An optical sensing system and method

Abstract

The present application discloses an optical sensing system and method, including a measurement module, a detection module, and a processing module; wherein, the detection module includes a coupler, a first light source, an optical amplifier, a filter, and a photodetector connected in sequence; the measurement module is used to measure a physical quantity to be measured and output a sensing optical signal according to the measurement situation; the coupler is connected to the measurement module; the first light source is used to emit a detection optical signal with a preset wavelength; the optical amplifier is used to receive the sensing optical signal and the detection optical signal through the coupler and perform amplification processing on the sensing optical signal and the detection optical signal; the filter is used to filter out the amplified sensing optical signal and output the amplified detection optical signal; the photodetector is used to convert the amplified detection optical signal into an electrical signal; the processing module is connected to the photodetector and is used to determine the measured value of the physical quantity to be measured according to the change of the value of the electrical signal. The present application improves the measurement accuracy of the physical quantity to be measured.

Description

Technical Field

[0001] The present application relates to the field of optical sensing technology, and in particular, to an optical sensing system and method. Background Art

[0002] The principle of the optical sensor system to measure the physical quantity to be measured is: the external physical quantity modulates the optical sensor to change the characteristic parameters of the optical signal reflected by the optical sensor (for example, the characteristic parameters can be wavelength, light intensity and power, etc.). Then, the demodulation module demodulates the change of the characteristic parameters of the optical signal reflected by the optical sensor, and determines the measured value of the physical quantity to be measured based on the change of the above characteristic parameters.

[0003] Among them, in the wavelength modulation optical sensing system, after the external physical quantity modulates the optical sensor, the central wavelength of the optical signal reflected by the optical sensor will change. Therefore, in order to obtain the measured value of the physical quantity to be measured, the demodulation module must accurately demodulate the slight changes in the central wavelength of the optical signal reflected by the optical sensor. In the prior art, the commonly used demodulation method is to first convert the change in the central wavelength of the optical signal reflected by the optical sensor into the intensity change of the optical signal through an adjustable filter. Then, the intensity change of the optical signal is converted into the change of the electrical signal through a photodetector, and finally the change of the central wavelength of the optical signal reflected by the optical sensor is determined by the change of the above-mentioned electrical signal. Exemplarily, the electrical signal can be a current signal.

[0004] However, in the above method, in order to ensure the demodulation accuracy, it is necessary to ensure that the responsiveness of the photodetector to light signals of different wavelengths is consistent, that is, as shown in formula (1), it is necessary to ensure that when light signals of different wavelengths are incident on the photodetector, the ratio of the incident light intensity to the output current is a constant.

[0005] R(λ)=I(λ) / P(λ) (1)

[0006] Among them, P(λ) is the incident light intensity at wavelength λ, and I(λ) is the current of the photodetector under the action of the incident light intensity P(λ).

[0007] However, due to uncontrollable defects introduced during the preparation process and differences in the absorption coefficients of semiconductor materials at different wavelengths, photodetectors in actual applications have different responsivities at different wavelengths, that is, different currents will be generated when light signals of the same intensity but different wavelengths are incident on the photodetector. This greatly reduces the demodulation accuracy of the demodulation module and seriously affects the measurement accuracy of the optical sensing system. Summary of the invention

[0008] The purpose of the present application is to provide an optical sensing system and method to improve the measurement accuracy of the physical quantity to be measured.

[0009] Embodiments of the present application are implemented as follows:

[0010] On the one hand, the present application provides an optical sensing system, including a measurement module, a detection module, and a processing module; wherein, the detection module includes a coupler, a first light source, an optical amplifier, a filter, and a photodetector; the measurement module is used to measure a physical quantity to be measured and output a sensing optical signal according to the measurement situation; the coupler is connected to the measurement module; the first light source is connected to the coupler and is used to emit a detection optical signal with a preset wavelength; the optical amplifier is connected to the coupler and is used to receive the sensing optical signal and the detection optical signal through the coupler and perform amplification processing on the sensing optical signal and the detection optical signal; the filter is connected to the optical amplifier and is used to filter out the amplified sensing optical signal and output the amplified detection optical signal; the photodetector is connected to the filter and is used to convert the amplified detection optical signal into an electrical signal; the processing module is connected to the photodetector and is used to receive the electrical signal and determine the measured value of the physical quantity according to the change of the value of the electrical signal.

