A multi-channel shift circulator

Abstract

The present application relates to the field of optical communication technology, and specifically relates to a kind of multi-channel shift circulator.It includes optical fiber unit, birefringent crystal, polarization unit, transmission or reflection unit, polarizer and reflecting element;Optical fiber unit includes at least four optical fibers, and optical signal can enter and reach birefringent crystal along any optical fiber, and birefringent crystal is used to split beam O light and E light;Transmission or reflection unit includes a plurality of PBS films, and the setting number of PBS film is same with optical fiber;Polarization unit changes the polarization state of O light and E light, so that O light and E light pass through corresponding PBS film;Enter polarizer and reflect back to polarizer by reflecting element, change the polarization state of O light and E light, so that O light and E light are reflected on corresponding PBS film to adjacent PBS film;Polarization unit can change the polarization state of reflected light, so that reflected light is combined after birefringent crystal and exits along corresponding optical fiber.Equipped with more than three ports to adapt to the application scene of the transmission of optical signal.

Description

Technical Field

[0001] This invention relates to the field of optical communication technology, and in particular to a multi-channel shift circulator. Background Technology

[0002] Circulators have advantages such as simple structure, high stability, high sensitivity, and strong anti-interference ability, and are widely used in the field of optical communication. Common circulators have three communication ports; when an optical signal is input from any port, it outputs from the next port in a specific order. However, in some special transmission scenarios, more than three ports are required for optical signal transmission, which common circulators cannot achieve. 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 is not possible with commonly used circulators.

[0004] This 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 arranged sequentially along an optical path; the optical fiber unit includes a fixed base and at least four optical fibers disposed on the fixed base and arranged parallel to each other, allowing optical signals to enter and reach the birefringent crystal along any of the optical fibers, the birefringent crystal being used to split the optical signal into O-beams and E-beams; the transmission or reflection unit includes multiple PBS films, the number of which is the same as the number of optical fibers, and each PBS film is correspondingly disposed on the optical path of each optical fiber; the polarization unit can change the polarization state of the O-beams and the E-beams so that both the O-beams and E-beams pass through their corresponding PBS films; they enter the polarizer and are reflected back to the polarizer by the reflection element, the polarizer being able to change the polarization state of the O-beams and the E-beams so that both the O-beams and E-beams are reflected onto adjacent PBS films on their corresponding PBS films; 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 corresponding optical fiber.

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

[0006] Optionally, the polarization unit includes a Faraday rotator and a plurality of half-wave plate assemblies arranged sequentially along the optical path. The number of half-wave plate assemblies corresponds to the number of optical fibers. Each half-wave plate assembly 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 uses a quarter-wave plate.

[0008] Optionally, the PBS film is deposited on a glass crystal, and the angle between the PBS film and the O-ray and the E-ray 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 waveplate is 22.5 degrees, the optical axis angle of the second waveplate 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, which is deposited on one side of the quarter-wave plate.

[0011] Optionally, the reflective film is a high-reflectivity 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 together with adhesive.

[0014] Compared with the prior art, the multi-channel shift circulator provided in this embodiment of the invention has the following advantages: optical signals can enter the multi-channel shift circulator along the port of any optical fiber and exit along the port of the next adjacent optical fiber, thereby realizing the transmission of optical signals. Specifically, refer to... Figure 1This example illustrates the transmission process of an optical signal from fiber port 1 to fiber port 2. The optical signal enters along fiber port 1 and reaches a birefringent crystal, which splits the optical signal into O-beams and E-beams. The polarization unit changes the polarization states of the O-beams and E-beams so that both pass through their corresponding PBS films and enter the polarizer. After being reflected back to the polarizer by the reflection element, the polarizer changes the polarization states of the O-beams and E-beams so that both are reflected onto their corresponding PBS films and onto an adjacent PBS film (i.e., the PBS film along the optical path of fiber port 2). The polarization unit changes the polarization state of the reflected light so that the reflected light is combined by the birefringent crystal and emitted along fiber port 2, completing the transmission of the optical signal. The fiber unit in this embodiment includes at least four parallel optical fibers. Figure 1 and Figure 2 Optical signals 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 achieve the shifting function, so as to adapt to application scenarios that require more than three ports to realize the transmission of optical signals. Attached Figure Description

