CN110554463B

CN110554463B - Optical integration device and circulator

Info

Publication number: CN110554463B
Application number: CN201810542291.5A
Authority: CN
Inventors: 吕海峰; 陈达鑫; 黄坚龙; 徐燕
Original assignee: Oupulian Network Communication American Branch Co ltd; Zhuhai FTZ Oplink Communications Inc
Current assignee: Oupulian Network Communication American Branch Co ltd; Zhuhai FTZ Oplink Communications Inc
Priority date: 2018-05-30
Filing date: 2018-05-30
Publication date: 2022-12-30
Anticipated expiration: 2038-05-30
Also published as: TWM575117U; CN110554463A

Abstract

The invention provides a light integration device and a circulator. The optical integration device comprises a circulator, an input/output optical port positioned at one side of the circulator, an optical input port positioned at the other side of the circulator and an optical output port. The circulator comprises a first polarization beam splitter prism, a second polarization beam splitter prism and a third polarization beam splitter prism, and a first Faraday rotator is arranged between the first polarization beam splitter prism and the second polarization beam splitter prism. And a second Faraday rotation piece is arranged between the second polarization beam splitter prism and the third polarization beam splitter prism. The reverse light entering from the input/output optical port is output to the optical input port through the twice isolation action of the first Faraday rotator and the second Faraday rotator, so that the influence on a laser signal source can be effectively reduced. And the reverse light entering from the light output port is isolated once only through the second Faraday rotator and is output to the input and output light ports, so that the isolation requirement can be met, and the cost can be reduced.

Description

Optical integration device and circulator

Technical Field

The invention relates to the technical field of optical fiber communication, in particular to an optical integration device and a circulator used by the same.

Background

Chinese patent CN205229520U discloses a single-fiber bidirectional BOSA structure, which includes a light emitting group and a light receiving group, an array circulator group, a wavelength division multiplexing/demultiplexing group, and an optical fiber interface. A plurality of first optical signals emitted by the light emitting group are transmitted to the wavelength division multiplexing/demultiplexing group through the array circulator group, and are divided and multiplexed into one path of optical signals to be transmitted to the optical fiber interface for transmission. One path of optical signal emitted by the optical fiber interface is transmitted to the wavelength division multiplexing/demultiplexing group, demultiplexed into a plurality of second optical signals, and transmitted to the optical receiving group through the array circulator group. In the single-fiber bidirectional BOSA structure of CN205229520U, laser passes through the Faraday rotator only once from the light emitting group to the optical fiber interface, and is isolated only once. Due to the extinction ratio and wavelength dependent properties of faraday rotators, single-stage isolation can only be made slightly more than 30dB within a 30nm bandwidth. However, when the laser is output from the light emitting group, the laser energy is high, and if the isolation is not large enough, the backward laser reflected from the optical fiber interface still has large energy, which will have great influence on the laser signal source of the light emitting group, reduce the light emitting efficiency, and even damage the light emitting group.

Disclosure of Invention

The invention aims to provide an optical integrator and a circulator, which can better isolate reverse light and ensure the stable work of a laser signal source of an optical emission group.

The present invention provides a light integrating device, comprising: a circulator and a light receiving component, an input/output optical port located at one side of the circulator, an optical input port and an optical output port located at the other side of the circulator, wherein the circulator includes: a first polarization beam splitter prism, a second polarization beam splitter prism and a third polarization beam splitter prism; a first Faraday rotator is arranged between the first polarization beam splitter prism and the second polarization beam splitter prism; a second Faraday rotator is arranged between the second polarization beam splitter prism and the third polarization beam splitter prism; a first signal light input from the optical input port passes through the first polarization beam splitter prism, the first faraday rotator, the second polarization beam splitter prism, the second faraday rotator and the third polarization beam splitter prism in sequence and is output to the input/output optical port; and a second signal light input from the input/output optical port passes through the third polarization beam splitter prism, the second faraday rotator, the second polarization beam splitter prism and the first polarization beam splitter prism in sequence, is output to the light receiving assembly, and is output to the outside through the optical output port.

