CN210072249U - Miniature optical circulator - Google Patents

Abstract

The utility model relates to the field of optical fiber communication equipment, in particular to a micro optical circulator, which comprises a first collimator, a circulator core and a second collimator, wherein the first collimator is a double-optical-fiber collimator, the second collimator is a single-optical-fiber collimator, the optical circulator also comprises an optical path angle matching device which consists of a first polarization beam splitter prism, an optical rotation device and a second polarization beam splitter prism, the first and the second polarization beam splitter prisms are both provided with polarization beam splitting films, the lower end surface of the first polarization beam splitter prism and the upper end surface of the second polarization beam splitter prism are both provided with high reflection films, the light path angle matching device is arranged between the first collimator and the circulator core, the micro optical circulator has the advantages of simple structure, ultra-small volume, low insertion loss, low polarization-dependent loss and the like, can realize the three-port looping function, and can also realize the four-port looping function through optimization.

Description

Miniature optical circulator

Technical Field

The utility model relates to an optical fiber communication equipment field especially relates to a miniature optical circulator.

Background

The optical circulator is a nonreciprocal optical device with multi-port input and output, and has the function of enabling optical signals to be transmitted only along a specified port sequence, and the optical circulator separates forward transmission optical signals from reverse transmission optical signals in the same optical fiber. Referring to fig. 2, an example of an optical circulator for single-fiber bidirectional communication is shown. At this time, port 1 is connected to the data transmitter, port 2 is connected to the external network, and port 3 is connected to the signal receiver. Data can be sent from the transmitter to the external network through the port 1 of the optical circulator and the external signal enters the optical circulator through the port 2, which becomes an important device in the bidirectional communication due to the sequential transmission characteristic of the optical circulator. In data centers and 5G applications, it is necessary to place one or even two circulators in a small space with limited space to form a transceiver module with doubled density, and in such applications, the size of the circulator becomes the most critical requirement.

The existing optical circulator is generally composed of a collimator and a circulator core connected with an input port and an output port, for example, the optical circulator with the publication number of CN1144080C, and the circulator core is composed of two optical rotation devices based on a wollaston prism, or the circulator core is composed of two optical rotation devices based on a birefringent crystal, as for the optical circulator with a compact structure with the publication number of CN202025159U, the structural scheme of the wollaston prism or the birefringent crystal has the characteristics of multiple components and complex structure, which causes the miniaturization of the whole circulator to be difficult, and cannot meet the requirement of the coming 5G era.

SUMMERY OF THE UTILITY MODEL

The utility model provides a miniature optical circulator has simple structure, the volume is super little, insertion loss is low, the relevant loss of polarization is low grade advantage, both can realize three-port loop function, also can realize four-port loop function through optimizing.

The technical scheme for realizing the purpose of the utility model is as follows,

a micro optical circulator comprises a first collimator, a circulator core and a second collimator which are sequentially connected according to an optical path, wherein the first collimator is a double-optical-fiber collimator, the second collimator is a single-optical-fiber collimator, the optical circulator also comprises an optical path angle matching device, the circulator core is composed of a first polarization beam splitter prism, an optical rotation device and a second polarization beam splitter prism which are sequentially arranged, polarization beam splitting films for dividing the first polarization beam splitter prism and the second polarization beam splitter prism into an upper part and a lower part are respectively arranged in the first polarization beam splitter prism and the second polarization beam splitter prism, high-reflection films are respectively arranged on the lower end surface of the first polarization beam splitter prism and the upper end surface of the second polarization beam splitter prism, the optical path angle matching device is arranged between the first collimator and the circulator core, when the micro optical circulator is in operation, the first collimator is connected with a first optical fiber and a third optical fiber, the second collimator is connected with a second optical fiber, and the light beam of the first optical fiber is coupled to the second optical fiber, and coupling the light beam of the second optical fiber to a third optical fiber for emission.

Further, the optical rotation device comprises a magneto-optical crystal, a glass slide and a magnetic sheet matched with the magneto-optical crystal, wherein the magneto-optical crystal and the glass slide are arranged along the direction from the first polarization beam splitter prism to the second polarization beam splitter prism or are arranged along the direction from the second polarization beam splitter prism to the first polarization beam splitter prism.

