High performance reflective optical circulator

Abstract

This invention provides a high-performance reflective optical circulator, comprising a collimator array, a first birefringent crystal at one end of the collimator array, a half-wave plate group at the end of the first birefringent crystal away from the collimator array, a wedge plate group at the end of the half-wave plate group away from the first birefringent crystal, the wedge plate group comprising multiple wedge plates, the number of wedge plates being equal to the number of collimators, a rotating device at the end of the wedge plate group away from the half-wave plate group, a second birefringent crystal at the end of the rotating device away from the wedge plate group, a polarization state conversion device at the end of the second birefringent crystal away from the rotating device, and a reflecting device at the end of the polarization state conversion device away from the second birefringent crystal, wherein the refractive surface of each wedge plate away from the half-wave plate group is inclined relative to the reflecting surface of the reflecting device, and the inclination directions of the refractive surfaces of two adjacent wedge plates relative to the reflecting surface are opposite. This invention can reduce the return loss of the optical circulator.

Description

Technical Field

[0001] This invention relates to the technical field of optical communication devices, specifically a high-performance reflective optical circulator. Background Technology

[0002] As fiber optic communication systems evolve towards high-speed, high-density integration, the miniaturization and high performance of optical components have become critical requirements. Traditional transmissive optical circulators employ a straight-through optical path design, which, while enabling directional signal transmission, results in large sizes and complex optical component stacking, making it difficult to meet the packaging requirements of compact optical modules. Therefore, reflective optical circulators have begun to be widely used in fiber optic communication systems.

[0003] Existing reflective optical circulators feature a unique folded optical path structure. By replacing some optical elements with reflective end faces, the size of the circulator can be significantly reduced. Most existing reflective circulators are implemented using a combination of a beam-splitting crystal and a Faraday rotator, but none of them effectively suppress the echo interference caused by multiple reflections at the optical interface, resulting in a return loss that is generally below 50dB.

[0004] In existing reflective optical circulators, reflected light from the interfaces of various optical components partially returns to the input port along its original path. This returned beam, especially in high-speed communication systems, causes signal crosstalk and signal-to-noise ratio degradation. To address this, some existing optical circulators coat the device surface with an anti-reflection film. While this partially alleviates the problem, film processing errors and incident angle sensitivity still result in insufficient return loss stability of reflective optical circulators in wide-band or high / low temperature environments. Therefore, how to maintain the compact structure of reflective optical circulators while simultaneously reducing their return loss has become a pressing issue.

[0005] Chinese utility model patent CN208314250U discloses a miniature optical circulator, which includes a first collimator, a first polarizing beam splitter, a first waveplate, a first birefringent wedge plate, a first magneto-optical crystal, a second birefringent wedge plate, a second magneto-optical crystal, a second waveplate, a second polarizing beam splitter, and a second collimator, arranged sequentially along the optical path from the incident direction to the exit direction. The two birefringent wedge plates in this design are used to change the propagation direction of the beam, but they do not reduce the return loss of the optical circulator. Furthermore, this optical circulator is still a transmissive type, resulting in a relatively large size. Summary of the Invention

[0006] The purpose of this invention is to provide a high-performance reflective optical circulator with small size and low return loss.

[0007] To achieve the above objectives, the high-performance reflective optical circulator provided by the present invention has a collimator array, which includes multiple collimators. A first birefringent crystal is disposed at one end of the collimator array, and a half-wave plate group is disposed at the end of the first birefringent crystal away from the collimator array. A wedge plate group is disposed at the end of the half-wave plate group away from the first birefringent crystal, and the wedge plate group includes multiple wedge plates, the number of wedge plates being equal to the number of collimators, and each wedge plate corresponding to one collimator. A rotating device is disposed at the end of the wedge plate group away from the half-wave plate group, and a second birefringent crystal is disposed at the end of the rotating device away from the wedge plate group. A polarization state conversion device is disposed at the end of the second birefringent crystal away from the rotating device, and a reflecting device is disposed at the end of the polarization state conversion device away from the second birefringent crystal. The refractive surface of each wedge plate away from the half-wave plate group is inclined to the reflecting surface of the reflecting device, and the inclination directions of the refractive surfaces of two adjacent wedge plates relative to the reflecting surface are opposite.

