A circulator

Abstract

The application relates to the field of optical transmission technology and particularly relates to a circulator. The circulator comprises a light splitting and combining element, a polarization unit, a refractive unit and a reflecting element arranged along an optical path, the light splitting and combining element being connected with at least a first optical fiber and a second optical fiber; first incident light can pass through the light splitting and combining element, the polarization unit and the refractive unit along the first optical fiber in sequence, so that the first incident light is incident to the reflecting element at a first preset included angle to be reflected, and then passes through the refractive unit, the polarization unit and the light splitting and combining element in sequence to be emitted from the second optical fiber; wherein the light splitting and combining element is used for splitting the first incident light into o light and e light, or combining the o light and the e light to be emitted from the second optical fiber. The circulator can be adapted to the working environment of the communication ports on the same side, and the first optical fiber and the second optical fiber are connected with corresponding communication elements respectively to realize the purpose of signal transmission, so that the applicability of the circulator is improved.

Description

Technical Field

[0001] This invention relates to the field of optical transmission technology, and in particular to a circulator. Background Technology

[0002] Circulators are widely used for signal transmission due to their high isolation performance. Current circulators typically have three connection ports in different directions, which are then connected to corresponding communication ports to achieve signal transmission. However, this type of circulator is not suitable for applications with multiple communication ports on the same side, resulting in significant application limitations. Summary of the Invention

[0003] The technical problem to be solved by the embodiments of the present invention is to provide a circulator to solve the problem that the circulator in the prior art cannot be applied to the working environment of multiple communication ports on the same side, which has great limitations.

[0004] This invention discloses a circulator, comprising: a beam splitter / combiner element, a polarization unit, a refraction unit, and a reflection element arranged along an optical path. The beam splitter / combiner element is connected to at least a first optical fiber and a second optical fiber. A first incident light can pass sequentially along the first optical fiber through the beam splitter / combiner element, the polarization unit, and the refraction unit, so that the first incident light is incident at a first preset angle to the reflection element for reflection, and then sequentially passes through the refraction unit, the polarization unit, and the beam splitter / combiner element and exits from the second optical fiber. The beam splitter / combiner element is used to split the first incident light into o-ray and e-ray, or to combine the o-ray and e-ray before exiting from the second optical fiber.

[0005] Optionally, the polarization unit includes a half-wave plate module and a rotator plate arranged along the optical path. The half-wave plate module includes a first half-wave plate, a second half-wave plate, a third half-wave plate, and a fourth half-wave plate. The o-light and e-light can pass through the first half-wave plate, the second half-wave plate, and the rotator plate in sequence to change their polarization states and then be output as o-light to the refraction unit. The o-light reflected to the polarization unit can pass through the rotator plate, the fourth half-wave plate, and the third half-wave plate in sequence to change their polarization states and then be output as o-light and e-light.

[0006] Optionally, the refraction unit includes a first refraction element, a seventh half-wave plate, and a second refraction element, with the seventh half-wave plate located between the first and second refraction elements. After passing through the seventh half-wave plate, the o-ray changes its polarization state and is converted into e-ray, which then enters the second refraction element for refraction, so that the e-ray is incident on the reflective element at the first preset angle for reflection. The reflected e-ray enters the second refraction element for refraction, and after passing through the seventh half-wave plate, changes its polarization state and is converted back into o-ray, which then passes through the first refraction element and is output.

[0007] Optionally, the optical splitter / combiner is further connected to a third optical fiber, and the half-wave plate module further includes a fifth half-wave plate and a sixth half-wave plate;

[0008] The second incident light is split into o-light and e-light along the third optical fiber by the optical splitting and combining element. The o-light and e-light can be sequentially passed through the third half-wave plate, the fourth half-wave plate, and the optical rotator to change their polarization state, and then output as e-light to the refraction unit. The e-light enters the first refraction element for refraction, and is converted into o-light by changing its polarization state through the seventh half-wave plate. The o-light is incident on the reflection element at a second preset angle for reflection. The reflected o-light is converted into e-light by changing its polarization state through the seventh half-wave plate, enters the first refraction element for refraction, and is then output to the polarization unit. The e-light entering the polarization unit can be sequentially passed through the optical rotator, the sixth half-wave plate, and the fifth half-wave plate to change its polarization state, and then output as o-light and e-light to the optical splitting and combining element. The o-light and e-light are combined by the optical splitting and combining element and then emitted from the third optical fiber.