[0011] In one embodiment, the measurement module includes a second light source, a demodulator, a circulator, and a sensing unit; wherein, the second light source is used to emit a light source signal; the demodulator is connected to the second light source; the circulator is connected to the demodulator and the coupler; the sensing unit is connected to the circulator and is used to receive the light source signal through the circulator, measure the physical quantity to be measured based on the light source signal, and output a sensing optical signal according to the measurement situation.

[0012] In one embodiment, the sensing unit includes a fiber Bragg grating sensor, and the fiber Bragg grating sensor is connected to the circulator.

[0013] In one embodiment, the sensing unit is an optical sensing array, and the sensing unit includes a plurality of sequentially connected optical sensors; wherein, the coupler has a first input end, a second input end, and an output end; the circulator has a first port, a second port, and a third port, and the second port is connected to the first port and the third port; the output end of the second light source is connected to the input end of the demodulator; the first port is connected to the output end of the demodulator, and the second port is connected to the first optical sensor in the optical sensor array; the first input end is connected to the third port, the second input end is connected to the output end of the first light source; the output end of the coupler is connected to the input end of the optical amplifier; the output end of the optical amplifier is connected to the input end of the filter; the output end of the filter is connected to the output end of the photodetector; the output end of the photodetector is connected to the input end of the processing module.

[0014] In one embodiment, the sensing unit is an optical sensing array including a plurality of sequentially connected optical sensors; the optical sensing system further includes a driving circuit; wherein, the driving circuit is connected to the demodulator and is configured to output a driving voltage to the demodulator, so that the demodulator scans back and forth within the range of the reflection wavelength of the sensing unit, thereby changing the light intensity value of the sensing optical signal; wherein, the sensing optical signal is output by any one of the optical sensors in the optical sensing array; the optical amplifier is further configured to reduce the amplification factor for the detected optical signal when the light intensity value of the sensing optical signal reaches the maximum, so that the value of the electrical signal reaches the minimum; wherein, when the transmission wavelength of the demodulator coincides with the wavelength of the sensing optical signal, the light intensity value of the sensing optical signal reaches the maximum; the processing module is further configured to determine the measured value of the physical quantity to be measured based on the driving voltage value output by the driving circuit when the value of the electrical signal reaches the minimum.

[0015] In one embodiment, the processing module includes a data acquisition unit and a data processing unit; wherein, the data acquisition unit is connected to the photodetector; the data processing unit is connected to the data acquisition unit and is configured to receive the electrical signal through the data acquisition unit and determine the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0016] In one embodiment, the optical amplifier is a semiconductor optical amplifier or an erbium-doped fiber amplifier.

[0017] In one embodiment, the demodulator is a Fabry-Perot tunable filter or a tunable fiber Bragg grating filter; the filter is a band-pass filter.

[0018] On the other hand, the present application provides an optical sensing method, including:

[0019] The measurement module outputs a sensing optical signal according to the measurement of the physical quantity to be measured.

[0020] After the detection module receives the sensing optical signal and the detected optical signal with a preset wavelength emitted by the first light source, the optical amplifier amplifies the sensing optical signal and the detected optical signal; the filter receives the amplified sensing optical signal and the amplified detected optical signal, and filters out the amplified sensing optical signal; the photodetector receives the amplified detected optical signal and converts the amplified detected optical signal into an electrical signal.

[0021] After the processing module receives the electrical signal, it determines the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0022] In one embodiment, after the detection module receives the sensing optical signal and the detected optical signal with a preset wavelength emitted by the first light source, the optical amplifier amplifies the sensing optical signal and the detected optical signal, including:

[0023] When the optical amplifier detects that the optical intensity value of the sensing optical signal reaches the maximum, the amplification factor of the probing optical signal is reduced, so that the value of the electrical signal output by the photodetector reaches the minimum; wherein, the driving circuit outputs a driving voltage to the demodulator, causing the demodulator to scan back and forth within the reflection wavelength range of the sensing unit. When the transmission wavelength of the demodulator coincides with the wavelength of the sensing optical signal, the optical intensity value of the sensing optical signal reaches the maximum;

[0024] The processing module receives the electrical signal and determines the measured value of the physical quantity to be measured according to the change of the value of the electrical signal, including:

[0025] When the processing module detects that the value of the electrical signal reaches the minimum, it determines the measured value of the physical quantity to be measured based on the value of the driving voltage.