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

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

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

[0018] Figure 3 This is an exploded structural diagram of the multi-channel shift circulator provided in an embodiment of the present invention;

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

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

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

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

[0023] The labels for the attached figures are as follows:

[0024] 10. Fiber optic unit; 110. Mounting base; 120. Fiber optic cable; 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 Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] This invention provides a multi-channel shift circulator, such as... Figures 1 to 4 As shown, the optical structure 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 sequentially along the optical path. The optical fiber unit 10 includes a mounting base 110 and at least four optical fibers 120 arranged parallel to each other on the mounting base 110. Optical signals can enter and reach the birefringent crystal 20 along any of the optical fibers 120. The birefringent crystal 20 is used to split the optical signal into O-beams and E-beams. The transmission or reflection unit 40 includes multiple PBS films 410, and the number of PBS films 410 is the same as that of the optical fibers 120. Each polarization unit 30 is positioned on the optical path of each optical fiber 120. The polarization unit 30 can change the polarization state of the O-light and E-light so that both O-light and E-light pass through the corresponding PBS film 410. The O-light and E-light 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 E-light so that both O-light and E-light are 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 is bundled by the birefringent crystal 20 and emitted along the corresponding optical fiber 120.

[0027] The optical signal can enter the multi-channel shift circulator along any port of the optical fiber 120 and exit along the port of the next adjacent optical fiber 120 to achieve optical signal transmission. Specifically, refer to... Figure 1This example illustrates the transmission process of an optical signal from optical fiber port 120 to optical fiber port 220. The optical signal enters and reaches the birefringent crystal 20 along optical fiber port 120. The birefringent crystal 20 splits the optical signal into O-light and E-light. The polarization unit 30 changes the polarization state of the O-light and E-light so that both O-light and E-light pass through their respective PBS films 410, enter the polarizer 50, and are reflected back to the polarizer 50 by a reflective element. The polarizer 50 then changes the polarization state of the O-light and E-light so that both O-light and E-light are reflected on their respective PBS films 410 to the next adjacent PBS film 410 (i.e., the PBS film 410 on the optical path where optical fiber port 2 is located). The polarization unit 30 changes the polarization state of the reflected light so that the reflected light is combined by the birefringent crystal 20 and then emitted along optical fiber port 220, completing the transmission of the optical signal. In this embodiment, the optical fiber unit 10 includes at least four parallel optical fibers 120. Figure 1 and Figure 2 Optical signals can be transmitted from fiber optic port 120 to fiber optic port 1202, or from fiber optic port 1202 to fiber optic port 1203, or from fiber optic port 1203 to fiber optic port 1204, or from fiber optic port 1204 to fiber optic port 1205, and so on. All optical signals are moved from the original port to the next adjacent port to achieve the shifting function, so as to adapt to application scenarios that require 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 transmissions.

[0029] As a preferred embodiment of this invention, such as Figures 1 to 4 As shown, a lens unit 60 is provided between the fiber unit 10 and the birefringent crystal 20. The lens unit 60 includes a mounting frame 610 and multiple lenses 620 fixed on the mounting frame 610. The number of lenses 620 corresponds to the number of optical fibers 120, and they are arranged one-to-one on the optical path of each optical fiber 120.

[0030] The lens unit 60 is configured to improve the stability of optical signal transmission. The lens unit 60 includes a mounting frame 610 and multiple lenses 620 fixed on the mounting frame 610. The mounting frame 610 is used to fix the multiple lenses 620. The number of lenses 620 corresponds to the number of optical fibers 120 and is located on the optical path of each optical fiber 120. In this embodiment, the lens 620 is a collimating lens 620.