[0009] Optionally, the first optical fiber, the second optical fiber, and the third optical fiber are arranged parallel to each other at a preset distance and are located on the same side of the optical splitting and combining element.

[0010] Optionally, the circulator further includes a lens disposed between the half-wave plate module and the optical rotator.

[0011] Optionally, the optical splitting and combining element is a birefringent crystal, and the optical axis angle of the optical splitting and combining element is 45 degrees along the direction of the first incident light.

[0012] Optionally, the optical axis angle of the first half-wave plate and the fourth half-wave plate is -22.5 degrees, and the optical axis angle of the second half-wave plate and the third half-wave plate is 22.5 degrees; the optical rotator is a 45-degree optical rotator.

[0013] Optionally, the optical axis angle of the fifth half-wave plate is -22.5 degrees, and the optical axis angle of the sixth half-wave plate is 22.5 degrees.

[0014] Optionally, the first and second refractive elements are birefringent crystals, and the optical axis angles of the first and second refractive elements along the plane perpendicular to the first incident light are both 45 degrees, and the optical axis angle of the seventh half-wave plate is also 45 degrees.

[0015] Compared with the prior art, the beneficial effects of the circulator provided in this invention are as follows: This invention uses a beam splitter / combiner to split the first incident light into o-rays and e-rays, and a polarization unit to change the polarization states of the o-rays and e-rays. This allows the first incident light to enter the refraction unit as o-rays. Under the action of the refraction unit, the o-rays can enter the reflection element at a first preset angle as e-rays for reflection. The reflected e-rays, under the action of the refraction unit, can enter the polarization unit as o-rays, and under the action of the polarization unit, their polarization states are changed so that they enter the beam splitter / combiner in the forms of o-rays and e-rays, are combined, and then exit from the second optical fiber. The circulator of this invention can adapt to working environments where communication ports are on the same side. By connecting the first and second optical fibers to corresponding communication elements respectively, it achieves signal transmission, thus improving the applicability of the circulator of this invention. Attached Figure Description

[0016] 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:

[0017] Figure 1 This is a schematic diagram of the structure of the circulator provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of the half-wave plate module provided in an embodiment of the present invention;

[0019] Figure 3 This is a diagram showing the optical path and polarization state changes from the first optical fiber to the second optical fiber provided in an embodiment of the present invention;

[0020] Figure 4 This is a diagram showing the optical path and polarization state changes from the second optical fiber to the third optical fiber provided in an embodiment of the present invention.

[0021] The figures are labeled as follows: 10, optical splitting and combining element; 20, polarization unit; 21, half-wave plate module; 211, first half-wave plate; 212, second half-wave plate; 213, third half-wave plate; 214, fourth half-wave plate; 215, fifth half-wave plate; 216, sixth half-wave plate; 22, optical rotator; 30, refraction unit; 31, first refractor; 32, seventh half-wave plate; 33, second refractor; 40, reflection element; 50, first optical fiber; 60, second optical fiber; 70, third optical fiber; 80, lens. Detailed Implementation

[0022] 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.

[0023] The arrows in the attached diagram indicate the direction of optical transmission.