[0026] The beneficial effect of this application compared with the prior art is that the optical sensing system in this application includes a detection module, a measurement module, and a processing module; the measurement module is used to measure the physical quantity to be measured and output a sensing optical signal according to the measurement situation; the detection module is connected to the measurement module and is used to receive the sensing optical signal and the probing optical signal with a preset wavelength emitted by the first light source in the detection module, and is also used to amplify the sensing optical signal and the probing optical signal simultaneously. Further, it is also used to convert the amplified probing optical signal into an electrical signal for output; the processing module is connected to the detection module and is used to receive the electrical signal and determine the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0027] Compared with the prior art, in which the central wavelength change of the sensing optical signal is determined by the optical intensity change of the sensing optical signals with different wavelengths; in this application, the central wavelength change of the sensing optical signal is determined by the optical intensity change of the probing optical signal with a fixed wavelength, effectively eliminating the response degree difference of the photodetector to optical signals with different wavelengths, fully ensuring the demodulation accuracy, and improving the measurement accuracy of the optical sensing system. Description of the Drawings

[0028] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0029] Figure 1 It is a schematic structural diagram of an optical sensing system shown in an embodiment of this application;

[0030] Figure 2 It is a schematic structural diagram of an optical sensing system shown in an embodiment of this application;

[0031] Figure 3 Schematic diagram of the flow of sensing optical signals and detection optical signals in the detection module shown in an embodiment of the present application;

[0032] Figure 4 Schematic diagram of the cross - gain modulation effect in the optical amplifier shown in an embodiment of the present application;

[0033] Figure 5 Schematic flow chart of the optical sensing method shown in an embodiment of the present application.

[0034] Icon:

[0035] 1 - Optical sensing system; 10 - Measurement module; 11 - Second light source; 12 - Demodulator; 13 - Circulator; 14 - Sensing unit; 15 - Optical sensor; 20 - Detection module; 21 - First light source; 22 - Coupler; 23 - Optical amplifier; 24 - Filter; 25 - Photoelectric detector; 30 - Processing module; 31 - Data acquisition unit; 32 - Data processing unit; 40 - Drive circuit. Detailed implementation manners

[0036] The terms "first", "second", "third", etc. are only used for distinguishing descriptions, do not represent the serial number of arrangement, and cannot be understood as indicating or implying relative importance.

[0037] In addition, terms such as "horizontal", "vertical", "overhanging", etc. do not mean that the components are required to be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0038] In the description of the present application, it should be noted that the orientation or positional relationship indicated by terms such as "inside", "outside", "left", "right", "up", "down", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of this application is usually placed during use. It is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application.

[0039] In the description of the present application, unless otherwise clearly specified and limited, the terms "set", "install", "connected", "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements.

[0040] The technical solutions of the present application will be clearly and completely described below with reference to the drawings.