[0031] As a preferred embodiment of this invention, such as Figure 5As shown, the polarization unit 30 includes a Faraday rotator 310 and a plurality of half-wave plate assemblies 320 arranged sequentially along the optical path. The number of half-wave plate assemblies 320 corresponds to the number of optical fibers 120. 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-ray and E-ray, the first waveplate 321 is used to change the polarization state of the O-ray, and the second waveplate 322 is used to change the polarization state of the E-ray, so that the O-ray and E-ray can rotate at a certain angle. In practical applications, the O-ray passes through the Faraday rotator 310 and the first waveplate 321 to change its polarization state, and the E-ray passes through the Faraday rotator 310 and the second waveplate 322 to change its polarization state.

[0033] In a preferred embodiment, the polarizer 50 employs a quarter-wave plate; the PBS film 410 is deposited on a glass crystal, and the angle between the PBS film 410 and the O-beam and E-beam is 45 degrees. These settings ensure efficient transmission along optical fibers 120port1 to 120port2, 120port2 to 120port3, and so on.

[0034] As a preferred 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 waveplate 321 is 22.5 degrees, the optical axis angle of the second waveplate 322 is 67.5 degrees, and the optical axis angle of the quarter-wave plate is 45 degrees.

[0035] The optical axis angles of each optical element defined in this embodiment are... Figure 4 In the middle, viewed from left to right. The above limitations on the optical axis angles of the birefringent crystal 20, the first waveplate 321, the second waveplate 322, and the quarter-waveplate are all to allow the O-beam and E-beam to rotate by a certain angle so that the optical signal can be transmitted from fiber optic port 120 to fiber optic port 1202, or from fiber optic port 1202 to fiber optic port 1203, or from fiber optic port 1203 to fiber optic port 1204, or from fiber optic port 1204 to fiber optic port 1205, and so on. All optical signals are shifted from the original port to the next adjacent port, realizing the shifting function.

[0036] As a preferred embodiment, the reflective element is a reflective film, which is deposited on one side of the quarter-wave plate.

[0037] When the reflective film is installed, it is coated on a quarter-wave plate. While playing a reflective role, it can 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 embodiment, a high-reflectivity film is used for the reflective film. This allows for more effective reflection of light and improves the efficiency of the optical system.

[0039] In a preferred embodiment, the birefringent crystal 20 is a lithium niobate crystal, thereby separating the optical signal into O-light and E-light.

[0040] In a preferred embodiment, the fiber optic unit 10, birefringent crystal 20, polarization unit 30, transmission or reflection unit 40, and polarizer 50 are all bonded together with adhesive. This improves the stability and compactness of the connections between the components of the multi-channel shift circulator. It eliminates the need for individual coupling of optical elements in a free-space optics manner, significantly reducing the difficulty of application.