[0024] This invention provides a circulator, such as... Figure 1 As shown, the circulator includes: a beam splitter / combiner element 10, a polarization unit 20, a refraction unit 30, and a reflection element 40 arranged along the optical path. The beam splitter / combiner element 10 is connected to at least a first optical fiber 50 and a second optical fiber 60. A first incident light can pass sequentially along the first optical fiber 50 through the beam splitter / combiner element 10, the polarization unit 20, and the refraction unit 30, so that the first incident light is incident at a first preset angle to the reflection element 40 for reflection, and then sequentially passes through the refraction unit 30, the polarization unit 20, and the beam splitter / combiner element 10 and exits from the second optical fiber 60. The beam splitter / combiner element 10 is used to split the first incident light into o-light and e-light, or to combine the o-light and e-light and then exit from the second optical fiber 60.

[0025] In this embodiment, a beam splitter / combiner 10 is used to split the first incident light into o-ray and e-ray. A polarization unit 20 is used to change the polarization state of the o-ray and e-ray, so that the first incident light enters the refraction unit 30 in the form of o-ray. Under the action of the refraction unit 30, the o-ray can cause the first incident light to enter the reflection element 40 in the form of e-ray at a first preset angle for reflection. The reflected e-ray, under the action of the refraction unit 30, can enter the polarization unit 20 in the form of o-ray, and under the action of the polarization unit 20, its polarization state is changed so that it enters the beam splitter / combiner 10 in the form of o-ray and e-ray and is combined before exiting from the second optical fiber 60. The circulator of the present invention can adapt to working environments where the communication ports are on the same side. By connecting the first optical fiber 50 and the second optical fiber 60 to the corresponding communication elements respectively, the purpose of signal transmission is achieved, thus improving the applicability of the circulator of the present invention.

[0026] As a preferred embodiment, refer to Figure 2 The polarization unit 20 includes a half-wave plate module 21 and a rotator 22 arranged along the optical path. The half-wave plate module 21 includes a first half-wave plate 211, a second half-wave plate 212, a third half-wave plate 213, and a fourth half-wave plate 214. The o-light and e-light can pass through the first half-wave plate 211, the second half-wave plate 212, and the rotator 22 in sequence to change their polarization state and then be output as o-light to the refraction unit 30. The o-light reflected to the polarization unit 20 can pass through the rotator 22, the fourth half-wave plate 214, and the third half-wave plate 213 in sequence to change their polarization state and then be output as o-light and e-light.

[0027] In this embodiment, the polarization unit 20 includes a half-wave plate module 21 and a rotator 22 arranged along the optical path. The half-wave plate module 21 includes a first half-wave plate 211, a second half-wave plate 212, a third half-wave plate 213, and a fourth half-wave plate 214. After the light is split by the optical splitter 10, the o-beam and e-beam rotate counterclockwise by 45 degrees when the o-beam passes through the first half-wave plate 211, and the e-beam rotates clockwise by 45 degrees when it passes through the second half-wave plate 212. When the o-beam and e-beam pass through the rotator 22, they both rotate clockwise by 45 degrees. At this time, the o-beam rotates a cumulative 0 degrees and remains unchanged; the e-beam rotates a cumulative 90 degrees and becomes o-beam. Thus, the two beams of light separated by the optical splitter 10 are converted into o-beams and finally output from the rotator 22 to the refraction unit 30 in the form of two o-beams. The two o-beams reflected to polarization unit 20 pass in opposite directions through optical rotator 22, each rotating 45 degrees clockwise. They then pass in opposite directions through half-wave plate module 21, and through third half-wave plate 213, rotate 45 degrees counterclockwise, accumulating a total rotation of 0 degrees, keeping the o-beams unchanged. The light passing through fourth half-wave plate 214 rotates 45 degrees clockwise, accumulating a total rotation of 90 degrees, converting into e-beams. At this point, the o-beams and e-beams output from half-wave plate module 21 are output to optical splitter / combiner element 10. The polarization states of the o-beams and e-beams are the same as those of the light entering the first fiber 50 after passing through optical splitter / combiner element 10, but their positions differ. After passing through optical splitter / combiner element 10 again, they can be combined into a single beam, which converges at the position of the second fiber 60 and exits from the second fiber 60, achieving the purpose of optical signal transmission.

