Multi-channel shifting circulator

Abstract

The invention relates to the technical field of optical communication, in particular to a multi-channel shifting circulator. Comprising an optical fiber unit, a birefringent crystal, a polarization unit, a transmission or reflection unit, a polarizer and a reflection element, the optical fiber unit comprises at least four optical fibers, an optical signal can enter and reach the birefringent crystal along any optical fiber, and the birefringent crystal is used for splitting the optical signal into O light and E light; the transmission or reflection unit comprises a plurality of PBS films, and the number of the PBS films is the same as that of the optical fibers; the polarization unit changes the polarization states of the O light and the E light, so that the O light and the E light pass through the corresponding PBS films; the light enters the polarizer and is reflected back to the polarizer through the reflecting element, and the polarization states of the O light and the E light are changed, so that the O light and the E light are reflected to the adjacent PBS films on the corresponding PBS films; and the polarization unit can change the polarization state of the reflected light, so that the reflected light is emitted along the corresponding optical fiber after being combined by the birefringent crystal. Therefore, the method is suitable for a transmission application scene requiring more than three ports to realize optical signals.

Description

Technical Field

[0001] The invention relates to the technical field of optical communication, in particular to a multi-channel shift circulator. Background Art

[0002] Circulators have the advantages of simple structure, high stability, high sensitivity, and strong anti-interference ability. They are widely used in the field of optical communications. Common circulators have three communication ports. When the optical signal is input from any port, it will be output from the next port in a specific order. In some special transmission scenarios, more than three ports are required to realize the transmission of optical signals, which cannot be achieved by common circulators. Summary of the invention

[0003] The technical problem to be solved by the embodiments of the present invention is to provide a multi-channel shift circulator to solve the problem in the prior art that in some special transmission scenarios, more than three ports are required to realize the transmission of optical signals, which cannot be achieved by commonly used circulators.

[0004] The invention discloses a multi-channel shift circulator, comprising: an optical fiber unit, a birefringent crystal, a polarization unit, a transmission or reflection unit, a polarizer and a reflection element which are sequentially arranged along an optical path; the optical fiber unit comprises a fixing seat and at least four optical fibers which are arranged on the fixing seat and are arranged in parallel with each other, an optical signal can enter and reach the birefringent crystal along any of the optical fibers, and the birefringent crystal is used to split the optical signal into O light and E light; the transmission or reflection unit comprises a plurality of PBS films, the number of the PBS films being the same as that of the optical fibers, and being arranged one by one on the optical path where each of the optical fibers is located; the polarization unit can change the polarization state of the O light and the E light, so that the O light and the E light both pass through the corresponding PBS films, enter the polarizer and are reflected back to the polarizer through the reflection element, the polarizer can change the polarization state of the O light and the E light, so that the O light and the E light both reflect on the corresponding PBS films to the adjacent PBS films; the polarization unit can change the polarization state of the reflected light, so that the reflected light is emitted along the corresponding optical fiber after being combined by the birefringent crystal.

[0005] Optionally, a lens unit is arranged between the optical fiber unit and the birefringent crystal, and the lens unit includes a mounting frame and a plurality of lenses fixed on the mounting frame. The number of the lenses corresponds to the number of the optical fibers and are arranged one-to-one on the optical path where each of the optical fibers is located.

[0006] Optionally, the polarization unit includes a Faraday rotator and multiple half-wave plate assemblies arranged in sequence along the optical path, the number of the half-wave plate assemblies arranged corresponds to the number of the optical fibers, and each of the half-wave plate assemblies includes a first wave plate and a second wave plate; the Faraday rotator is used to change the polarization state of the O light and the E light, the first wave plate is used to change the polarization state of the O light, and the second wave plate is used to change the polarization state of the E light.

[0007] Optionally, the polarizer is a quarter wave plate.

[0008] Optionally, the PBS film is plated on a glass crystal, and an included angle between the PBS film and the O light and the E light is 45 degrees.

[0009] Optionally, along the incident direction of the optical signal, the optical axis angle of the birefringent crystal is 45 degrees, the optical axis angle of the first wave plate is 22.5 degrees, the optical axis angle of the second wave plate is 67.5 degrees, and the optical axis angle of the quarter wave plate is 45 degrees.