[0008] As can be seen from the above scheme, because a wedge plate group is set between the half-wave plate group and the rotating device, and each collimator corresponds to one wedge plate, and the refractive surface of each wedge plate is inclined to the reflective surface of the reflective device, the light incident from each collimator, after passing through the refractive surface of the corresponding wedge plate, will be emitted at a certain angle of inclination. After the light beam is reflected by the mirror, the optical path of the reflected beam is different from that of the light beam incident on the mirror. Therefore, the paths of the reflected beam and the incident beam can be separated, thereby completely blocking the optical path of the reflected beam returning to the input port, which can significantly reduce the return loss of the reflective optical circulator.

[0009] Furthermore, since the wedge plate is very small, adding a wedge plate group between the half-wave plate group and the rotating device does not cause a significant increase in the size of the reflective optical circulator. This allows the reflective optical circulator to maintain its compact structure and achieve a performance leap while maintaining the original device size, making it particularly suitable for high-density optical module packaging scenarios.

[0010] A preferred embodiment is that each wedge includes a long side and a short side relative to the arrangement, and in two adjacent wedges, the long side of one wedge is adjacent to the long side of the other wedge, or the short side of one wedge is adjacent to the short side of the other wedge.

[0011] As can be seen, any two adjacent wedges are either adjacent to each other by their long sides or by their short sides, which makes the arrangement of the wedge group very compact and is beneficial for the packaging of the wedge group.

[0012] A further proposed solution is that the long sides of each wedge are equal, and the short sides of each wedge are equal.

[0013] Therefore, it can be seen that multiple wedges in the wedge plate assembly are made using wedges of the same size and shape, with adjacent wedges arranged in a flipped configuration. This reduces material costs and helps lower the production cost of the reflective optical circulator.

[0014] A further embodiment includes a light-transmitting surface disposed opposite to the refractive surface, with the light-transmitting surface parallel to the reflective surface. Preferably, the light-transmitting surfaces of all wedges are on the same plane.

[0015] As can be seen, the light-transmitting surfaces of all the wedges in the wedge plate group are on the same plane, which makes the packaging of the wedge plate group very compact and is conducive to the miniaturization of the optical circulator.

[0016] A further approach is that each collimator has a fiber core, and the fiber core of at least one collimator is eccentrically positioned.

[0017] Because of the wedge plate, the spot of the reflected beam will be offset to a certain extent. In order to ensure that the collimator can receive the beam, the fiber core needs to be eccentrically set so that the reflected beam can be incident on the fiber core.

[0018] A further approach is to arrange multiple collimators in the collimator array along a first direction, such that the distance between the fiber core of the middle collimator and the fiber core of the collimator on the first side is not equal to the distance between the fiber core of the middle collimator and the fiber core of the collimator on the second side.

[0019] Therefore, by making reasonable eccentric settings for the fiber cores of different collimators according to the arrangement of each optical path, it can be ensured that each port can transmit and receive optical signals.

[0020] A further approach is to arrange multiple collimators of the collimator array along a first direction, with the multiple collimators being distributed at unequal intervals.

[0021] An even more advanced approach is to use a quarter-wave plate or a Faraday rotator as the polarization state conversion device.

[0022] A further step is to have two sets of collimator arrays, each set including three collimators; and two sets of wedge plate groups, each set including three wedge plates.

[0023] Therefore, a reflective optical circulator can include multiple collimator arrays to expand the port capacity, thereby realizing a three-port optical circulator or a six-port optical circulator. Furthermore, the beam transmission within the two collimator arrays can share some components, such as a half-wave plate group, a birefringent crystal, and a reflective device, making the six-port optical circulator structure very compact. Attached Figure Description

[0024] Figure 1 This is a structural diagram from the first perspective of the first embodiment of the high-performance reflective optical circulator of the present invention.

[0025] Figure 2 This is a structural diagram from a second perspective of the first embodiment of the high-performance reflective optical circulator of the present invention.

[0026] Figure 3 This is the optical path diagram from the first perspective of the first embodiment of the high-performance reflective optical circulator of the present invention.

[0027] Figure 4 This is the optical path diagram from the second perspective of the first embodiment of the high-performance reflective optical circulator of the present invention.

[0028] Figure 5 This is a structural diagram of the wedge plate assembly in the first embodiment of the high-performance reflective optical circulator of the present invention.

