Miniature reflective circulator

Abstract

The utility model relates to a miniature reflective circulator, which comprises three optical fiber heads, a first birefringent crystal, a half-wave plate, a first wave plate, an optical rotation assembly, a double-bevel prism, a second birefringent crystal, a quarter-wave plate and a reflector which are sequentially arranged along the direction of an optical path, according to the utility model, single-side input and output of optical signals can be realized through a reflective structure, and an array structure can be conveniently formed for use; meanwhile, the reflection type structure can effectively reduce the size of the product; the arrangement of the magnetic element provides an installation plane for the optical device in the packaging sleeve, thereby facilitating the assembly of various optical devices, facilitating the improvement of the installation precision, and simplifying the installation. The arrangement of the double-break-angle prism can further optimize the parallel effect between the light beams in the light beam transmission process, and reduces the coupling difficulty.

Description

Technical Field

[0001] This utility model relates to the field of optical technology, and in particular to a miniature reflective circulator. Background Technology

[0002] Various optical devices are widely used in current fiber optic communication systems, among which optical circulators are a common type. An optical circulator is a multi-port non-reciprocal optical device whose function is to ensure that optical signals are transmitted sequentially along designated ports, thereby achieving bidirectional optical signal transmission over a single optical fiber. Typically, an optical circulator has three or more ports. When an optical signal is input through any port, it can be output sequentially from the next port with minimal loss, while the loss to all other ports from that port is significant, making them non-connected ports.

[0003] Optical circulators, due to their non-reciprocity, are crucial components in bidirectional communication, enabling the separation of forward and reverse-transmitting light. They can be used in single-fiber bidirectional communication, fiber Bragg grating (FBG) combinations, erbium-doped fiber amplifiers (EDFAs), wavelength division multiplexing (WDM), dispersion compensation, and as couplers in optical time domain reflectometers (OTDRs) and fiber optic gyroscopes (Sagnac interferometers), effectively improving the performance of fiber optic communication systems.

[0004] Currently, the most widely used optical circulator is the single-channel three-port optical circulator. This type of circulator adopts a transmission structure, with ports one and three on the first side of the circulator and port two on the second side. A series of optical elements are arranged in the middle of the circulator to change the propagation direction of the light beam. However, in some scenarios where optical circulators are used, it is necessary to use two or more optical circulators simultaneously. If traditional single-channel three-port optical circulators are used, the space required for arranging the circulators increases with the number of circulators used, which is not conducive to the miniaturization of the devices used in optical fiber communication systems. Utility Model Content

[0005] To address the aforementioned problems in the prior art, this invention provides a miniature reflective circulator.

[0006] To achieve the above objectives, the main technical solutions adopted by this utility model include:

[0007] A miniature reflective circulator includes three fiber optic heads; the emitting end of each fiber optic head is provided with a first birefringent crystal; the first birefringent crystal is used to decompose input light in any state into two polarization components with perpendicular polarization directions or to combine two polarization components with perpendicular polarization directions into a single beam; a half-wave plate is provided at the end of the first birefringent crystal away from the three fiber optic heads; a first wave plate is provided at the end of the half-wave plate away from the first birefringent crystal; the first wave plate covers only the input and output paths of one of the polarization components decomposed by the first birefringent crystal; a light-rotating component is provided at the end of the first wave plate away from the half-wave plate; a double-fold prism is provided at the end of the light-rotating component away from the first wave plate; a second birefringent crystal is provided at the end of the double-fold prism away from the light-rotating component; a quarter-wave plate is provided at the end of the second birefringent crystal away from the double-fold prism; a reflector is provided at the end of the quarter-wave plate away from the second birefringent crystal; the optical axis of the first birefringent crystal and the optical axis of the second birefringent crystal are in different directions.

[0008] In one embodiment of the present invention, a packaging sleeve for encapsulating the micro reflective circulator is also included.