Furthermore, the upper end surface of the first polarization beam splitter prism is an inclined surface provided with a high reflection film, the light path angle matching device is a wedge angle sheet, the wedge angle sheet is arranged between the first polarization beam splitter prism and the first collimator,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence and is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end face of the first polarization beam splitting prism and then horizontally emitted from the emergent face, after being refracted by the wedge angle piece, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

Further, the optical path angle matching device is a flat wedge piece which is arranged between the first polarization beam splitter prism and the first collimator,

the light beam incident from the first optical fiber passes through the first collimator, the flat part of the flat wedge angle sheet, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end face of the first polarization beam splitting prism and then horizontally emitted from the emergent face, after being refracted by the wedge angle part of the flat wedge angle sheet, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

Further, the light path angle matching device is a roof prism which is arranged between the first polarization beam splitter prism and the first collimator, the first collimator is vertical to the circulator core and parallel to the second collimator,

the light beam incident from the first optical fiber passes through the first collimator, the lower part of the roof prism, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence and is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitter prism, the optical rotation device and the first polarization beam splitter prism, is reflected by the upper end face of the first polarization beam splitter prism and then horizontally emitted from the emergent face, after being refracted by the upper part of the roof prism, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

Further, the upper end surface of the first polarization beam splitter prism is a horizontal plane, the optical path angle matching device is a plane reflector, the plane reflector is arranged above the first polarization beam splitter prism,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and the light beam is emitted from the second optical fiber; the light beam incident from the second optical fiber passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism in sequence, and is emitted from the upper end face of the first polarization beam splitting prism, under the reflection of the plane transmitting mirror, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

Further, the upper end surface of the first polarization beam splitter prism is provided with a high reflection film, the included angle between the high reflection film and the horizontal plane is less than 45 degrees, the light path angle matching device is a first polarization beam splitter prism,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and the light beam is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end face of the first polarization beam splitting prism and refracted by the emergent face of the first polarization beam splitting prism and then is emitted, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

Further, the second collimator is a double-optical-fiber collimator, the lower end face of the second polarization beam splitter prism is provided with a high-reflection film, the included angle between the lower end face of the second polarization beam splitter prism and the horizontal plane is less than 45 degrees, the light path angle matching device is a first polarization beam splitter prism and a second polarization beam splitter prism, when the light path angle matching device works, the second collimator is connected with the second optical fiber and the fourth optical fiber,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and the light beam is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end surface of the first polarization beam splitting prism and refracted by the emergent surface of the first polarization beam splitting prism and then is emitted, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber; the light beam incident from the third optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device and the second polarization beam splitter prism in sequence, is reflected by the lower end face of the second polarization beam splitter prism and refracted by the emergent face of the second polarization beam splitter prism, and then is emitted, the light path angle of the light beam is matched with the output deflection angle of the fourth optical fiber in the second collimator, and the light beam enters the second collimator and is emitted from the fourth optical fiber.

The utility model provides a miniature optical circulator, establish the circulator core with two polarization beam splitting prisms and an optical rotation device as the basis, utilized polarization beam splitting prism can be on enough little longitudinal distance, to a bundle of arbitrary polarization state light, decomposed into two bundles of mutually perpendicular polarized light, and produced the lateral separation distance of arbitrary size; on the contrary, two beams of polarized light perpendicular to each other can be combined into one beam. Compared with the prior art, the micro optical circulator adopts fewer optical rotation devices, saves components, and has the advantages of simple and compact structure, smaller volume, low insertion loss and low polarization-dependent loss.

Drawings

Fig. 1 is a schematic structural view of an optical circulator according to an embodiment of the present invention;

fig. 2 is a schematic diagram of an optical path incident from a first optical fiber when an optical circulator according to a first embodiment of the present invention is in operation;

fig. 3 is a schematic diagram of an optical path incident from a second optical fiber when the optical circulator according to the first embodiment of the present invention is in operation;

fig. 4 is a schematic diagram of an optical path incident from the first optical fiber when the optical circulator according to the second embodiment of the present invention is in operation;

fig. 5 is a schematic diagram of an optical path incident from the second optical fiber when the optical circulator according to the second embodiment of the present invention is in operation;

fig. 6 is a schematic diagram of an optical path incident from the first optical fiber when the optical circulator according to the third embodiment of the present invention is in operation;

fig. 7 is a schematic diagram of an optical path incident from the second optical fiber when the optical circulator according to the third embodiment of the present invention is in operation;

fig. 8 is a schematic structural view of a four-light circulator according to an embodiment of the present invention;

fig. 9 is a schematic diagram of an optical path incident from the first optical fiber when the optical circulator according to the fourth embodiment of the present invention is in operation;

