KR102512538B1 - Low-crosstalk single-core bi-directional optical assembly - Google Patents

Abstract

The present invention provides a low-crosstalk single-core bi-directional optical assembly (200), which includes one input/output terminal (201), one polarization beam splitting coupler (202), one first polarization reflector (203) and one 2 polarization reflectors 204, at least one optical signal transmitting unit 205, one optical signal receiving unit 206 and one diaphragm 207 are included, and the diaphragm 207 is one light transmitting area 2072 and one inner light-shielding region 2071, wherein the inner light-shielding region 2071 blocks the crosstalk optical signal 210 reflected or projected to the optical signal receiving unit 206 by the polarization beam splitting combiner 202. It consists of In addition, by providing incident end surfaces 2011 and 2021 of the input/output terminal 201 and the polarization beam splitting coupler 202 at an angle greater than 8 degrees to the output optical signal 209, crosstalk reflected on the end faces 2011 and 2021 By causing the optical signal 2012 to depart from the main communication optical path, the energy of the crosstalk optical signals 210 and 2012 reaching the optical signal receiving unit 206 is reduced, and the signal received by the optical signal receiving unit 206 It effectively improves the quality of the signal and implements bi-directional transmission of optical signals of the same wavelength or close wavelength with a high signal-to-noise ratio.

Description

Low-crosstalk single-core bi-directional optical assembly

The present invention relates to the field of optical communication technology, and more particularly to a low-crosstalk same-wavelength or near-wavelength single-core optical assembly.

High-speed data transmission is the cornerstone of the modern information society, and as the amount of information increases drastically, the amount of data that needs to be transmitted in a single optical fiber is increasing. In addition to increasing the data modulation rate and using more wavelengths, the data transmission capacity of the optical fiber can be doubled by transmitting in both directions on one strand of optical fiber and using a low-cost single-core bidirectional optical transmit and receive module, which is widely used in the telecommunication field. It is an effective and implementable method that is adopted.

In addition, modern communication networks place increasingly high requirements on clock synchronization. Conventional optical transmission/reception modules adopt two strands of optical fiber to transmit and receive optical signals, respectively. In practical applications, it is very difficult to synchronize clocks because the propagation delay of the two signals is not consistent due to the length difference between the two strands of optical fiber. this happens Bidirectional transmission of single-strand optical fibers can eliminate the effects of fiber length differences and meet the clock synchronization requirements at this stage. In addition, using the same or close (wavelength difference less than 40nm) wavelengths for single-strand fiber bidirectional transmission can effectively overcome the residual delay caused by dispersion, and greatly improve the clock synchronization accuracy of the network, enabling clock synchronization in next-generation networks such as 5G. requirements can be met.

In addition, the use of single-core bidirectional transmission of the same wavelength or near wavelength overcomes the difficulty of pairing optical transmission and reception modules in the existing dual-wavelength single-core bidirectional transmission technology, and makes network configuration and connection more flexible.

Based on the above advantages, the prior art has provided several same-wavelength or near-wavelength single-core bi-directional optical assembly technologies. For example, a technology using a power divider (Chinese Patent Application No. 201110282629.6), which uses fewer components and lower cost, but has an additional 6 dB optical power loss, and the lost optical power is prone to crosstalk. US Patent 7039278B1 uses optical circulator technology to prevent additional light output loss, but is excessively bulky and is not suitable for the allowable optical assembly mechanical size of existing single-core bi-directional optical transceiver modules. Chinese patent 201410604190.8 uses a sub-wavelength polarization reflector to prevent additional light output loss and proposes a technical solution with a small size, enabling the same or near-wavelength single-core bi-directional transmission under the existing optical assembly size.

