Fiber bragg grating demodulator

Abstract

The utility model discloses a fiber bragg grating demodulator, which comprises a shell, and a laser, an optical path module, a driving circuit, a main control circuit and a bracket which are arranged in the shell. The light path module is connected with the laser, the driving circuit and the external grating, the light path module is used for transmitting laser generated by the laser to the external grating and receiving reflected light reflected by the external grating, and the driving circuit is connected with the laser and the main control circuit. The driving circuit is used for driving the laser, converting reflected light into digital signals and transmitting the digital signals to the master control circuit, and the master control circuit is connected with the driving circuit to control the driving circuit. The fiber bragg grating demodulator of the utility model can realize integrated installation in a 3U case of a train, realizes rapid access of equipment, and solves the adaptability problems of voltage resistance, insulation, EMC electromagnetic compatibility and the like on the train. The wireless design is adopted except the optical fiber, so that inaccurate measurement and device damage caused by impact and vibration can be effectively avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of optical fiber grating demodulation, and in particular relates to an optical fiber grating demodulator. Background Art

[0002] The fiber Bragg grating demodulator uses the frequency-selective reflection and transmission of the optical signal by the fiber Bragg grating to resolve the input optical signal into a series of spectral components of specific frequencies. Then, the relevant information of the input optical signal is obtained by demodulating and detecting it through devices such as spectrometers or photodiodes. The working principle of the fiber Bragg grating is to use the periodic refractive index changes in the optical fiber to form reflected light strips. These strips are within the visible light or near-infrared spectrum, and their frequency intervals can be achieved by adjusting the manufacturing parameters of the fiber Bragg grating.

[0003] Fiber Bragg grating interrogators are widely used in many fields, including long-term health monitoring of bridges, dams, buildings, etc., damage and danger assessment of dams, roads, and bridges in earthquake zones, continuous monitoring of the structural integrity of ships and aircraft, and measurements in electromagnetic fields or harsh corrosion environments. Among them, in the application scenario of monitoring optical fibers in train carriages, existing fiber Bragg grating interrogators cannot be integrated in the 3U chassis of the train, and it is difficult to achieve rapid plugging and unplugging during operation, and it is impossible to quickly access the equipment. In addition, it is difficult for existing fiber Bragg grating interrogators to solve the adaptability problems of high and low temperature, alternating humidity and heat, power supply overvoltage, insulation, EMC electromagnetic compatibility, shock and vibration on the train at a low cost.

[0004] Therefore, in view of the above technical problems, it is necessary to provide a fiber Bragg grating demodulator.

[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 fiber Bragg grating demodulator, which solves the problem that the existing fiber Bragg grating demodulator cannot be applied to train compartment optical fiber monitoring.

[0007] In order to achieve the above-mentioned purpose, a specific embodiment of the utility model provides a fiber Bragg grating demodulator, including a shell and a laser, an optical path module, a driving circuit, a main control circuit and a bracket arranged in the shell; the optical path module is connected to the laser, the driving circuit and the external grating, the optical path module is used to transmit the laser generated by the laser to the external grating and receive the reflected light reflected by the external grating, the driving circuit is connected to the laser and the main control circuit, the driving circuit is used to drive the laser and convert the reflected light into a digital signal and transmit it to the main control circuit, the main control circuit is connected to the driving circuit to control the driving circuit; the shell includes a first mounting plate and a front panel and a top shell fixedly mounted on the first mounting plate, the main control circuit is arranged on the surface of the first mounting plate, the bracket is fixedly mounted on the first mounting plate, and the bracket is used to install the laser, the optical path module and the driving circuit.

[0008] In one or more embodiments of the present invention, the bracket includes a column mounted on a first mounting plate and a second mounting plate mounted on the column, the laser and the optical path module are mounted on the second mounting plate, and the driving circuit is arranged on the surface of the second mounting plate.

