Optical fiber light path fixing device of a laser gas sensor

Abstract

The utility model relates to a kind of optical fiber optical path fixing device of laser gas sensor, including multilayer circuit board and optical fiber device fixed structural member, the back of optical fiber device fixed structural member is equipped with the clamping groove of fixed signal laser and indicating laser, signal laser and indicating laser are connected with the bottom layer circuit board of multilayer circuit board;Optical fiber device fixed structural member peripheral side is equipped with several through holes;The center light outlet of optical fiber device fixed structural member is symmetrically equipped with the recess structure of fixed optical fiber coupler, wavelength division multiplexer and heat shrink protection sleeve two sides.It is integrated as compact whole by multilayer circuit board and optical fiber device fixed structural member in the utility model, replace the way that traditional optical fiber device is connected through interface and flange, effectively reduce the device volume, improve internal space utilization;Replace traditional space optical path by optical fiber optical path design, signal laser and indicating laser are coupled into a laser emission by wavelength division multiplexer, reduce the fine adjustment demand to laser.

Description

Technical Field

[0001] This utility model relates to the field of laser gas sensors, specifically to a fiber optic path fixing device for a laser gas sensor. Background Technology

[0002] In the field of laser gas sensor technology, through-beam open-circuit laser gas detectors have important applications in open space gas concentration detection due to their advantages such as fast response speed, high measurement accuracy, and strong anti-interference ability. The working principle of laser gas sensors is based on infrared spectral absorption. They achieve accurate detection of the gas concentration distance product by detecting changes in the absorption intensity of light at a specific wavelength. However, normal operation requires that the infrared laser emitted from the transmitting end be accurately received by the receiving end. Therefore, they are typically designed with an indicator laser emitting visible green light and a signal laser emitting infrared laser light.

[0003] Traditional technology employs a spatial optical path design, where two laser beams are directly emitted into an open environment. Since the signal laser is invisible infrared light, it needs to be indicated by a visible indicator laser. This requires that the deviation between the two laser beams be within a small range within a working distance of 5 to 100 meters. Therefore, the lasers need to be finely adjusted and fixed, which is a complicated and time-consuming process that consumes a lot of human resources.

[0004] Meanwhile, traditional fiber optic devices are mostly connected via fiber optic interfaces and flanges. When there are many fiber optic components inside the transmitting sensor, this connection structure occupies a large amount of internal space, resulting in a large device size and low space utilization. In addition, the lack of orderly guidance and fixation of the fiber optics inside the device makes them prone to bending, which in turn leads to optical power attenuation and affects detection accuracy and stability.

[0005] The aforementioned problems have adversely affected the installation and debugging efficiency, space compactness, and optical path stability of laser gas sensors, and urgently need to be improved. Utility Model Content

[0006] To address the problems of cumbersome and time-consuming laser debugging processes in existing through-beam open-circuit laser gas detectors, as well as the large space occupation and easy bending and loss of optical fibers caused by the connection of optical fiber devices through interfaces and flanges, this utility model provides an optical fiber path fixing device for laser gas sensors.

[0007] The technical solution of this utility model is as follows:

[0008] A fiber optic path fixing device for a laser gas sensor includes an upper multilayer circuit board and a lower fiber optic device fixing structure. The multilayer circuit board is fixedly connected to the back of the fiber optic device fixing structure. The back of the fiber optic device fixing structure has a first slot and a second slot for fixing a signal laser and an indicator laser, respectively. The signal laser and the indicator laser are connected to the bottom circuit board of the multilayer circuit board through pin headers. The periphery of the fiber optic device fixing structure has several through holes for fiber optic cables to pass from one side of the fiber optic device fixing structure to the other side. The center of the fiber optic device fixing structure has an output port for fixing a fiber optic collimator. The output port has symmetrical groove structures on both sides for embedding fiber optic couplers, wavelength division multiplexers, and heat-shrinkable protective sleeves.

[0009] As a preferred technical solution of this utility model, the multilayer circuit board is configured with a power supply circuit, a signal processing circuit and a laser driving circuit, and the laser driving circuit is located on the bottommost circuit board. The bottommost circuit board is also soldered with a photodetector with a reference gas chamber.