[0009] In one embodiment of the present invention, the optical rotation component includes a magnetic element and a magneto-optical crystal disposed within the magnetic element; the magneto-optical crystal is located between the first waveplate and the double-angle prism.

[0010] In one embodiment of the present invention, the magnetic element includes a first magnet and a second magnet disposed at both ends of the magneto-optical crystal; the length of the first magnet is greater than the length of the second magnet.

[0011] In one embodiment of the present invention, the first magnet includes an arc surface for engaging with the inner wall of the encapsulation sleeve and a first mounting plane disposed opposite to the arc surface; the second magnet has a second mounting plane disposed opposite to the first mounting plane; the side of the second magnet facing away from the second mounting plane engages with the inner wall of the encapsulation sleeve.

[0012] In one embodiment of the present invention, the length of the first magnet is greater than or equal to the maximum distance between the first birefringent crystal and the second birefringent crystal; the length of the second magnet is greater than the minimum distance between the first birefringent crystal and the second birefringent crystal, and the second magnet is disposed relative to the space between the first birefringent crystal and the second birefringent crystal.

[0013] In one embodiment of this utility model, the three fiber optic heads include a first fiber, a second fiber, and a third fiber arranged in parallel; the first fiber, the second fiber, and the third fiber are located on the same horizontal plane.

[0014] In one embodiment of the present invention, the double-angle prism includes a first plane disposed opposite to the magneto-optical crystal and a second plane disposed away from the magneto-optical crystal; the area of ​​the second plane is smaller than the area of ​​the first plane; and angled bevels are formed on both sides of the second plane.

[0015] The beneficial effects of this utility model are: the reflective structure enables single-sided input and output of optical signals, facilitating the formation of an array structure for use; at the same time, the reflective structure can effectively reduce the product size; the setting of the magnetic element provides a mounting plane for the optical devices inside the encapsulation sleeve, facilitating the assembly of various optical devices, improving installation accuracy, and simplifying installation; the setting of the double-angle prism can further optimize the parallelism between beams during beam transmission and reduce coupling difficulty. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is an exploded view of the structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the double-angled prism structure of this utility model;

[0019] Figure 3 This is a top view of the optical path of the circulator of this utility model;

[0020] Figure 4 This is a front view of the optical path of the circulator of this utility model;

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Three-fiber connector; 11. First fiber; 12. Second fiber; 13. Third fiber; 2. First birefringent crystal; 3. Half-wave plate; 4. First wave plate; 5. Optical rotation component; 51. Magneto-optic crystal; 52. Magnetic element; 521. First magnet; 5211. Curved surface; 5212. First mounting plane; 522. Second magnet; 5221. Second mounting plane; 6. Double-angled prism; 61. First plane; 62. Second plane; 63. Angle bevel; 7. Second birefringent crystal; 8. Quarter-wave plate; 9. Mirror; 100. Encapsulation sleeve. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Therefore, the following detailed description of the embodiments of this utility model provided in the accompanying drawings is not intended to limit the scope of the claimed utility model, but merely represents selected embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0024] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" 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 an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] Example:

[0027] See Figure 1A miniature reflective circulator includes three fiber heads 1, a first birefringent crystal 2, a half-wave plate 3, a first wave plate 4, an optical rotation component 5, a bi-fold prism 6, a second birefringent crystal 7, a quarter-wave plate 8, and a reflector 9 arranged sequentially along the optical path. The first birefringent crystal 2 is used to decompose an input light in any state into two polarization components with perpendicular polarization directions, or to combine two polarization components with perpendicular polarization directions into a single beam. The optical axis of the first birefringent crystal 2 is different from that of the second birefringent crystal 7, resulting in different deflection directions of the beam. The first wave plate 4 only covers the input and output paths of one of the polarization components decomposed by the first birefringent crystal 2; it can be understood that the first wave plate 4 only acts on half of the beam to rotate its polarization direction.