[0028] The polarization unit 20 configured in this embodiment can change the polarization state of o-light and e-light through the action of the first half-wave plate 211, the second half-wave plate 212, the third half-wave plate 213, the fourth half-wave plate 214, and the optical rotator 22, and achieve the purpose of converting the two, so as to realize the transmission of the first incident light along the first optical fiber 50, which is reflected by the reflecting element 40 and then transmitted in the opposite direction to exit from the second optical fiber 60, thereby realizing the purpose of optical signal transmission.

[0029] As a preferred embodiment, the refraction unit 30 includes a first refraction element 31, a seventh half-wave plate 32, and a second refraction element 33. The seventh half-wave plate 32 is located between the first refraction element 31 and the second refraction element 33. After passing through the seventh half-wave plate 32, the o-light changes its polarization state and is converted into e-light, which then enters the second refraction element 33 for refraction, so that the e-light is incident on the reflective element 40 at a first preset angle for reflection. The reflected e-light enters the second refraction element 33 for refraction, and after passing through the seventh half-wave plate 32, changes its polarization state and is converted into o-light, which is then output through the first refraction element 31.

[0030] In this embodiment, the refraction unit 30 includes a first refraction element 31, a seventh half-wave plate 32, and a second refraction element 33. The two o-beams output from the optical rotator 22 do not refract when passing through the first refraction element 31, and the transmission direction of the light path remains unchanged. The two o-beams enter the seventh half-wave plate 32, where their polarization state rotates by 90 degrees, transforming them into two e-beams. These e-beams then enter the second refraction element 33 and undergo refraction, changing the transmission direction of the light path. This allows the two e-beams to be incident on the reflective element 40 at a first preset angle for reflection. The reflected e-beams then refract when passing through the second refraction element 33, changing the transmission direction of the light path. The two e-beams then enter the seventh half-wave plate 32, where their polarization state rotates by 90 degrees, transforming them into two o-beams. When these o-beams enter the first refraction element 31, they do not refract, and the transmission direction of the light path remains unchanged. Finally, the light path outputs from the refraction unit 30 as two o-beams.

[0031] The refraction unit 30 configured in this embodiment can, under the action of the first refraction element 31, the seventh half-wave plate 32 and the second refraction element 33, and according to the difference in refractive indices of o-ray and e-ray in the first refraction element 31 and the second refraction element 33, enable the e-ray output from the second refraction element 33 at a first preset angle to enter the reflector for reflection, and enable the reflected e-ray to enter the second refraction element 33 for refraction, and after passing through the seventh half-wave plate 32, change its polarization state and be converted into o-ray, which is then output through the first refraction element 31.

[0032] The purpose of setting the first preset angle in this embodiment is to prevent the light path from entering the reflector perpendicularly and then returning along the original path after reflection. The size of the first preset angle can be adjusted according to the actual working conditions, and no specific limitation is made in this embodiment.

[0033] As a preferred embodiment, refer to Figure 1 and Figure 2 The optical splitter / combiner 10 is also connected to a third optical fiber 70, and the half-wave plate module 21 also includes a fifth half-wave plate 215 and a sixth half-wave plate 216.

[0034] The second incident light is split into o-light and e-light by the optical splitter / combiner 10 along the third optical fiber 70. The o-light and e-light can be successively passed through the third half-wave plate 213, the fourth half-wave plate 214 and the optical rotator 22 to change their polarization state and then output as e-light to the refraction unit 30. The e-light enters the first refraction element 31 for refraction and is converted into o-light by the seventh half-wave plate 32. The o-light is incident on the reflection element 40 at the second preset angle for reflection. The reflected o-light is converted into e-light by the seventh half-wave plate 32 and then refracted by the first refraction element 31 before being output to the polarization unit 20. The e-light entering the polarization unit 20 can be successively passed through the optical rotator 22, the sixth half-wave plate 216 and the fifth half-wave plate 215 to change their polarization state and then output as o-light and e-light to the optical splitter / combiner 10. The o-light and e-light are combined by the optical splitter / combiner 10 and then emitted from the third optical fiber 70.