[0010] Optionally, the reflective element is a reflective film, and the reflective film is plated on one side of the quarter-wave plate.

[0011] Optionally, the reflective film is a high-reflective film.

[0012] Optionally, the birefringent crystal is a lithium niobate crystal.

[0013] Optionally, the optical fiber unit, the birefringent crystal, the polarization unit, the transmission or reflection unit, and the polarizer are all bonded by glue.

[0014] Compared with the prior art, the multi-channel shift circulator provided by the embodiment of the present invention has the beneficial effect that the optical signal can enter the multi-channel shift circulator along the port of any optical fiber and be emitted along the port of the next adjacent optical fiber to realize the transmission of the optical signal. Figure 1, an example of the transmission process of an optical signal from optical fiber port 1 to optical fiber port 2; the optical signal can enter along optical fiber port 1 and reach the birefringent crystal, the birefringent crystal can split the optical signal into O light and E light, the polarization unit can change the polarization state of the O light and the E light, so that the O light and the E light both pass through the corresponding PBS film, and enter the polarizer and are reflected back to the polarizer by the reflecting element, the polarizer can change the polarization state of the O light and the E light, so that the O light and the light beam E light are reflected on the corresponding PBS film to the adjacent PBS film (that is, the PBS film set on the optical path where the optical fiber port 2 is located); the polarization unit can change the polarization state of the reflected light, so that the reflected light is combined by the birefringent crystal and then emitted along the optical fiber port 2, completing the transmission of the optical signal. The optical fiber unit of this embodiment includes at least four parallel optical fibers, referring to Figure 1 and Figure 2 , the optical signal can be transmitted from fiber port 1 to fiber port 2, or from fiber port 2 to fiber port 3, or from fiber port 3 to fiber port 4, or from fiber port 4 to fiber port 5, and so on. All optical signals are moved from the original port to the next adjacent port to realize the shifting function to adapt to the application scenarios that require more than three ports to realize the transmission of optical signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0016] Figure 1 is an overall schematic diagram of a multi-channel shift circulator provided by an embodiment of the present invention;

[0017] Figure 2 is a top view of a multi-channel shift circulator provided by an embodiment of the present invention;

[0018] Figure 3 is a schematic diagram of an exploded structure of a multi-channel shift circulator provided by an embodiment of the present invention;

[0019] Figure 4 is a schematic diagram of optical path transmission of a multi-channel shift circulator provided by an embodiment of the present invention;

[0020] Figure 5 is a schematic structural diagram of a half-wave plate assembly provided by an embodiment of the present invention;

[0021] Figure 6 is a schematic diagram of the change in polarization state of O light during transmission provided by an embodiment of the present invention;

[0022] Figure 7is a schematic diagram of the change in polarization state of E light during transmission provided by an embodiment of the present invention;

[0023] The reference numerals in the figures are:

[0024] 10. Optical fiber unit; 110. Fixing seat; 120. Optical fiber; 20. Birefringent crystal; 30. Polarization unit; 310. Faraday rotator; 320. Half-wave plate assembly; 321. First wave plate; 322. Second wave plate; 40. Transmission or reflection unit; 410. PBS film; 50. Polarizer; 60. Lens unit; 610. Mounting frame; 620. Lens. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0026] The embodiment of the present invention provides a multi-channel shift circulator, such as Figures 1 to 4 As shown, it includes an optical fiber unit 10, a birefringent crystal 20, a polarization unit 30, a transmission or reflection unit 40, a polarizer 50 and a reflection element arranged in sequence along the optical path; the optical fiber unit 10 includes a fixing seat 110 and at least four optical fibers 120 arranged on the fixing seat 110 and arranged parallel to each other, and the optical signal can enter and reach the birefringent crystal 20 along any optical fiber 120, and the birefringent crystal 20 is used to split the optical signal into O light and E light; the transmission or reflection unit 40 includes a plurality of PBS films 410, and the number of the PBS films 410 is the same as that of the optical fibers 120 , and are arranged one by one on the optical path of each optical fiber 120; the polarization unit 30 can change the polarization state of the O light and the E light so that the O light and the E light can both pass through the corresponding PBS film 410; enter the polarizer 50 and be reflected back to the polarizer 50 through the reflecting element, and the polarizer 50 can change the polarization state of the O light and the E light so that the O light and the E light can both be reflected on the corresponding PBS film 410 to the next adjacent PBS film 410; the polarization unit 30 can change the polarization state of the reflected light so that the reflected light can be emitted along the corresponding optical fiber 120 after being combined by the birefringent crystal 20.