[0009] In one or more embodiments of the present invention, the first mounting board and the second mounting board are PCB circuit boards.

[0010] In one or more embodiments of the present invention, a heat sink is mounted on the second mounting plate, and the laser is fixedly mounted to the heat sink.

[0011] In one or more embodiments of the present invention, a connection base connected to the main control circuit is installed on the first mounting board, and a connection terminal connected to the drive circuit and installed in cooperation with the connection base is installed on the second mounting board.

[0012] In one or more embodiments of the present invention, a multi-function interface connected to the main control circuit is installed on a side of the first mounting plate away from the front panel, and the top shell is provided with a making way groove for making way for the multi-function interface.

[0013] In one or more embodiments of the present invention, a fiber optic connector connected to the optical path module and a communication interface connected to the main control circuit are installed on the front panel, and the fiber optic connector is used to connect to an external grating.

[0014] In one or more embodiments of the present invention, a TEC cooling chip is installed on the laser.

[0015] In one or more embodiments of the present invention, a protection circuit connected to the main control circuit is also provided on the first mounting board.

[0016] In one or more embodiments of the present invention, a ventilation slot is provided on the top shell.

[0017] Compared with the prior art, the fiber grating demodulator of the utility model can be integrated and installed in the 3U chassis of the train, solving the problem that the existing demodulator equipment is not suitable for 3U miniaturization. In view of the actual structure of the 3U chassis, the optical fiber connector, communication interface and multi-function interface that need to be wired and plugged in are exposed respectively, which is convenient for quick plugging and wiring, and realizes the rapid access of the equipment. By installing TEC cooling chips and radiators for the laser, the operating temperature is guaranteed to be within the appropriate range, so that the data accuracy meets the test requirements. By adding protection circuits, the adaptability problems such as pressure resistance, insulation, and EMC electromagnetic compatibility on the train are solved. The whole equipment is mostly integrated, with no mechanical moving parts inside. Except for the optical fiber, all wireless designs are adopted, which can effectively avoid inaccurate measurements and device damage caused by impact and vibration. 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 front overall structural diagram of a demodulator in one embodiment of the utility model.

[0020] Figure 2 This is a back overall structural diagram of a demodulator in one embodiment of the utility model.

[0021] Figure 3 1 is an internal structure diagram of a demodulator in one embodiment of the utility model.

[0022] Figure 4 FIG. 2 is another internal structure diagram of a demodulator in one embodiment of the utility model.

[0023] Figure 5 This is a diagram of the laser installation of a demodulator in one embodiment of the utility model.

[0024] Figure 6 The figure is a principle diagram of the optical path of a demodulator in one embodiment of the utility model. DETAILED DESCRIPTION

[0025] 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.

[0026] The term "coupled" or "connected" or "connected" in the specification includes 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 purpose, 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.

[0027] like Figures 1 to 3 As shown, a fiber Bragg grating demodulator in an embodiment of the utility model comprises a housing 1 and a laser (not shown in the figure) arranged in the housing 1 , an optical path module 2 , a driving circuit 3 , a main control circuit 4 and a bracket 5 .

[0028] The optical path module 2 is connected to the laser, the driving circuit 3 and the external grating. The optical path module 2 is used to transmit the laser generated by the laser to the external grating and receive the reflected light reflected by the external grating. The driving circuit 3 is connected to the laser and the main control circuit 4. The driving circuit 3 is used to drive the laser and convert the reflected light into a digital signal and transmit it to the main control circuit 4. The main control circuit 4 is connected to the driving circuit 3 to control the driving circuit 3.

[0029] The shell 1 includes a first mounting plate 11 and a front panel 12 and a top shell 13 fixedly mounted on the first mounting plate 11. The main control circuit 4 is arranged on the surface of the first mounting plate 11. The bracket 5 is fixedly mounted on the first mounting plate 11. The bracket 5 is used to install the laser, the optical path module 2 and the driving circuit 3.

