Multi-channel optical fiber coupler

Abstract

The utility model relates to a multi-channel optical fiber coupler which comprises a shell, collimating lenses and a micro-lens array lens, the shell is provided with a plurality of channels, the input end of each channel is connected with an optical fiber through an optical fiber interface, each channel is fixedly provided with the collimating lens, and the micro-lens array lens is connected with the collimating lens. The input end of each channel is provided with the micro-lens array lens, the collimating lens is configured to collimate emergent light beams on an optical fiber so as to form collimated light and then emit the collimated light to the micro-lens array lens, and the micro-lens array lens is configured to dodging the collimated light so as to form uniform collimated light and then emit the uniform collimated light. The optical fiber coupler is simple in module structure design, good in system sealing performance, high in stability, high in power density, small in energy loss and easy to integrate. The coupler design is suitable for a multi-beam photon counting laser radar, optical signals of multiple channels can be processed at the same time, and the detection efficiency of a system is improved.

Description

Technical Field

[0001] This application relates to the field of optical communication, and particularly to a multi-channel fiber optic coupler. Background Art

[0002] A fiber optic coupler is used to transfer an optical signal from one optical fiber to another to achieve signal transmission. In an optical fiber network, it connects different parts between optical fibers, such as connecting an optical cable to an optical transceiver, an optical module to an optical multiplexer, etc. A fiber optic coupler plays a role in transferring an optical signal from a light source to a sensor in an optical fiber sensing system, realizing the connection between an optical fiber sensor and a control system. For example, fiber Bragg grating sensors, fiber Raman sensors, etc. all need to use fiber optic couplers for signal coupling and decoupling. Low coupling efficiency will lead to loss of optical signals and affect the overall performance of the system.

[0003] A multi-beam photon counting lidar transmits the received laser echo light to a PMT detector through an optical fiber. Generally, a pair of fiber optic connectors are required when connecting two optical fibers, which has the following disadvantages: 1) The product structure size is large; 2) The assembly process is cumbersome; 3) The fiber optic coupling efficiency is low; 4) The temperature range is limited.

[0004] In order to solve the above problems, the applicant has designed and provided a fiber optic coupler module for connecting a PMT detector. Summary of the Utility Model

[0005] This application provides a multi-channel fiber optic coupler, which can improve the optical signal reception efficiency.

[0006] The multi-channel fiber optic coupler provided by this application adopts the following technical solutions:

[0007] A multi-channel fiber optic coupler includes a housing, a collimating lens, and a microlens array lens. The housing is provided with a plurality of channels. The input end of each channel is connected to an optical fiber through an optical fiber interface. The collimating lens is fixedly installed on each channel. The input end of each channel is provided with the microlens array lens. The collimating lens is configured to collimate the outgoing light beam on the optical fiber to form collimated light and then emit it onto the microlens array lens. The microlens array lens is configured to perform light homogenization processing on the collimated light to form uniform collimated light and then emit it.

[0008] Further improvement: A stepped structure for fixedly mounting the collimating lens is provided at the output end of the channel. A first rubber gasket is provided between the end face of the stepped structure and the collimating lens. Multiple micro-lens array lenses are integrally processed into a single-piece lens. A lens retaining ring is provided between the single-piece lens and the collimating lens. Multiple lens retaining rings are integrally connected to form an integral lens retaining cylinder. A head is provided on the housing for tightly fixing the micro-lens array lens. A second rubber gasket is provided between the head and the micro-lens array lens.

[0009] Further improvement: A flange is provided on the housing. The flange and the head are connected by screws. A plurality of fixed ear plates are circumferentially distributed on the flange.

[0010] Further improvement: The thermal expansion coefficients of the housing and the head are 10 - 12×10 -5 / °C, and the thermal expansion coefficients of the collimating lens and the micro-lens array lens are 5.5×10 -7 / °C or less.

[0011] Further improvement: The number of channels is at least four arranged in a rectangular array.

[0012] Further improvement: A detector receiving screen is provided behind the micro-lens array lens. The detector receiving screen is used to convert the received optical signal into an electrical signal.