[0029] Figure 6 This is a structural diagram of the collimator array in the first embodiment of the high-performance reflective optical circulator of the present invention.

[0030] Figure 7 This is a structural diagram of the second embodiment of the high-performance reflective optical circulator of the present invention.

[0031] Figure 8 This is a structural diagram of the collimator array in the second embodiment of the high-performance reflective optical circulator of the present invention.

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0033] The high-performance reflective optical circulator of this invention is used in fiber optic communication networks to enable beam transmission along a specific optical path. Furthermore, to reduce the return loss of the reflective optical circulator, this invention improves the structure by adding a wedge plate to the optical path to separate the incident and reflected beams on the reflecting surface of the reflective device. This blocks the optical path of the reflected beam returning to the input port, significantly reducing the return loss of the reflective optical circulator.

[0034] First embodiment:

[0035] See Figure 1 and Figure 2The high-performance reflective optical circulator of this embodiment has a first collimator array 10, which includes multiple collimators, such as a first collimator 11, a second collimator 12, and a third collimator 13, arranged sequentially along the x-axis. The x-axis is the first direction in this embodiment. Preferably, the first collimator 11, the second collimator 12, and the third collimator 13 are parallel to each other. A first birefringent crystal 21 is disposed at one end of the first collimator array 10, and a first half-wave plate group 22 is disposed at the end of the first birefringent crystal 21 away from the first collimator array 10. The first half-wave plate group 22 has two half-wave plates, namely a first half-wave plate 23 and a second half-wave plate 24, wherein the first half-wave plate 23 and the second half-wave plate 24 are respectively located on two optical paths of the first birefringent crystal 21. Furthermore, the optical axes of the first half-wave plate 23 and the second half-wave plate 24 do not coincide. Specifically, the optical axis of the first half-wave plate 23 after being flipped is the same as that of the second half-wave plate 24. In this way, the two beams of light with orthogonal polarization states after passing through the first birefringent crystal 21 will pass through the first half-wave plate 23 and the second half-wave plate 24 in the first half-wave plate group 22, respectively.

[0036] A first wedge-shaped plate group 25 is provided at the end of the first half-wave plate group 22 that is away from the first birefringent crystal 21. See Figure 5 The first wedge plate group 25 includes three wedge plates: a first wedge plate 26, a second wedge plate 27, and a third wedge plate 28. These three wedge plates are arranged adjacent to each other along the x-axis. Specifically, the first wedge plate 26 is adjacent to the second wedge plate 27, and the second wedge plate 27 is adjacent to the third wedge plate 28. Each wedge plate has a long side, a short side, a refractive surface, and a light-transmitting surface. For example, the first wedge plate 26 has a first long side 262, a first short side 261, a first refractive surface 263, and a first light-transmitting surface 264; the second wedge plate 27 has a second long side 271, a second short side 272, a second refractive surface 273, and a second light-transmitting surface 274; and the third wedge plate 28 has a third long side 282, a third short side 281, a third refractive surface 283, and a third light-transmitting surface 284. Furthermore, the first long side 262 of the first wedge plate 26 is adjacent to the second long side 271 of the second wedge plate 27, and the second short side 272 of the second wedge plate 27 is adjacent to the third short side 281 of the third wedge plate 28.

[0037] Since each wedge has a long side and a short side, the refractive surface of each wedge is inclined to the light-transmitting surface. For example, the first refractive surface 263 of the first wedge 26 is inclined to the first light-transmitting surface 264, and the inclination directions of the refractive surfaces of two adjacent wedges are opposite. Furthermore, the light-transmitting surfaces of the three wedges are all on the same plane, that is, the first light-transmitting surface 264, the second light-transmitting surface 274, and the third light-transmitting surface 284 are all on the same plane. This arrangement is advantageous for the encapsulation of the first wedge assembly 25.

[0038] In addition, the number of wedge plates is equal to the number of collimators, and the three wedge plates correspond one-to-one with the three collimators. That is, the first collimator 11 corresponds to the first wedge plate 26, the second collimator 12 corresponds to the second wedge plate 27, and the third collimator 13 corresponds to the third wedge plate 28, so that the beam emitted from each collimator can pass through the corresponding wedge plate.