[0010] As a preferred technical solution of this utility model, the multilayer circuit board is connected to the back of the optical fiber device fixing structure by fasteners that penetrate its edge, and a support is provided between adjacent two circuit boards and between the bottom circuit board and the optical fiber device fixing structure.

[0011] Furthermore, the fastener is a screw, the support is a stud, and several screws are evenly distributed and pass through the edge of the multi-layer circuit board from top to bottom. The tail end of the screw is threaded to the back of the optical fiber device fixing structure. Each screw is fitted with several studs, and the studs are supported between two adjacent circuit boards or between the bottom circuit board and the optical fiber device fixing structure.

[0012] As a preferred technical solution of this utility model, the back of the optical fiber device fixing structure is provided with screw holes around the first slot. After the signal laser is embedded in the first slot, the screw holes on its base plate correspond to the screw holes around the first slot and are fixed by screws.

[0013] As a preferred embodiment of this utility model, the second slot has a screw hole, the indicator laser is assembled in a fixed base, and is connected and fixed by a screw hole on one side of the fixed base corresponding to the screw hole of the second slot.

[0014] As a preferred embodiment of this utility model, the back edge of the through hole is chamfered, and the through hole has an inlet slot.

[0015] As a preferred technical solution of this utility model, the front edge of the optical fiber device fixing structure is provided with a guide groove corresponding to the through hole, and the bottom of the guide groove extends inclinedly to both sides of the through hole to the front surface of the optical fiber device fixing structure.

[0016] As a preferred technical solution of this utility model, the front edge of the optical fiber device fixing structure is provided with a plurality of optical fiber line limiting members, which are used to accommodate optical fiber lines.

[0017] Furthermore, one end of the optical fiber limiting member is fixedly connected to the edge of the optical fiber device fixing structure, and the other end is provided with a bending section that extends toward the center of the optical fiber device fixing structure. This bending section is used to clamp the optical fiber.

[0018] As a preferred embodiment of this utility model, the groove structure includes a large groove and a small groove. The large groove is used to fix the fiber optic coupler or wavelength division multiplexer, and the small groove is used to fix the heat-shrinkable protective sleeve.

[0019] Furthermore, the groove structure is composed of several parallel convex strips, with two adjacent convex strips forming a groove, and the length of the convex strips in the large groove is greater than the length of the convex strips in the small groove.

[0020] The advantages of this utility model based on the above solution are as follows:

[0021] This utility model adopts a design that fixes the multi-layer circuit board and the optical fiber device fixing structure, integrating the circuit part and the optical path fixing part into a compact whole, replacing the traditional optical fiber device connection through interface and flange, effectively reducing the size of the device and improving the internal space utilization; the first and second slots on the back of the optical fiber device fixing structure can stably fix the signal laser and the indicator laser respectively, and together with the connection of the pin header to the bottom circuit board, it ensures the firmness of the laser installation and the reliability of the circuit connection.

[0022] This invention replaces the traditional spatial optical path with an optical fiber optical path design. The signal laser and the indicator laser are coupled into a single laser beam through a wavelength division multiplexer. This avoids the problem of needing to finely adjust the two laser beams in the traditional spatial optical path to ensure that the deviation is within the allowable range. This reduces the need for fine adjustment of the laser, reduces the complexity of the adjustment process, and saves manpower and time costs.

[0023] The through holes on the periphery of the optical fiber device fixing structure provide an orderly passage for the optical fiber, ensuring the orderliness of the optical fiber path and avoiding mutual interference caused by the disordered distribution of optical fibers.

[0024] The optical fiber device fixing structure has a central light outlet on the front side to fix the optical fiber collimator. The symmetrical groove structures on both sides of the light outlet fix the optical fiber coupler, wavelength division multiplexer and heat shrink protective sleeve. This achieves orderly partitioning and fixing of optical path components, which not only ensures the stable installation of each component, but also avoids mutual collision and interference between components. At the same time, it provides a protective space for the optical fiber splice and reduces the risk of damage to the splice from external factors. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of this utility model;

[0026] Figure 2 A front view of the fixing structure for optical fiber devices;

[0027] Figure 3 This is an exploded view of the structure of this utility model;

[0028] Figure 4 This is a diagram of the fiber optic path of a through-beam open-circuit laser gas sensor.

