Dense distribution type optical fiber demodulation device

Abstract

The utility model discloses a dense distribution type optical fiber demodulation device, which comprises a shell, a mounting plate arranged in the shell, and an optical path module, a photoelectric conversion module and a circuit board which are arranged on the mounting plate, the mounting plate is insulated from the shell, and a control circuit is arranged on the circuit board. The light path module is connected with the photoelectric conversion module, the control circuit and the external grating, the light path module is used for generating pulsed light, transmitting the pulsed light to the external grating, receiving reflected light reflected by the external grating and transmitting the reflected light to the control circuit, and the photoelectric conversion module converts the reflected light into an electric signal; and the control circuit is connected with the photoelectric conversion module and external equipment, and is used for processing the electric signal, controlling the optical path module and supplying power to the optical path module and the photoelectric conversion module. The densely distributed optical fiber demodulation device integrally adopts an explosion-proof design, internal circuits and devices are insulated from the shell, full isolation of an electric power system is realized, the anti-electromagnetic interference performance is strong, and the densely distributed optical fiber demodulation device is suitable for severe working environments.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical fiber demodulation, and in particular relates to a densely distributed optical fiber demodulation device. Background Art

[0002] The basic principle of optical fiber sensing and measurement technology is: when the sensing optical fiber is affected by external factors such as stress, strain, temperature, electric field, magnetic field and chemical field, the light waves transmitted in the optical fiber are easily modulated by these external fields or quantities, so the characterization parameters of the light waves such as intensity, phase, frequency, polarization state, etc. will change accordingly. By detecting the changes in these parameters and establishing the relationship between them and the measured parameters, the sensing and measurement of the external measured parameters can be achieved.

[0003] Densely distributed fiber Bragg grating (weak fiber Bragg grating) is a special fiber Bragg grating with extremely weak reflectivity. Based on time division multiplexing technology, that is, when fiber Bragg gratings are connected in series, the reflection time of gratings at different positions to the same incident light is different, so multiple weak grating sensing units can be multiplexed on the same optical fiber. This technology combines the sensing advantages of fiber Bragg gratings and the positioning advantages of optical time domain technology, and can realize real-time monitoring of long-distance projects.

[0004] In special application places such as mines, the existing densely distributed optical fiber demodulation equipment is difficult to meet the relevant national standards. The main problems are the equipment's insufficient explosion-proof, fire-proof and other weather resistance, as well as poor anti-interference and reduced service life in harsh environments.

[0005] The information disclosed in this background technology section is only intended to increase the understanding of the overall background of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to a person skilled in the art. Utility Model Content

[0006] The utility model aims to provide a densely distributed optical fiber demodulation device, which can be suitable for harsh environments such as mines.

[0007] In order to achieve the above-mentioned purpose, a specific embodiment of the utility model provides a densely distributed optical fiber demodulation device, characterized in that it includes a shell, a mounting plate installed inside the shell, and an optical path module, a photoelectric conversion module and a circuit board installed on the mounting plate, the mounting plate is insulated from the shell, and a control circuit is arranged on the circuit board, the optical path module is connected with the photoelectric conversion module, the control circuit and an external grating, the optical path module is used to generate pulse light and transmit the pulse light to the external grating, and receive reflected light reflected by the external grating and transmit the reflected light to the control circuit, the photoelectric conversion module is used to convert the reflected light into an electrical signal, the control circuit is connected with the photoelectric conversion module and an external device, and the control circuit is used to process the electrical signal, control the optical path module, supply power to the optical path module and the photoelectric conversion module, and transmit data with the external device.

[0008] In one or more embodiments of the utility model, the optical path module includes a laser, a pulse modulator, a circulator and an optical switch; the laser is used to generate a laser signal, the pulse modulator is connected to the laser to modulate the laser signal and generate pulse light, the first end of the circulator is connected to the pulse modulator to receive the pulse light, the second end of the circulator is connected to an external grating through the optical switch to transfer the pulse light to the external grating and receive the reflected light reflected by the external grating, the optical switch is used to control the on and off between the second end of the circulator and the external grating, and the third end of the circulator is connected to the photoelectric conversion module to transfer the reflected light to the photoelectric conversion module; the control circuit is connected to the laser, the pulse modulator and the optical switch, and the control circuit is used to control the opening and closing of the laser, the pulse modulator and the optical switch, and to supply power to the laser, the pulse modulator and the optical switch.