fig. 10 is a schematic view of an optical path incident from the second optical fiber when the optical circulator according to the fourth embodiment of the present invention is in operation;

fig. 11 is a schematic structural diagram of a circulator core of a five-optical circulator according to an embodiment of the present invention;

fig. 12 is a schematic view of an optical path incident from the first optical fiber when the optical circulator according to the fifth embodiment of the present invention is in operation;

fig. 13 is a schematic view of an optical path incident from the second optical fiber when the optical circulator according to the fifth embodiment of the present invention is in operation;

fig. 14 is a schematic diagram of a circulator core structure of a six-optical circulator according to an embodiment of the present invention;

fig. 15 is a schematic view of an optical path incident from the first optical fiber when the optical circulator according to the sixth embodiment of the present invention is in operation;

fig. 16 is a schematic view of an optical path incident from the second optical fiber when the optical circulator according to the sixth embodiment of the present invention is in operation;

fig. 17 is a schematic view of an optical path incident from the third optical fiber when the optical circulator according to the sixth embodiment of the present invention is in operation.

Detailed Description

The present invention will be described in detail with reference to the following embodiments.

First embodiment, referring to fig. 1 to 3, the micro optical circulator includes a first collimator 11, an optical path angle matching device 3, a circulator core 2, and a second collimator 12, which are sequentially connected and installed in a housing 1, the first collimator 11 is a dual optical fiber collimator and is connected to a first optical fiber 111 and a third optical fiber 112, the second collimator 12 is a single optical fiber collimator and is connected to a second optical fiber 121, the optical path angle matching device 3 is a wedge plate, the circulator core 2 is composed of a first polarization beam splitter 21, an optical rotator 23, and a second polarization beam splitter 22, which are sequentially arranged, the optical rotator 23 is composed of a magneto-optical crystal 231, a glass plate 232, and a magnetic sheet 4, which are arranged in the housing 1 and are separated into two parts, a polarization beam splitting film is arranged in each of the first polarization beam splitter 21 and the second polarization beam splitter 22, the lower end surface 211 of the first polarization splitting prism 21 and the upper end surface 221 of the second polarization splitting prism 22 are both provided with a high-reflection film, the upper end surface 212 of the first polarization splitting prism 21 is an inclined surface provided with a high-reflection film, and the wedge angle sheet is arranged between the emergent surface of the first polarization splitting prism 11 and the first collimator 11;

the optical path and the circular path of the micro optical circulator in the first embodiment are as follows: referring to fig. 2, a light beam incident from a first optical fiber 111 passes through a first collimator 11, enters a first polarization splitting prism 21, is split into two S light beams and two P light beams with mutually perpendicular polarization directions, and then enters a rotation device 23, the rotation device 23 performs non-mutually-different rotation on the S light and the P light, then enters a second polarization splitting prism 22 for beam combination, and then enters a second collimator 12, and then exits from a second optical fiber 121; referring to fig. 3, the light beam incident from the second optical fiber 121 passes through the second collimator 12, enters the second polarization splitting prism 22, is split into two S light beams and P light beams with mutually perpendicular polarization directions, enters the optical rotation device 23, the optical rotation device 23 performs non-mutually-different rotation on the S light and the P light, the S light and the P light beams are combined by the first polarization splitting prism 21, the S light beams are reflected by the upper end surface 212 of the first polarization splitting prism 21 and horizontally emitted from the emitting surface, the light beam is refracted by the wedge angle plate, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber 112 in the first collimator 11, and the light beam enters the first collimator 11 and is emitted from the third optical fiber 112.

In the second embodiment, the structure of the micro optical circulator is different from that in the first embodiment in that the optical path angle matching device 3 is a flat wedge, the flat wedge is arranged between the exit surface of the first polarization splitting prism 21 and the first collimator 11, and other structures are the same;

the optical path and the circular path of the micro optical circulator in the second embodiment are as follows: referring to fig. 4, a light beam incident from the first optical fiber 111 passes through the first collimator 11 and the flat part of the flat wedge, enters the first polarization splitting prism 21, is split into two S light beams and P light beams with mutually perpendicular polarization directions, and enters the optical rotation device 23, the optical rotation device 23 performs non-mutually-different rotation on the S light and the P light, enters the second polarization splitting prism 22, is combined, enters the second collimator 12, and exits from the second optical fiber 121; referring to fig. 5, a light beam incident from the second optical fiber 121 passes through the second collimator 12, enters the second polarization splitting prism 22, is split into two S light beams and P light beams with mutually perpendicular polarization directions, and then enters the optical rotation device 23, the optical rotation device 23 performs non-mutually-different rotation on the S light and the P light, then the S light and the P light beams are combined by the first polarization splitting prism 21, the combined light beams are reflected by the upper end surface 212 of the first polarization splitting prism 21 and then horizontally emitted from the emitting surface, and after being refracted by the wedge angle part of the flat wedge angle plate, the optical path angle of the light beam is matched with the output deflection angle of the third optical fiber 112 in the first collimator 11, and the light beam enters the first collimator 11 and then emitted from the third optical fiber 112.