[0029] Figure 5 This is a schematic diagram of the optical fiber path of the transmitting device part of the laser gas sensor.

[0030] In the diagram,

[0031] 1. Fixing structure for optical fiber devices;

[0032] 11. First slot; 12. Second slot; 13. Through hole; 131. Chamfer; 132. Guide groove; 14. Light outlet;

[0033] 15. Large groove; 16. Small groove; 17. Fiber optic cable limiting component;

[0034] 2. Multilayer circuit board;

[0035] 21. First circuit board; 22. Second circuit board; 23. Third circuit board; 24. Stud; 25. Screw;

[0036] 3. Signal laser; 4. Indicator laser. Detailed Implementation

[0037] To better understand the purpose, technical solution, and technical effects of this utility model, the following description, in conjunction with the accompanying drawings and embodiments, will provide further explanation. It should be noted that similar reference numerals and letters in the following drawings indicate similar items; therefore, once an item is defined in one drawing, it does not need further definition and explanation in subsequent drawings. It is also stated that the embodiments described below are only for explaining this utility model and are not intended to limit it.

[0038] It should be noted that when a component is referred to as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intermediate component. When a component is referred to as "connected to" another component, it can be directly connected to the other component or there may be an intermediate component.

[0039] The indicated orientation or positional relationship is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product is usually placed when in use, or the orientation or positional relationship in which a person skilled in the art would normally understand it, or the orientation or positional relationship in which the product is usually placed when in use. It is only for the purpose of facilitating the description of this application and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] The terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or specifying the number of technical features. “Several” means two or more, unless otherwise expressly and specifically defined.

[0041] like Figure 4 and Figure 5 As shown, a through-beam open-circuit laser gas detector (or sensor) consists of a transmitting unit and a receiving unit. The overall optical path design first involves the transmitting end's driving circuit driving the signal laser and the indicator laser. The signal laser is split by a fiber optic coupler. 10% of the signal laser passes through a reference gas cell and then to the photodetector inside the transmitting end, converting the optical signal into an electrical signal. A program algorithm then monitors and calibrates the wavelength of the signal laser in real time. The remaining 90% of the signal laser and the indicator laser are coupled into a single laser beam by a wavelength division multiplexer, then collimated by a fiber optic collimator and directed into an open space to detect the gas concentration. This beam is then received by the receiving end, focused by a convex lens, and filtered to remove the green indicator laser light. Finally, it is received by the photodetector inside the receiving end, converting the optical signal into an electrical signal. A program algorithm then calculates the product of the concentration and distance of the gas to be measured. The fiber optic path frame of the through-beam open-circuit laser gas detector is shown below. Figure 4 As shown.

[0042] like Figures 1 to 3 As shown, this utility model studies the transmitting device part of a laser gas detector sensor. Specifically, it discloses a fiber optic path fixing device for a laser gas sensor, comprising an upper multilayer circuit board 2 and a lower fiber optic device fixing structure 1, with the back of the multilayer circuit board 2 fixedly connected to the back of the fiber optic device fixing structure 1. In this embodiment, the multilayer circuit board has three layers, forming a three-layer circuit board.

[0043] The multilayer circuit board 2 comprises, from top to bottom, a first circuit board 21, a second circuit board 22, and a third circuit board 23. The power supply circuit is distributed across these three circuit boards. The signal processing circuit is located on the second and third circuit boards 22 and 23. The laser driving circuit is primarily located on the third circuit board 23, which also houses a photodetector with a reference gas chamber. This layered structure clearly separates circuit functions. The power supply circuit provides stable power to the entire device, the driving circuit specifically drives the signal laser 3 and the indicator laser 4, and the signal processing circuit focuses on processing photoelectric signals to calculate the gas concentration-distance product. This modular division of labor reduces mutual interference between circuits, improving circuit stability and signal processing efficiency. Furthermore, the photodetector with a reference gas chamber is directly soldered onto the third circuit board 23, eliminating the additional connection steps between the detector and the circuit in traditional devices and reducing signal errors caused by loose connections.