[0013] Further improvement: A plurality of receiving areas are provided on the detector receiving screen. The receiving areas correspond to the channels one by one. A plurality of pixels arranged at uniform intervals are provided in the receiving areas.

[0014] Further improvement: The number of pixels in each receiving area is at least four arranged in a rectangular array. The light spots projected in the channels are evenly distributed to all the pixels in the corresponding receiving areas.

[0015] Further improvement: A plurality of light homogenizing areas are provided on the micro-lens array lens. The light homogenizing areas correspond to the receiving areas one by one.

[0016] In summary, the module has a simple structure design, good system sealing performance, strong stability, high power density, low energy loss, and is easy to integrate. The coupler design is applicable to multi-beam photon counting lidar, can process optical signals of multiple channels simultaneously, and improves the detection efficiency of the system. The module structure design matches the pixel size of the PMT detector.

[0017] This application includes at least one of the following beneficial technical effects:

[0018] 1. Integrated design: By integrating multiple fiber optic interfaces through multiple channels on the housing, the use of traditional fiber optic connectors is reduced, thus reducing the overall size of the product. The integrated and modular design simplifies the maintenance and replacement processes and reduces the maintenance cost.

[0019] 2. Simplified assembly process: The fiber optic coupler adopts an integrated module design, reducing the cumbersome assembly process and improving the assembly efficiency and reliability. The modular design enables the fiber optic coupler to flexibly configure the number of channels according to needs, facilitating expansion and upgrade.

[0020] 3. Improved fiber optic coupling efficiency: The collimating lens converts the outgoing light beam in the fiber into collimated light, and then the homogenizing process is carried out through the microlens array lens, effectively improving the coupling efficiency of the optical signal.

[0021] 4. Temperature adaptability: The received heat source mainly comes from the irradiation of the laser and the temperature change brought by the external environment. The overall system optics of this module has a high transmittance of more than 98%, so that only less than 2% of the laser energy is conducted to the module through the collimating lens and the microlens array, with little impact. It can adapt to the environmental temperature change range of -10°C to 45°C. The coupler can maintain good performance at different temperatures, expanding its operating temperature range.

[0022] 5. Improved optical signal reception efficiency: By optimizing the optical path design, the loss of optical signal during transmission is reduced, and the efficiency of the PMT detector receiving the optical signal is improved. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of the fiber optic coupler module (sectioned along the channel axis).

[0024] Figure 2 is an exploded view of the fiber optic coupler module.

[0025] Figure 3 are perspective views of the front and back sides of the module assembly.

[0026] Figure 4 is a schematic diagram of the distribution of the collimated light spot on the detector receiving screen (photosensitive surface).

[0027] Figure 5 is a schematic structural diagram of the microlens array lens (consistent with the partition of the detector receiving screen).

[0028] Explanation of the reference numerals: 1. Shell, 2. Collimating lens, 3. Microlens array lens, 4. Channel, 5. Optical fiber interface, 6. First rubber gasket, 7. Lens pressure cylinder, 8. Head, 9. Second rubber gasket, 10. Detector receiving screen, 11. Receiving area, 12. Pixel, 13. Uniform light area, 14. Flange, 15. Fixing ear plate, 16. Collimating light spot, 17. Microprism unit. DETAILED DESCRIPTION

[0029] The following is combined with Figures 1-5 This application is described in further detail.

[0030] The embodiment of the present application discloses a multi-channel optical fiber coupler.

[0031] Reference Figure 1 A multi-channel fiber coupler comprises a housing 1, a collimating lens 2 and a microlens array lens 3. The housing 1 is provided with a plurality of channels 4. The input end of each channel 4 is connected to an optical fiber through an optical fiber interface 5. The collimating lens 2 is fixedly mounted on each channel 4. The input end of each channel 4 is provided with the microlens array lens 3. The collimating lens 2 is configured to collimate the outgoing light beam on the optical fiber to form collimated light and then emit it to the microlens array lens 3. The microlens array lens 3 is configured to homogenize the collimated light to form uniform collimated light and then emit it. The fiber coupler adopts a modular design, which reduces the cumbersome assembly process and improves the assembly efficiency and reliability. The modular design allows the fiber coupler to flexibly configure the number of channels as needed, which is convenient for expansion and upgrading. The collimating lens collimates the outgoing light beam in the optical fiber into parallel light, and then homogenizes it through the microlens array lens, which effectively improves the coupling efficiency of the optical signal.

