input end of the tunable optical filter 2 and the first photodetector 4. The first photodetector 4 detects the split signal input to the first photodetector 4 and generates a first detection signal. The first detection signal is amplified by the first signal amplifier and input to the main controller 1. The main controller 1 calculates the input optical power signal based on the amplified first detection signal.

[0047] The split signal input to the tunable optical filter 2 is filtered by the tunable optical filter 2 and output to the input end of the second optical splitter 5. After being split by the second optical splitter 5, the main splitting end of the second optical splitter 5 serves as the output end of the output collection channel to send output light. The second photodetector 6 detects the split signal input to the second photodetector 6 and generates a second detection signal. The second detection signal is amplified by the second signal amplifier and input to the main controller 1. The main controller 1 calculates the output optical power signal based on the amplified second detection signal. The input optical power signal is used to represent the input optical power, and the output optical power signal is used to represent the output optical power.

[0048] Furthermore, the main controller 1 is further configured to determine a control state of the tunable optical filter 2 according to the input optical power signal and the output optical power signal.

[0049] Specifically, during closed-loop control, the main controller 1 determines whether to control the long-wave control voltage and the short-wave control voltage based on the presence of input or output light and the stability of the input or output light. When the main controller 1 determines that there is no input or output light, it stops controlling the long-wave control voltage and the short-wave control voltage. When the main controller 1 determines that the input or output light is stable, it also stops controlling the long-wave control voltage and the short-wave control voltage.

[0050] Optionally, when the input optical power signal is less than or equal to the input no-light threshold, the main controller 1 determines that the input light is no light; when the output optical power signal is less than or equal to the output no-light threshold, the main controller 1 determines that the output light is no light. When the difference between the maximum and minimum values ​​of the input optical power signal is less than or equal to the input stability threshold, the main controller 1 determines that the input light is stable; when the difference between the maximum and minimum values ​​of the output optical power signal is less than or equal to the output stability threshold, the main controller 1 determines that the output light is stable. The values ​​of the input no-light threshold, output no-light threshold, input stability threshold, and output stability threshold can be selected based on actual conditions.

[0051] Furthermore, the voltage amplification circuit includes a long-wave control voltage amplification circuit and a short-wave control voltage amplification circuit. The long-wave control voltage output terminal of the main controller 1 is connected to the long-wave control terminal of the tunable optical filter 2 via the long-wave control voltage amplification circuit, and the short-wave control voltage output terminal of the main controller 1 is connected to the short-wave control terminal of the tunable optical filter 2 via the short-wave control voltage amplification circuit. The long-wave control voltage amplification circuit amplifies the long-wave control voltage, and the short-wave control voltage amplification circuit amplifies the short-wave control voltage.

[0052] In this embodiment, the long-wave control voltage amplifier circuit has the same circuit structure as the short-wave control voltage amplifier circuit. Figure 2 As shown, the long-wave control voltage amplifying circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, an operational amplifier U1 and a capacitor C1, wherein the non-inverting input terminal of the operational amplifier U1 is connected to the long-wave control voltage output terminal through the resistor R1 for receiving the long-wave control voltage; the inverting input terminal of the operational amplifier U1 is grounded through the resistor R3, and is connected to the output terminal of the operational amplifier U1 through the resistor R2; the ground terminal of the operational amplifier U1 is grounded, and the power supply terminal of the operational amplifier U1 is connected to the power supply voltage VCC and is grounded through the capacitor C1.

[0053] The shortwave control voltage amplifying circuit includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, an operational amplifier U2 and a capacitor C2, wherein the non-inverting input terminal of the operational amplifier U2 is connected to the shortwave control voltage output terminal through the resistor R5 for receiving the shortwave control voltage; the inverting input terminal of the operational amplifier U2 is grounded through the resistor R7, and is connected to the output terminal of the operational amplifier U2 through the resistor R6; the ground terminal of the operational amplifier U2 is grounded, and the power supply terminal of the operational amplifier U2 is connected to the power supply voltage VCC and is grounded through the capacitor C2.

[0054] The output end of the operational amplifier U1 is connected to the first pin of the plug J1 through the resistor R4, and the first pin of the plug J1 is connected to the long-wave control voltage output end; the output end of the operational amplifier U2 is connected to the third pin of the plug J1 through the resistor R8, and the third pin of the plug J1 is connected to the short-wave control voltage output end, and the second pin of the plug J1 is grounded.

[0055] Since the circuit structure of the long-wave control voltage amplifier circuit is the same as that of the short-wave control voltage amplifier circuit, its working principle is also the same. The following takes the long-wave control voltage amplifier circuit as an example to describe the working principle of the voltage amplifier circuit in detail. In the long-wave control voltage amplifier circuit, the non-inverting input terminal of the operational amplifier U1 is connected to the long-wave control voltage V through the resistor R1. VVL , long wave control voltage V VVL The long-wave control voltage amplifier circuit amplifies it into a long-wave output voltage V LW Output to the long-wave control terminal of the tunable optical filter 2. According to the analysis principle of the operational amplifier, the voltage at the same-direction input terminal and the voltage at the inverting input terminal of the operational amplifier U1 are approximately equal, and the current at the same-direction input terminal and the current at the inverting input terminal are 0, then the voltage at the inverting input terminal of the operational amplifier U1 is V VVL , so when the resistance values ​​of R1-R4 are all R, V LW =(R+R)*(V VVL / R) to achieve the amplification of the long-wave control voltage.