[0044] The multilayer circuit board 2 is mounted on the back of the fiber optic device fixing structure 1 using studs 24 and screws 25. The studs are made of copper. During assembly, several screws 25 are first passed through the top layer first circuit board 21 from top to bottom. Then, a stud A is fitted onto each screw 25. The bottom of the screw 25 is then passed through the middle layer second circuit board 22, so that the top of the second circuit board 22 abuts against the stud A. Next, a stud B is fitted onto each screw 25. Then, the bottom of the screw 25 is passed through the bottom layer third circuit board 23, so that the top of the third circuit board 23 abuts against the stud B. Finally, a stud C is fitted onto each screw 25. The bottom of the screw 25 is then screwed and fixed to the back of the fiber optic device fixing structure 1, so that the bottom of the stud C abuts against the back of the fiber optic device fixing structure 1.

[0045] In one specific embodiment, the multilayer circuit board 2 is fixedly connected to the back of the fiber optic device fixing structure 1 by three screws 25. The three screws 25 are triangularly distributed, passing through the edge of the multilayer circuit board 2 from top to bottom, and the tail of the screw 25 is threaded to the back of the fiber optic device fixing structure 1; and each screw 25 is fitted with three studs (studs A, B, and C), each stud being supported between two adjacent circuit boards, or between the bottom circuit board and the fiber optic device fixing structure 1. As shown above, studs A are supported between the first circuit board 21 and the second circuit board 22, studs B are supported between the second circuit board 22 and the third circuit board 23, and studs C are supported between the third circuit board 23 and the fiber optic device fixing structure 1. This embodiment forms a stable support through the triangularly distributed screws, and at the same time, the height of the studs 24 ensures that a preset distance is maintained between each circuit board layer and between the bottom circuit board and the structure, thus completing the assembly of the multilayer circuit board 2 and the fiber optic device fixing structure 1.

[0046] In this invention, the back of the fiber optic device fixing structure 1 is provided with a first slot 11 for fixing a signal laser 3 and a second slot 12 for fixing an indicator laser 4. The signal laser 3 is installed in the first slot 11, and the indicator laser 4 is installed in the second slot 12. Furthermore, the signal laser 3 and the indicator laser 4 are connected to the bottom circuit board of the multilayer circuit board 2 via their respective pin headers. The step of assembling the signal laser 3 and the indicator laser 4 onto the fiber optic device fixing structure 1 should be performed before the assembly step of the fiber optic device fixing structure 1 with the multilayer circuit board 2; that is, the signal laser 3 and the indicator laser 4 should be assembled onto the back of the fiber optic device fixing structure 1 first, and then the fiber optic device fixing structure 1 should be assembled with the multilayer circuit board 2.

[0047] In one specific embodiment, the back of the fiber optic device fixing structure 1 is provided with screw holes around the first slot 11. After the signal laser 3 is embedded in the first slot 11, the screw holes on its base plate correspond to the screw holes around the first slot 11 and are fixed by screws. The second slot 12 is provided with screw holes. A fixing seat is adapted to the size of the second slot 12. The fixing seat has a mounting position for mounting the indicator laser 4 in the middle. The fixing seat also has screw holes on one side. When the fixing seat is embedded in the second slot 12, the screw holes of the fixing seat and the second slot 12 correspond. The indicator laser 4 is mounted in the second slot 12 through the fixing seat.

[0048] When assembling the signal laser 3, first insert the signal laser 3 into the first slot 11 on the back of the fiber optic device fixing structure 1, ensuring that the screw holes on the laser base plate are precisely aligned with the pre-set screw holes around the first slot 11. Then, pass screws through the corresponding screw holes and tighten them to securely fix the signal laser 3. When assembling the indicator laser 4, assemble the indicator laser 4 into the mounting position of the fixing base, ensuring that the screw holes on one side of the fixing base correspond to the screw holes in the second slot 12. Tighten the screws to mount the indicator laser 4 in the second slot via the fixing base. After fixing, connect the power supply pins of the signal laser 3 and the indicator laser 4 to the bottom circuit board (i.e., the third circuit board 23) of the multilayer circuit board 2 to achieve circuit conduction. Simultaneously, assemble the fiber optic device fixing structure 1 below the multilayer circuit board 2. The first slot 11 and the second slot 12, through shape matching, position and fix the signal laser 3 and the indicator laser 4, ensuring the accuracy and stability of the installation of the two lasers and avoiding positional displacement caused by vibration and other factors during use. This also guarantees the initial alignment accuracy of the lasers with subsequent optical path components. The direct connection between the pin header and the underlying circuit board simplifies circuit wiring while ensuring the reliability of power supply and signal transmission.