[0009] In one or more embodiments of the present utility model, the optical path module also includes a fixed attenuator and an adjustable attenuator, the fixed attenuator is connected to the laser and the pulse modulator, the fixed attenuator is used to adjust the intensity of the laser signal, the adjustable attenuator is connected to the third end of the circulator and the photoelectric conversion module, the adjustable attenuator is used to adjust the intensity of the reflected light, and the control circuit is also used to control the adjustable attenuator.

[0010] In one or more embodiments of the present utility model, the photoelectric conversion module includes a photoelectric converter, an amplifier circuit and a temperature control chip. The photoelectric converter is connected to the optical path module to convert the reflected light into a primary electrical signal. The amplifier circuit is connected to the photoelectric converter and the control circuit to amplify the primary electrical signal and generate an electrical signal. The temperature control chip is used to control the temperature of the amplifier circuit. The control circuit is connected to the photoelectric converter, the amplifier circuit and the temperature control chip to power the photoelectric converter, the amplifier circuit and the temperature control chip.

[0011] In one or more embodiments of the present utility model, the control circuit includes a power module, a clock module, an analog-to-digital conversion module and a control module, the power module is connected to an external power supply, an optical path module, a photoelectric conversion module, a clock module, an analog-to-digital conversion module and a control module, the power module is used to convert the external power supply voltage into the voltage required by the optical path module, the photoelectric conversion module, the clock module, the analog-to-digital conversion module and the control module; the clock module is connected to the control module and the analog-to-digital conversion module to generate a clock signal; the analog-to-digital conversion module is connected to the photoelectric conversion module and the control module, the analog-to-digital conversion module is used to convert the electrical signal into a digital signal based on the clock signal and transmit the digital signal to the control module; the control module is connected to an external device, a laser, a pulse modulator, an optical switch and an adjustable attenuator to control the opening and closing of the laser, the pulse modulator, the optical switch, adjust the adjustable attenuator and transmit data with an external device.

[0012] In one or more embodiments of the present invention, the analog-to-digital conversion module includes a differential driver, an analog-to-digital converter and a phase-locked loop, the differential driver is connected to the photoelectric conversion module to convert the electrical signal into a differential signal, the phase-locked loop is connected to the clock module to adjust the clock signal and generate a phase-locked clock signal, and the analog-to-digital converter is connected to the differential driver, the phase-locked loop and the control module to convert the differential signal into a digital signal based on the phase-locked clock signal and transmit the digital signal to the control module.

[0013] In one or more embodiments of the present invention, the mounting board is an epoxy insulation board.

[0014] In one or more embodiments of the present invention, the densely distributed optical fiber demodulation device also includes a heat sink and a heat conductive block. The heat sink is insulated from the circuit board, the heat conductive block is fixedly installed on the housing, and thermally conductive silicone is sandwiched between the heat sink and the heat conductive block.

[0015] In one or more embodiments of the utility model, a communication interface, a power interface and an optical path connector are installed on the shell, the control circuit is connected to the communication interface and the power interface, the communication interface is used to connect an external device, the power interface is used to connect an external power supply, the optical path connector is connected to the optical path module, and the optical path connector is used to connect an external grating.

[0016] In one or more embodiments of the present invention, the optical switch is a 1*n optical switch, the optical switch is connected to n external gratings, and the optical switch is used to control the on-off between the second end of the circulator and the n external gratings.

[0017] Compared with the prior art, the densely distributed optical fiber demodulation device of the utility model adopts an overall explosion-proof design, and the internal circuits and devices are insulated from the shell to achieve full isolation of the power system, with strong resistance to electromagnetic interference, and is suitable for harsh environments such as mining areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a diagram showing the internal structure of a densely distributed optical fiber demodulation device in one embodiment of the utility model.

[0020] Figure 2 This is a system schematic diagram of a densely distributed optical fiber demodulation device in one embodiment of the utility model.

[0021] Figure 3 It is a front view of a densely distributed optical fiber demodulation device in one embodiment of the utility model. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0023] The words "coupled" or "connected" or "connected" in the specification include both direct connection and indirect connection. Indirect connection is a connection through an intermediate medium, such as a connection through an electrically conductive medium, which may have parasitic inductance or parasitic capacitance; indirect connection may also include connection through other active or passive devices on the basis of achieving the same or similar functional purposes, such as connection through circuits or components such as switches and follower circuits. In addition, in the present utility model, words such as "first" and "second" are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply that there is a certain actual relationship, quantity or order between these technical features.