However, in the conventional same-wavelength or near-wavelength single-core bidirectional optical assembly technology, an optical signal transmission unit and an optical signal reception unit are packaged in a single transmission/reception integrated optical assembly, and a part of an output optical signal transmitted from a local optical signal transmission unit is localized. Crosstalk is formed when the optical signal reaches the receiving unit, resulting in a high signal error rate, which is a common problem in the conventional same-wavelength or near-wavelength single-core bidirectional optical assembly technology. An optical crosstalk signal usually occurs in reflection or projection of an optical interface, and as shown in FIG. It is composed of a unit 106, a polarization beam splitting combiner 102, a first polarization reflector 103 and a second polarization reflector 104, and the polarization beam splitting combiner 102 includes a functional surface 1022 in a diagonal direction. The polarization state beam splitting and beam combining are implemented in this function. An incident optical signal (not shown) is input to the polarization beam splitting combiner 102 through the input/output terminal 101, and is decomposed into two polarization states perpendicular to each other, to the first polarization reflector 103 and the second polarization reflector 104, respectively. ), and at the same time being reflected, the polarization state is rotated by 90 degrees, and then combined by the polarization beam splitting combiner 102 to form a single beam having the same direction and received by the optical signal receiving unit 106. The output optical signal 108 emitted from the optical signal transmission unit 105 has a single polarization state, and after passing through the first polarization reflector 103, the polarization state rotates to form a polarization beam splitting combiner 102 for projection. Forms a polarization state signal 109 that passes through. In the drawing, it is indicated as P light, and its polarization state is indicated by “|”. However, for various reasons, the output optical signal 109 cannot have an infinite polarization extinction ratio and always includes a small amount of S-polarization state, which is indicated by “•”. This portion of the S polarization state optical signal is directly reflected by the functional surface 1022 to the polarization beam splitting combiner 102, and is therefore received by the optical signal receiving unit 106 to form a crosstalk optical signal. In addition, for the P polarization state of the outgoing optical signal 109, the functional surface 1022 cannot achieve an infinite extinction rate, and some optical signals are reflected to the optical signal receiving unit 106 to form crosstalk, so that the functional surface 1022 The crosstalk signal 110 formed by reflection on ) has both P polarization and S polarization, and is referred to as a first crosstalk optical signal.

Another source of the crosstalk signal is the residual reflection 111 generated at the incident end face 1021 on one side opposite to the input/output terminal 101 of the polarization beam splitting coupler 102 after the output optical signal passes through the functional surface 1022. ), and the residual reflection 112 generated at the interface 1011 of the input/output terminal 101, and the reflected optical signal of these two parts is regarded as a part of the incident optical signal and is projected to the polarization beam splitting combiner 102 and 1 is reflected through the polarization reflector 103, the polarization state is rotated by 90 degrees, and is reflected through the functional surface 1022 of the polarization beam splitting combiner 102 again, and the incident optical signal reaches the optical signal receiving unit 106 Accordingly, the second crosstalk optical signal 113 is formed.

The above discussion relates to a configuration method in which the output optical signal passes through the functional surface 1022 of the polarization beam splitting combiner 102 in a projection method and reaches the input/output terminal 101, and the output optical signal passes through the polarization beam splitting combiner in a reflection method ( 102), that is, the optical signal transmission unit 105 is on one side of the second polarization reflector, and the formation mechanism of the crosstalk optical signal is similar. In this case, the first crosstalk signal ( 110) is projected from the outgoing optical signal and formed through the functional surface 1022. The formation mechanism of the second crosstalk signal 113 is the same as described above, and is formed by residual reflection on the incident end face 1021 of the polarization beam splitting coupler 102 or the incident end face 1011 of the input/output terminal 101.

In the case of the same wavelength application, since the transmission and reception wavelengths are the same, the crosstalk light cannot be blocked by applying a wavelength filter in front of the optical signal receiving unit, otherwise the input incident optical signal is also blocked. In the case of near-wavelength applications, a wavelength filter can be used in front of the optical signal receiving unit, but since the optical transmitting and receiving modules at both ends of the optical fiber must be used in pairs, process application and inventory management problems occur, and flexibility of network connection is lost.

Conventional same-wavelength or near-wavelength single-core bidirectional optical assembly technology cannot effectively overcome an optical signal crosstalk problem occurring in a local optical signal receiving unit due to an output optical signal emitted from a local optical signal transmitting unit.

An aspect of an embodiment of the present invention provides a low-crosstalk single core bi-directional optical assembly comprising: an input/output terminal, a polarization beam splitting combiner, a first polarization reflector, a second polarization reflector, and at least one optical beam splitting coupler. A signal transmitting unit, an optical signal receiving unit and a diaphragm are included, and the diaphragm includes a light transmitting area and an inner light blocking area.

The input/output terminal is configured to input and output an optical signal, and the input/output terminal includes one first incident end face toward one side of the polarization beam splitting coupler.