[0035] In this embodiment, a third optical fiber 70 is set up and connected to a communication port. It works with the second optical fiber 60 to form an optical signal transmission. Specifically, the second incident light is split into o-light and e-light by the optical splitter / combiner 10 along the third optical fiber 70. The o-light is rotated 45 degrees clockwise by the third half-wave plate 213, and the e-light is rotated 45 degrees counterclockwise by the fourth half-wave plate 214. When the o-light and e-light pass through the optical rotator 22, they are both rotated 45 degrees clockwise. At this time, the o-light has rotated a total of 90 degrees and is converted into e-light. The e-light has rotated a total of 0 degrees and remains unchanged. Thus, the two beams of light separated by the optical splitter / combiner 10 are converted into e-light. Finally, the two beams of e-light are output from the optical rotator 22 to the refraction unit 30. The two e-beams output from the optical rotator 22 are refracted when they pass through the first refractive element 31, changing the direction of light transmission. The refracted e-beams then enter the seventh half-wave plate 32, where their polarization states are rotated by 90 degrees, transforming them into two o-beams. When these o-beams enter the second refractive element 33, no refraction occurs, and the direction of light transmission remains unchanged. This allows the two o-beams to be incident on the reflective element 40 at a first preset angle for reflection. The reflected o-beams then pass through the second refractive element 33 without refraction, and the direction of light transmission remains unchanged. The two o-beams then enter the seventh half-wave plate 32, where their polarization states are rotated by 90 degrees, transforming them into two e-beams. When these e-beams enter the first refractive element 31, refraction occurs, changing the direction of light transmission. Finally, the light path outputs from the refraction unit 30 as two e-beams. The two e-beams reflected to polarization unit 20 pass in opposite directions through optical rotator 22, each rotating 45 degrees clockwise. They then pass in opposite directions through half-wave plate module 21. The light passing through the fifth half-wave plate 215 rotates 45 degrees clockwise, accumulating a 90-degree rotation, and is converted into o-beams. The light passing through the sixth half-wave plate 216 rotates 45 degrees counterclockwise, accumulating a 0-degree rotation, keeping the e-beams unchanged. At this point, the o-beams and e-beams output from half-wave plate module 21 are sent to optical splitting and combining element 10. The polarization states of the o-beams and e-beams are the same as those of the light entering the second fiber 60 after passing through crystal 1, but their positions differ. After passing through optical splitting and combining element 10, they can be combined into a single beam, which converges at the position of the third fiber 70 and exits from the third fiber 70, achieving the purpose of optical signal transmission.

[0036] As a preferred embodiment, the first optical fiber 50, the second optical fiber 60 and the third optical fiber 70 are arranged parallel to each other at a preset distance and are located on the same side of the optical splitting and combining element 10.

[0037] In this embodiment, the first optical fiber 50, the second optical fiber 60, and the third optical fiber 70 are located on the same side of the optical splitter / combiner element 10 to facilitate signal transmission in application environments where multiple communication ports are on the same side. Furthermore, the first optical fiber 50, the second optical fiber 60, and the third optical fiber 70 can maintain a preset distance from each other to accommodate multiple communication ports in different locations, thereby improving the applicability of the circulator in this embodiment. The preset distance is adjusted according to the relative positions of the multiple communication ports in actual working conditions, and is not specifically limited in this embodiment.

[0038] As a preferred embodiment, the circulator further includes a lens 80, which is disposed between the half-wave plate module 21 and the optical rotator 22.

[0039] Among them, a lens 80 is set as a reference. Figure 1 When the light path travels from left to right, the lens 80 converts the diverging light into collimated light, and when the light path travels in the opposite direction from right to left, the lens 80 converts the collimated light into converging light. The polarization state does not change during this process.

[0040] As a preferred embodiment, the optical splitting and combining element 10 is a birefringent crystal, and the optical axis angle of the optical splitting and combining element 10 is 45 degrees along the direction of the first incident light.