[0030] In one embodiment, the fiber Bragg grating interrogator is installed in a 3U chassis, with the front panel 12 facing the outside of the chassis.

[0031] like Figure 3As shown, the bracket 5 includes a column 51 mounted on the first mounting plate 11 and a second mounting plate 52 mounted on the column 51, the optical path module 2 is mounted on the second mounting plate 52, and the driving circuit 3 is arranged on the surface of the second mounting plate 52. A heat sink 61 is also mounted on the second mounting plate 52.

[0032] In one embodiment, four columns 51 are provided and are respectively located at the four vertices of the second mounting plate 52. The column 51 is provided with an internal thread, and the two ends of the column 51 are fixedly mounted to the first mounting plate 11 and the second mounting plate 52 by bolts. Four support columns 53 are installed on the side of the second mounting plate 52 away from the first mounting plate 11, and the optical path module 2 is installed on the support columns 53. The installation method of the support columns 53, the second mounting plate 52 and the optical path module 2 is the same as the installation method of the column 51, the first mounting plate 11 and the second mounting plate 52. The heat sink 61 is installed between the optical path module 2 and the first mounting plate 11.

[0033] Preferably, the first mounting board 11 and the second mounting board 52 are both PCB circuit boards. The driving circuit 3 and the main control circuit 4 can be respectively arranged on the second mounting board 52 and the first mounting board 11 by printing, packaging and welding.

[0034] In one embodiment, the main control circuit 4 includes a control module, a clock circuit, a humidity and temperature sensor, a storage module, a lighting module and a protection circuit.

[0035] Among them, the storage module specifically includes a memory card and a flash memory chip. The clock circuit, the humidity and temperature sensor, the memory card, the flash memory chip and the lighting module are all connected to the control module, and the clock circuit is used to provide accurate time for digital signal acquisition. The humidity and temperature sensor is used to provide humidity and temperature information of the environment in which the demodulation system works, so as to detect whether the environment in which the system is located is abnormal, and to subsequently analyze the reliability of the data and the cause of the abnormality. The memory card is used to store digital signals and the corresponding time, temperature and humidity data. The flash memory chip is used to store system parameters to prevent data loss when the system is accidentally powered off. The lighting module is used to provide lighting signals indicating power supply and working status. By setting functional devices such as clock circuits, sensors, and memories, the data collected by the system is diversified and the system functions are enriched. The protection circuit includes an overvoltage and overcurrent protection circuit and an EMC protection circuit, which are used to solve adaptability problems such as withstand voltage, insulation, and EMC electromagnetic compatibility on the train. The control module is used to control the drive circuit 3 and the signal interaction between the drive circuit 3, the clock circuit, the humidity and temperature sensor, the storage module, the lighting module and the protection circuit.

[0036] In one embodiment, the driving circuit 3 includes a photodetector 31, an analog-to-digital converter and a driving chip. The photodetector 31 is connected to the optical path module 2 and is used to convert the reflected light reflected by the grating into an electrical signal. The analog-to-digital converter is connected to the photodetector 31 to convert the electrical signal into a digital signal. The driving chip is connected to the laser, the analog-to-digital converter and the control module of the main control circuit 4. The driving chip is used to transmit the digital signal to the control module and drive the laser based on the control of the control module.

[0037] The second mounting board 52 is provided with a JTAG interface 32 and an RS232 debugging interface 33 connected to the driving circuit 3 . The JTAG interface 32 and the RS232 debugging interface 33 are used for burning and debugging the program of the driving chip.

[0038] like Figure 3 and Figure 4 As shown, a connection base 41 connected to the main control circuit 4 is installed on the first mounting plate 11, and a connection terminal 34 connected to the drive circuit 3 and installed in cooperation with the connection base 41 is installed on the second mounting plate 52. The main control circuit 4 and the drive circuit 3 are connected only through the connection base 41 and the connection terminal 34, and the two are connected in a plug-in manner, so that the fiber Bragg grating demodulator adopts a wireless design except for the optical fiber, and there is no mechanical moving part inside, which can effectively avoid inaccurate measurement and device damage caused by impact and vibration.