[0041] Please refer to Figure 1 , which is a schematic structural diagram of the optical sensing system 1 shown in an embodiment of the present application. As Figure 1 shown, the optical sensing system 1 in the present application includes a measurement module 10, a detection module 20, and a processing module 30; the detection module 20 includes a coupler 22, a first light source 21, an optical amplifier 23, a filter 24, and a photodetector 25. The measurement module 10 is configured to measure a physical quantity to be measured and output a sensing optical signal according to the measurement situation; exemplarily, the physical quantity to be measured may be pressure, temperature, speed, acceleration, etc.; the coupler 22 is connected to the measurement module 10; the first light source 21 is connected to the coupler 22 and is configured to emit a detection optical signal with a preset wavelength; the optical amplifier 23 is connected to the coupler 22 and is configured to receive the sensing optical signal and the detection optical signal through the coupler 22 and perform amplification processing on the sensing optical signal and the detection optical signal. Exemplarily, the optical amplifier 23 may be a semiconductor optical amplifier 23 (SOA), or an erbium-doped fiber amplifier. The filter 24 is connected to the optical amplifier 23 and is configured to filter out the amplified sensing optical signal and output the amplified detection optical signal; the photodetector 25 is connected to the filter 24 and is configured to convert the amplified detection optical signal into an electrical signal. Exemplarily, the photodetector 25 may be any one of an indium gallium arsenide photodiode detector, a silicon detector, a cadmium sulfide detector, a photomultiplier tube, and an avalanche diode; the processing module 30 is connected to the filter 24 and is configured to receive the above electrical signal and determine the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0042] Specifically, as Figure 1 shown, the coupler 22 includes a first input end d, a second input end e, and an output end f; the output end of the measurement module 10 is connected to the first input end d of the coupler 22; the output end of the first light source 21 is connected to the second input end e of the coupler 22; the output end f of the coupler 22 is connected to the input end of the optical amplifier 23; the output end of the optical amplifier 23 is connected to the input end of the filter 24; the output end of the filter 24 is connected to the input end of the photodetector 25; the output end of the photodetector 25 is connected to the input end of the processing module 30.

[0043] During an operation process, when the optical sensing system 1 measures the physical quantity to be measured, the measurement module 10 outputs a sensing optical signal to the detection module 20 according to the measurement situation of the physical quantity to be measured. After receiving the above-mentioned sensing optical signal and the detection optical signal with a preset wavelength continuously emitted by the first light source 21, the optical amplifier 23 in the detection module 20 will amplify the sensing optical signal and the detection optical signal simultaneously, and after the amplification is completed, output the amplified sensing optical signal and detection optical signal to the filter 24. After receiving the amplified sensing optical signal and detection optical signal, the filter 24 will filter out the amplified sensing optical signal and only output the amplified detection optical signal to the photodetector 25. After receiving the amplified detection optical signal, the photodetector 25 converts the detection optical signal into an electrical signal and outputs it to the processing module 30, so that after receiving the electrical signal, the processing module 30 can determine the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0044] Therefore, it can be seen that compared with the prior art, in which the demodulation method determines the change of the central wavelength of the sensing optical signal by monitoring the change of the optical intensity of the sensing optical signals with different wavelengths; in this application, the demodulation method determines the change of the central wavelength of the sensing optical signal by detecting the change of the optical intensity of the detection optical signal with a fixed wavelength, effectively eliminating the response degree difference of the photodetector 25 to the optical signals with different wavelengths, fully ensuring the demodulation accuracy, and improving the measurement accuracy of the optical sensing system 1.

[0045] Please refer to Figure 2 , which is a schematic structural diagram of the optical sensing system 1 provided by an embodiment of this application. As Figure 2 shown, the measurement module 10 in this application includes a second light source 11, a demodulator 12, a circulator 13 and a sensing unit 14. Among them, the second light source 11 is used to emit a light source signal. Exemplarily, the second light source 11 can be a laser of ASE type or a laser of SLED type; the demodulator 12 is connected to the second light source 11. Exemplarily, the demodulator 12 can be a Fiber Fabry-Perot Tunable Filter or a tunable fiber grating filter; the circulator 13 is connected to the demodulator 12, the coupler 22 and the sensing unit 14; specifically, as Figure 2As shown, the circulator 13 has a first port a, a second port b, and a third port c, and the second port b is connected to the first port a and the third port c. The output end of the second light source 11 is connected to the input end of the demodulator 12; the first port a of the circulator 13 is connected to the output end of the demodulator 12; the second port b of the circulator 13 is connected to the sensing unit 14; the third port c of the circulator 13 is connected to the first input end d of the coupler 22; wherein, the sensing unit 14 is configured to receive the light source signal through the circulator 13, measure the physical quantity to be measured based on the light source signal, and output a sensing optical signal according to the measurement situation.