[0049] In this invention, the optical fiber device fixing structure 1 has several through holes 13 on its periphery, and each through hole 13 has a cable inlet slot. The through holes 13 are used to allow optical fibers to pass from one side of the optical fiber device fixing structure 1 to the other side. For example, the optical fibers of the signal laser 3 and the indicator laser 4 pass through the through holes 13 to the front side of the optical fiber device fixing structure 1; the optical fibers of the optical fiber coupler and the wavelength division multiplexer pass through the through holes 13 to the back side of the optical fiber device fixing structure 1.

[0050] In a preferred embodiment, the back edge of the through hole 13 is chamfered 131. The front edge of the fiber optic device fixing structure 1 is provided with a guide groove 132 corresponding to the through hole 13. The bottom of the guide groove 132 extends obliquely to both sides of the through hole 13 to the front surface of the fiber optic device fixing structure 1.

[0051] During assembly, the fiber optic cables of the signal laser 3 and the indicator laser 4 are inserted into the holes through the inlet slots of the through-holes 13. The chamfer 131 on the back edge ensures a smooth transition of the fiber optic cables, reducing bending stress during insertion. The fiber optic cable through-hole 13 reaches the front of the fiber optic device fixing structure 1, runs along the inclined bottom of the guide groove 132 to the front edge, and is then introduced into the interior of the front of the fiber optic device fixing structure 1 near the fiber optic coupler or wavelength division multiplexer, correspondingly connecting to the fiber optic coupler or wavelength division multiplexer. Similarly, the fiber optic cables of the fiber optic coupler or wavelength division multiplexer are inserted into other empty through-holes 13 through the inlet slots. The inclined structure of the front guide groove 132 and the chamfer 131 on the back edge complete the transition, and the through-hole 13 reaches the back of the fiber optic device fixing structure 1, correspondingly connecting to the fiber optic collimator or the photodetector with a reference gas cell.

[0052] This invention replaces the traditional spatial optical path with an optical fiber optical path design. The signal laser and the indicator laser are coupled into a single laser beam via a wavelength division multiplexer. This avoids the problem of needing to finely adjust the two laser beams in the traditional spatial optical path to ensure that the deviation is within the allowable range. This reduces the need for fine adjustment of the laser, reduces the complexity of the adjustment process, and saves manpower and time costs.

[0053] The through-hole 13 provides a dedicated channel for the optical fiber, which, together with the inlet slot, facilitates the rapid insertion and positioning of the optical fiber, preventing its disordered distribution within the optical fiber device fixing structure 1. The chamfer 131 on the back edge works in conjunction with the guide groove 132 on the front, ensuring the optical fiber maintains an arc greater than the minimum bending radius during insertion, effectively preventing power loss due to excessive bending and ensuring the stability of the optical path transmission. Furthermore, the inclined extension design of the guide groove 132 further guides and limits the direction of the optical fiber, reducing fiber displacement caused by external vibrations and other factors.

[0054] In a preferred embodiment, the front edge of the fiber optic device fixing structure 1 is provided with several fiber optic line limiting members 17, which are used to accommodate fiber optic lines. When the fiber optic lines of the signal laser 3 and the indicator laser 4 pass through the through-hole 13 to the front, they extend along the inclined direction of the guide groove 132, and are then embedded in the fiber optic line limiting members 17. This allows the fiber optic lines to be orderly wound along the inner ring of the outer wall of the front of the fiber optic device fixing structure 1, ensuring that each fiber optic line is limited and maintains a preset bending radius. By accommodating and fixing the fiber optic lines, the fiber optic line limiting members 17 prevent the fibers from being randomly scattered or tangled on the front of the fiber optic device fixing structure 1, making the fiber optic path more orderly and reducing mutual interference or accidental pulling caused by messy fibers.