[0039] The first mounting board 11 is also provided with a JLINK interface 42 connected to the main control circuit 4 , and the JLINK interface 42 is used for burning and debugging the program of the control module.

[0040] like Figure 4 and Figure 2 As shown, a multifunctional interface 43 connected to the main control circuit 4 is installed on the side of the first mounting plate 11 away from the front panel 12, and a make way slot for the multifunctional interface 43 is provided on the top shell 13. In one embodiment, the multifunctional interface 43 is a 64-pin socket, which is used to provide power, CAN and RS485 interfaces for the main control circuit 4. A 64-pin connector is provided in the 3U chassis corresponding to the multifunctional socket. When the fiber grating demodulator is pushed into the chassis, the 64-pin connector can be directly inserted into the multifunctional socket. As long as the fiber grating demodulator is correctly installed, the device wiring can be completed, eliminating the need for additional plugging and unplugging and wiring actions, and realizing rapid access to the device.

[0041] like Figure 5As shown, the laser 62 is fixedly mounted on the side of the heat sink 61 close to the second mounting plate 52, and the second mounting plate 52 is also provided with a through hole (not shown) for accommodating the laser 62. A TEC cooling chip is also mounted on the laser 62. The heat sink 61 and the TEC cooling chip jointly ensure that the operating temperature of the laser 62 is within a suitable range, so that the data accuracy meets the test requirements.

[0042] like Figure 6 As shown, the optical path module 2 includes an isolator 21, a first optical splitter 22 and a plurality of second optical splitters 23. The input end of the first optical splitter 22 is connected to the laser 62 through the isolator 21 to receive the laser, and the plurality of output ends of the first optical splitter 22 are connected to the first end A of the corresponding second optical splitter 23, and the second end B of the second optical splitter 23 is connected to the external grating to transmit the laser to the external grating and receive the optical signal reflected by the external grating, and the third end C of the second optical splitter 23 is connected to the driving circuit 3. In this embodiment, the isolator 21 is used to isolate the reflected light to avoid interfering with the laser 62, the first optical splitter 22 divides the laser into 8 optical signals, and 8 second optical splitters 23 are provided, each of which is used as a test channel, so that one fiber Bragg grating demodulator can monitor 8 data points at the same time, greatly improving the working efficiency.

[0043] The second optical splitter 23 is preferably a one-to-two PLC optical splitter or a two-to-two PLC optical splitter with one port left vacant. Both of these PLC optical splitters are small in size, simple in structure, and low in cost. Their functions are similar to those of optical circulators or couplers, but they are cheaper, which helps to reduce the cost of the entire device.

[0044] like Figure 1 As shown, the front panel 12 is provided with an optical fiber connector connected to the second end B of the second optical splitter 23 and a communication interface 44 connected to the control module. The optical fiber connector is used to connect the external grating, so that the optical path module 2 and the external grating form a complete fiber Bragg grating sensing loop and realize the fiber Bragg grating demodulation function. The communication interface 44 is used for information transmission between the control module and the outside. Specifically, the communication interface 44 is a Dcode12 network port connector.