[0032] As attached Figure 2 As shown, a first rubber gasket 6 is provided between the collimating lens 2 and the housing 1, a lens pressing ring is provided between the collimating lens 2 and the microlens array lens 3, and a plurality of the lens pressing rings are integrally connected to form an integrated lens pressing cylinder 7. The collimating lenses 2 on a plurality of channels are fixed in the housing 1 by the integrated square lens pressing cylinder 7, and the first rubber gasket 6 ensures that the collimating lenses 2 on each channel are subjected to uniform force, thereby reducing assembly errors caused by manufacturing precision.

[0033] The housing 1 is detachably fixedly provided with a sealing head 8, which is a gland or end cap, and is a component used to fix the end of a pipe. The sealing head 8 is provided with a window for light emission, and the surface of the microlens array lens 3 is exposed on the window. A second rubber gasket 9 is provided between the sealing head 8 and the microlens array lens 3, and the first rubber gasket 6 ensures that the microlens array lens 3 is subjected to uniform force, avoids damage to the lens, and reduces assembly errors caused by manufacturing precision.

[0034] As shown in the appendix Figure 3 As shown, a flange 14 is provided on the housing 1. The flange 14 is connected to the head by screws. The head 8 is fixed to the housing 1 by four screws and simultaneously presses the microlens array lens 3 through the second rubber washer 9, so that each part is compacted and fixed into one body by four screws and rubber washers. A plurality of fixed ear plates 15 are circumferentially distributed on the flange 14 for connecting the housing to the detector by screws.

[0035] The thermal expansion coefficients of the housing 1 and the head 8 are 10 - 12×10 -5 / °C, and the thermal expansion coefficients of the collimating lens 2 and the microlens array lens 3 are below 5.5×10 -7 / °C. The materials of the housing 1 and the head 8 can be made of polytetrafluoroethylene, and the materials of the collimating lens 2 and the microlens array lens 3 can be made of fused quartz. Through the above parameter settings, the dimensional deformation caused by temperature rise is only in the micron order and will not affect the operation of the module.

[0036] The number of the channels 4 is at least four arranged in a rectangular array, or an integer multiple of four. The four-channel fiber coupler module is composed of 4 groups of optical fibers, collimating lenses and microlenses (which can form a microlens array lens).

[0037] As shown in the appendix Figure 4 As shown, a detector receiving screen 10 is provided behind the microlens array lens 3. The detector receiving screen 10 is used to convert the received optical signal into an electrical signal.

[0038] A plurality of receiving areas 11 are provided on the detector receiving screen 10. The receiving areas 11 correspond to the channels 4 one by one, and a plurality of pixels 12 arranged at uniform intervals are provided in the receiving areas 11.

[0039] The number of pixels 12 in each receiving area 11 is at least four arranged in a rectangular array. The center of the distribution of the pixels 12 in the receiving area 11 is aligned with the central axis of the corresponding channel 4, so that the light spots projected in the channel 4 are evenly distributed on all the pixels 12 in the receiving area 11. As shown in the appendix Figure 4 As shown, each optical fiber is coupled to the surfaces of 2×2 = 4 pixels, and 4 collimated light spots 16 are distributed on each detector surface. The parameters of the detector receiving screen 10 are as follows: 1) There are a total of 4×4 = 16 pixels, and there are ineffective areas with a certain interval between individual pixels; 2) The overall external dimension refers to Figure 5 the structure of the microlens array lens 3.

[0040] As shown in the appendix Figure 5As shown, there are multiple light homogenizing regions 13 on the microlens array lens 3, and the light homogenizing regions 13 correspond one by one to the receiving regions 11. The number of microprism units 17 on the microlens array lens 3 is consistent with the number of pixels on the detector receiving screen 10. The parameters of the microlens are as follows: 1) The microlens array is consistent with the detector partition, and the structural dimensions meet the interface requirements; 2) It is used to reduce the energy loss caused by the pixel gap.