[0041] For a detailed description of the optical signal's process in the multi-channel shift circulator, please refer to [link / reference]. Figure 4 The arrow indicates the transmission path of the optical signal. Figure 6 and Figure 7The arrows indicate the polarization state and the transmission direction of the optical signal. More specifically, after the optical signal enters through Port1, it is incident on the birefringent crystal 20, forming O-light (S-polarized state) and E-light (P-polarized state). The O-light continues to pass through the Faraday rotator 310 (polarization direction rotated 45 degrees clockwise) and the first waveplate 321 (polarization direction rotated 45 degrees clockwise), while the E-light passes through the Faraday rotator 310 (polarization direction rotated 45 degrees clockwise) and the second waveplate 322 (polarization direction rotated 45 degrees counterclockwise). The polarization state of the O-light changes to P-polarized state, and the E-light also changes to P-polarized state; then the O-light... The light (P-polarized state) and the E-light (P-polarized state) continue to propagate to the PBS film 410 corresponding to the transmission or reflection unit 40. Both the O-light (P-polarized state) and the E-light (P-polarized state) pass through the PBS film 410 and are transmitted to the polarizer 50. After being reflected by the reflective film on the outside of the polarizer 50 (quarter-wave plate), they return along the same path. At this point, it is equivalent to the O-light (P-polarized state) and the E-light (P-polarized state) passing through the polarizer 50 (quarter-wave plate) twice. The O-light changes from the P-polarized state to the S-polarized state, and the E-light changes from the P-polarized state to the S-polarized state. At this point, the reflected light O (S-polarized state) and E (S-polarized state) will be reflected at PBS film 410 and reach the next adjacent PBS film 410. Similarly, the O (S-polarized state) and E (S-polarized state) light will continue to be reflected at the adjacent PBS film 410. The reflected O (S-polarized state) light passes through the corresponding first waveplate 321 (polarization direction rotated 45 degrees clockwise) and Faraday rotator 310 (polarization direction rotated 45 degrees counterclockwise), and the polarization state of the O light becomes S-polarized; the E (S-polarized state) light passes through the corresponding... With the second waveplate 322 (polarization direction rotated 45 degrees counterclockwise) and the Faraday rotator 310 (polarization direction rotated 45 degrees clockwise and counterclockwise), the polarization state of the E light changes to the P polarization state. That is, when the reflected O light and E light return to the birefringent crystal 20, their polarization states are S polarization state and P polarization state, respectively. Therefore, they are combined into a single beam, which is then focused into the fiber 120 through the lens 620 and emitted from the fiber 120 port2. Thus, the above optical path completes the transmission from fiber 120 port1 to fiber 120 port2.

[0042] This embodiment provides an example with 5 optical fibers 120. The number of optical fibers 120 is not specifically limited here and can be set according to the actual application scenario.

[0043] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A multi-channel shift circulator, characterized in that, include: The optical fiber unit, birefringent crystal, polarization unit, transmission or reflection unit, polarizer and reflection element are arranged sequentially along the optical path; The optical fiber unit includes a fixed base and at least four optical fibers arranged parallel to each other and on the same side on the fixed base. The optical signal can enter and reach the birefringent crystal along any of the optical fibers. The birefringent crystal is used to split the optical signal into O light and E light. The transmission or reflection unit includes multiple PBS films, the number of which is the same as the number of optical fibers, and each PBS film is disposed in a corresponding manner on the optical path of each optical fiber. The polarization unit can change the polarization state of the O light and the E light so that both the O light and the E light pass through the corresponding PBS film; The light enters the polarizer and is 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 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 bundled by the birefringent crystal and then emitted along the corresponding optical fiber. The polarization unit includes a Faraday rotator plate and a plurality of half-wave plate assemblies arranged sequentially along the optical path. The number of half-wave plate assemblies corresponds to the number of optical fibers. Each half-wave plate assembly includes a first wave plate and a second wave plate. The Faraday rotator is used to change the polarization state of the O-ray and the E-ray, the first waveplate is used to change the polarization state of the O-ray, and the second waveplate is used to change the polarization state of the E-ray. The polarizer uses a quarter-wave plate; The PBS film is deposited on a glass crystal, and the angle between the PBS film and the O-ray and the E-ray is 45 degrees. Along the incident direction of the light signal, the optical axis angle of the birefringent crystal is 45 degrees, the optical axis angle of the first waveplate is 22.5 degrees, the optical axis angle of the second waveplate is 67.5 degrees, and the optical axis angle of the quarter-wave plate is 45 degrees.

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

3. The multi-channel shift circulator according to claim 1, characterized in that, The reflective element is a reflective film, which is deposited on one side of the quarter-wave plate.

4. The multi-channel shift circulator according to claim 3, characterized in that, The reflective film is a high-reflectivity film.

5. The multi-channel shift circulator according to any one of claims 1 to 4, characterized in that, The birefringent crystal is a lithium niobate crystal.

6. The multi-channel shift circulator according to claim 5, characterized in that, The optical fiber unit, the birefringent crystal, the polarization unit, the transmission or reflection unit, and two of the polarizers are bonded together with adhesive.

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