The diagonal direction of the polarization beam splitting combiner includes one functional plane, and is configured to split one optical signal into two mutually perpendicular polarized signals, and combine two mutually perpendicular polarized signals into one optical signal. Further, the polarization beam splitting coupler includes one second incident end face toward one side of the input/output terminal.

At least one of the first polarization reflector and the second polarization reflector includes a 45 degree Faraday rotator and a sub-wavelength grating polarization reflector, wherein the sub-wavelength grating polarization reflector generates an optical signal of a specific polarization state and project an optical signal perpendicular to the polarization state of the reflected optical signal.

The optical signal transmission unit is configured to emit an exit optical signal, and the optical signal transmission unit includes a focusing lens.

The optical signal receiving unit is configured to receive an incident optical signal, and the optical signal receiving unit includes a focusing lens.

the input/output terminal receives an incident optical signal including at least one wavelength, and couples the incident optical signal to the polarization beam splitting coupler; the incident optical signal is decomposed into a first polarization state optical signal and a second polarization state optical signal perpendicular to each other by the polarization beam splitting combiner; The first polarization state optical signal is projected through the polarization beam splitting coupler, propagates to the first polarization reflector, and is reflected back by the first polarization reflector to the polarization beam splitting coupler, and the polarization state is the initial polarization state. turns perpendicular to; The second polarization state optical signal is reflected through the polarization beam splitting combiner and propagated to the second polarization reflector, and is reflected by the second polarization reflector to the polarization beam splitting combiner and returned, and the polarization state is the initial polarization state. turns perpendicular to; The optical signal of the first polarization state whose polarization state is changed is reflected through the polarization beam split coupler, and the optical signal of the second polarization state whose polarization state is changed is projected through the polarization beam split coupler, so that two light beams in the same direction are formed. A signal is formed, propagated through the light transmission area of the diaphragm, and received by the optical signal receiving unit.

the optical signal transmitting unit emits an outgoing optical signal that includes at least one wavelength, and the outgoing optical signal has a single polarization state; When the optical signal transmission unit is located on one side of the first polarization reflector, the outgoing optical signal is sequentially projected to the input/output terminal via the first polarization reflector and the polarization beam splitting coupler; When the optical signal transmission unit is located on one side of the second polarization reflector, the outgoing optical signal is projected to the polarization beam splitting coupler via the second polarization reflector, and to the input/output terminal via the polarization beam splitting coupler. reflected and output.

When the outgoing optical signal is projected or reflected to the input/output terminal via the polarization beam splitting combiner, a part of the outgoing optical signal is reflected or projected by the functional surface of the polarization beam splitting coupler to form a first crosstalk optical signal; propagates toward the optical signal receiving unit.

the diaphragm is configured to confine an optical signal, the diaphragm is positioned between the polarization beam splitting combiner and the optical signal receiving unit, and the light spot of the first crosstalk optical signal is positioned at a position where the light point is smallest; The light blocking area inside the diaphragm is greater than or equal to the size of a light spot formed by propagation of the first crosstalk optical signal to the position of the diaphragm, and blocks the first crosstalk optical signal so that the first crosstalk optical signal is not propagated to the optical signal receiving unit. used to do

In one embodiment, the angle between the normal of the first incident end face of the input/output terminal and the output optical signal is greater than 0 degree and less than 82 degrees, and the normal of the second incident end face of the polarization beam splitting coupler and the incident light signal. The angle between the light signals is greater than 0 degrees and less than 82 degrees.

When the outgoing optical signal passes through the polarization beam splitting coupler and is projected to the input/output terminal, a part of the outgoing optical signal is reflected by the first or second incident end face to form a second crosstalk optical signal, and the second crosstalk optical signal A signal propagates in a reverse direction away from the outgoing optical signal.

In one embodiment, an angle between the normal of the first incident end face of the input/output terminal and the output optical signal is greater than 8 degrees, and an angle between the normal of the second incident end face of the polarization beam splitting coupler and the output optical signal. is greater than 8 degrees.

In one embodiment, the first incident end surface of the input/output terminal and the second incident end surface of the polarization beam splitting coupler are directly bonded and connected by a refractive index matching adhesive.

In one embodiment, the angle between the outgoing optical signal and the normal of the functional plane of the polarization beam splitting coupler is 34 degrees to 44 degrees or 46 degrees to 56 degrees; An inner light-shielding area of the diaphragm is out of the center of the light-transmitting area.

