Free space light detection receiving module

Abstract

The utility model relates to a free space light detection receiving module. The free space light detection receiving module comprises a receiving part arranged along a light path direction; a first narrowband filter, a main light receiving part, an active optical fiber and an output end assembly; four receiving detectors are uniformly distributed in the circumferential direction of the main light receiving part; the main light receiving part comprises a pump light reflecting film, a first lens and a first double-optical-fiber head which are arranged along a light path; and a pump light source is arranged between the main light receiving part and the output end assembly so as to couple pump light into the active optical fiber. According to the utility model, the four receiving detectors are arranged, so that the receiving function of the detectors at four positions can be realized; the intensity of incident light in different directions can be changed, and the four receiving detectors are used for judging and correcting the contra-rotating direction according to the angle change and the light intensity change; the sizes of the receiving part and the main light receiving part are set to be different, and the receiving lenses with different sizes are designed, so that the receiving of different intensities and sensitivities is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, and particularly relates to a free space optical detection and receiving module. Background Art

[0002] In a wireless optical communication system, the communication sub-system and the acquisition, alignment and tracking sub-system, as well as inside the acquisition, alignment and tracking sub-system, do not have a completely co-aperture structure. Therefore, it is necessary to ensure precise coaxiality of multiple optical axes, including: 1. Coaxiality of the acquisition / crude tracking detection optical axis; 2. Coaxiality of the precise tracking detection optical axis; 3. Coaxiality of the communication optical axis. This not only makes the structure complex, but also inevitably leads to great difficulties in the overall design, processing and alignment of the wireless optical communication system, and the cost cannot be reduced.

[0003] In the prior art, a part of the received communication optical energy is separated and used as the beacon optical energy, and accordingly, the acquisition, alignment and tracking in the wireless optical communication process are completed. Such a scheme can also simplify the structure and reduce the volume, weight and energy consumption. Since the communication optical receiving optical system can only focus a part of the received optical signal on a photodetector with a micron-scale, the optical energy loss is already large. After separating a part for acquisition, alignment and tracking, the optical signal is further weakened. Therefore, it is necessary to increase the transmitted optical intensity to make up for it, which in turn increases the weight, volume and power consumption of the device. Summary of the Utility Model

[0004] In order to solve the above problems of the prior art, the utility model provides a free space optical detection and receiving module.

[0005] In order to achieve the above purpose, the main technical solutions adopted by the utility model include:

[0006] A free space optical detection and receiving module includes a receiving part arranged along the optical path direction; a first narrowband filter, a main optical receiving part, an active optical fiber, and an output end component; four receiving detectors are evenly distributed circumferentially around the main optical receiving part; the main optical receiving part includes a pump light reflection film, a first lens and a first double fiber head arranged along the optical path; a pump light source is arranged between the main optical receiving part and the output end component to couple pump light into the active optical fiber.

[0007] Further, the receiving part is composed of a convex lens and a concave lens; the size of the receiving part is larger than that of the main optical receiving part.

[0008] Further, the pump light wavelength of the pump light source is 980 nm.

[0009] Further, the first double fiber head includes a first optical fiber and a second optical fiber; the first optical fiber is coupled with the pump light source; the second optical fiber is coupled with the active optical fiber.

[0010] Further, the pump light reflection film reflects and couples the pump light of the pump light source into the active optical fiber.

[0011] Further, the output end assembly includes a second double fiber head, a birefringent crystal, a wave plate, a second lens, an optically active crystal, a second narrowband filter, a partial reflection film, and a photodiode arranged along the optical path.

[0012] Further, the second double fiber head includes a third optical fiber and a fourth optical fiber; the third optical fiber is coupled to the active optical fiber; the fourth optical fiber is the output end.

[0013] Further, the pump light source is connected to the output end assembly, and the reverse pumping couples the pump light into the active optical fiber.

[0014] The beneficial effects of the present utility model are as follows: By providing four receiving detectors, the receiving function of the detectors at four positions can be realized; for incident light in different directions, the intensity will change, and the four receiving detectors are used to judge and correct the rotation direction according to the angle change and the light intensity change; by setting the sizes of the receiving part and the main light receiving part differently and designing receiving lenses of different sizes, receiving with different intensities and sensitivities is ensured; the pump light input by the pump light source pre-amplifies the received signal, and then the effective signal is detected and analyzed to obtain higher sensitivity and detection distance; the interference light in the signal light is filtered by the first narrowband filter, and the second narrowband filter can be used to eliminate the reverse ASE stray light and the local oscillator stray light of the active optical fiber. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present utility model, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 It is a schematic structural diagram of the present utility model;

[0017] Figure 2 It is a schematic structural diagram of the main optical receiver and the receiving detector of the present utility model;

[0018] Explanation of the reference numerals: 100, receiving unit; 110, first narrow-band filter; 120, main light receiving unit; 121, pump light reflective film; 122, first lens; 123, first dual-fiber head; 124, first optical fiber; 125, second optical fiber; 130, receiving detector; 140, pump light source; 150, active optical fiber; 160, second dual-fiber head; 161, third optical fiber; 162, fourth optical fiber; 163, birefringent crystal; 164, wave plate; 165, second lens; 166, optical rotation crystal; 167, second narrow-band filter; 168, partial reflective film; 170, photodiode; 180, output end component. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model. Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the utility model for which protection is sought, but merely represents the selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the utility model.