[0046] In one embodiment, as Figure 4 shown, the sensing unit 14 is an optical sensing array, including a plurality of sequentially connected optical sensors 15; for example, each optical sensor 15 can be a fiber Bragg grating sensor. At this time, the second port b of the circulator 13 is connected to the first fiber Bragg grating sensor in the optical sensing array.

[0047] In another embodiment, the sensing unit 14 includes a fiber Bragg grating sensor, and the second port b of the circulator 13 is connected to the fiber Bragg grating sensor.

[0048] As Figure 2 shown, the optical sensing system 1 further includes a driving circuit 40; wherein, the output end of the driving circuit 40 is connected to the input end of the demodulator 12, and is configured to output a driving voltage to the demodulator 12, so that the demodulator 12 scans back and forth within the reflection wavelength range of the sensing unit 14, thereby changing the light intensity value of the sensing optical signal. The processing module 30 further includes a data acquisition unit 31 and a data processing unit 32; wherein, the input end 31 of the data acquisition unit 31 is connected to the output end of the photodetector 25; the input end of the data processing unit 32 is connected to the output end of the data acquisition unit 31; the data processing unit 32 is configured to receive the electrical signal output by the photodetector 25 through the data acquisition unit 31, and determine the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0049] In one embodiment, the driving circuit 40 can be integrated in the data processing unit 32, so that the driving voltage can be output to the demodulator 12 through the data processing unit 32.

[0050] The following details Figure 2 the working principle of the optical sensing system 1 shown in

[0051] When the optical sensing system 1 measures the physical quantity to be measured, the light source signal emitted by the second light source device 11 enters the sensing unit 14 through the first port a and the second port b of the circulator 13. Any one of the optical sensors 15 in the sensing unit 14 reflects the sensing optical signal to the optical amplifier 23 through the second port b, the third port c of the circulator 13, the first input end d and the output end f of the coupler 22 according to the measurement of the physical quantity to be measured. At the same time, the detection optical signal with a preset wavelength emitted by the first light source device 21 also enters the optical amplifier 23 through the second output end e and the output end f of the coupler 22. At this time, the demodulator 12 will scan back and forth near the central wavelength of the reflected optical signal of the sensing unit 14 under the drive of the drive voltage output by the drive circuit 40 in real time, causing the light intensity of the sensing optical signal to change. Among them, when the demodulator 12 scans to the coincidence of its transmission wavelength and the central wavelength of the sensing optical signal, the light intensity value of the sensing optical signal reaches the maximum.

[0052] After receiving the sensing optical signal and the detection optical signal, the optical amplifier 23 will amplify the sensing optical signal and the detection optical signal according to the light intensity values of the sensing optical signal and the detection optical signal, and output the amplified sensing optical signal and detection optical signal to the filter 24 at the end of the amplification. However, due to the cross-gain modulation effect of the optical amplifier 23 itself (as Figure 4 shown), that is, after the sensing optical signal with strong light intensity modulates the gain of the amplifier, the amplifier will simultaneously modulate the gain of the detection optical signal. Specifically, when the light intensity of the sensing optical signal increases, the gain of the optical amplifier 23 is suppressed and suddenly decreases, resulting in a sudden decrease in the amplification factor of the detection optical signal; when the light intensity of the sensing optical signal decreases, since the gain of the optical amplifier 23 is not suppressed, the detection optical signal will be normally amplified. Therefore, due to the existence of the cross-gain modulation effect, when the light intensity value of the sensing optical signal reaches the maximum, the optical amplifier 23 will reduce the amplification factor of the detection optical signal, making the light intensity value of the detection optical signal output from the optical amplifier 23 reach the minimum.

[0053] After receiving the above amplified sensing optical signal and detection optical signal, the filter 24, such as Figure 3As shown, the amplified sensing optical signal will be filtered out, and only the amplified detection optical signal will be sent to the photodetector 25. After receiving the amplified detection optical signal, the photodetector 25 converts it into an electrical signal and sends the electrical signal to the data acquisition unit 31 when the conversion is successful. Among them, when the optical intensity value of the detection optical signal reaches the minimum, the value of the above electrical signal also reaches the minimum. After receiving the above electrical signal, the data acquisition unit 31 sends it to the data processing unit 32, so that the data processing unit 32 determines the measured value of the physical quantity to be measured according to the change of the above electrical signal. Specifically, when the value of the electrical signal reaches the minimum, the data processing unit 32 can determine the offset of the center wavelength of the sensing optical signal based on the driving voltage value output by the driving circuit 40. Then, the data processing unit 32 can obtain the measured value of the physical quantity to be measured through a certain signal processing algorithm.