The present invention also provides a circulator, including an input/output optical port located at one side of the circulator, an optical input port and an optical output port located at the other side of the circulator, the circulator including: a first polarization beam splitter prism, a second polarization beam splitter prism and a third polarization beam splitter prism; a first Faraday rotator is arranged between the first polarization beam splitter prism and the second polarization beam splitter prism; a second Faraday rotator is arranged between the second polarization beam splitter prism and the third polarization beam splitter prism; the first signal light input from the light input port sequentially passes through the first polarization beam splitter prism, the first Faraday rotator, the second polarization beam splitter prism, the second Faraday rotator and the third polarization beam splitter prism and is output to the input/output light port; the second signal light input from the input/output optical port passes through the third polarization beam splitter prism, the second Faraday rotator, the second polarization beam splitter prism and the first polarization beam splitter prism in sequence and then is output to the optical output port; the first Faraday rotator is only arranged on the optical path of the first signal light, and no Faraday rotator is arranged on the optical path of the second signal light between the first polarization beam splitter prism and the second polarization beam splitter prism.

Compared with the traditional optical integration device, the optical integration device has the advantages that the first optical signal entering from the optical input port passes through the circulator and then is output from the input/output optical port, and only once isolation is carried out on reverse light. In the transmission process of the optical integration device and the circulator, the optical path of the first signal light respectively passes through the first Faraday rotator and the second Faraday rotator, namely, the reverse light is isolated twice, so that good isolation can be realized in a large bandwidth range, and the influence on a light source signal caused by the fact that the reverse light improperly returns to a laser light source is avoided. In the transmission process of the second signal light from the input/output optical port to the optical output port, the second signal light only passes through the second Faraday rotator instead of the first Faraday rotator, and reverse light is isolated once, so that the isolation requirement can be met, the loss of the second signal light in the transmission process can be reduced, and the cost is reduced.

Drawings

FIG. 1 is a schematic structural diagram of a light integrating device according to the preferred embodiment;

FIG. 2 is a schematic perspective view of the circulator and turning prism shown in FIG. 1 with a compensator added;

fig. 3 is a schematic diagram illustrating a change of the polarization state of the half-wave plate 141 shown in fig. 2 for the first signal light;

fig. 4 is a schematic diagram illustrating a change of the polarization state of the half-wave plate 142 shown in fig. 2 for the first signal light;

fig. 5 is a schematic diagram illustrating a change in polarization state of the half-wave plate 143 shown in fig. 2 for the first signal light;

fig. 6 is a schematic diagram illustrating a change of the polarization state of the first signal light by the half-wave plate 144 shown in fig. 2;

fig. 7 is an optical path diagram of first signal light from the optical input port to the input-output optical port in fig. 1;

FIG. 8 is a side view of the optical path diagram of FIG. 7;

fig. 9 is an optical path diagram of second signal light from the input-output optical port to the optical output port of fig. 1, in which a compensator is added;

FIG. 10 is a side view of the optical path diagram according to FIG. 9;

FIG. 11 is a schematic diagram of the reverse isolated optical path from the input and output optical ports to the optical input port of FIG. 1;

fig. 12 is a schematic diagram of the reverse isolated optical path from the optical output port to the input-output optical port in fig. 1.

The reference numerals are explained below: 10. a circulator; 11. a polarization splitting prism; 111. a first polarization splitting prism; 112. a second polarization beam splitter prism; 113. a third polarization beam splitter prism; 12. a Faraday rotator; 121. a first Faraday rotator; 122. a second Faraday rotator; 13. a half-wave plate; 141. 142, 143, 144, half-wave plate; 15. a magnetic plate; 16. a compensation plate; 2. a light receiving member; 20. a demultiplexer; 21. a glass carrier; 22. a narrow band filter; 23. a lens; 30. an optical input port; 32. a collimating lens; 40. an input-output optical port; 42. a focusing lens; 44. an optical fiber connector; 50. an optical output port; 60. a turning prism; l1, first signal light; l2, second signal light.

Detailed Description

While this invention is susceptible of embodiment in different forms, there is shown in the drawings and will herein be described in detail, specific embodiments thereof with the understanding that the present description is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to that as illustrated.