The third embodiment is different from the first embodiment in that the optical path angle matching device 3 is a roof prism, the roof prism is arranged between the exit surface of the first polarization splitting prism 21 and the first collimator 11, and the axes of the first collimator 11 and the second collimator 12 are parallel and perpendicular to the exit surface of the circulator core 2, so that the micro optical circulator can be packaged conveniently, the structure is more compact, and other structures are the same as the first embodiment;

the optical path circular path of the micro optical circulator in the third embodiment is as follows: referring to fig. 6, a light beam incident from a first optical fiber 111 passes through a first collimator 11, enters the lower part of a roof prism, and enters a first polarization splitting prism 21 through refraction, the first polarization splitting prism 21 splits the incident light into two S light and P light with mutually perpendicular polarization directions, and the two S light and the P light enter a light rotation device 23, the light rotation device 23 performs non-mutually-different rotation on the S light and the P light, then the two S light and the P light enter a second polarization splitting prism 22 for beam combination, and then the two S light and the P light enter a second collimator 12 and are emitted from a second optical fiber 121; referring to fig. 7, a light beam incident from the second optical fiber 121 passes through the second collimator 12, enters the second polarization splitting prism 22, is split into two S light beams and P light beams with mutually perpendicular polarization directions, and enters the optical rotation device 23, the optical rotation device 23 performs non-mutually-different rotation on the S light and the P light, then the S light and the P light beams are combined by the first polarization splitting prism 21, the combined light beams are reflected by the upper end surface 212 of the first polarization splitting prism 21 and horizontally emitted from the emitting surface, the reflected light beams are refracted by the upper part of the roof prism, the optical path angle of the light beams is matched with the output deflection angle of the third optical fiber 112 in the first collimator 11, and the light beams enter the first collimator 11 and are emitted from the third optical fiber 112.

In the fourth embodiment, referring to fig. 1 and fig. 8 to 10, the structure of the micro optical circulator is different from the first embodiment in that the upper end surface 212 of the first polarization splitting prism 21 is a horizontal plane and is an exit surface, the optical path angle matching device 3 is a plane mirror, the plane mirror is disposed above the first polarization splitting prism 21, and other structures are the same as the first embodiment;

the optical path and the circular path of the micro optical circulator in the fourth embodiment are as follows: referring to fig. 9, a light beam incident from a first optical fiber 111 passes through a first collimator 11, is divided into two S light and P light with mutually perpendicular polarization directions in a first polarization splitting prism 21, and enters a rotation device 23, the rotation device 23 performs non-mutually-different rotation on the S light and the P light, then enters a second polarization splitting prism 22, is combined and then is emitted, and then enters a second collimator 12, and the light beam is emitted from a second optical fiber 121; referring to fig. 10, the light beam incident from the second optical fiber 121 passes through the second collimator 12, is split into two S light and P light with mutually perpendicular polarization directions in the second polarization splitting prism 22, enters the optical rotation device 23, the optical rotation device 23 performs non-differential rotation on the S light and the P light, enters the first polarization splitting prism 21 for beam combination, and exits from the upper end surface 212 of the first polarization splitting prism 21, the optical path angle of the light beam is matched with the output deflection angle of the third optical fiber 112 in the first collimator 11 under reflection of the plane emitter, and the light beam enters the first collimator 11 and exits from the third optical fiber 112.