[0054] In one embodiment, in addition to modulating the detection optical signal by using the cross-gain modulation effect of the optical amplifier 23, the cross-phase modulation effect or the four-wave mixing effect of the optical amplifier 23 can also be used to modulate the detection optical signal.

[0055] In one embodiment, the method for achieving high-precision demodulation of wavelength conversion based on the cross-gain modulation effect of the semiconductor optical amplifier 23 (SOA) in the present application is applicable not only to the tunable filter demodulation method described in the specific solution, but also to wavelength demodulation methods such as diffraction grating demodulation method, tunable laser demodulation method, arrayed waveguide grating demodulation method, etc.

[0056] In one embodiment, only the single-channel demodulation method is described in the present application. If it is necessary to expand the number of channels, the number of optical sensing channels can be increased by using a multi-channel splitter after the tunable filter 24. The optical path structure of the increased channels is the same as that described in the specific solution only in terms of the number increase, and will not be elaborated here.

[0057] In one embodiment, the reflection spectrum of the optical sensor 15 is used to modulate the detection optical signal in the present application. In actual use, the transmission spectrum of the optical sensor 15 can be used to replace the reflection spectrum to modulate the detection optical signal.

[0058] Please refer to Figure 5 , which is a schematic flowchart of the optical sensing method provided by an embodiment of the present application. As Figure 5 shown, the method includes the following steps S210-step S230.

[0059] Step S210: The measurement module 10 outputs a sensing optical signal according to the measurement of the physical quantity to be measured.

[0060] Step S220: After the detection module 20 receives the sensing optical signal and the detection optical signal with a preset wavelength emitted by the first light source 21, the optical amplifier 23 amplifies the sensing optical signal and the detection optical signal; the filter 24 receives the amplified sensing optical signal and the amplified detection optical signal, and filters out the amplified detection optical signal; the photodetector 25 receives the amplified detection optical signal and converts the amplified detection optical signal into an electrical signal.

[0061] Step S230: After the processing module 30 receives the electrical signal, it determines the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

[0062] In one embodiment, step S220 includes: when the optical amplifier 23 detects that the optical intensity value of the sensing optical signal reaches the maximum, reducing the amplification factor of the detection optical signal, so that the value of the electrical signal output by the photodetector 25 reaches the minimum; wherein, the drive circuit 40 outputs a drive voltage to the demodulator 12, causing the demodulator 12 to scan back and forth within the reflection wavelength range of the sensing unit 14. When the transmission wavelength of the demodulator 12 coincides with the wavelength of the sensing optical signal, the optical intensity value of the sensing optical signal reaches the maximum.

[0063] In one embodiment, step S230 includes: when the processing module 30 detects that the value of the electrical signal reaches the minimum, determining the measured value of the physical quantity to be measured based on the value of the drive voltage.

[0064] Specifically, for the specific working principles of each step in the optical sensing method of this embodiment, please refer to the above explanation of the optical sensing system 1 part, and details are not described herein again.