Thus, a feature indicated in this specification is intended to describe one of the features of an embodiment of the invention and does not imply that every embodiment of the invention must have the described feature. Further, it should be noted that this specification describes many features. Although some features may be combined to show a possible system design, these features may also be used in other combinations not explicitly described. Thus, the combinations illustrated are not intended to be limiting unless otherwise specified.

In the embodiments shown in the drawings, directional references (such as upper, lower, left, right, front and rear) are used to explain the structure and movement of the various elements of the invention, rather than absolute, and relative. These descriptions are appropriate when the elements are in the positions shown in the drawings. If the description of the positions of these elements changes, the indication of these directions changes accordingly.

The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

Referring to fig. 1, the present invention provides a light integration device. The light integration device mainly includes a circulator 10 and a light receiving element 2. The light integrating device is provided with three ports. Wherein the first port is an optical input port 30 located at one side of the circulator 10. The second port is an input/output port 40 on the other side of the circulator 10. The third port is an optical output port 50 located on the same side of the circulator 10 as the optical input port 30. Wherein the optical input port 30 is preferably directly connected to an optical transmitter (not shown), such as a laser diode, the input/output optical port 40 is preferably connected to an optical cable (not shown) for bi-directional transmission of optical signals, and the optical output port 50 is preferably connected to a plurality of output optical fibers (not shown).

The light receiving element 2 is disposed at one side of the circulator 10 and is disposed opposite to the light output port 50, wherein the light receiving element 2 may be a focusing lens (not shown) or a demultiplexer 20, and the embodiment specifically takes the light receiving element 2 as a demultiplexer 20 for illustration.

The first signal light L1 entering from the optical input port 30 passes through the circulator 10 to reach the input/output optical port 40. The second signal light L2 entering from the input/output optical port 40 passes through the circulator 10 to reach the demultiplexer 20, is decomposed into signal light of several wavelengths by the demultiplexer 20, and is transmitted to the optical output port 50. Specifically, the first signal light L1 entering from the optical input port 30 is shaped into a collimated light by the collimating lens 32, and then passes through the circulator 10 to reach a focusing lens 42, and the focusing lens 42 collimates the first signal light L1 and then converges the collimated light to an end surface of an optical fiber connector 44, so as to be output to the outside through the optical fiber connector 44 (i.e., the input/output optical port 40). The second signal light L2 entering from the optical fiber connector 44 at the input/output optical port 40 is also shaped into a collimated light by the collimating lens 42, and then enters the demultiplexer 20 through the circulator 10, and finally is output from the optical output port 50.

Referring to fig. 1 and 2, the circulator 10 includes three polarization splitting prisms 11, two faraday rotators 12, a half-wave plate 13, and four half-

wave plates

141, 142, 143, and 144. Three polarization splitting prisms 11 are disposed relatively in parallel along the Z-axis. The faraday rotator 12 and the half-

wave plates

13, 141, 142, 143, and 144 are provided between two adjacent polarization splitting prisms 11.

The polarization beam splitter 11 includes a first polarization beam splitter 111, a second polarization beam splitter 112 and a third polarization beam splitter 113. The first polarization splitting prism 111 is disposed near the optical input port 30, the second polarization splitting prism 112 is disposed on the side of the first polarization splitting prism 111 away from the optical input port 30, and the third polarization splitting prism 113 is disposed near the input/output optical port 40. The first polarization beam splitter prism 111, the second polarization beam splitter prism 112 and the third polarization beam splitter prism 113 are preferably PBS rhombic prisms, wherein the PBS film direction on the second polarization beam splitter prism 112 and the PBS film direction on the first polarization beam splitter prism 111 and the third polarization beam splitter prism 113 form an included angle of 90 degrees.

The two faraday rotators 12 include a first faraday rotator 121 and a second faraday rotator 122. Specifically, in the present embodiment, both of the faraday rotators 12 can rotate the polarization angle of the signal light by 45 degrees.