[0024] like Figure 1As shown, a densely distributed optical fiber demodulation device in one embodiment of the utility model includes a housing 11, a mounting plate 12 installed inside the housing 11, and an optical path module, a photoelectric conversion module and a circuit board installed on the mounting plate 12. The mounting plate 12 is insulated from the housing 11, and a control circuit is provided on the circuit board.

[0025] Specifically, the shell 11 is made of stainless steel and has good explosion-proof capability. The mounting plate 12 is an epoxy insulating plate. By mounting the optical path module, the photoelectric conversion module and the circuit board on the mounting plate 12, the shell 11 is isolated from the internal circuits and devices, thereby effectively preventing electromagnetic interference and improving explosion-proof performance.

[0026] The control circuit is arranged on the surface of the circuit board by printing, welding or the like.

[0027] like Figure 2 As shown, the optical path module is connected to the photoelectric conversion module, the control circuit and the external grating. The optical path module is used to generate pulse light and transmit the pulse light to the external grating, as well as to receive reflected light reflected by the external grating and transmit the reflected light to the control circuit. The photoelectric conversion module is used to convert the reflected light into an electrical signal. The control circuit is connected to the photoelectric conversion module and the external device. The control circuit is used to process the electrical signal, control the optical path module, supply power to the optical path module and the photoelectric conversion module, and transmit data with the external device.

[0028] Specifically, the optical path module includes a laser 21 , a pulse modulator 23 , a fixed attenuator 22 , an adjustable attenuator 26 , a circulator 24 and an optical switch 25 .

[0029] The laser 21 is used to generate a laser signal. In one embodiment, the laser 21 is a tunable laser 21, and the laser signal is a continuous light with a wavelength ranging from 1528nm to 1568nm.

[0030] The fixed attenuator 22 is connected to the laser 21 and the pulse modulator 23. The fixed attenuator 22 is used to adjust the intensity of the laser signal so that the laser signal is attenuated with a fixed attenuation value, thereby ensuring that the laser signal enters the pulse modulator 23 with appropriate power and intensity.

[0031] The pulse modulator 23 is used to modulate the laser signal and generate pulse light. In one embodiment, the pulse modulator 23 is a SOA type electro-optical pulse modulator 23 with a pulse width of 10ns and an extinction ratio of >23dB. The pulse modulator 23 is also used to amplify the pulse light to ensure that the pulse light has a certain intensity and avoid the pulse light being attenuated in the rear optical path, which makes it difficult to accurately detect the group.

[0032] The first end of the circulator 24 is connected to the pulse modulator 23 to receive pulse light, the second end of the circulator 24 is connected to the external grating through the optical switch 25 to transmit the pulse light to the external grating and receive the reflected light reflected by the external grating, the optical switch 25 is used to control the on-off between the second end of the circulator 24 and the external grating, the third end of the circulator 24 is connected to the adjustable attenuator 26 to transmit the reflected light to the adjustable attenuator 26, the adjustable attenuator 26 is used to adjust the intensity of the reflected light and transmit the adjusted reflected light to the photoelectric conversion module.

[0033] The control circuit is connected to the laser 21, the pulse modulator 23, the optical switch 25 and the adjustable attenuator 26. The control circuit is used to control the opening and closing of the laser 21, the pulse modulator 23 and the optical switch 25, adjust the adjustable attenuator 26, and supply power to the laser 21, the pulse modulator 23 and the optical switch 25.

[0034] The optical switch is a 1*n optical switch, which is connected to n external gratings. The optical switch is used to control the on / off between the second end of the circulator and the n external gratings.

[0035] In one embodiment, the optical switch 25 is a 1*16 MEMS optical switch, and 16 external gratings are provided. The multi-channel optical switch plays the role of expanding the external grating array. After each data acquisition on an external grating is completed, the second end of the circulator 24 is connected to the next grating through the 1*16 MEMS optical switch, and then the data on the next grating is acquired.

[0036] In other embodiments, the number and type of channels of the optical switch 25 may be determined according to actual needs.

[0037] The external grating is specifically an identical weak fiber grating array, in which each grating has approximately the same operating wavelength range. The pulse light will be reflected at each grating point. The position of each grating point can be obtained by measuring the time from the pulse light being emitted from the starting point to the reflected light from each grating point back to the starting point. The intensity of the reflected light is related to the spectral characteristics of the grating point. The reflection is strongest at its central wavelength, and the farther away from its central wavelength, the weaker the reflection. The change in the central wavelength reflects the change in the physical quantity of the grating point.