[0041] In this embodiment, the optical splitting and combining element 10 is a birefringent crystal, and the optical axis angle of the optical splitting and combining element 10 is 45 degrees along the direction of the first incident light. The purpose is to make the first incident light split into o light and e light after passing through the optical splitting and combining element 10. Figure 1 The direction of the dashed line at point 10 of the optical splitter / combiner indicates the direction of the optical axis angle.

[0042] The optical splitter / combiner element 10, the first refractive element 31, and the second refractive element 33 are birefringent crystals, such as rutile (CaCO3), calcite (TiO3), and yttrium vanadate (YVO4). Yttrium vanadate is preferred as the material for the optical splitter / combiner element 10. Yttrium vanadate is a birefringent crystal material with excellent physical and optical properties, including a wide light transmission range, high transmittance, large birefringence coefficient, and ease of processing.

[0043] in Figure 1 The direction of the dashed lines at the first refractive element 31 and the second refractive element 33 indicates the direction of the optical axis angle.

[0044] In this embodiment, the reflective element 40 is a reflector.

[0045] As a preferred embodiment, the optical axis angle of the first half-wave plate 211 and the fourth half-wave plate 214 is -22.5 degrees, and the optical axis angle of the second half-wave plate 212 and the third half-wave plate 213 is 22.5 degrees; the optical rotator 22 is a 45-degree optical rotator.

[0046] In this embodiment, the optical axis angle between the first half-wave plate 211 and the fourth half-wave plate 214 is -22.5 degrees, and the optical axis angle between the second half-wave plate 212 and the third half-wave plate 213 is 22.5 degrees. The optical rotator 22 is a 45-degree optical rotator, the purpose of which is to realize the change of the polarization state of light as described above.

[0047] As a preferred embodiment, the optical axis angle of the fifth half-wave plate 215 is -22.5 degrees, and the optical axis angle of the sixth half-wave plate 216 is 22.5 degrees.

[0048] In this embodiment, the optical axis angle of the fifth half-wave plate 215 is set to -22.5 degrees, and the optical axis angle of the sixth half-wave plate 216 is set to 22.5 degrees. The purpose is to achieve the change in the polarization state of light as described above.

[0049] As a preferred embodiment, the first refractive element 31 and the second refractive element 33 are birefringent crystals, and their optical axis angles are both 45 degrees. The optical axis angle of the seventh half-wave plate 32 is also 45 degrees.

[0050] In this embodiment, the first refractive element 31 and the second refractive element 33 are birefringent crystals. Along the plane perpendicular to the first incident light, the optical axis angles of the first refractive element 31 and the second refractive element 33 are both 45 degrees. This ensures that the o-light does not refract when passing through the first refractive element 31 and the second refractive element 33, while the e-light does refract when passing through the first refractive element 31 and the second refractive element 33. This is to ensure the transmission of the light path in this embodiment. The purpose of setting the optical axis angle of the seventh half-wave plate 32 to 45 degrees is to realize the change of the polarization state of light as described above.

[0051] See Figure 3 This embodiment illustrates the optical path and polarization state changes from the first optical fiber 50 to the second optical fiber 60:

[0052] (1) The light entering through the first optical fiber 50 is split into o-light and e-light by the optical splitter / combiner 10;

[0053] (2) After passing through the first half-wave plate 211, the o-light rotates 45 degrees counterclockwise; after passing through the second half-wave plate 212, the e-light rotates 45 degrees clockwise.

[0054] (3) When o and e rays pass through a lens of 80°, their polarization states do not change, but the divergent light becomes collimated light.

[0055] (4) After passing through the optical rotator 22, both the o and e rays are rotated 45 degrees clockwise; the o ray rotates a total of 0 degrees and remains unchanged; the e ray rotates a total of 90 degrees and becomes the o ray; at this point, the polarization states of the two separated beams are converted into o rays.