As shown in fig. 7 and 8, the first faraday rotator 121 is provided between the first polarization beam splitter prism 111 and the second polarization beam splitter prism 112. The first faraday rotator 121 is disposed only on the optical path of the first signal light L1 between the optical input port 30 and the input/output optical port 40. The polarization direction of the first signal light L1 passing through the first faraday rotator 121 is rotated counterclockwise by 45 degrees. A first half-wave plate set is disposed between the first polarization splitting prism 111 and the second polarization splitting prism 112, and includes two half-

wave plates

141 and 142 arranged in parallel and a single half-wave plate 13. The half-wave plate 13 is disposed only on the optical path of the second signal light L2 from the input/output optical port 40 to the optical output port 50.

The second faraday rotator 122 is provided between the second polarization beam splitter 112 and the third polarization beam splitter 113. A second half-wave plate set is arranged between the second polarization splitting prism 112 and the third polarization splitting prism 113, and comprises two half-

wave plates

143, 144 arranged in parallel.

As shown in fig. 7 and 8, specifically, on the optical path along which the first signal light L1 propagates, two half-

wave plates

141 and 142 are preferably disposed between the first polarization splitting prism 111 and the first faraday rotator 121. Two half-

wave plates

143, 144 are preferably provided between the second Faraday rotator 122 and the third polarization splitting prism 113. The first signal light L1 input from the optical input port 30 passes through the first polarization splitting prism 111, the half-

wave plates

141 and 142, the first faraday rotator 121, the second polarization splitting prism 112, the second faraday rotator 122, the half-

wave plates

143 and 144, and the third polarization splitting prism 113 in this order, and is output to the input/output optical port 40. It is worth mentioning that in other embodiments not shown, the positions of the two half-

wave plates

141, 142 and the first faraday rotator 121 may be interchanged; the positions of the two half-

wave plates

143, 144 and the second faraday rotator 122 may also be interchanged.

As shown in fig. 9 and 10, the half-wave plate 13 provided between the first polarization splitting prism 111 and the second polarization splitting prism 112 is provided only on the optical path of the second signal light L2 from the input/output optical port 40 to the optical output port 50, with respect to the second signal light L2 input from the input/output optical port 40 and output from the optical output port 50. The second signal light L2 input from the input/output optical port 40 passes through the third polarization beam splitter 113, the half-

wave plates

143, 144, the second faraday rotator 122, the second polarization beam splitter 112, the half-wave plate 13, the compensator 16 (which may be omitted in some cases), and the first polarization beam splitter 111 in this order, and is output to the demultiplexer 20 and then to the optical output port 50.

Specifically, in this embodiment, an included angle between the crystal axis direction of the half-wave plate 13 and the polarization direction is 45 degrees, and the polarization direction of one of the polarized light of the second signal light L2 will rotate by 90 degrees after passing through the half-wave plate 13. Referring to fig. 3-6, the half-

wave plates

141 and 144 rotate the polarization direction of one of the polarized light beams of the first signal light L1 by 45 degrees clockwise, and the half-

wave plates

142 and 143 rotate the polarization direction of one of the polarized light beams of the first signal light L1 by 45 degrees counterclockwise.

The transmission principle of the optical path will be described with reference to the characteristics of the polarization beam splitter prism 11, the faraday rotator 12, and the half-

wave plates

13, 141, 142, 143, and 144:

referring to fig. 7 and 8, the first signal light L1 propagates from the optical input port 30 to the input/output optical port 40. The direction of the main optical path from the optical input port 30 to the input-output optical port 40 is substantially the direction of the Z-axis, as indicated by the coordinates on the incident beam side. The first signal light L1 entering the optical input port 30 is decomposed into X-direction polarized light (P-polarized light) and Y-direction polarized light (S-polarized light) having orthogonal polarization directions by the first polarization splitting prism 111, and then the polarization state is observed along the direction of the Z-axis of the optical transmission direction, and the change in the polarization state in the XY plane is shown as coordinates in the figure.

As shown in fig. 7, the first signal light L1 enters from the optical input port 30 and is output from the input/output optical port 40 by the following process: the first signal light L1 is decomposed into X-direction polarized light and Y-direction polarized light having polarization directions perpendicular to each other by the first polarization splitting prism 111. The X-direction polarized light pen passes through the first polarization splitting prism 111, and the y-direction polarized light is reflected at the PBS film of the first polarization splitting prism 111.