[0038] like Figure 2 As shown, the photoelectric conversion module includes a photoelectric converter 31, an amplifier circuit 32 and a temperature control chip 33. The photoelectric converter 31 is connected to the adjustable attenuator 26 to convert the reflected light into a primary electrical signal. The amplifier circuit 32 is connected to the photoelectric converter 31 and the control circuit to amplify the primary electrical signal and generate an electrical signal. The temperature control chip 33 is used to control the temperature of the amplifier circuit 32 to ensure that the signal amplification is not interfered by the external temperature change. The control circuit is connected to the photoelectric converter 31, the amplifier circuit 32 and the temperature control chip 33 to supply power to the photoelectric converter 31, the amplifier circuit 32 and the temperature control chip 33.

[0039] The control circuit includes a power module 41, a clock module 42, an analog-to-digital conversion module and a control module 43. The power module 41 is connected to an external power source, a laser 21, a pulse modulator 23, an optical switch 25, a photoelectric conversion module, a clock module 42, an analog-to-digital conversion module and a control module 43. The power module 41 is used to convert an external power supply voltage into a voltage required by the laser 21, the pulse modulator 23, the optical switch 25, the photoelectric conversion module, the clock module 42, the analog-to-digital conversion module and the control module 43.

[0040] In one embodiment, the power module 41 is internally provided with an overcurrent protection circuit and an overshoot circuit to prevent overcurrent and overvoltage from damaging the circuit, avoid electric sparks caused by high voltage, and ensure the power safety of the equipment. The external power supply is 12V DC, the voltage required by the laser 21, the pulse modulator 23, and the optical switch 25 is 5V, and the voltage required by the photoelectric conversion module is ±5V. The circuit board is provided with a ±5V voltage output port. The power module 41 converts the 12V DC into ±5V voltage and outputs it to the ±5V voltage output port. The laser 21, the pulse modulator 23, the optical switch 25, and the photoelectric conversion module are connected to the ±5V voltage output port to obtain the required voltage.

[0041] The power module 41 can also convert 12V DC into 3.3V and 1.8V power. The clock module 42, analog-to-digital conversion module and control module 43 on the circuit board are directly connected to the power module 41 to obtain the required voltage.

[0042] In other embodiments, the voltage generated by the power module 41 is determined according to actual needs.

[0043] The clock module 42 is connected to the control module 43 and the analog-to-digital conversion module to generate a clock signal.

[0044] The analog-to-digital conversion module is connected to the amplifying circuit 32 and the control module 43 , and is used for converting the electrical signal into a digital signal based on the clock signal and transmitting the digital signal to the control module 43 .

[0045] Specifically, the analog-to-digital conversion module includes a differential driver 44, an analog-to-digital converter 45, and a phase-locked loop 46. The differential driver is connected to the amplifier circuit 32 to convert the electrical signal into a differential signal, the phase-locked loop 46 is connected to the clock module 42 to adjust the clock signal and generate a phase-locked clock signal, and the analog-to-digital converter 45 is connected to the differential driver, the phase-locked loop 46, and the control module 43 to convert the differential signal into a digital signal based on the phase-locked clock signal, and transmit the digital signal to the control module 43.

[0046] The phase-locked clock signal improves the accuracy of the comparative clock signal, which helps the analog-to-digital converter 45 to sample the differential signal with higher accuracy and convert it into a digital signal.

[0047] The control module 43 is connected to the external device, the laser 21, the pulse modulator 23, the optical switch 25 and the adjustable attenuator 26 to control the opening and closing of the laser 21, the pulse modulator 23 and the optical switch 25, adjust the attenuation value of the adjustable attenuator 26 and perform data transmission with the external device.

[0048] In one embodiment, the control module 43 is specifically an FPGA chip. The circuit board is provided with a laser 21 interface, a pulse modulator 23 interface, an optical switch 25 interface, an adjustable attenuator 26 interface and a network interface connected to the control module 43 and corresponding devices. The control module 43 receives a control signal sent by an external device through the network interface and transmits a digital signal to the external device.