[0055] In one specific embodiment, one end of the fiber optic cable limiting member 17 is fixedly connected to the edge of the fiber optic device fixing structure 1, and the other end has a bending section extending towards the center of the fiber optic device fixing structure 1. This bending section is arc-shaped or hook-shaped and is used to clamp the fiber optic cable. After the fiber optic cable extends to the front side through the through hole 13 and the guide groove 132, the fiber optic cable is inserted into the gap formed between the bending section and the front side of the fiber optic device fixing structure 1, thereby clamping and fixing the fiber optic cable through the bending section.

[0056] In this invention, the optical fiber device fixing structure 1 has a light-emitting port 14 at its center on the front side, which is used to fix the optical fiber collimator. Symmetrical groove groups are provided on both sides of the light-emitting port 14, including a large groove 15 for fixing the optical fiber coupler or wavelength division multiplexer and a small groove 16 for fixing the heat-shrinkable protective sleeve. During assembly, the output optical fiber (i.e., the optical fiber line) of the wavelength division multiplexer is fused to the optical fiber collimator, and the fusion point is wrapped with a heat-shrinkable protective sleeve and fixed in the nearby small groove 16. Then, the main body of the optical fiber collimator is embedded into the light-emitting port 14 and fixed by interference fit or screws, ensuring that the output end face of the optical fiber collimator is perpendicular to the front side of the optical fiber device fixing structure 1, ensuring that the laser beam combined by the wavelength division multiplexer can be collimated and emitted along the axis of the light-emitting port 14. The fixing of the optical fiber collimator by the light-emitting port 14 ensures the positional accuracy of the collimator in the device, avoids angular deviation caused by vibration or assembly errors, thereby ensuring the stability of the emission direction of the composite laser and enabling the laser to be accurately directed towards the receiving device.

[0057] In one specific embodiment, several protrusions are machined on the front side of the fiber optic device fixing structure 1 along a direction parallel to the axis of the light outlet 14, forming a groove between adjacent protrusions. The large groove 15, used to fix the fiber optic coupler or wavelength division multiplexer, is composed of longer protrusions, the width and depth of which match the external dimensions of the fiber optic coupler or wavelength division multiplexer. The small groove 16, used to fix the heat-shrinkable protective sleeve, is composed of shorter protrusions, the width and depth of which are adapted to the size of the heat-shrinkable protective sleeve. The length of the protrusions in the large groove 15 is greater than the length of the protrusions in the small groove 16. During assembly, the fiber optic coupler or wavelength division multiplexer is embedded in the large groove 15, using the limiting effect of the protrusions to prevent lateral movement; the fusion splice with the heat-shrinkable protective sleeve is placed in the small groove 16, where the protrusions constrain and prevent the fusion splice from wobbling.

[0058] This invention utilizes parallel protrusions to form large and small grooves 16, enabling precise partitioning and fixing of devices of different sizes without the need for additional complex structures, thus simplifying the manufacturing process of the fiber optic device fixing structure 1. Simultaneously, the protrusion structure enhances the overall rigidity of the front side of the fiber optic device fixing structure 1, improving the device's resistance to deformation.

[0059] In summary, the fiber optic path fixing device for the laser gas sensor of this utility model first fixes the signal laser 3 and the indicator laser 4 to the corresponding slots on the back of the fiber optic device fixing structure 1 with screws. The four outermost through holes 13 of the structure (i.e., the fiber optic device fixing structure 1) pass through the front from the back, ensuring that the bending radius of the fiber optic line is greater than the minimum bending radius when passing through the structure, thus avoiding optical power loss due to fiber bending.

[0060] In practical use:

[0061] 1. Allow a large bending radius for the optical fibers emitting from the signal laser 3 and the indicator laser 4, and select a suitable through hole 13 to pass them from the back to the front of the fixing component. Six optical fiber fixing limiters are installed on the outer wall of the front of the structural component by screws. After the optical fibers emitting from the signal laser 3 and the indicator laser 4 pass through the through hole 13, they are wound around the inner ring of the outer wall of the structural component along the guide groove 132 through the optical fiber limiting component 17.