[0039] A rotating device is provided at the end of the first wedge plate group 25 away from the first half-wave plate group 22. In this embodiment, the rotating device is a first Faraday rotator plate 31. Preferably, a magnet is provided on the outer periphery of the first Faraday rotator plate 31, and the first Faraday rotator plate 31 can rotate the polarization state of the linear polarization state by 45° under a saturated magnetic field.

[0040] A second birefringent crystal 32 is disposed at the end of the first Faraday rotator 31 away from the first half-wave plate group 22, and the optical axis of the first birefringent crystal 21 and the optical axis of the second birefringent crystal 32 are respectively on two mutually orthogonal planes.

[0041] A polarization state conversion device is disposed at the end of the second birefringent crystal 32 away from the rotating device. In this embodiment, the polarization state conversion device is a first quarter-wave plate 33. Preferably, the first quarter-wave plate 33 can be attached to the end face of the second birefringent crystal 32. In other embodiments, a Faraday rotator plate can be used instead of the first quarter-wave plate for the polarization state conversion device.

[0042] A reflective device is provided at the end of the first quarter-wave plate 33 away from the second birefringent crystal 32. In this embodiment, the reflective device is a first reflector 35, with the reflecting surface of the first reflector 35 facing the first quarter-wave plate 33. Furthermore, the light-transmitting surfaces of the three wedge plates are all parallel to the reflecting surface of the first reflector 35. Preferably, all components of the high-performance reflective optical circulator in this embodiment are encapsulated in a single sleeve, thereby achieving miniaturization and integrated assembly of the high-performance reflective optical circulator.

[0043] In this embodiment, a first wedge plate group 25 is provided between the first half-wave plate group 22 and the first Faraday rotator plate 31. Each wedge plate in the first wedge plate group 25 has the same shape and size, and adjacent wedge plates are arranged in a vertically flipped configuration along the x-axis. For example, the first wedge plate 26 and the second wedge plate 27 are vertically flipped, as are the second wedge plate 27 and the third wedge plate 28. Furthermore, with the reflecting surface of the first reflector 35 as a reference, the refractive surfaces of adjacent wedge plates have opposite tilt directions. For example, the first refractive surface 263 of the first wedge plate 26 gradually tilts towards the first reflector 35 from top to bottom, while the second refractive surface 273 of the second wedge plate 27 tilts away from the first reflector 35 from top to bottom. Additionally, with the reflecting surface of the first reflector 35 as a reference, the angle between the first refractive surface 263 of the first wedge plate 26 and the reflecting surface is equal to the angle between the second refractive surface 273 of the second wedge plate 27 and the reflecting surface.

[0044] The following is combined with Figure 3 and Figure 4 The optical path of a high-performance reflective optical circulator is introduced. The example is a beam emitted from the first collimator 11. After the beam L11 from the first collimator 11 enters the first birefringent crystal 21, it is split into two beams, L21 and L31. One beam of L21 and L31 is normal light, and the other is abnormal light. The two beams L21 and L31 propagate in different directions, such as... Figure 4 As shown, beams L21 and L31 are translated laterally along the y-axis, but the transmission paths of the two beams L21 and L31 in the x-axis direction overlap.

[0045] When light beams L21 and L31 exit from the first birefringent crystal 21, they pass through the first half-wave plate 23 and the second half-wave plate 24, respectively. Since the optical axes of the first half-wave plate 23 and the second half-wave plate 24 are opposite, the polarization directions of light beams L21 and L31 after passing through the half-wave plate group are the same. Next, the light beams will sequentially pass through the first wedge plate group 25 and the first Faraday rotator plate 31. When a saturated magnetic field is applied to the first Faraday rotator plate 31, the polarization directions of the two light beams will simultaneously rotate by 45°, and they will enter the second birefringent crystal 32 along the normal light path. Figure 4 As shown, after being incident on the second birefringent crystal 32, two beams L22 and L23 are formed respectively. Both beams propagate along the abnormal light path within the second birefringent crystal 32, that is... Figure 3 As shown in L12, the propagation paths of beams L22 and L23 will be deflected, that is, they will be shifted in the x-axis direction towards the direction of the second collimator 12.