[0065] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A light sensing system, characterized in that, Comprising: A measurement module, configured to measure a physical quantity to be measured and output a sensing optical signal according to the measurement situation; A detection module, comprising: A coupler, connected to the measurement module; A first light source, connected to the coupler, for emitting a detection optical signal with a preset wavelength; An optical amplifier, connected to the coupler, for receiving the sensing optical signal and the detection optical signal through the coupler and performing amplification processing on the sensing optical signal and the detection optical signal; A filter, connected to the optical amplifier, for filtering the amplified sensing optical signal and outputting the amplified detection optical signal; A photodetector, connected to the filter, for converting the amplified detection optical signal into an electrical signal; A processing module, connected to the photodetector, for receiving the electrical signal and determining the measured value of the physical quantity to be measured according to the change of the value of the electrical signal; The measurement module comprises: A second light source, for emitting a light source signal; A demodulator, connected to the second light source; A circulator, connected to the demodulator and the coupler; A sensing unit, connected to the circulator, for receiving the light source signal through the circulator, measuring the physical quantity to be measured based on the light source signal, and outputting a sensing optical signal according to the measurement situation; The sensing unit is an optical sensor array, comprising a plurality of sequentially connected optical sensors; The optical sensing system further comprises: A driving circuit, connected to the demodulator, for outputting a driving voltage to the demodulator to cause the demodulator to scan back and forth within the reflection wavelength range of the sensing unit, thereby changing the light intensity value of the sensing optical signal; wherein, the sensing optical signal is output by any one of the optical sensors in the optical sensor array; The optical amplifier is further configured to reduce the amplification factor of the detection optical signal when the light intensity value of the sensing optical signal reaches the maximum, so that the value of the electrical signal reaches the minimum; wherein, when the transmission wavelength of the demodulator coincides with the wavelength of the sensing optical signal, the light intensity value of the sensing optical signal reaches the maximum; The processing module is further configured to determine the measured value of the physical quantity to be measured based on the driving voltage value output by the driving circuit when the value of the electrical signal reaches the minimum.

2. The optical sensing system according to claim 1, characterized in that, The coupler has a first input end, a second input end and an output end; the circulator has a first port, a second port and a third port, and the second port is connected to the first port and the third port; The output end of the second light source is connected to the input end of the demodulator; the first port is connected to the output end of the demodulator, the second port is connected to the first optical sensor in the optical sensor array; the first input end is connected to the third port, the second input end is connected to the output end of the first light source; the output end of the coupler is connected to the input end of the optical amplifier; the output end of the optical amplifier is connected to the input end of the filter; the output end of the filter is connected to the input end of the photodetector; the output end of the photodetector is connected to the input end of the processing module.

3. The optical sensing system according to claim 1, characterized in that, The processing module comprises: A data acquisition unit, connected to the photodetector; A data processing unit, connected to the data acquisition unit, for receiving the electrical signal through the data acquisition unit and determining the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

4. The optical sensing system according to claim 1, wherein The optical amplifier is a semiconductor optical amplifier or an erbium-doped fiber amplifier.

5. The optical sensing system according to claim 1, characterized in that, The demodulator is a Fabry-Perot tunable filter or a tunable fiber Bragg grating filter; the filter is a band-pass filter.

6. A light sensing method, characterized in that, Applied to the optical sensing system according to any one of claims 1-5, the method includes: The measurement module outputs a sensing optical signal according to the measurement of the physical quantity to be measured. After the detection module receives the sensing optical signal and the detection optical signal with a preset wavelength emitted by the first light source, the optical amplifier amplifies the sensing optical signal and the detection optical signal; the filter receives the amplified sensing optical signal and the amplified detection optical signal, and filters out the amplified sensing optical signal; the photodetector receives the amplified detection optical signal and converts the amplified detection optical signal into an electrical signal. After the processing module receives the electrical signal, it determines the measured value of the physical quantity to be measured according to the change of the value of the electrical signal.

7. The optical sensing method according to claim 6, wherein After the detection module receives the sensing optical signal and the detection optical signal with a preset wavelength emitted by the first light source, the optical amplifier amplifies the sensing optical signal and the detection optical signal, including: When the optical amplifier detects that the light intensity value of the sensing optical signal reaches the maximum, the amplification factor of the detection optical signal is reduced, so that the value of the electrical signal output by the photodetector reaches the minimum; wherein, the drive circuit outputs a drive voltage to the demodulator, so that the demodulator scans back and forth within the reflection wavelength range of the sensing unit. When the transmission wavelength of the demodulator coincides with the wavelength of the sensing optical signal, the light intensity value of the sensing optical signal reaches the maximum. The processing module receives the electrical signal and determines the measured value of the physical quantity to be measured according to the change of the value of the electrical signal, including: When the processing module detects that the value of the electrical signal reaches the minimum, the measured value of the physical quantity to be measured is determined based on the value of the drive voltage.

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