[0028] In one embodiment of this utility model, the three-fiber head 1 includes a first fiber 11, a second fiber 12, and a third fiber 13 arranged in parallel; the first fiber 11, the second fiber 12, and the third fiber 13 are located on the same horizontal plane, such as... Figure 1 As shown, the first optical fiber 11, the second optical fiber 12, and the third optical fiber 13 are located on the yz plane.

[0029] In one embodiment of the present invention, a packaging sleeve 100 for encapsulating the micro reflective circulator is also included. The packaging sleeve 100 generally has an outermost part, and a space for accommodating optical elements is formed inside it. It can be understood that the packaging sleeve 100 is a cylindrical structure.

[0030] In one embodiment of this utility model, the optical rotation component 5 includes a magnetic element 52 and a magneto-optical crystal 51 disposed within the magnetic element 52; the magneto-optical crystal 51 is located between the first waveplate 4 and the double-angle prism 6; the magnetic element 52 is disposed outside the magneto-optical crystal 51 to provide a stable magnetic field to control the optical rotation direction of the magneto-optical crystal 51; in one embodiment, the magneto-optical crystal 51 can be an energized coil, thereby allowing current in both directions to be passed through as needed to form magnetic fields in both directions.

[0031] In one embodiment of this utility model, the magnetic element 52 includes a first magnet 521 and a second magnet 522 disposed at both ends of the magneto-optical crystal 51; the length of the first magnet 521 is greater than the length of the second magnet 522, and the length is... Figure 1 The z-direction in the middle.

[0032] In one embodiment of this utility model, the first magnet 521 includes an arc surface 5211 for cooperating with the inner wall of the encapsulation sleeve 100 and a first mounting plane 5212 disposed opposite to the arc surface 5211. After the arc surface 5211 cooperates with the encapsulation sleeve 100, the first magnet 521 and the encapsulation sleeve 100 have a larger contact area, resulting in a better fixing effect for the first magnet 521. The second magnet 522 is provided with a second mounting plane 5221 disposed opposite to the first mounting plane 5212. The side of the second magnet 522 away from the second mounting plane 5221 mates with the inner sidewall of the encapsulation sleeve 100; by setting the first mounting plane 5212, an effective and reliable mounting plane can be provided for the optical components inside the circulator, which facilitates the fixing of each component and helps to improve the accuracy of each component during installation; the second magnet 522 is shorter, which can reduce costs. Since the first mounting plane 5212 provides sufficient installation space, it can already ensure the fixing of each component. The second mounting plane 5221 provided by the second magnet 522 is mainly used to provide auxiliary support.

[0033] In one embodiment of this utility model, the length of the first magnet 521 is greater than or equal to the maximum distance between the first birefringent crystal 2 and the second birefringent crystal 7, so as to provide a large-area stable support / fixing effect; the length of the second magnet 522 is greater than the minimum distance between the first birefringent crystal 2 and the second birefringent crystal 7, and the second magnet 522 is set relative to the space between the first birefringent crystal 2 and the second birefringent crystal 7; the second mounting plane 5221 is mainly used to support and fix the double-angle prism 6 and the magneto-optical crystal 51; the half-wave plate 3 can be directly fixed on the end face of the first birefringent crystal 2 to reduce the size of the product.

[0034] In one embodiment of the present invention, the bi-fold prism 6 includes a first plane 61 disposed opposite to the magneto-optical crystal 51 and a second plane 62 disposed away from the magneto-optical crystal 51; the area of ​​the second plane 62 is smaller than the area of ​​the first plane 61; and beveled surfaces 63 are formed on both sides of the second plane 62. With this structure, the two polarization components decomposed by the first birefringent crystal 2 can be transmitted in the circulator with better parallelism.

[0035] Please refer to Figure 4 ,in Figure 4 a is a side view of the optical path in the miniature reflective circulator of this invention, showing the transmission of the light beam from the first optical fiber 11 to the second optical fiber 12.