[0027] The optical signal can enter the multi-channel shift circulator along the port of any optical fiber 120 and be emitted along the port of the next adjacent optical fiber 120 to achieve the transmission of the optical signal. Figure 1, an example of the transmission process of the optical signal from the optical fiber 120 port 1 to the optical fiber 120 port 2; the optical signal can enter and reach the birefringent crystal 20 along the optical fiber 120 port 1, the birefringent crystal 20 can split the optical signal into O light and E light, the polarization unit 30 can change the polarization state of the O light and the E light, so that the O light and the E light both pass through the corresponding PBS film 410, and enter the polarizer 50 and are reflected back to the polarizer 50 by the reflective element, the polarizer 50 can change the polarization state of the O light and the E light, so that the O light and the E light are reflected on the corresponding PBS film 410 to the next adjacent PBS film 410 (that is, the PBS film 410 set on the optical path where the optical fiber 120 port 2 is located); the polarization unit 30 can change the polarization state of the reflected light, so that the reflected light is combined by the birefringent crystal 20 and then emitted along the optical fiber 120 port 2, completing the transmission of the optical signal. The optical fiber unit 10 of this embodiment includes at least four parallel optical fibers 120, referring to Figure 1 and Figure 2 , the optical signal can be transmitted from optical fiber 120port1 to optical fiber 120port2, or from optical fiber 120port2 to optical fiber 120port3, or from optical fiber 120port3 to optical fiber 120port4, or from optical fiber 120port4 to optical fiber 120port5, and so on. All optical signals are moved from the original port to the next adjacent port to realize the shifting function to adapt to the application scenario that requires more than three ports to realize the transmission of optical signals.

[0028] In this embodiment, refer to Figure 2 Except for the first and last channels (where port1 and port5 are located), the middle channels are all bidirectional transmission channels.

[0029] As a preferred solution of this embodiment, Figures 1 to 4 As shown, a lens unit 60 is arranged between the optical fiber unit 10 and the birefringent crystal 20. The lens unit 60 includes a mounting frame 610 and a plurality of lenses 620 fixed on the mounting frame 610. The number of lenses 620 corresponds to the number of optical fibers 120, and are arranged one by one on the optical path where each optical fiber 120 is located.

[0030] Among them, in order to improve the stability of optical signal transmission, the lens unit 60 is configured to include a mounting frame 610 and a plurality of lenses 620 fixed on the mounting frame 610. The mounting frame 610 is used to fix the plurality of lenses 620. The configuration of the lenses 620 corresponds to the number of optical fibers 120, and on the optical path where each optical fiber 120 is located, the lens 620 of this embodiment uses a collimating lens 620.

[0031] As a preferred solution of this embodiment, Figure 5As shown, the polarization unit 30 includes a Faraday rotator 310 and a plurality of half-wave plate assemblies 320 sequentially arranged along the optical path. The number of the half-wave plate assemblies 320 corresponds to the number of the optical fibers 120, and each half-wave plate assembly 320 includes a first wave plate 321 and a second wave plate 322. The Faraday rotator 310 is used to change the polarization state of the O light and the E light, the first wave plate 321 is used to change the polarization state of the O light, and the second wave plate 322 is used to change the polarization state of the E light.

[0032] The Faraday rotator 310 is used to change the polarization state of the O light and the E light, the first wave plate 321 is used to change the polarization state of the O light, and the second wave plate 322 is used to change the polarization state of the E light, so that the O light and the E light can rotate at a certain angle. In actual application, the O light passes through the Faraday rotator 310 and the first wave plate 321 to change its polarization state, and the E light passes through the Faraday rotator 310 and the second wave plate 322 to change its polarization state.