[0041] In summary, the mechanical structure of this module from left to right is successively the laser receiving end (housing 1) of the coupler, the collimating lens 2, the lens barrel 7, the microlens array lens 3, and the end cap 8. The optical fiber interface 5 at the left end of the housing 1 is designed according to the standard SMA905 interface. Considering the optical divergence angle and distance, it is ensured that the laser emitted by the laser can reach the collimating lens 2 smoothly; the laser is collimated by the collimating lens 2 and then homogenized by the microlens array lens 3, and is irradiated onto the detector receiving screen 10 (photosensitive surface) behind through the window at the center of the end cap 8 at the right end. The microlens (or microprism) array is used to improve the filling rate of the detector pixels and reduce the energy loss caused by the pixel gap.

[0042] The above are all the preferred embodiments of this application. The protection scope of this application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A multi-channel optical fiber coupler, comprising a housing (1), a collimating lens (2) and a microlens array lens (3), characterized in that: The housing (1) is provided with a plurality of channels (4), the input end of each channel (4) is connected to an optical fiber through an optical fiber interface (5), the collimating lens (2) is fixedly mounted on each channel (4), the input end of each channel (4) is provided with the microlens array lens (3), the collimating lens (2) is configured to collimate the outgoing light beam on the optical fiber to form collimated light and then emit it to the microlens array lens (3), and the microlens array lens (3) is configured to perform uniform light processing on the collimated light to form uniform collimated light and then emit it.

2. A multi-channel optical fiber coupler according to claim 1, characterized in that: The output end of the channel (4) is provided with a step structure for fixing and installing the collimating lens (2); a first rubber gasket (6) is provided between the end surface of the step structure and the collimating lens (2); a plurality of the microlens array lenses (3) are integrated and processed into a single lens; a lens pressing ring is provided between the single lens and the collimating lens (2); the plurality of lens pressing rings are integrally connected to form an integrated lens pressing cylinder (7); a sealing head (8) for pressing and fixing the microlens array lens (3) is provided on the housing (1); a second rubber gasket (9) is provided between the sealing head (8) and the microlens array lens (3).

3. A multi-channel optical fiber coupler according to claim 2, characterized in that: The shell (1) is provided with a flange (14), the flange (14) and the head (8) are connected by screws, and a plurality of fixing ear plates (15) are distributed circumferentially on the flange (14).

4. A multi-channel optical fiber coupler according to claim 2, characterized in that: The thermal expansion coefficient of the shell (1) and the head (8) is 10 to 12*10 -5 / °C, the thermal expansion coefficient of the collimating lens (2) and the microlens array lens (3) is 5.5*10 -7 / ℃ below.

5. The multi-channel optical fiber coupler according to claim 1, characterized in that: The number of the channels (4) is at least four and is distributed in a rectangular arrangement.

6. A multi-channel optical fiber coupler according to any one of claims 1 to 5, characterized in that: A detector receiving screen (10) is provided behind the microlens array lens (3), and the detector receiving screen (10) is used to convert received optical signals into electrical signals.

7. A multi-channel optical fiber coupler according to claim 6, characterized in that: The detector receiving screen (10) is provided with a plurality of receiving areas (11), the receiving areas (11) correspond to the channels (4) one by one, and a plurality of evenly spaced picture elements (12) are provided in the receiving areas (11).

8. A multi-channel optical fiber coupler according to claim 7, characterized in that: The number of picture elements (12) in each receiving area (11) is at least four distributed in a rectangular array, and the light spot projected in the channel (4) is evenly distributed to all the picture elements (12) in the corresponding receiving area (11).

9. The multi-channel optical fiber coupler according to claim 7, characterized in that: The microlens array lens (3) is provided with a plurality of light-homogenizing areas (13), and the light-homogenizing areas (13) correspond one to one with the receiving areas (11).

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