In one embodiment, the diaphragm further includes an external light-blocking region for blocking the crosstalk optical signal and the spurious optical signal from being incident to the optical signal receiving unit.

In one embodiment, the sub-wavelength grating polarization reflector includes any one of three types of gratings: a sub-wavelength non-metallic dielectric grating, a sub-wavelength metal grating, or a combination grating of a sub-wavelength non-metallic dielectric and sub-wavelength metal.

Alternatively, the sub-wavelength grating polarization reflector is made by forming one of the three gratings through a microfabrication process on one light passing surface of the 45 degree Faraday rotator.

At most one of the first polarization reflector and the second polarization reflector is composed of a 1/4 wave plate and a reflective mirror, and the reflective mirror is fixed to one light passing plane of the 1/4 wave plate. It is formed by plating either a reflective metal film or a highly reflective multilayer dielectric thin film.

Alternatively, at most one of the first polarization reflector and the second polarization reflector is composed of one 45-degree Faraday rotator and one reflective mirror, and the reflective mirror is fixed to one light passing surface of the 45-degree Faraday rotator. It is formed by plating either a reflective metal film or a highly reflective multilayer dielectric thin film.

In one embodiment, the polarization beam splitting combiner is a multilayer dielectric thin film type polarization beam splitting coupler or a sub-wavelength grating type polarization beam splitting coupler.

In one embodiment, the light blocking area is a light reflection type or light absorption type light blocking area.

Another aspect of an embodiment of the present invention provides a low-crosstalk single-core bi-directional optical assembly comprising: one input/output terminal, one polarization beam splitting coupler, one first polarization reflector, one second polarization reflector, at least one An optical signal transmitting unit and one signal receiving unit are included.

The input/output terminal is configured to input an incident optical signal and output an outgoing optical signal, and the input/output terminal includes one first incident end face toward one side of the polarization beam splitting coupler.

The diagonal direction of the polarization beam splitting combiner includes one functional plane, and is configured to split one optical signal into two mutually perpendicular polarized signals, and combine two mutually perpendicular polarized signals into one optical signal. Further, the polarization beam splitting coupler includes one second incident end face toward one side of the input/output terminal.

The angle between the normal of the first incident end face of the input/output terminal and the outgoing optical signal is greater than 0 degrees and less than 82 degrees, and the angle between the normal of the second incident end face of the polarization beam splitting coupler and the incident optical signal is greater than 0 degrees and less than 82 degrees.

At least one of the first polarization reflector and the second polarization reflector includes a 45 degree Faraday rotator and a sub-wavelength grating polarization reflector, wherein the sub-wavelength grating polarization reflector generates an optical signal of a specific polarization state and project an optical signal perpendicular to the polarization state of the reflected optical signal.

The optical signal transmission unit is configured to emit an exit optical signal, and the optical signal transmission unit includes a focusing lens.

The optical signal receiving unit is configured to receive an incident optical signal, and the optical signal receiving unit includes a focusing lens.

the input/output terminal receives an incident optical signal including at least one wavelength, and couples the incident optical signal to the polarization beam splitting combiner; the incident optical signal is decomposed into a first polarization state optical signal and a second polarization state optical signal perpendicular to each other by the polarization beam splitting combiner; The first polarization state optical signal is projected through the polarization beam splitting coupler, propagates to the first polarization reflector, and is reflected back by the first polarization reflector to the polarization beam splitting coupler, and the polarization state is the initial polarization state. turns perpendicular to; The second polarization state optical signal is reflected through the polarization beam splitting combiner and propagated to the second polarization reflector, and is reflected by the second polarization reflector to the polarization beam splitting combiner and returned, and the polarization state is the initial polarization state. turns perpendicular to; The optical signal of the first polarization state whose polarization state is changed is reflected through the polarization beam split coupler, and the optical signal of the second polarization state whose polarization state is changed is projected through the polarization beam split coupler, so that two light beams in the same direction are formed. A signal is formed, propagated to the optical signal receiving unit, and received.

the optical signal transmitting unit emits an outgoing optical signal that includes at least one wavelength, and the outgoing optical signal has a single polarization state; When the optical signal transmission unit is located on one side of the first polarization reflector, the outgoing optical signal is sequentially projected to the input/output terminal via the first polarization reflector and the polarization beam splitting coupler; When the optical signal transmission unit is located on one side of the second polarization reflector, the outgoing optical signal is projected to the polarization beam splitting coupler via the second polarization reflector, and to the input/output terminal via the polarization beam splitting coupler. reflected and output.