[0046] Then, the beams will be incident on the first quarter-wave plate 33, and the polarization directions of the two beams will rotate by 45°. Next, the two beams will be incident on the first reflecting mirror 35, forming beams L23 and L33 respectively. After reflection, beams L23 and L33 pass through the first quarter-wave plate 33 again, and the polarization directions of the two beams rotate again. Therefore, the polarization directions of the two beams rotate a total of 90° after passing through the first quarter-wave plate 33 twice. Thus, the polarization directions of beams L23 and L33 incident on the second birefringent crystal 32 the second time are perpendicular to those of beams L22 and L32 incident on the first time. Therefore, beams L23 and L33 incident on the second birefringent crystal 32 the second time are normal light, meaning that beam L23 will propagate along the direction of normal light within the second birefringent crystal 32. Figure 3 As shown, propagating along the path of beam L14, it can be seen that compared to the path of beam L12, beam L14 is laterally offset in the x-axis direction, shifting towards the direction of the second collimator 12. Similarly, beam L33 also propagates along the normal light direction.

[0047] Next, beams L23 and L33 pass through the first Faraday rotator 31 and the first half-wave plate group 22, with beam L23 passing through the first half-wave plate 23 and beam L33 passing through the second half-wave plate 24. After entering the first birefringent crystal 21, beams L23 and L33 respectively form beams L24 and L34, which combine within the first birefringent crystal 21 to form beam L16. Finally, beam L16 exits from the second collimator 12. It can be seen that the beam exiting from the first collimator 11 will exit from the second collimator 12, and similarly, the beam entering from the second collimator 12 will exit from the third collimator 13. This achieves unidirectional transmission of the optical path, thus realizing the function of an optical circulator.

[0048] In addition, due to the wedge plate, when the light beam L11 passes through the first wedge plate 26, it will also be refracted on the first refractive surface 263. For example, when the light beam L11 is incident on the first wedge plate 26 in a direction perpendicular to the first light-transmitting surface 264 of the first wedge plate 26, since a certain angle is formed between the first refractive surface 263 and the first light-transmitting surface 264, when the light beam L11 exits from the first refractive surface 263, the exit angle is not perpendicular to the first light-transmitting surface 264, but has a certain angle with the first light-transmitting surface 264. Then, after passing through the first Faraday rotator 31, the beam L11, when the beam L12 formed by the second birefringent crystal 32 is deflected towards the second collimator 12, has a larger deflection angle along the x-axis compared to a conventional reflective optical circulator. This results in the beam L12 not exiting in a direction perpendicular to the end face of the second birefringent crystal 32, but exiting at a certain tilt angle. The beam L13 formed after exiting is also not incident on the first reflector 35 in a direction perpendicular to the reflecting surface of the first reflector 35. Therefore, the optical path of the reflected beam L14 is not the same as that of the incident beam L13. This achieves the separation of the optical paths of the incident beam L13 and the reflected beam L14 on the reflecting surface, thereby completely blocking the optical path of the reflected beam returning to the input port and significantly reducing the return loss of the reflective optical circulator.

[0049] After reflection, the light beam L14 enters the second birefringent crystal 32 and forms a light beam L15. After exiting the second birefringent crystal 32, light beam L15 passes through the second wedge plate 27. Since the second refractive surface 273 of the second wedge plate 27 is also inclined to the reflecting surface, and the inclination direction of the second refractive surface 273 is opposite to the inclination direction of the first refractive surface 263, light beam L15 enters the second wedge plate 27 in an inclined direction, and light beam L15 is refracted again within the second wedge plate 27. After passing through the first half-wave plate group 22 and the first birefringent crystal 21 again, light beam L15 finally exits from the second collimator 12.

[0050] The light beam L41 emitted from the second collimator 12 passes through the first birefringent crystal 21 and the first half-wave plate group 22 before entering the second wedge plate 27. It is also refracted on the second refractive surface 273 of the second wedge plate 27, and then enters the second birefringent crystal 32 to form light beam L42. The light beam L43 emitted from the second birefringent crystal 32 does not enter the first reflector 35 at an angle perpendicular to the reflecting surface of the first reflector 35. Therefore, the optical path of the reflected light beam L44 is different from that of the incident light beam L43, thus completely blocking the optical path of the reflected light beam returning to the input port. After entering the second birefringent crystal 32, the light beam L44 forms light beam L45, passes through the first Faraday rotator plate 31 again, passes through the third wedge plate 28, and is refracted on the third wedge plate 28. Then, the light beam L45 passes through the first half-wave plate group 22 and passes through the first birefringent crystal 21 again to form light beam L46, and finally exits from the third collimator 13.