[0036] Specifically, the light beam emitted from the first fiber 11 of the three-fiber head 1 is optically processed by the lens built into the three-fiber head 1 and converted into a parallel light beam 111 before being emitted. It should be noted that the light beam emitted from the three-fiber head 1 is collimated light, and the three-fiber head 1 integrates optical devices for realizing the collimation function; in a specific embodiment, the three-fiber head 1 can also be composed of three independent collimating devices.

[0037] When the parallel beam 111 is incident on the first birefringent crystal 2, based on the birefringence characteristics of the first birefringent crystal 2, the beam is separated into two beams with mutually perpendicular polarization states and separated along the x-direction, which are defined as normal light 111o and anomalous light 111e, respectively. Figure 4 The xy-plane cross-section of b clearly shows the polarization states of the normal light 111o and the anomalous light 111e. Subsequently, the normal light 111o and the anomalous light 111e are both incident on the half-wave plate 3. Under the influence of the half-wave plate 3, the polarization directions of both beams rotate clockwise by 45°. Figure 4 The xy-plane cross-sectional view of part b visually presents the polarization state change process, which forms beams 112 and 113 after this transformation. Among them, beam 112 further passes through the first waveplate 4 set in its optical path. Under the optical action of the first waveplate 4, the polarization state of beam 112 is rotated by 90°, thereby achieving consistency with the polarization state of beam 113.

[0038] The aforementioned beams 112 and 113 continue to propagate and enter the magneto-optical crystal 51. Under the magneto-optical effect of the crystal 51, the polarization direction of the two beams rotates counterclockwise by 45°, and the polarization direction is now along the x-axis. Next, the two beams pass through the bi-fold prism 6, which further collimates them, outputting them as parallel beams and incident on the second birefringent crystal 7. During the transmission through the bi-fold prism 6 and the second birefringent crystal 7, the polarization state of the two beams remains unchanged. Subsequently, the two beams pass through the quarter-wave plate 8. Under the optical properties of the quarter-wave plate 8, both beams are converted into circularly polarized light. After being reflected by the mirror 9, the two circularly polarized beams propagate in the opposite direction along the original optical path. When they pass through the quarter-wave plate 8 again, the circularly polarized light is converted back into linearly polarized light, and the polarization direction of the linearly polarized light is now along the y-axis.

[0039] When the two linearly polarized beams pass through the second birefringent crystal 7, because the second birefringent crystal 7 has the functional characteristic of resolving a parallel beam into two beams with mutually perpendicular polarization states and separated along the y-axis, and because the polarization directions of the two beams are parallel to the optical axis of the second birefringent crystal 7, the propagation directions of the two beams are shifted along the y-axis. This shift characteristic can be referenced... Figure 3 As shown.

[0040] See Figure 4 c. After their propagation direction shifts along the y-axis, the two beams of light continue to propagate forward. When they pass through the double-angle prism 6, their polarization direction remains unchanged. Subsequently, the two beams of light re-enter the magneto-optical crystal 51. Under the action of the magneto-optical crystal 51, their polarization direction rotates counterclockwise by 45°, forming beam 114 and beam 115. Among them, beam 114 further passes through the first waveplate 4, and its polarization state is rotated by 90°, while the polarization state of beam 115 remains unchanged. Next, the two beams of light pass through the half-waveplate 3. Under the action of the half-waveplate 3, the polarization direction of the two beams of light rotates counterclockwise again by 45°. At this time, the polarization direction of beam 114 becomes the y-axis direction, marked as 111oˊ; the polarization direction of beam 115 becomes the x-axis direction, marked as 111eˊ. Figure 4 The xy-plane cross-sectional view of d illustrates in detail the change process of the polarization states of the two beams. It can be seen that the polarization states of the two reflected beams change from initially being parallel to each other to being perpendicular, denoted as 111oˊ and 111eˊ respectively. Finally, the two beams enter the first birefringent crystal 2, which performs its beam combining function, combining the two beams into one beam, namely the combined beam 111ˊ. This combined beam 111ˊ is coupled into the second optical fiber 12 of the three-fiber connector 1, thus completing the complete transmission process of the beam from the first optical fiber 11 to the second optical fiber 12.