When the outgoing optical signal is projected or reflected to the input/output terminal via the polarization beam splitting coupler, some of the outgoing optical signal is reflected by the first incident end surface of the input/output terminal or the second incident end surface of the polarization beam split coupler, A second crosstalk optical signal is formed, and the second crosstalk optical signal propagates in a reverse direction leaving the outgoing optical signal.

In one embodiment, an angle between the normal of the first incident end face of the input/output terminal and the output optical signal is greater than 8 degrees, and an angle between the normal of the second incident end face of the polarization beam splitting coupler and the output optical signal. is greater than 8 degrees.

In one embodiment, the first incident end surface of the input/output terminal and the second incident end surface of the polarization beam splitting coupler are directly bonded and connected by a refractive index matching adhesive.

In one embodiment, the angle between the outgoing optical signal and the normal of the functional plane of the polarization beam splitting combiner is 34 degrees to 44 degrees or 46 degrees to 56 degrees.

In one embodiment, the sub-wavelength grating polarization reflector includes any one of three types of gratings: a sub-wavelength non-metallic dielectric grating, a sub-wavelength metal grating, or a combination grating of a sub-wavelength non-metallic dielectric and sub-wavelength metal.

Alternatively, the sub-wavelength grating polarization reflector is made by forming one of the three gratings through a microfabrication process on one light passing surface of the 45 degree Faraday rotator.

At most one of the first polarization reflector and the second polarization reflector is composed of a 1/4 wave plate and a reflective mirror, and the reflective mirror is fixed to one light passing plane of the 1/4 wave plate. It is formed by plating either a reflective metal film or a highly reflective multilayer dielectric thin film.

Alternatively, at most one of the first polarization reflector and the second polarization reflector is composed of one 45-degree Faraday rotator and one reflective mirror, and the reflective mirror is fixed to one light passing surface of the 45-degree Faraday rotator. It is formed by plating either a reflective metal film or a highly reflective multilayer dielectric thin film.

In one embodiment, the polarization beam splitting combiner is a multilayer dielectric thin film type polarization beam splitting coupler or a sub-wavelength grating type polarization beam splitting coupler.

Beneficial effects of the present invention are as follows. One aspect of the embodiment of the present invention is one input/output terminal, one polarization beam splitting combiner, one first polarization reflector, one second polarization reflector, at least one optical signal transmission unit, one optical signal reception unit, and one A low-crosstalk single-core bidirectional optical assembly comprising a diaphragm, wherein the diaphragm includes an inner light-shielding region for blocking a crosstalk optical signal reflected or projected by a polarization beam splitting combiner to an optical signal receiving unit, so that the crosstalk optical signal is By preventing the optical signal receiving unit from reaching the optical signal receiving unit, crosstalk of the optical signal emitted from the optical signal transmitting unit to the optical signal receiving unit is effectively reduced, realizing single-core bi-directional transmission of optical signals of the same wavelength or near wavelength with a high signal-to-noise ratio. do.

Another aspect of the embodiment of the present invention includes one input/output terminal, one polarization beam splitting combiner, one first polarization reflector, one second polarization reflector, at least one optical signal transmission unit and one optical signal reception unit. Provides a low-crosstalk single-core bidirectional optical assembly that provides a low-crosstalk single-core bidirectional optical assembly, wherein the included angle between the normal of the incident surface of the input and output terminals and the output optical signal is greater than 0 degrees and smaller than 82 degrees, and the angle between the normal of the incident surface of the polarization beam splitting coupler and the output optical signal is The included angle is greater than 0 degrees and less than 82 degrees, and the incident end surface of the polarization beam splitting coupler or the incident end surface of the input/output terminal causes the crosstalk optical signal reflected by the polarization beam splitting coupler to deviate from the propagation path, so that the outgoing light of the optical signal transmission unit Crosstalk of the signal to the optical signal receiving unit is effectively reduced, realizing single-core bi-directional transmission of the same wavelength or near-wavelength optical signal with a high signal-to-noise ratio.