[0056] Furthermore, when the main controller 1 adjusts the long-wave control voltage and the short-wave control voltage, it is also necessary to determine the current long-wave control voltage and the short-wave control voltage. If the long-wave control voltage or the short-wave control voltage starts to change from 0V, it is necessary to first reduce the long-wave control voltage and the short-wave control voltage to 0V, and then adjust them to the corresponding voltages respectively to ensure the control accuracy of the filtering frequency of the adjustable optical filter 2.

[0057] It should be noted that the devices used in various parts of this application are existing structures in the field, and the internal circuit structures of each device are not described in detail here. The terms "first" and "second" used in the above description are for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated.

[0058] The above description is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiment. It is understood that other improvements and variations directly derived or imagined by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the scope of protection of the present invention.

Claims

1. A control system for a tunable optical filter, characterized in that: It includes an input acquisition channel connected to the input end of the tunable optical filter, an output acquisition channel connected to the output end of the tunable optical filter, and a voltage amplifying circuit connected to the control end group of the tunable optical filter; The input acquisition channel is connected to the first signal acquisition terminal of the main controller, the output acquisition channel is connected to the second signal acquisition terminal of the main controller, and the input terminal of the voltage amplification circuit is connected to the control voltage output terminal group of the main controller; The input acquisition channel is used to acquire input optical power signals, and the output acquisition channel is used to acquire output optical power signals; The main controller is used to control the output voltage of the voltage amplifier circuit so that the tunable optical filter operates at a preset filtering frequency. The main controller is also used to adjust the output voltage of the voltage amplifier circuit according to the output optical power signal after the tunable optical filter operates at the preset filtering frequency, so as to adjust the filtering frequency of the tunable optical filter.

2. The control system of the tunable optical filter according to claim 1, characterized in that: The input acquisition channel includes a first optical splitter and a first photodetector, wherein: The main splitting end of the first splitter is connected to the input end of the tunable optical filter, the auxiliary splitting end of the first splitter is connected to the input end of the first photodetector, and the output end of the first photodetector is connected to the first signal acquisition end of the main controller.

3. The control system of the tunable optical filter according to claim 2, characterized in that: The output collection channel includes a second optical splitter and a second photodetector, wherein: The input end of the second optical splitter is connected to the output end of the tunable optical filter, the auxiliary optical splitting end of the second optical splitter is connected to the input end of the second photodetector, and the output end of the second photodetector is connected to the second signal acquisition end of the main controller.

4. The control system of the tunable optical filter according to claim 3, characterized in that: The input acquisition channel further includes a first signal amplifier, and the output acquisition channel further includes a second signal amplifier; The output end of the first photodetector is connected to the first signal acquisition end of the main controller through a first signal amplifier; The output end of the second photodetector is connected to the second signal collection end of the main controller through a second signal amplifier.

5. The control system of the tunable optical filter according to claim 1, characterized in that: The voltage amplifying circuit includes a long-wave control voltage amplifying circuit and a short-wave control voltage amplifying circuit; The control end group of the tunable optical filter includes a long-wave control end and a short-wave control end, and the control voltage output end group of the main controller includes a long-wave control voltage output end and a short-wave control voltage output end; The long-wave control voltage output terminal of the main controller is connected to the long-wave control terminal of the adjustable optical filter through the long-wave control voltage amplifier circuit, and the short-wave control voltage output terminal of the main controller is connected to the short-wave control terminal of the adjustable optical filter through the short-wave control voltage amplifier circuit.

6. The control system of the tunable optical filter according to claim 5, characterized in that: The long-wave control voltage amplifying circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, an operational amplifier U1 and a capacitor C1, wherein: The non-inverting input terminal of the operational amplifier U1 is connected to the long-wave control voltage output terminal through the resistor R1 for receiving the long-wave control voltage; the inverting input terminal of the operational amplifier U1 is grounded through the resistor R3 and connected to the output terminal of the operational amplifier U1 through the resistor R2; The ground terminal of the operational amplifier U1 is grounded, and the power supply terminal of the operational amplifier U1 is connected to the power supply voltage VCC and is grounded through the capacitor C1.

7. The control system of the tunable optical filter according to claim 6, characterized in that: The short-wave control voltage amplifying circuit includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, an operational amplifier U2 and a capacitor C2, wherein: The non-inverting input terminal of the operational amplifier U2 is connected to the shortwave control voltage output terminal through a resistor R5 for receiving the shortwave control voltage; the inverting input terminal of the operational amplifier U2 is grounded through a resistor R7 and connected to the output terminal of the operational amplifier U2 through a resistor R6; The ground terminal of the operational amplifier U2 is grounded, and the power supply terminal of the operational amplifier U2 is connected to the power supply voltage VCC and is grounded through the capacitor C2.

8. The control system of the tunable optical filter according to claim 7, characterized in that: The output end of the operational amplifier U1 is connected to the first pin of the plug J1 through the resistor R4, and the first pin of the plug J1 is connected to the long-wave control voltage output end; The output end of the operational amplifier U2 is connected to the third pin of the plug J1 through the resistor R8. The third pin of the plug J1 is connected to the shortwave control voltage output end. The second pin of the plug J1 is grounded.

9. The control system of the tunable optical filter according to claim 7, characterized in that: The main controller is also used to store the corresponding relationship between the filtering frequency and the long-wave control voltage and the short-wave control voltage.

10. The control system of the tunable optical filter according to any one of claims 1 to 9, characterized in that: The main controller is further configured to determine a control state of the tunable optical filter according to the input optical power signal and the output optical power signal.

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