[0051] Because of the three wedges, the light beam is refracted as it passes through them. Therefore, the active change in the beam's propagation direction will cause a certain offset in the received beam spot. For example, when the beam emitted from the first collimator 11 is reflected and incident on the second collimator 12, the beam spot will not be at the center of the second collimator 12, but rather deviate from its center. If the fiber core of the second collimator 12 is located at its center, the energy of the returned beam spot will overflow from the fiber receiving end face, reducing the energy of the output beam.

[0052] Therefore, this embodiment requires special treatment of the fiber core of the straightener, see [link to documentation]. Figure 6 The first fiber core 14 of the first collimator 11 is located at the center of the first collimator 11, but the second fiber core 15 of the second collimator 12 is offset from the center of the second collimator 12, and the third fiber core 16 of the third collimator 13 is also offset from the center of the third collimator 13. Therefore, the fiber cores of the second collimator 12 and the third collimator 13 are eccentrically arranged. Furthermore, taking the second collimator 12 located in the middle as a reference, the distance between the first fiber core 14 and the second fiber core 15 is L01, and the distance between the second fiber core 15 and the third fiber core 16 is L02. Figure 6 It can be seen that L01 is smaller than L02, therefore, the three fiber cores of the three collimators are not evenly distributed.

[0053] Of course, in other embodiments, the collimators of the collimator array may all be collimators with the fiber core located at the center, but the collimators are not evenly distributed, but unequally distributed. For example, the distance between the first collimator and the second collimator is small, while the distance between the second collimator and the third collimator is large.

[0054] The reflective optical circulator in the above embodiment is a three-port optical circulator. In practical applications, the reflective optical circulator can also be a six-port optical circulator.

[0055] Second embodiment:

[0056] See Figure 7 This embodiment is a six-port reflective optical circulator, including two collimator arrays: a second collimator array 40 and a third collimator array 45. The second collimator array 40 includes three collimators: a fourth collimator 41, a fifth collimator 42, and a sixth collimator 43. The third collimator array 45 includes three collimators: a seventh collimator 46, an eighth collimator 47, and a ninth collimator 48. The fourth collimator 41, the fifth collimator 42, the sixth collimator 43, the seventh collimator 46, the eighth collimator 47, and the ninth collimator 48 are arranged sequentially along the x-axis, and the collimators are parallel to each other.

[0057] A third birefringent crystal 51 is provided at one end of the second collimator array 40 and the third collimator array 45. A second half-wave plate group 52 is provided at the end of the third birefringent crystal 51 away from the second collimator array 40 and the third collimator array 45. The second half-wave plate group 52 has two half-wave plates, which are located on the two optical paths of the third birefringent crystal 51 respectively.

[0058] Two sets of wedge plates are provided at the end of the second half-wave plate group 52 away from the third birefringent crystal 51: a second wedge plate group 53 and a third wedge plate group 54. The second wedge plate group 53 includes three wedge plates arranged along the x-axis, and the third wedge plate group 54 also includes three wedge plates arranged along the x-axis. All six wedge plates are identical in shape and size, each including a long side, a short side, a refractive surface, and a light-transmitting surface. The refractive surface is tilted relative to the transmitted light, and the light-transmitting surfaces of all wedge plates are on the same plane. Furthermore, the second wedge plate group 53 and the third wedge plate group 54 are mirror-symmetrically arranged along the x-axis. The structure and arrangement of the second wedge plate group 53 are the same as those of the first wedge plate group in the first embodiment, and will not be described again.

[0059] A rotating device is provided at one end of the two sets of wedge plates away from the second half-wave plate group 52. In this embodiment, the rotating device is a second Faraday rotator 58. A fourth birefringent crystal 55 is provided at one end of the second Faraday rotator 58 away from the two sets of wedge plates.

[0060] A polarization state conversion device is provided at the end of the fourth birefringent crystal 55 away from the rotating device. In this embodiment, the polarization state conversion device is a second quarter-wave plate 56. A second reflecting mirror 57, which serves as a reflecting device, is provided at the end of the second quarter-wave plate 56 away from the fourth birefringent crystal 55. The reflecting surface of the second reflecting mirror 57 faces the second quarter-wave plate 56.