[0033] As a preferred solution of this embodiment, the polarizer 50 is a quarter wave plate; the PBS film 410 is plated on a glass crystal, and the angle between the PBS film 410 and the O light and the E light is 45 degrees. The above configuration is used to ensure the transmission efficiency along the optical fiber 120port1 to the optical fiber 120port2, the optical fiber 120port2 to the optical fiber 120port3, ...

[0034] As a preferred solution of this embodiment, along the incident direction of the optical signal, the optical axis angle of the birefringent crystal 20 is 45 degrees, the optical axis angle of the first wave plate 321 is 22.5 degrees, the optical axis angle of the second wave plate 322 is 67.5 degrees, and the optical axis angle of the quarter wave plate is 45 degrees.

[0035] The optical axis angles of the optical elements defined in this embodiment are Figure 4 The above limits on the optical axis angles of the birefringent crystal 20, the first wave plate 321, the second wave plate 322, and the quarter wave plate are all for the purpose of rotating the O light and the E light by a certain angle, so that the optical signal can be transmitted from the optical fiber 120port1 to the optical fiber 120port2, or from the optical fiber 120port2 to the optical fiber 120port3, or from the optical fiber 120port3 to the optical fiber 120port4, or from the optical fiber 120port4 to the optical fiber 120port5, and so on. All optical signals are shifted from the original port to the next adjacent port to achieve the shifting function.

[0036] As a preferred solution of this embodiment, the reflective element is a reflective film, and the reflective film is plated on one side of the quarter-wave plate.

[0037] When the reflective film is set, it is plated on the quarter wave plate, which can not only play a reflective role but also improve the compactness of the multi-channel shift circulator and reduce the overall volume of the multi-channel shift circulator.

[0038] As a preferred solution of this embodiment, the reflective film is a high-reflective film, which can more effectively reflect light and improve the efficiency of the optical system.

[0039] As a preferred solution of this embodiment, the birefringent crystal 20 is a lithium niobate crystal, so as to separate the optical signal into O light and E light.

[0040] As a preferred solution of this embodiment, the optical fiber unit 10, the birefringent crystal 20, the polarization unit 30, the transmission or reflection unit 40, and the polarizer 50 are all bonded by glue. This improves the connection stability and compactness between the components of the multi-channel shift circulator. It is not necessary to couple the optical components one by one in the manner of free space optics, which greatly reduces the difficulty of application.

[0041] For detailed information about the optical signal in the multi-channel shift circulator, refer to Figure 4 , the arrow direction is the transmission path of the optical signal, Figure 6 and Figure 7The arrow direction is the polarization state direction and the transmission direction of the optical signal. More specifically, after the optical signal enters along Port 1, it is incident on the birefringent crystal 20, forming O light (S polarization state) and E light (P polarization state). The O light continues to pass through the Faraday rotator 310 (polarization direction rotates 45 degrees clockwise) and the first wave plate 321 (polarization direction rotates 45 degrees clockwise), and the E light passes through the Faraday rotator 310 (polarization direction rotates 45 degrees clockwise) and the second wave plate 322 (polarization direction rotates 45 degrees counterclockwise). The polarization state of the O light changes to the P polarization state, and the E light also changes to the P polarization state; then the O light passes through the Faraday rotator 310 (polarization direction rotates 45 degrees clockwise) and the second wave plate 322 (polarization direction rotates 45 degrees counterclockwise). The O light (P polarization state) and the E light (P polarization state) continue to be transmitted to the PBS film 410 corresponding to the transmission or reflection unit 40. The O light (P polarization state) and the E light (P polarization state) are both transmitted through the PBS film 410 and transmitted to the polarizer 50. Then, they are reflected by the reflection film outside the polarizer 50 (quarter wave plate) and return to the original path. Here, it is equivalent to that the O light (P polarization state) and the E light (P polarization state) have passed through the polarizer 50 (quarter wave plate) twice. The O light changes from the P polarization state to the S polarization state, and the E light changes from the P polarization state to the S polarization state. At this time, the reflected light O light (S polarization state) and the reflected light E light (S polarization state) will be reflected at the PBS film 410 and reach the next adjacent PBS film 410. Similarly, the adjacent PBS film 410 will continue to reflect the O light (S polarization state) and the E light (S polarization state). The reflected light O light (S polarization state) passes through the corresponding first wave plate 321 (polarization direction rotated 45 degrees clockwise) and the Faraday rotator 310 (polarization direction rotated 45 degrees counterclockwise), and the polarization state of the O light changes to the S polarization state; the E light (S polarization state) passes through the corresponding The second wave plate 322 (polarization direction rotated 45 degrees counterclockwise) and the Faraday rotator 310 (polarization direction rotated 45 degrees clockwise), the polarization state of the E light changes to the P polarization state, that is, when the reflected light O light and the E light return to the birefringent crystal 20, the polarization states are S polarization state and P polarization state respectively, so they are combined into one light beam, and then converged into the inside of the optical fiber 120 through the lens 620, and emitted from the optical fiber 120Port2. At this point, the above optical path completes the transmission from the optical fiber 120port1 to the optical fiber 120port2.