In order to explain the technical solutions of the embodiments of the present invention more clearly, the following briefly introduces the accompanying drawings necessary for the description of the embodiments. In the following description, the accompanying drawings are only some embodiments of the invention, and those skilled in the art to which the present invention belongs If you do, you can get other drawings based on these drawings without creative work.
1 is a schematic diagram showing crosstalk sources of the same wavelength or near wavelength single-core bidirectional optical assembly in the prior art.
2 is a structural diagram of a low-crosstalk single-core bi-directional optical assembly according to a first embodiment of the present invention.
3 and 4 are structural diagrams of a polarization beam splitting combiner according to a first embodiment of the present invention.
5 and 6 are structural diagrams of a polarization reflector according to a first embodiment of the present invention.
7 is a structural diagram of a diaphragm according to Embodiment 1 of the present invention.
8 is a structural diagram of a low-crosstalk single-core bi-directional optical assembly according to a second embodiment of the present invention.
9 is a structural diagram of a low-crosstalk single-core bi-directional optical assembly according to a third embodiment of the present invention.

In order that those skilled in the art to which the present invention belongs can better understand the technical solutions of the present invention, the following clearly describes the technical solutions of the embodiments of the present invention together with the accompanying drawings of the embodiments of the present invention, and the described embodiments represent the present invention. Some, but not all, examples of All other embodiments obtained by a person skilled in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

The term “comprising” and all variations thereof in the specification and claims of the present invention and the accompanying drawings is intended to mean a non-exclusive inclusion. In addition, terms such as “first” and “second” are used to distinguish different objects, not to describe a specific order.

Example 1

As shown in FIG. 2, this embodiment provides a low-crosstalk single-core bi-directional optical assembly 200, which includes one input/output terminal 201, one polarization beam splitting combiner 202, and one first A polarization reflector 203 and one second polarization reflector 204, at least one optical signal transmission unit 205, one optical signal reception unit 206 and one diaphragm 207 are included, and the diaphragm 207 ) includes one inner light-blocking region 2071 and one light-transmitting region 2072 .

For convenience of description, in the accompanying drawings of all embodiments of the present invention, “|” and “ㆍ” denote the polarization directions of the first polarization state optical signal and the second polarization state optical signal, respectively, and the first polarization state optical signal and The polarization directions of the second polarization state optical signals are perpendicular to each other.

In this embodiment, the input/output terminal 201 is configured to input and output an optical signal, and the input/output terminal 201 includes a first incident end face 2011 toward one side of the polarization beam splitting coupler 202.

In a specific application, the input/output end may be an optical fiber specifically configured to be connected to a polarization beam splitting combiner to realize transmission of an optical signal.

In this embodiment, the diagonal direction of the polarization beam splitting combiner 202 includes one functional surface 2022, and is configured to split one optical signal into two mutually perpendicular polarized signals, and two mutually perpendicular polarized signals. It is further configured to combine the polarized signals into one optical signal. The polarization beam splitting combiner 202 includes one second incident end face 2021 toward one side of the input/output terminal 201 .

In one embodiment, the polarization beam splitting combiner is a multilayer dielectric thin film type polarization beam splitting coupler or a sub-wavelength grating type polarization beam splitting coupler.

As shown in FIG. 3, a multilayer dielectric thin film type polarization beam splitting combiner is exemplarily shown, and propagation directions and polarization states when an incident optical signal and an outgoing optical signal pass through the multilayer dielectric thin film type polarization beam splitting combiner are exemplarily shown. It became.

As shown in FIG. 4, the sub-wavelength grating-type polarization beam splitting combiner is exemplarily shown, and the propagation direction and polarization state when the incident optical signal and the outgoing optical signal pass through the sub-wavelength grating-type polarization beam splitting combiner are exemplary. was shown as

3 and 4, an incident optical signal 301 includes optical signals of two polarization states perpendicular to each other, and incident optical signals of different polarization states are respectively projected and reflected by a polarization beam splitting coupler, and projected. It is decomposed into an optical signal 302 propagating along the path and an optical signal 303 propagating along the reflection path, and after the optical signal 302 is emitted by the first polarization reflector, the polarization state is changed to the optical signal 302 After the optical signal 303 is reflected by the second polarization reflector, the polarization state changes to the optical signal 305 perpendicular to the optical signal 303, and the optical signal 304 ) and the optical signal 305 are combined into an optical signal 306 in the same direction.