[0020] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "front end", "rear end", "two ends", "one end", "the other end" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] A free space optical detection and reception module, comprising a receiving part 100, a first narrowband filter 110, a main optical receiving part 120, an active optical fiber 150, and an output end assembly 180 arranged along the optical path direction; the receiving part 100 consists of right lenses; in one embodiment, the receiving part 100 includes a convex lens and a concave lens; the first narrowband filter 110 is used to filter out stray light in the signal light and reduce signal interference; four receiving detectors 130 are evenly distributed circumferentially on the main optical receiving part 120; the receiving detectors 130 are also used to receive the signal light incident from the receiving part 100; the main optical receiving part 120 includes a pump light reflection film 121, a first lens 122, and a first double fiber head 123 arranged along the optical path; a pump light source 140 is provided between the main optical receiving part 120 and the output end assembly 180 to couple pump light into the active optical fiber 150, so as to realize pre-amplification of the signal light; by setting four receiving detectors 130, the receiving functions of four positions can be realized. Since the intensity of incident light in different directions will change, and the light intensities and angles received by the four receiving detectors 130 are different, the correction direction can be conveniently judged, the rapid alignment of the receiving module can be realized, and the intensity of the received signal light can be increased; in one embodiment, the size of the receiving part 100 is larger than the size of the main optical receiving part 120. Through different size settings, that is, the design of receiving lenses with different sizes, the reception of different intensities and sensitivities can be ensured, and at the same time, the signal light can be received by the main optical receiving part 120 and the receiving detectors simultaneously.

[0023] In one embodiment, the pump light wavelength of the pump light source 140 is 980 nm; the first double fiber head 123 includes a first optical fiber 124 and a second optical fiber 125; the first optical fiber 124 is coupled to the pump light source 140; the second optical fiber 125 is coupled to the active optical fiber 150; the pump light emitted by the pump light source 140 is reflected by the pump light reflection film 121 and then coupled into the second optical fiber 125, and then propagates along the optical path direction into the active optical fiber 150 to realize amplification of the signal light;

[0024] In one embodiment, the output end component 180 includes a second double fiber head 160, a birefringent crystal 163, a wave plate 164, a second lens 165, an optically active crystal 166, a second narrowband filter 167, a partial reflection film 168, and a photodiode 170 arranged along the optical path; the second active optical fiber 150 includes a third optical fiber 161 and a fourth optical fiber 162; the third optical fiber 161 is coupled to the active optical fiber 150; the fourth optical fiber 162 is a signal output end; the output end component 180 realizes the function of an isolator, isolating the return of reflected light, and at the same time also realizes the monitoring of the amplified signal light; the setting of the second narrowband filter 167 can be used to eliminate the reverse ASE stray light and the local oscillator stray light in the active optical fiber 150. Through the settings of the first narrowband filter 110 and the second narrowband filter 167, the noise in the signal light is effectively reduced, and amplified output is achieved, improving the sensitivity.

[0025] In one embodiment, the pump light source 140 is connected to the output end component 180, and the reverse pump couples the pump light into the active optical fiber 150. Another pump light reflection film is also arranged in the output end component 180. This pump light reflection film is preferably arranged at one end of the second lens 165 close to the optically active crystal 166, so as to realize the reverse pumping of the pump light. Cooperating with the pump light reflection film 121 in the first lens 122, the effect of isolating the pump light in the active optical fiber 150 can be achieved, improving the utilization rate of the pump light.

[0026] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A free space optical detection receiving module, characterized in that: The invention comprises a receiving part (100) arranged along the optical path, a first narrowband filter (110), a main light receiving part (120), an active optical fiber (150), and an output end assembly (180); four receiving detectors (130) are evenly distributed in the circumference of the main light receiving part (120); the main light receiving part (120) comprises a pump light reflection film (121), a first lens (122), and a first dual optical fiber head (123) arranged along the optical path; and a pump light source (140) is arranged between the main light receiving part (120) and the output end assembly (180) to couple the pump light into the active optical fiber (150).

2. A free-space optical detection receiving module according to claim 1, characterized in that: The receiving part (100) comprises a convex lens and a concave lens; the size of the receiving part (100) is larger than the size of the main light receiving part (120).

3. A free-space optical detection receiving module according to claim 1, characterized in that: The pump light wavelength of the pump light source (140) is 980 nm.

4. A free-space optical detection receiving module according to claim 1, characterized in that: The first dual-fiber head (123) comprises a first optical fiber (124) and a second optical fiber (125); the first optical fiber (124) is coupled to a pump light source (140); and the second optical fiber (125) is coupled to an active optical fiber (150).

5. A free-space optical detection receiving module according to claim 4, characterized in that: The pump light reflection film (121) reflects and couples the pump light of the pump light source (140) into the active optical fiber (150).

6. A free-space optical detection receiving module according to claim 1, characterized in that: The output end assembly (180) comprises a second dual-fiber head (160) arranged along the optical path, a birefringent crystal (163), a wave plate (164), a second lens (165), an optical rotation crystal (166), a second narrow-band filter (167), a partial reflection film (168), and a photodiode (170).

7. A free-space optical detection receiving module according to claim 6, characterized in that: The second dual-fiber head (160) comprises a third optical fiber (161) and a fourth optical fiber (162); the third optical fiber (161) is coupled to the active optical fiber (150); and the fourth optical fiber (162) is an output end.

8. The free-space optical detection receiving module according to claim 1, characterized in that: The pump light source (140) is connected to the output end component (180), and reverse pumping is used to couple the pump light into the active optical fiber (150).

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