[0042] In this embodiment, an example is given in which five optical fibers 120 are provided. The number of optical fibers 120 provided is not specifically limited here and can be set according to actual application scenarios.

[0043] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A multi-channel shift circulator, characterized in that: include: An optical fiber unit, a birefringent crystal, a polarization unit, a transmission or reflection unit, a polarizer and a reflection element are sequentially arranged along the optical path; The optical fiber unit comprises a fixing seat and at least four optical fibers arranged on the fixing seat and arranged parallel to each other, and the optical signal can enter along any of the optical fibers and reach the birefringent crystal, and the birefringent crystal is used to split the optical signal into O light and E light; The transmission or reflection unit includes a plurality of PBS films, the number of which is the same as the number of the optical fibers, and the PBS films are arranged one by one on the optical path where each of the optical fibers is located; The polarization unit is capable of changing the polarization states of the O light and the E light so that both the O light and the E light pass through the corresponding PBS film; Entering the polarizer and being reflected back to the polarizer by the reflective element, the polarizer can change the polarization state of the O light and the E light so that the O light and the E light are both reflected on the corresponding PBS film to the next adjacent PBS film; The polarization unit can change the polarization state of the reflected light so that the reflected light is emitted along the corresponding optical fiber after being combined by the birefringent crystal.

2. The multi-channel shift circulator according to claim 1, characterized in that: A lens unit is arranged between the optical fiber unit and the birefringent crystal. The lens unit includes a mounting frame and a plurality of lenses fixed on the mounting frame. The number of the lenses corresponds to the number of the optical fibers and are arranged one by one on the optical path where each optical fiber is located.

3. The multi-channel shift circulator according to claim 2, characterized in that: The polarization unit comprises a Faraday rotator and a plurality of half-wave plate assemblies sequentially arranged along the optical path, the number of the half-wave plate assemblies arranged corresponds to the number of the optical fibers, and each of the half-wave plate assemblies comprises a first wave plate and a second wave plate; The Faraday rotator is used to change the polarization state of the O light and the E light, the first wave plate is used to change the polarization state of the O light, and the second wave plate is used to change the polarization state of the E light.

4. The multi-channel shift circulator according to claim 3, characterized in that: The polarizer is a quarter wave plate.

5. The multi-channel shift circulator according to claim 4, characterized in that: The PBS film is plated on a glass crystal, and the angle between the PBS film, the O light and the E light is 45 degrees.

6. The multi-channel shift circulator according to claim 5, characterized in that: Along the incident direction of the optical signal, the optical axis angle of the birefringent crystal is 45 degrees, the optical axis angle of the first wave plate is 22.5 degrees, the optical axis angle of the second wave plate is 67.5 degrees, and the optical axis angle of the quarter wave plate is 45 degrees.

7. The multi-channel shift circulator according to claim 4, characterized in that: The reflective element is a reflective film, and the reflective film is plated on one side of the quarter wave plate.

8. The multi-channel shift circulator according to claim 7, characterized in that: The reflective film is a high reflective film.

9. The multi-channel shift circulator according to any one of claims 1 to 8, characterized in that: The birefringent crystal is a lithium niobate crystal.

10. The multi-channel shift circulator according to claim 9, characterized in that: The optical fiber unit, the birefringent crystal, the polarization unit, the transmission or reflection unit, and the polarizer are all bonded together by glue.

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