[0062] 2. The signal laser 3 and the fiber optic coupler are fused together, leaving a longer fiber optic cable wrapped around the inner ring of the outer wall of the structural component via the fiber optic cable limiting member 17. This fixes the fusion point with the heat-shrinkable protective sleeve in the small groove 16 on the front side, while the fiber optic coupler is fixed in the large groove 15 on the front side. The 10% optical power output fiber of the fiber optic coupler passes through the through hole 13 around the inner ring of the outer wall of the structural component via the fiber optic cable limiting member 17, and is then fused with the photodetector with the reference gas chamber. The 90% optical power output fiber of the fiber optic coupler and the output fiber of the indicator laser are fused with the wavelength division multiplexer respectively. The longer fiber optic cable is wrapped around the inner ring of the outer wall via the fiber optic cable limiting member 17, fixing the fusion point with the heat-shrinkable protective sleeve in the small groove 16. The wavelength division multiplexer is fixed in the large groove 15.

[0063] 3. Pass the optical fiber output from the wavelength division multiplexer through the optical fiber limiting member 17 around the inner ring of the outer wall and through the through hole 13, and then fuse it with the optical fiber collimator. The optical fiber collimator is fixed in the light outlet 14 in the center of the structural component.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] The above embodiments only illustrate several implementation methods of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An optical fiber light path fixing device of a laser gas sensor, characterized by, It includes an upper multilayer circuit board and a lower optical fiber device fixing structure, wherein the multilayer circuit board is fixedly connected to the back of the optical fiber device fixing structure; The optical fiber device fixing structure has two slots on its back for fixing the signal laser and the indicator laser, respectively. The signal laser and the indicator laser are connected to the bottom circuit board of the multilayer circuit board. The optical fiber device fixing structure is provided with several through holes on its periphery, allowing the optical fiber to pass from one side of the optical fiber device fixing structure to the other side. The optical fiber device fixing structure has a light output port for fixing the optical fiber collimator at its center, and groove structures for embedding optical fiber couplers, wavelength division multiplexers and heat shrink protective sleeves are symmetrically provided on both sides of the light output port.

2. The optical fiber light path fixing device of a laser gas sensor according to claim 1, characterized by The multilayer circuit board is equipped with a power supply circuit, a signal processing circuit, and a laser driving circuit, with the laser driving circuit located on the bottommost circuit board. The bottommost circuit board is also soldered with a photodetector with a reference gas chamber.

3. The optical fiber light path fixing device of a laser gas sensor according to claim 1 or 2, characterized in that, The multilayer circuit board is connected to the back of the optical fiber device fixing structure by fasteners that penetrate its edge, and support members are provided between adjacent two circuit boards and between the bottom circuit board and the optical fiber device fixing structure.

4. The optical fiber light path fixing device of a laser gas sensor according to claim 3, wherein The fastener is a screw, and the support is a stud. Several screws are evenly distributed and pass through the edge of the multi-layer circuit board from top to bottom. The tail end of the screw is threaded to the back of the optical fiber device fixing structure. Each screw is fitted with several studs, and the studs are supported between two adjacent circuit boards or between the bottom circuit board and the optical fiber device fixing structure.

5. The optical fiber light path fixing device of a laser gas sensor according to claim 1, wherein The back of the optical fiber device fixing structure is provided with screw holes around the first slot. After the signal laser is embedded in the first slot, the screw holes on its base plate correspond to the screw holes around the first slot and are fixed by screws.

6. The optical fiber light path fixing device of a laser gas sensor according to claim 1, wherein The second slot, which houses the indicator laser, has a screw hole inside. The indicator laser is mounted in a fixed base and is connected and fixed by a screw hole on one side of the fixed base corresponding to the screw hole in the second slot.

7. The optical fiber light path fixing device of a laser gas sensor according to claim 1, wherein The through hole has an inlet slot, and the back edge of the through hole is chamfered.

8. A fiber-optic light path fixture for a laser gas sensor according to claim 7, characterized in that The front edge of the optical fiber device fixing structure is provided with a guide groove corresponding to the through hole. The bottom of the guide groove extends inclinedly to both sides of the through hole to the front surface of the optical fiber device fixing structure.

9. The fiber optic path fixing device for a laser gas sensor according to claim 1, characterized in that, The front edge of the optical fiber device fixing structure is provided with several optical fiber line limiting members, which are used to accommodate optical fiber lines.

10. The optical fiber light path fixing device of a laser gas sensor according to claim 1, wherein The groove structure includes a large groove and a small groove. The large groove is used to fix the fiber optic coupler or wavelength division multiplexer, and the small groove is used to fix the heat shrink protective sleeve.

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