Fifth embodiment, referring to fig. 8 and fig. 11 to 13, the micro optical circulator structure is different from the fourth embodiment in that a high reflective film is disposed on an upper end surface 212 of the first polarization splitting prism 21 and has an angle smaller than 45 ° with a horizontal plane, the optical path angle matching device is the first polarization splitting prism 21, and other structures are the same as the fourth embodiment;

the optical path and the circular path of the micro optical circulator in the fifth embodiment are as follows: referring to fig. 12, a light beam incident from a first optical fiber 111 passes through a first collimator 11, is split into two S light and P light with polarization directions perpendicular to each other in a first polarization splitting prism 21, and enters a rotation device 23, the rotation device 23 performs non-differential rotation on the S light and the P light, then enters a second polarization splitting prism 22, is combined and then is emitted, and enters a second collimator 12, and the light beam is emitted from a second optical fiber 121; referring to fig. 13, the light beam incident from the second optical fiber 121 passes through the second collimator 12 and the second polarization splitting prism 22 in sequence, is split into two S light beams and P light beams with mutually perpendicular polarization directions, and then enters the optical rotation device 23, the optical rotation device 23 performs non-differential rotation on the S light and the P light beams, the S light beams and the P light beams enter the first polarization splitting prism 21 for beam combination, and then are reflected by the upper end surface of the first polarization splitting prism 21 and refracted by the exit surface of the first polarization splitting prism 21 for exit, the light beam optical path angle is matched with the output deflection angle of the third optical fiber 112 in the first collimator 11, and the light beams enter the first collimator 11 and exit from the third optical fiber 112.

Sixth embodiment, referring to fig. 8, 11 and 14, the micro optical circulator structure is different from the fifth embodiment in that the second collimator 12 is a dual-fiber collimator, the lower end surface 222 of the second polarization splitting prism 22 is provided with a high-reflection film, and an included angle with a horizontal plane is less than 45 °, the second collimator 12 is connected with the second and fourth optical fibers, the optical path angle matching devices are the first polarization splitting prism 21 and the second polarization splitting prism 22, and other structures are the same as the fifth embodiment;

the optical path and the circular path of the micro optical circulator in the sixth embodiment are as follows: referring to fig. 15, a light beam incident from a first optical fiber 111 passes through a first collimator 11 in sequence, the light beam is divided into two S light beams and two P light beams with mutually perpendicular polarization directions in a first polarization splitting prism 21 and then enters a rotation device 23, the rotation device 23 performs non-differential rotation on the S light beam and the P light beam, then the S light beam and the P light beam enter a second polarization splitting prism 22 to be combined and then emitted, the combined light beam enters a second collimator 12, and the light beam is emitted from a second optical fiber 121; referring to fig. 16, the light beam incident from the second optical fiber 121 passes through the second collimator 12 and the second polarization splitting prism 22 in sequence, is split into two S light beams and P light beams with mutually perpendicular polarization directions, and then the two S light beams and the P light beams enter the optical rotation device 23, the optical rotation device 23 performs non-mutually-different rotation on the S light and the P light beams, and then the two S light beams and the P light beams enter the first polarization splitting prism 21 for combination, and then the two S light beams are reflected by the upper end surface 212 of the first polarization splitting prism 21 and refracted by the emergent surface of the first polarization splitting prism 21, and then the two S light beams are emitted, wherein the light path angle of the light beam is matched with the output deflection angle of the third optical fiber 112 in the first collimator 11, and the light; referring to fig. 17, a light beam incident from the third optical fiber 112 passes through the first collimator 11, enters the first polarization splitting prism 21, is split into two S light beams and P light beams with mutually perpendicular polarization directions in the first polarization splitting prism 21 after being reflected by the reflection surface 212, enters the optical rotation device 23, enters the second polarization splitting prism 22 after the optical rotation device 23 rotates the S light beam and the P light beam non-differently, is combined, is reflected by the lower end surface 222 of the second polarization splitting prism 22 and is refracted by the exit surface of the second polarization splitting prism 22, and is emitted, and the light beam optical path angle is matched with the output deflection angle of the fourth optical fiber 122 in the second collimator 12, enters the second collimator 12, and is emitted from the fourth optical fiber 122.

The above-mentioned preferred embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above-mentioned are only preferred embodiments of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included within the scope of the present invention.

Claims (8)

1. A micro optical circulator comprises a first collimator, a circulator core and a second collimator which are sequentially connected according to an optical path, wherein the first collimator is a double-optical-fiber collimator, the second collimator is a single-optical-fiber collimator, and the micro optical circulator is characterized by further comprising an optical path angle matching device, the circulator core consists of a first polarization beam splitter prism, an optical rotation device and a second polarization beam splitter prism which are sequentially arranged, polarization beam splitting films for dividing the first polarization beam splitter prism and the second polarization beam splitter prism into an upper part and a lower part are respectively arranged in the first polarization beam splitter prism and the second polarization beam splitter prism, high-reflection films are respectively arranged on the lower end surface of the first polarization beam splitter prism and the upper end surface of the second polarization beam splitter prism, the optical path angle matching device is arranged between the first collimator and the circulator core, when the micro optical circulator is in operation, the first collimator is connected with a first optical fiber and a third optical fiber, the second collimator is connected with a second optical fiber, and the micro optical circulator couples a light beam of the first optical fiber to the second optical fiber, and coupling the light beam of the second optical fiber to a third optical fiber for emission.