[0049] like Figure 1 As shown, in one embodiment, two circuit boards are provided, namely, a first circuit board 13 and a second circuit board 14. The second circuit board 14 is fixed on the mounting plate 12 by bolts, and the first circuit board 13 is fixed on the second circuit board 14 by insulating bolts. The control module 43 in the control circuit is provided on the first circuit board 13, and the power supply module 41, the analog-to-digital conversion module, the clock module 42, the ±5V voltage output port, the laser 21 interface, the pulse modulator 23 interface, the optical switch 25 interface, the adjustable attenuator 26 interface and the network interface are all provided on the second circuit board 14. Both the first circuit board 13 and the second circuit board 14 adopt a double-sided design.

[0050] The second circuit board 14 is provided with a connection socket connected to the laser 21 interface, the pulse modulator 23 interface, the optical switch 25 interface, the adjustable attenuator 26 interface, the clock module 42, the network interface, the analog-to-digital converter 45 and the power module 41. The first circuit board 13 is provided with a connection terminal connected to the control module 43, and the connection terminal is installed and electrically connected with the connection socket. The control module 43 is connected to the corresponding components and interfaces on the second circuit board 14 through the connection terminal and the connection socket.

[0051] By placing the control circuits on two circuit boards and adopting a double-sided design, the circuit board area is greatly reduced, and the risk of the circuit board being damaged by external forces is reduced. The first circuit board 13 and the second circuit board 14 are connected via a connection seat and a connection terminal, and the two are connected in a plug-in manner without mechanical moving parts or connecting wires, which can effectively avoid inaccurate measurements and device damage caused by impact and vibration.

[0052] In other embodiments, the control circuit may be arranged on two circuit boards in other combinations according to actual needs. Alternatively, only one circuit board may be arranged or more circuit boards may be arranged, and the arrangement of the control circuit on the circuit board may be adjusted.

[0053] In one embodiment, a heat sink 15 and a heat conducting block 16 are further provided in the housing 11. The heat sink 15 is insulated and installed with the first circuit board 13 by means of insulating bolts, the heat conducting block 16 is fixedly installed with the housing 11, and a heat conducting silica gel 17 is sandwiched between the heat sink 15 and the heat conducting block 16. The heat sink 15 is used to dissipate heat for the first circuit board 13 and the second circuit board 14, and at the same time, insulation between the heat sink 15 and the first circuit board 13 and insulation between the heat conducting block 16 and the heat sink 15 are ensured, thereby improving the heat dissipation effect.

[0054] like Figure 1 As shown, a bracket 18 is also fixedly mounted on the mounting plate 12, and a pulse modulator 23, a circulator 24, an optical switch 25, an adjustable attenuator 26 and a photoelectric conversion module are all mounted on the bracket 18. A laser 21, a fixed attenuator 22, a first circuit board 13, a second circuit board 14 and a heat sink 15 are arranged between the mounting plate 12 and the bracket 18. The entire device has a compact internal structure, stable installation, firm connection and high stability.

[0055] Four hanging angles 19 are also installed on the outside of the shell 11. The shell 11 and the hanging angles 19 are fixed by a full welding process to ensure that the fixing parts used to install the shell 11 are firmly connected to the shell 11, thereby improving the safety of the equipment.

[0056] like Figure 3 As shown, a communication interface 52, a power interface 51 and an optical path connector 53 are installed on the housing 11. The network interface is connected to the communication interface 52, and the communication interface 52 is used to connect an external device. The power module 41 is connected to the power interface 51, and the power interface 51 is used to connect an external power source. The optical path connector 53 is connected to the optical path module, and the optical path connector 53 is used to connect an external grating.

[0057] Preferably, the communication interface 52, the power interface 51 and the optical connector 53 are all aviation plugs, which have a high protection level and high durability, and are completely insulated from the housing 11 to avoid electromagnetic interference. Through structural improvement, the device only retains three necessary interfaces, which minimizes the risk of problems caused by the interfaces.

[0058] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0059] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A densely distributed optical fiber demodulation device, characterized in that: It includes a shell, a mounting plate installed inside the shell, and an optical path module, a photoelectric conversion module and a circuit board installed on the mounting plate, the mounting plate is insulated from the shell, and a control circuit is arranged on the circuit board, the optical path module is connected with the photoelectric conversion module, the control circuit and an external grating, the optical path module is used to generate pulse light and transmit the pulse light to the external grating, and receive reflected light reflected by the external grating and transmit the reflected light to the control circuit, the photoelectric conversion module is used to convert the reflected light into an electrical signal, the control circuit is connected with the photoelectric conversion module and an external device, and the control circuit is used to process the electrical signal, control the optical path module, supply power to the optical path module and the photoelectric conversion module, and transmit data with the external device.