As shown in fig. 7 and 8, the X-direction polarized light in the lower portion of fig. 7 passes through the half-wave plate 142 and is then rotated 45 degrees counterclockwise, passes through the first faraday rotator 121 and is then rotated 45 degrees counterclockwise, and the polarization direction is changed to the Y direction. Since the second polarization splitting prism 112 is disposed perpendicular to the first polarization splitting prism 111, the polarized light in the Y direction can pass through the second polarization splitting prism 112. Then, after rotating it by 45 degrees counterclockwise by the second faraday rotator 122 and by 45 degrees clockwise by the half-wave plate 144, the polarization direction is maintained in the Y direction. Then, the third polarization splitting prism 113 reflects the light to the input/output optical port 40.

As shown in fig. 7 and 8, the polarized light in the Y direction above fig. 7 is reflected by the first polarization splitting prism 111, then clockwise rotated by 45 degrees by the half-wave plate 141, and then counterclockwise rotated by 45 degrees by the first faraday rotator 121, and then the polarization direction is maintained in the Y direction, so that the pen passes through the second polarization splitting prism 112, then counterclockwise rotated by 45 degrees by the second faraday rotator 122, and further counterclockwise rotated by 45 degrees by the half-wave plate 143, and the polarization direction is changed to the X direction, and then directly passes through the third polarization splitting prism 113. Thus, the X-direction polarized light and the Y-direction polarized light are recombined by the third polarization splitting prism 113 to the first signal light L1 and output to the input/output optical port 40.

Referring to fig. 9 and 10, the process of transmitting the second signal light L2 entering from the input/output optical port 40 to the optical output port 50 through the circulator 10 is as follows: the second signal light L2 entering the input/output optical port 40 is first split into X-direction polarized light (P-polarized light) and Y-direction polarized light (S-polarized light) by the third polarization beam splitter prism 113.

As shown in fig. 9, the X-polarized light passes through the half-wave plate 143 and is rotated by 45 degrees counterclockwise, and the second faraday rotator 122 rotates by 45 degrees clockwise again, and the polarization direction is maintained in the X direction. The Y-direction polarized light in the lower part of the figure is rotated clockwise by 45 degrees by the half-wave plate 144 and then rotated clockwise by 45 degrees by the second faraday rotator 122, and the polarization direction is changed to the X-direction. As shown in fig. 10, two beams of polarized light in the X direction are reflected and propagate along the Y axis for a certain distance while passing through the second polarization splitting prism 112, and then continue to propagate along the Z axis after being reflected.

As shown in fig. 9 and 10, the polarized light above fig. 9 passes through the second polarization splitting prism 112, then passes through the half-wave plate 13, the polarization direction is rotated by 90 degrees, and is converted into the polarized light in the Y direction, and the polarized light is reflected by the first polarization splitting prism 111 and reaches the light output port 50. The polarized light in the lower part of fig. 9 passes through the second polarization splitting prism 112, then passes through the compensator 16, the polarization state thereof is maintained in the X direction, and directly passes through the first polarization splitting prism 111 to reach the light output port 50.

Fig. 11 is a schematic diagram of the second order reverse isolation from the input-output optical port 40 to the optical input port 30. As can be seen from the foregoing fig. 9 and 10, in an ideal case, the light input from the input/output optical port 40, after passing through the half-