[0056] (5) Two beams of o-light are incident on the first refractive element 31 and refracted according to the o-light;

[0057] (6) After passing through the seventh half-wave plate 32, both o-beams are converted into e-beams and refracted according to the e-beam pattern;

[0058] (7) The two beams of e light are reflected from the reflecting element 40, and then pass in the opposite direction through the seventh half-wave plate 32, and are both converted into o light;

[0059] (8) The two beams of o light pass through the optical rotator 22 in opposite directions and both rotate 45 degrees clockwise;

[0060] (9) When two beams of o light pass through lens 80 in opposite directions, their polarization states do not change, but the collimated light becomes the converging light.

[0061] (10) Two beams of o light pass through half-wave plate module 21 in opposite directions: the light passing through the third half-wave plate 213 rotates 45 degrees counterclockwise, with a cumulative rotation of 0 degrees, keeping the o light unchanged; the light passing through the fourth half-wave plate 214 rotates 45 degrees clockwise, with a cumulative rotation of 90 degrees, and is converted into e light;

[0062] (11) The polarization states of o and e light are the same as those of the light entering the first optical fiber 50 after passing through the optical splitting and combining element 10, but their positions are different. After passing through the optical splitting and combining element 10 again, they can be combined into a beam of light and converged at the position of the second optical fiber 60.

[0063] See Figure 4 This embodiment shows the optical path and polarization state changes from the second fiber 60 to the third fiber 70:

[0064] (1) The light entering through the second optical fiber 60 is split into o-light and e-light by the optical splitter / combiner 10;

[0065] (2) After passing through the third half-wave plate 213, the o-light rotates 45 degrees clockwise; after passing through the fourth half-wave plate 214, the e-light rotates 45 degrees counterclockwise.

[0066] (3) When o and e rays pass through a lens of 80°, their polarization states do not change, but the divergent light becomes collimated light.

[0067] (4) Both the o and e beams are rotated 45 degrees clockwise after passing through the optical rotator 22; the o beam rotates a total of 90 degrees and is converted into the e beam; the e beam rotates a total of 0 degrees and remains unchanged; at this point, the polarization states of the two separated beams are converted into e beams.

[0068] (5) Two beams of e-light are incident on the first refraction element 31 and refracted according to the e-light principle;

[0069] (6) After passing through the seventh half-wave plate 32, both beams of e light are converted into o light and refracted according to the o light principle;

[0070] (7) The two beams of o light are reflected from the reflecting element 40 and then converted into e light after passing through the seventh half-wave plate 32;

[0071] (8) The two e-beams pass through the optical rotator 22 in opposite directions and both rotate 45 degrees clockwise;

[0072] (9) When two e-beams pass through lens 80 in opposite directions, their polarization states do not change, but the collimated light becomes the converging light.

[0073] (10) The two e-beams pass through the half-wave plate module 21 in opposite directions: the light passing through the fifth half-wave plate 215 rotates 45 degrees clockwise, and a total of 90 degrees, and is converted into o-beams; the light passing through the sixth half-wave plate 216 rotates 45 degrees counterclockwise, and a total of 0 degrees, keeping the e-beams unchanged.

[0074] (11) The polarization states of o and e light are the same as those of the light entering the second fiber 60 after passing through crystal 1, but their positions are different. After passing through the optical splitting and combining element 10, they can be combined into a beam of light and converged to the position of the third fiber 70.