[0061] Because two sets of wedge plates are used, the propagation direction of the light beam will be changed, resulting in a certain offset in the received light spot emission. Therefore, this embodiment will perform an off-center treatment on the fiber core of the straightener. See [link to documentation]. Figure 8 For example, the fourth fiber core 61 of the fourth collimator 41 is located at the center of the fourth collimator 41, but the fifth fiber core 62 of the fifth collimator 42 is off-center from the center of the fifth collimator 42. Similarly, the sixth fiber core 63 of the sixth collimator 43 is also off-center from the center of the sixth collimator 43, the seventh fiber core 66 of the seventh collimator 46 is also off-center from the center of the seventh collimator 46, the eighth fiber core 67 of the eighth collimator 47 is also off-center from the center of the eighth collimator 47, and the ninth fiber core 68 of the ninth collimator 48 is also off-center from the center of the ninth collimator 48.

[0062] Compared to the first embodiment, this embodiment has a larger number of collimators, and the two collimator arrays share a third birefringent crystal 51, a fourth birefringent crystal 55, a second quarter-wave plate 56, a second reflector 57, and other components. This ensures the miniaturization of the reflective optical circulator while providing more ports, reducing the return loss of the reflective optical circulator, and improving its performance. Furthermore, since the wedge plate has a very low production cost, this invention does not significantly increase the production cost of the reflective optical circulator.

[0063] Finally, it should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. High-performance reflective optical circulators, including: A collimator array, comprising a plurality of collimators, wherein a first birefringent crystal is disposed at one end of the collimator array, and a half-wave plate group is disposed at the end of the first birefringent crystal away from the collimator array; Its features are: A wedge plate group is provided at the end of the half-wave plate group away from the first birefringent crystal. The wedge plate group includes multiple wedge plates, the number of which is equal to the number of collimators, and each wedge plate corresponds to one collimator. A rotating device is provided at the end of the wedge plate group away from the half-wave plate group, and a second birefringent crystal is provided at the end of the rotating device away from the wedge plate group. A polarization state conversion device is provided at the end of the second birefringent crystal away from the rotating device, and a reflection device is provided at the end of the polarization state conversion device away from the second birefringent crystal; In this configuration, the refractive surface of each wedge plate away from the half-wave plate group is inclined to the reflective surface of the reflective device, and the refractive surfaces of two adjacent wedge plates are inclined in opposite directions relative to the reflective surface.

2. The high-performance reflective optical circulator according to claim 1, characterized in that: Each of the wedges includes a long side and a short side relative to the arrangement, wherein in two adjacent wedges, the long side of one wedge is adjacent to the long side of the other wedge, or the short side of one wedge is adjacent to the short side of the other wedge.

3. The high-performance reflective optical circulator according to claim 2, characterized in that: The long sides of each wedge are equal, and the short sides of each wedge are equal.

4. The high-performance reflective optical circulator according to claim 2, characterized in that: Each of the wedge plates includes a light-transmitting surface disposed opposite to the refractive surface, the light-transmitting surface being parallel to the reflective surface.

5. The high-performance reflective optical circulator according to claim 4, characterized in that: The light-transmitting surfaces of each wedge are on the same plane.

6. The high-performance reflective optical circulator according to any one of claims 1 to 5, characterized in that: Each of the collimators has a fiber core, and the fiber core of at least one of the collimators is eccentrically arranged.

7. The high-performance reflective optical circulator according to claim 6, characterized in that: The collimator array has multiple collimators arranged along a first direction. Among three adjacent collimators, the distance between the fiber core of the middle collimator and the fiber core of the collimator on the first side is not equal to the distance between the fiber core of the middle collimator and the fiber core of the collimator on the second side.

8. The high-performance reflective optical circulator according to any one of claims 1 to 5, characterized in that: The collimator array has multiple collimators arranged along a first direction, and the multiple collimators are not equidistant.

9. The high-performance reflective optical circulator according to any one of claims 1 to 5, characterized in that: The polarization state conversion device is a quarter-wave plate or a Faraday rotator plate.

10. The high-performance reflective optical circulator according to any one of claims 1 to 5, characterized in that: The collimator array consists of two groups, and each group of the collimator array includes three collimators. The number of wedge plates is two sets, and each set of wedge plates includes three wedge plates.

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