wave plates

143 and 144 and the second faraday rotator 122, is reflected by the second polarization splitting prism 112, and travels upward to the optical output port 50 by a certain distance, so as not to enter the optical input port 30, which is the first isolation of the light input from the input/output optical port 40. However, in actual cases, a small portion of light is not converted into the X-direction polarized light that can be reflected by the second polarization splitting prism 112 in a wide wavelength range due to the extinction ratio and the wavelength characteristics of the faraday rotator 122, and thus the small portion of the Y-direction polarized light (S-polarized light) can be directly transmitted through the second polarization splitting prism 112. The S-polarized light above fig. 11 passes through the first faraday rotator 121 and then rotates clockwise by 45 degrees, and then passes through the half-wave plate 141 and then rotates clockwise by 45 degrees, so that it becomes P-polarized light, and directly passes through the first polarization splitting prism 111 and cannot enter the optical input port 30. The S-polarized light below the position of fig. 11 passes through the first faraday rotator 121, then rotates clockwise by 45 degrees, then passes through the half-wave plate 142, rotates counterclockwise by 45 degrees, and is still S-polarized light, and is reflected by the first polarization splitting prism 111, and cannot enter the optical input port 30, so that the purpose of second isolation is achieved. Due to the extinction ratio and wavelength-dependent characteristics of the faraday rotator 12, the single-stage isolation can only be more than 30dB within a 30nm bandwidth. In this configuration, the backward light from the input/output optical port 40 to the optical input port 30 is isolated in two stages by the first faraday rotator 121 and the second faraday rotator 122, and the isolation can be 45dB or more. So that the reverse return of light from the input and output optical port 40 to the optical input port 30 (i.e., at the laser light source) can be effectively reduced over a larger bandwidth, affecting the light source signal.

Fig. 12 is an isolated schematic diagram of the reverse incoming light from the optical output port 50 to the input-output optical port 40. The P-polarized light pen in the lower part of fig. 12 passes through the first polarization beam splitter 111 and is reflected by the second polarization beam splitter 112 in the direction perpendicular to the paper surface, and then is rotated 45 degrees counterclockwise when passing through the second faraday rotator 122, and then is rotated 45 degrees clockwise by the half-wave plate 144, and still is P-polarized light, and therefore, the P-polarized light pen directly passes through the third polarization beam splitter 113 and cannot enter the input/output optical port 40; the S-polarized light in the upper part of fig. 12 is reflected by the first polarization splitting prism 111, changes its polarization direction by 90 degrees after passing through the half-wave plate 13, changes to P-polarized light, is reflected in a direction perpendicular to the paper by the second polarization splitting prism 112, is rotated counterclockwise by 45 degrees when passing through the second faraday rotator 122, is rotated counterclockwise by 45 degrees when passing through the half-wave plate 143, changes its polarization direction by 90 degrees, changes to S-polarized light, is reflected by the third polarization splitting prism 113, and cannot enter the input/output port 40. In this structure, the reverse light from the optical output port 50 to the input/output optical port 40 only passes through the second faraday rotator 122, and is isolated in a single stage, and since the energy of the second signal light L2 after long-distance transmission is usually small, the isolation degree is above 30dB, which can already meet the requirement on the isolation performance of the reverse light, and can reduce the loss of the second signal light L2 during the transmission process.

In this embodiment, the demultiplexer 20 is used to split the signal light with different wavelengths. The second signal light L2 input from the input/output optical port 40 passes through the third polarization splitting prism 113, the second faraday rotator 122, the second polarization splitting prism 112, and the first polarization splitting prism 111 in this order, and is output to the demultiplexer 20.

Referring to fig. 1, the demultiplexer 20 is preferably a Filter type demultiplexer. The demultiplexer 20 comprises a glass carrier 21 coated with a reflective film on one side, a plurality of narrow band filters 22. The demultiplexer 20 can adjust the splitting wavelength band corresponding to the demultiplexer 20 by adding or subtracting the narrow band filter 22 according to the requirement. In particular, the demultiplexer 20 comprises four narrow-band filters 22. The demultiplexer 20 can select the respective four wavelengths for splitting. A focusing lens 23 is placed behind each narrow band filter 22 to focus the light beam onto the receiving end face of the output fiber (not shown). The focusing lens 23 can be selected according to product requirements, and may be a spherical focusing lens or a self-focusing lens, or may be an already assembled lens array, etc. The plurality of sets of narrow band filters 22 may split the plurality of wavelength bands and finally the split light beams are output from the optical output port 50.

Referring to fig. 1 and 2, the circulator 10 of the present embodiment further includes a magnetic plate 15 in the form of a flat plate. The first faraday rotator 121 and the second faraday rotator 122 are disposed close to each other above the magnetic plate 15. The magnetic plate 15 is used to provide a magnetic field for the first faraday rotator 121 and the second faraday rotator 122 to ensure their normal operation.