[0045] like Figure 1 and Figure 2As shown, in one embodiment, both ends of the front panel 12 protrude beyond the intersection of the front panel 12 and the top shell 13. A positioning seat 121 is also provided on the side of the front panel 12 close to the top shell 13. The positioning seat 121 is located on the outside of the top shell 13. A positioning hole is provided on the positioning seat 121, and a positioning pin 122 is fixedly installed in one of the positioning holes. When the fiber grating demodulator housing 1 is installed in a 3U chassis, the protruding portion of the front panel 12 can be fixed to the 3U chassis by bolts or other means to facilitate the fixed installation of the fiber grating demodulator. The 3U chassis is also provided with through holes corresponding to the positioning pins 122. During installation, the positioning pins 122 are inserted into the through holes for pre-fixation to prevent the fiber grating demodulator from accidentally falling due to tilting or vibration when it is not completely installed and fixed. In other embodiments, according to the actual installation position and installation method of the fiber grating demodulator in the chassis, any part of the front panel 12 can be made to protrude from the intersection line of the front panel 12 and the top shell 13 or the intersection line of the front panel 12 and the first mounting plate 11 to achieve the function of fixed installation.

[0046] A handle 123 is installed on the front panel 12, and the handle 123 is used to pull out the fiber grating demodulator in the 3U chassis.

[0047] like Figure 1 and Figure 2 As shown, the top shell 13 includes an integrally formed top plate 131, two side plates 132 and a rear panel 133, the two side plates 132 are fixedly mounted on the first mounting plate 11, and the top plate 131 is fixedly mounted on the front panel 12. This not only facilitates the assembly of the fiber Bragg grating demodulator, reduces the number of components of the housing 1 to the greatest extent, but also effectively protects the internal components from damage due to impact and vibration.

[0048] The top shell 13 is provided with ventilation slots 134 for ventilating and cooling the components inside the fiber grating demodulator. Specifically, the ventilation slots 134 are provided on the two side plates 132 .

[0049] 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.

[0050] 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 fiber Bragg grating demodulator, characterized in that: It includes a housing, and a laser, an optical path module, a driving circuit, a main control circuit and a bracket arranged in the housing; The optical path module is connected to the laser, the driving circuit and the external grating, and is used to transmit the laser light generated by the laser to the external grating and receive the reflected light reflected by the external grating. The driving circuit is connected to the laser and the main control circuit, and is used to drive the laser and convert the reflected light into a digital signal and transmit it to the main control circuit. The main control circuit is connected to the driving circuit to control the driving circuit. The shell includes a first mounting plate and a front panel and a top shell fixedly mounted to the first mounting plate. The main control circuit is arranged on the surface of the first mounting plate. The bracket is fixedly mounted to the first mounting plate. The bracket is used to install the laser, the optical path module and the driving circuit.

2. The fiber Bragg grating demodulator according to claim 1, characterized in that: The bracket comprises a column mounted on a first mounting plate and a second mounting plate mounted on the column, the laser and the optical path module are mounted on the second mounting plate, and the driving circuit is arranged on the surface of the second mounting plate.

3. The fiber Bragg grating demodulator according to claim 2, characterized in that: The first mounting plate and the second mounting plate are PCB circuit boards.

4. The fiber Bragg grating demodulator according to claim 2, characterized in that: A heat sink is mounted on the second mounting plate, and the laser is fixedly mounted to the heat sink.

5. The fiber Bragg grating demodulator according to claim 2, characterized in that: A connection base connected to the main control circuit is installed on the first installation board, and a connection terminal connected to the drive circuit and installed in cooperation with the connection base is installed on the second installation board.

6. The fiber Bragg grating demodulator according to claim 1, characterized in that: A multifunctional interface connected to the main control circuit is installed on a side of the first installation plate away from the front panel, and a recess for making way for the multifunctional interface is provided on the top shell.

7. The fiber Bragg grating demodulator according to claim 1, characterized in that: The front panel is provided with an optical fiber connector connected to the optical path module and a communication interface connected to the main control circuit, and the optical fiber connector is used to connect to an external grating.

8. The fiber Bragg grating demodulator according to claim 1, characterized in that: A TEC cooling chip is installed on the laser.

9. The fiber Bragg grating demodulator according to claim 1, characterized in that: The first mounting board is also provided with a protection circuit connected to the main control circuit.

10. The fiber Bragg grating demodulator according to claim 1, characterized in that: The top shell is provided with ventilation slots.

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