In this embodiment, at least one of the first polarization reflector 203 and the second polarization reflector 204 includes a 45 degree Faraday rotator and a sub-wavelength grating polarization reflector, and the sub-wavelength grating polarization reflector has a specific It is configured to reflect an optical signal in a polarization state and project an optical signal perpendicular to the polarization state of the reflected optical signal.

In one embodiment, the sub-wavelength grating polarization reflector includes any one of three types of gratings: a sub-wavelength non-metallic dielectric grating, a sub-wavelength metal grating, or a combination grating of a sub-wavelength non-metallic dielectric and sub-wavelength metal.

In one embodiment, the sub-wavelength grating polarization reflector is made by forming one of the three gratings through a microfabrication process on one light passing surface of the 45 degree Faraday rotator.

In one embodiment, at most one of the first polarization reflector and the second polarization reflector is composed of one 1/4 wave plate and one reflective mirror, and the reflective mirror is one of the 1/4 wave plate. It is formed by plating any one of a highly reflective metal film or a highly reflective multilayer dielectric thin film on the light passage surface of the .

In one embodiment, at most one of the first polarization reflector and the second polarization reflector is configured by one 45-degree Faraday rotator and one reflective mirror, and the reflective mirror is one light of the 45-degree Faraday rotator. It is formed by plating either a highly reflective metal film or a highly reflective multilayer dielectric thin film on the passing surface.

As shown in FIG. 5, a second polarization reflector 204 composed of one 1/4 wave plate 501 and one reflective mirror 502 is shown as an example, where the 1/4 wave plate ( 501) forms an angle of 45 degrees with the polarization direction of the incident optical signal 503, and the incident optical signal 503 passes through the 1/4 wave plate 501, passes through the reflection mirror 502, and is reflected again. Passing through the 1/4 wave plate, the polarization state is rotated by 90 degrees and converted into an optical signal 504.

In a specific application, the quarter wave plate 501 in FIG. 5 can be equally replaced by a single 45-degree Faraday rotator, and after the incident light signal has passed through the 45-degree Faraday rotator twice, its polarization state is also rotated by 90 degrees. .

As shown in FIG. 6, a first polarization reflector 203 composed of one 45-degree Faraday rotator 601 and one sub-wavelength grating polarization reflector 602 is exemplarily shown, where an incident optical signal After passing through the 45-degree Faraday rotator 601, the polarization direction is rotated by 45 degrees, reflected by the sub-wavelength grating polarization reflector 602, and then passes through the 45-degree Faraday rotator 602 again, and the polarization direction changes. It is rotated again by 45 degrees, and the polarization state is changed to the optical signal 604 rotated by 90 degrees.

As shown in FIG. 6, when an outgoing optical signal 605 having a different polarization state from the incident optical signal 603 passes through the sub-wavelength grid polarization reflector 602, the sub-wavelength grid polarization reflector 602 is also projected by the Faraday rotator 601, and after the polarization direction of the outgoing optical signal 605 is rotated by 45 degrees by the 45 Faraday rotator 601, the propagation direction of the incident optical signal 603 is opposite and the polarization state is the same. The optical signal 606 can be reversely propagated to the input/output terminal 201 according to the optical path reversibility principle.

In this embodiment, the optical signal transmission unit 205 is configured to emit an outgoing optical signal, the emitted outgoing optical signal 208 has a single polarization state, and the optical signal transmission unit 205 is configured to transmit a focusing lens. include

In a specific application, the optical signal transmission unit 205 has a focusing function, and focuses the output optical signal output through the focusing lens to the first incident end surface 2011 of the input/output terminal 201, thereby enabling the input/output terminal 201 ) is configured to propagate the outgoing optical signal to an external optical communication path.

In this embodiment, the optical signal receiving unit 206 is configured to receive an optical signal, and the optical signal receiving unit 206 includes a focusing lens.

In a specific application, the optical signal receiving unit 206 has a focusing function, and is configured to implement a receiving function for the incident optical signal by focusing an incident optical signal to its light receiving end face through a focusing lens.