The first faraday rotator 121 and the second faraday rotator 122 are both disposed near the magnetic plate 15. Since the second signal light L2 passes through only the second faraday rotator 122 during propagation from the input/output optical port 40 to the optical output port 50, it does not need to pass through the first faraday rotator 121. Therefore, the first faraday rotator 121 only needs to be disposed at a portion through which the first signal light L1 near the magnetic plate 15 passes, and does not need to extend into the optical path of the second signal light L2 far from the magnetic plate 15, which can reduce the size of the first faraday rotator 121. In addition, since the garnet single crystal constituting the first faraday rotator 121 is very expensive, the reduction in volume is advantageous to reduce the product cost.

The first Faraday rotator 121 with a small volume can meet the requirement of an optical path, and the magnetic plate 15 with a small volume can meet the requirement of the first Faraday rotator 121 on a magnetic field, so that the space of a product is saved. Therefore, the magnetic plate 15 in the form of a flat plate is used for the

faraday rotator

121 and 122 of the circulator 10 to replace the conventional magnetic ring, so that the circulator occupies a smaller space, and the strength of the magnetic force can meet the requirement of the

faraday rotator

121 and 122, which is beneficial to product miniaturization.

Referring to fig. 2 and 9, the compensation plate 16 of the present embodiment is disposed between the second polarization splitting prism 112 and the third polarization splitting prism 113, and is only disposed on the light path through which the second signal light L2 between the input/output light port 40 and the light output port 50 passes. The compensator 16 and the half-wave plate 13 are preferably arranged in parallel on the side of the first polarization splitting prism 111 facing the second polarization splitting prism 112. One of the polarized lights decomposed from the second signal light L2 enters the first polarization splitting prism 111 through the half-wave plate 13, and if the other Shu Pianzhen light directly enters the first polarization splitting prism 111, an optical path difference is formed between the two polarized lights due to the half-wave plate 13, so that the compensator 16 needs to be introduced to compensate the optical path difference when there is a high requirement for signal quality, so as to ensure that the two polarized lights decomposed from the second signal light L2 can be combined through the first polarization splitting prism 111 and output to the demultiplexer 20 without distortion. Wherein the compensator 16 may be omitted in certain applications where the signal quality requirements are not high.

Referring to fig. 1, the light integration device of the present embodiment further includes a turning prism 60. The turning prism 60 is located on one side of the circulator 10 close to the optical input port 30, and is disposed opposite to the optical input port 30. The folding prism 60 is preferably a parallelogram having an inclination angle for folding the first signal light L1 so that the optical input port 30 of the optical integrator device can be distanced from the demultiplexer 20 to widen the distance between the optical input port 30 and the optical output port 50. The distance between the optical input port 30 and the optical output port 50 is sufficiently wide to facilitate the mounting of the demultiplexer 20.

The light integration device of the present invention fully combines the functions and characteristics of circulator 10 and demultiplexer 20 and is preferably integrally packaged in a sealed housing (not shown). Since the circulator 10 and the demultiplexer 20 are not independently packaged, the precision deviation introduced by independent packaging is reduced, and the three-dimensional space in the optical integrator is fully utilized for pure optical path propagation. The collimator of each port and the circulator 10 and the demultiplexer 20 can realize compensation among dimensional tolerance through flexible adjustment, so that the device has larger tolerance on the position tolerance of elements and is easy to produce.

Also, the light integration device is preferably fixed on a base plate (not shown) in the sealed housing, and the circulator 10 and the demultiplexer 20 are bonded on the base plate through an adhesive material, so as to enhance the stability and reliability of the product.

While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.