2. The densely distributed optical fiber demodulation device according to claim 1, characterized in that: The optical path module includes a laser, a pulse modulator, a circulator and an optical switch; The laser is used to generate a laser signal, the pulse modulator is connected to the laser to modulate the laser signal and generate pulse light, the first end of the circulator is connected to the pulse modulator to receive the pulse light, the second end of the circulator is connected to an external grating through an optical switch to transmit the pulse light to the external grating and receive the reflected light reflected by the external grating, the optical switch is used to control the on-off between the second end of the circulator and the external grating, and the third end of the circulator is connected to a photoelectric conversion module to transmit the reflected light to the photoelectric conversion module; The control circuit is connected to the laser, the pulse modulator and the optical switch, and is used to control the opening and closing of the laser, the pulse modulator and the optical switch, and to supply power to the laser, the pulse modulator and the optical switch.

3. The densely distributed optical fiber demodulation device according to claim 2, characterized in that: The optical path module also includes a fixed attenuator and an adjustable attenuator. The fixed attenuator is connected to the laser and the pulse modulator, and is used to adjust the intensity of the laser signal. The adjustable attenuator is connected to the third end of the circulator and the photoelectric conversion module, and is used to adjust the intensity of the reflected light. The control circuit is also used to control the adjustable attenuator.

4. The densely distributed optical fiber demodulation device according to claim 1, characterized in that: The photoelectric conversion module includes a photoelectric converter, an amplifier circuit and a temperature control chip. The photoelectric converter is connected to the optical path module to convert the reflected light into a primary electrical signal. The amplifier circuit is connected to the photoelectric converter and the control circuit to amplify the primary electrical signal and generate an electrical signal. The temperature control chip is used to control the temperature of the amplifier circuit. The control circuit is connected to the photoelectric converter, the amplifier circuit and the temperature control chip to power the photoelectric converter, the amplifier circuit and the temperature control chip.

5. The densely distributed optical fiber demodulation device according to claim 1, characterized in that: The control circuit includes a power module, a clock module, an analog-to-digital conversion module and a control module, wherein the power module is connected to an external power supply, an optical path module, a photoelectric conversion module, a clock module, an analog-to-digital conversion module and a control module, and the power module is used to convert an external power supply voltage into a voltage required by the optical path module, the photoelectric conversion module, the clock module, the analog-to-digital conversion module and the control module; The clock module is connected to the control module and the analog-to-digital conversion module to generate a clock signal; The analog-to-digital conversion module is connected to the photoelectric conversion module and the control module, and the analog-to-digital conversion module is used to convert the electrical signal into a digital signal based on the clock signal and transmit the digital signal to the control module; The control module is connected with the external device, the laser, the pulse modulator, the optical switch and the adjustable attenuator to control the opening and closing of the laser, the pulse modulator and the optical switch, adjust the adjustable attenuator and perform data transmission with the external device.

6. The densely distributed optical fiber demodulation device according to claim 5, characterized in that: The analog-to-digital conversion module includes a differential driver, an analog-to-digital converter and a phase-locked loop. The differential driver is connected to the photoelectric conversion module to convert the electrical signal into a differential signal. The phase-locked loop is connected to the clock module to adjust the clock signal and generate a phase-locked clock signal. The analog-to-digital converter is connected to the differential driver, the phase-locked loop and the control module to convert the differential signal into a digital signal based on the phase-locked clock signal and transmit the digital signal to the control module.

7. The densely distributed optical fiber demodulation device according to claim 1, characterized in that: The mounting plate is an epoxy insulation plate.

8. The densely distributed optical fiber demodulation device according to claim 1, characterized in that: The densely distributed optical fiber demodulation device further comprises a heat sink and a heat conducting block. The heat sink is insulated from the circuit board, the heat conducting block is fixedly mounted to the housing, and heat conducting silica gel is sandwiched between the heat sink and the heat conducting block.

9. The densely distributed optical fiber demodulation device according to claim 1, characterized in that: A communication interface, a power interface and an optical path connector are installed on the shell, the control circuit is connected to the communication interface and the power interface, the communication interface is used to connect to an external device, the power interface is used to connect to an external power supply, the optical path connector is connected to the optical path module, and the optical path connector is used to connect to an external grating.

10. The densely distributed optical fiber demodulation device according to claim 2, characterized in that: The optical switch is a 1*n optical switch, the optical switch is connected to n external gratings, and the optical switch is used to control the on-off between the second end of the circulator and the n external gratings.

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