[0075] 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 circulator, characterized in that, include: The optical splitting and combining element (10), polarization unit (20), refraction unit (30) and reflection element (40) are arranged along the optical path, and the optical splitting and combining element (10) is connected to at least a first optical fiber (50) and a second optical fiber (60). The first incident light can pass sequentially through the splitting and combining optical element (10), polarization unit (20) and refraction unit (30) along the first optical fiber (50) so that the first incident light is incident on the reflecting element (40) at a first preset angle for reflection, and then exits from the second optical fiber (60) sequentially through the refraction unit (30), the polarization unit (20) and the splitting and combining optical element (10); The optical splitting and combining element (10) is used to split the first incident light into o-light and e-light, or to combine the o-light and e-light and then emit them from the second optical fiber (60); The polarization unit (20) includes a half-wave plate module (21) and a rotator (22) arranged along the optical path. The half-wave plate module (21) includes a first half-wave plate (211), a second half-wave plate (212), a third half-wave plate (213), and a fourth half-wave plate (214). The o-light and e-light can pass through the first half-wave plate (211), the second half-wave plate (212), and the rotator (22) in sequence to change their polarization state and then be output as o-light to the refraction unit (30). The o-light reflected to the polarization unit (20) can pass through the rotator (22), the fourth half-wave plate (214), and the third half-wave plate (213) in sequence to change their polarization state and then be output as o-light and e-light. The refraction unit (30) includes a first refraction element (31), a seventh half-wave plate (32), and a second refraction element (33). The seventh half-wave plate (32) is located between the first refraction element (31) and the second refraction element (33). After passing through the seventh half-wave plate (32), the o-light changes its polarization state and becomes e-light, which enters the second refraction element (33) for refraction, so that the e-light is incident on the reflective element (40) at the first preset angle for reflection. The reflected e-light enters the second refraction element (33) for refraction, and after passing through the seventh half-wave plate (32), changes its polarization state and becomes o-light, which is then output after passing through the first refraction element (31). The splitting and combining optical element (10) is also connected to a third optical fiber (70), and the half-wave plate module (21) also includes a fifth half-wave plate (215) and a sixth half-wave plate (216). The second incident light is split into o-light and e-light along the third optical fiber (70) by the optical splitting and combining element (10). The o-light and e-light can be sequentially passed through the third half-wave plate (213), the fourth half-wave plate (214), and the optical rotator (22) to change their polarization state, and then output as e-light to the refraction unit (30). The e-light enters the first refraction element (31) for refraction, and changes its polarization state through the seventh half-wave plate (32) to become o-light. The o-light is incident on the reflection element (40) at a second preset angle for reflection. The reflected o-light is converted into e-light by the seventh half-wave plate (32) and then refracted by the first refractive element (31) before being output to the polarization unit (20). The e-light entering the polarization unit (20) can be converted into o-light and e-light by passing through the optical rotator (22), the sixth half-wave plate (216) and the fifth half-wave plate (215) in sequence to change its polarization state. The o-light and e-light are then output to the optical splitter / combiner (10) as o-light and e-light. The o-light and e-light are combined by the optical splitter / combiner (10) and then emitted from the third optical fiber (70). The first optical fiber (50), the second optical fiber (60) and the third optical fiber (70) are arranged parallel to each other at a preset distance and are located on the same side of the splitting and combining optical element (10).

2. The circulator according to claim 1, characterized in that, The circulator also includes: Lens (80) is disposed between the half-wave plate module and the optical rotator (22).

3. The circulator according to claim 1, characterized in that, The optical splitting and combining element (10) is a birefringent crystal, and the optical axis angle of the optical splitting and combining element (10) is 45 degrees along the direction of the first incident light.

4. The circulator according to claim 1, characterized in that, The optical axis angle of the first half-wave plate (211) and the fourth half-wave plate (214) is -22.5 degrees, and the optical axis angle of the second half-wave plate (212) and the third half-wave plate (213) is 22.5 degrees; the optical rotator (22) is a 45-degree optical rotator.

5. The circulator according to claim 1, characterized in that, The optical axis angle of the fifth half-wave plate (215) is -22.5 degrees, and the optical axis angle of the sixth half-wave plate (216) is 22.5 degrees.

6. The circulator according to claim 1, characterized in that, The first refractive element (31) and the second refractive element (33) are birefringent crystals. Along the plane perpendicular to the first incident light, the optical axis angle of the first refractive element (31) and the second refractive element (33) is 45 degrees, and the optical axis angle of the seventh half-wave plate is 45 degrees.

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