Claims

1. A light integrating device comprising: a circulator and a light receiving component, an input/output port at one side of the circulator, an optical input port and an optical output port at the other side of the circulator,

the circulator includes: a first polarization beam splitter prism, a second polarization beam splitter prism and a third polarization beam splitter prism; a first Faraday rotator is arranged between the first polarization beam splitter prism and the second polarization beam splitter prism; a second Faraday rotator is arranged between the second polarization beam splitter prism and the third polarization beam splitter prism;

a first signal light input from the optical input port passes through the first polarization beam splitter prism, the first faraday rotator, the second polarization beam splitter prism, the second faraday rotator and the third polarization beam splitter prism in sequence and is output to the input/output optical port; and a second signal light input from the input/output optical port passes through the third polarization beam splitter, the second faraday rotator, the second polarization beam splitter and the first polarization beam splitter in sequence, then is output to the light receiving assembly, and is output outwards through the optical output port, the first faraday rotator is only arranged on the optical path of the first signal light, and the second signal light passes through the second faraday rotator but not through the first faraday rotator.

2. The light integrating device of claim 1, wherein a first half wave plate set is disposed between the first polarization beam splitter prism and the second polarization beam splitter prism; a second half wave plate set is arranged between the second polarization beam splitter prism and the third polarization beam splitter prism.

3. The light integrating device of claim 2, wherein the first signal light passes through two first half-wave plates and the second half-wave plate in the first half-wave plate set, and the rotation angles of the two first half-wave plates are both 45 degrees.

4. The light integrating device of claim 3, wherein the second signal light passes through a first half-wave plate and the second half-wave plate in the first half-wave plate set, and a rotation angle of the first half-wave plate is 90 degrees.

5. The light integrating device of claim 4, wherein the circulator further comprises a compensation plate for compensating the optical path difference, the compensation plate is disposed between the second polarization splitting prism and the first polarization splitting prism, and is juxtaposed to the first half-wave plate whose rotation angle is 90 degrees.

6. The light integrating device of claim 4, wherein the first polarization splitting prism is disposed near the light input port, the second polarization splitting prism is disposed on a side of the first polarization splitting prism away from the light input port, and the third polarization splitting prism is disposed near the input-output light port; the first Faraday rotator and the second Faraday rotator can rotate the polarization angle of the signal light by 45 degrees; the first half wave plate set comprises two first half wave plates which are arranged in parallel and the rotation angle of which is 45 degrees, and a first half wave plate which is arranged independently and the rotation angle of which is 90 degrees.

7. The light integrating device of claim 1, wherein the circulator further comprises a magnetic plate for providing a magnetic field to the first Faraday rotator and the second Faraday rotator, both the first Faraday rotator and the second Faraday rotator being in close proximity to the magnetic plate.

8. The light integrating device of claim 1, further comprising a turning prism between the circulator and the light input port for turning the first signal light.

9. The light integrating device of any one of claims 1 to 8, wherein the light receiving element is a demultiplexer comprising a glass carrier coated with a reflective film on one side, a plurality of narrow band filters, and a plurality of focusing lenses corresponding to each of the narrow band filters, respectively.

10. The light integrating device of any one of claims 1-8, wherein the first polarizing beam splitter prism, the second polarizing beam splitter prism and the third polarizing beam splitter prism are all PBS rhombic prisms, and a PBS film direction on the second polarizing beam splitter prism forms an included angle of 90 degrees with a PBS film direction on the first polarizing beam splitter prism and the third polarizing beam splitter prism.

11. A circulator comprises an input/output optical port at one side of the circulator, an optical input port and an optical output port at the other side of the circulator,

the first signal light input from the optical input port sequentially passes through the first polarization splitting prism, the first Faraday rotator, the second polarization splitting prism, the second Faraday rotator and the third polarization splitting prism and is output to the input/output optical port; the second signal light input from the input/output optical port passes through the third polarization beam splitter prism, the second Faraday rotator, the second polarization beam splitter prism and the first polarization beam splitter prism in sequence and then is output to the optical output port; the first Faraday rotator is only arranged on the optical path of the first signal light, and no Faraday rotator is arranged on the optical path of the second signal light between the first polarization beam splitter prism and the second polarization beam splitter prism.

12. The circulator of claim 11, wherein a half-wave plate for rotating one of the polarized lights by 90 degrees is disposed on an optical path of the second signal light between the second polarization splitting prism and the first polarization splitting prism.