2. The micro optical circulator as claimed in claim 1, wherein the optical rotation device includes a magneto-optical crystal, a glass plate, and a magnetic sheet fitted to the magneto-optical crystal, and the magneto-optical crystal and the glass plate are arranged in a direction from the first polarization beam splitter prism to the second polarization beam splitter prism or in a direction from the second polarization beam splitter prism to the first polarization beam splitter prism.

3. The micro optical circulator as claimed in claim 1 or 2, wherein the upper end surface of the first polarization beam splitter prism is an inclined surface provided with a high reflection film, the optical path angle matching means is a wedge plate disposed between the first polarization beam splitter prism and the first collimator,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence and is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end face of the first polarization beam splitting prism and then horizontally emitted from the emergent face, after being refracted by the wedge angle piece, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

4. The micro optical circulator of claim 3, wherein the optical path angle matching device is a flat wedge disposed between the first polarization splitting prism and the first collimator,

the light beam incident from the first optical fiber passes through the first collimator, the flat part of the flat wedge angle sheet, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end face of the first polarization beam splitting prism and then horizontally emitted from the emergent face, after being refracted by the wedge angle part of the flat wedge angle sheet, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

5. The micro optical circulator of claim 3 wherein the optical path angle matching device is a roof prism disposed between the first polarization splitting prism and the first collimator perpendicular to the circulator core and parallel to the second collimator,

the light beam incident from the first optical fiber passes through the first collimator, the lower part of the roof prism, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence and is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitter prism, the optical rotation device and the first polarization beam splitter prism, is reflected by the upper end face of the first polarization beam splitter prism and then horizontally emitted from the emergent face, after being refracted by the upper part of the roof prism, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

6. The micro optical circulator of claim 1, wherein the upper end surface of the first polarization beam splitter prism is a horizontal surface, the optical path angle matching device is a plane mirror, the plane mirror is disposed above the first polarization beam splitter prism,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and the light beam is emitted from the second optical fiber; the light beam incident from the second optical fiber passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism in sequence, and is emitted from the upper end face of the first polarization beam splitting prism, under the reflection of the plane transmitting mirror, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

7. The micro optical circulator of claim 1, wherein the first polarization beam splitter prism has a high reflection film on an upper end surface thereof and has an angle of less than 45 ° with a horizontal plane, the optical path angle matching device is the first polarization beam splitter prism,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and the light beam is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end face of the first polarization beam splitting prism and refracted by the emergent face of the first polarization beam splitting prism and then is emitted, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber.

8. The micro optical circulator as claimed in claim 7, wherein the second collimator is a dual optical fiber collimator, the lower end surface of the second polarization beam splitter prism is provided with a high reflection film, the included angle between the lower end surface of the second polarization beam splitter prism and the horizontal plane is less than 45 degrees, the optical path angle matching device is a first polarization beam splitter prism and a second polarization beam splitter prism, and the second collimator is connected with the second and fourth optical fibers during operation,

the light beam incident from the first optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device, the second polarization beam splitter prism and the second collimator in sequence, and the light beam is emitted from the second optical fiber; the light beam incident from the second optical fiber sequentially passes through the second collimator, the second polarization beam splitting prism optical rotation device and the first polarization beam splitting prism, is reflected by the upper end surface of the first polarization beam splitting prism and refracted by the emergent surface of the first polarization beam splitting prism and then is emitted, the light path angle of the light beam is matched with the output deflection angle of the third optical fiber in the first collimator, and the light beam enters the first collimator and is emitted from the third optical fiber; the light beam incident from the third optical fiber passes through the first collimator, the first polarization beam splitter prism, the optical rotation device and the second polarization beam splitter prism in sequence, is reflected by the lower end face of the second polarization beam splitter prism and refracted by the emergent face of the second polarization beam splitter prism, and then is emitted, the light path angle of the light beam is matched with the output deflection angle of the fourth optical fiber in the second collimator, and the light beam enters the second collimator and is emitted from the fourth optical fiber.

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