[0041] It should be noted that the transmission process of the light beam from the second optical fiber 12 to the third optical fiber 13 is exactly the same as the transmission principle and process of the light beam from the first optical fiber 11 to the second optical fiber 12 described above.

[0042] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent modifications made based on the content of this utility model specification and drawings, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A miniature reflective circulator, characterized in that: The system includes a three-fiber head (1); the output end of the three-fiber head (1) is provided with a first birefringent crystal (2); the first birefringent crystal (2) is used to decompose an input light in any state into two polarization components with perpendicular polarization directions or to combine two polarization components with perpendicular polarization directions into a single beam; a half-wave plate (3) is provided at the end of the first birefringent crystal (2) away from the three-fiber head (1); a first wave plate (4) is provided at the end of the half-wave plate (3) away from the first birefringent crystal (2); the first wave plate (4) covers only the input and output paths of one of the polarization components decomposed by the first birefringent crystal (2). On the radial direction; the end of the first wave plate (4) away from the half-wave plate (3) is provided with an optical rotation component (5); the end of the optical rotation component (5) away from the first wave plate (4) is provided with a double-angle prism (6); the end of the double-angle prism (6) away from the optical rotation component (5) is provided with a second birefringent crystal (7); the end of the second birefringent crystal (7) away from the double-angle prism (6) is provided with a quarter-wave plate (8); the end of the quarter-wave plate (8) away from the second birefringent crystal (7) is provided with a reflector (9); the optical axis of the first birefringent crystal (2) is different from the optical axis of the second birefringent crystal (7).

2. The miniature reflective circulator according to claim 1, characterized in that: It also includes a packaging sleeve (100) for encapsulating the micro reflective circulator.

3. A miniature reflective circulator according to claim 2, characterized in that: The optical rotation component (5) includes a magnetic element (52) and a magneto-optical crystal (51) disposed within the magnetic element (52); the magneto-optical crystal (51) is located between the first waveplate (4) and the double-angle prism (6).

4. A miniature reflective circulator according to claim 3, characterized in that: The magnetic element (52) includes a first magnet (521) and a second magnet (522) disposed at both ends of the magneto-optical crystal (51); the length of the first magnet (521) is greater than the length of the second magnet (522).

5. A miniature reflective circulator according to claim 4, characterized in that: The first magnet (521) includes an arc surface (5211) for engaging with the inner wall of the encapsulation sleeve (100) and a first mounting plane (5212) disposed opposite to the arc surface (5211); the second magnet (522) is provided with a second mounting plane (5221) disposed opposite to the first mounting plane (5212); the side of the second magnet (522) facing away from the second mounting plane (5221) engages with the inner wall of the encapsulation sleeve (100).

6. A miniature reflective circulator according to claim 4, characterized in that: The length of the first magnet (521) is greater than or equal to the maximum distance between the first birefringent crystal (2) and the second birefringent crystal (7); the length of the second magnet (522) is greater than the minimum distance between the first birefringent crystal (2) and the second birefringent crystal (7), and the second magnet (522) is positioned relative to the space between the first birefringent crystal (2) and the second birefringent crystal (7).

7. A miniature reflective circulator according to claim 1, characterized in that: The three-fiber head (1) includes a first fiber (11), a second fiber (12), and a third fiber (13) arranged in parallel; the first fiber (11), the second fiber (12), and the third fiber (13) are located on the same horizontal plane.

8. A miniature reflective circulator according to claim 3, characterized in that: The double-angle prism (6) includes a first plane (61) disposed relative to the magneto-optical crystal (51) and a second plane (62) disposed away from the magneto-optical crystal (51); the area of ​​the second plane (62) is smaller than the area of ​​the first plane (61); angled slopes (63) are formed on both sides of the second plane (62).

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