As shown in Fig. 2, the polarization beam splitting combiner includes one functional surface 2022, and beam splitting and beam combining in a polarization state are realized by reflection and transmission in the functional surface 2022 through the beam. . After the outgoing optical signal 208 passes through the first polarization reflector 203, the polarization extinction rate of the formed outgoing optical signal 209 and the polarization extinction rate of the functional surface 2022 are limited, and the outgoing optical signal 208 is In terms of its function, a certain crosstalk optical signal is propagated in the direction of the optical signal receiving unit 206 to become the first crosstalk optical signal 210, and the first crosstalk optical signal due to the function of the focusing lens of the optical signal transmitting unit 205 (210) also has a focusing characteristic.

In this embodiment, the diaphragm 207 is configured to limit the optical signal, and the position of the diaphragm 207 is between the polarization beam splitting combiner 202 and the optical signal receiving unit 206, and the first crosstalk optical signal The light spot 210 is disposed at the smallest position, and the light blocking area 2071 inside the diaphragm 207 is larger than or equal to the size of the light spot formed by propagating the first crosstalk optical signal 210 to the diaphragm 207 position. , is used to block the first crosstalk optical signal 210 so that the first crosstalk optical signal 210 does not propagate to the optical signal receiving unit 206. Since the first crosstalk optical signal 210 has focusing characteristics, the light spot formed at the point of the diaphragm 207 is much smaller than the light spot of the incident light signal. The impact on losses is small.

In one embodiment, the included angle of the outgoing optical signal and the normal of the functional surface 2021 of the polarization beam splitting combiner 202 is not 45 degrees, for example, between 34 degrees and 44 degrees or between 46 degrees and 56 degrees. to make the included angle between the first crosstalk optical signal 210 in front of the optical signal receiving unit 206 and the incident optical signal greater than 0 degrees, so that the inner light-shielding region 2071 is out of the center of the incident optical signal and reduces the blockage of

In a specific application, the size, shape, and installation position of the diaphragm 207 and the light blocking region 2071 can be set according to actual needs. For example, the light-transmitting area 2072 and the inner light-shielding area 2071 of the diaphragm 207 are both circular, the diameter range of the light-transmitting area 2072 is 600 μm to 900 μm, and the diameter range of the inner light-shielding area 2071 is 30 μm to 100 μm. The inner light blocking region 2071 may have an arbitrary shape such as a rectangle, an ellipse, or a triangle.

In one embodiment, one external light blocking region 2073 is installed outside the light transmitting region 2072 of the diaphragm 207 . As shown in FIG. 7 , both the light transmitting area 2072 and the light blocking area 2071 are circular diaphragms 207, and the external light blocking area outside the light transmitting area 2072 and the light blocking area 2071 of the diaphragm 207 2073 is used to block other crosstalk optical signals and spurious optical signals from entering the optical signal receiving unit 206.

In one embodiment, the light blocking area is a reflective or absorptive light blocking area.

In a specific application, the reflective shading region may be a metal reflective mirror or a multilayer dielectric thin film reflective mirror, and the absorptive shading region may be made of a light absorbing material.

In a specific application, the optical signal transmitting unit includes a light emitting diode or a laser, and the optical signal receiving unit includes a photodiode or a photosensitive element. The optical signal transmission unit is installed on one side of the first polarization reflector or the second polarization reflector, and when the optical signal transmission unit is installed on one side of the first or second polarization reflector, the first or second polarization reflector on the one side It must consist of one 45-degree Faraday rotator and one sub-wavelength grating polarization reflector so that it is easy to project and pass the outgoing optical signal emitted from the optical signal transmission unit while reflecting the incident optical signal.

As shown in FIG. 2 , the optical signal transmission unit 205 is installed on one side of the first polarization reflector 203 as an example.

The operation principle of the low-crosstalk single-core bidirectional optical assembly 200 provided in this embodiment when receiving an incident optical signal, emitting an outgoing optical signal, and blocking a crosstalk signal is as follows.

When used for receiving an incident optical signal, the input/output end 201 receives an incident optical signal comprising at least one wavelength, and couples the incident optical signal to the polarization beam splitting coupler 202; The incident optical signal is decomposed into mutually perpendicular first polarization state optical signals and second polarization state optical signals by the polarization beam splitting combiner 202; The first polarization state optical signal is projected through the polarization beam splitting coupler 202, propagates to the first polarization reflector 203, and is reflected by the first polarization reflector 203 to the polarization beam splitting combiner 202 and returned. The polarization state changes perpendicular to its initial polarization state; The second polarization state optical signal is reflected through the polarization beam splitting combiner 202 and propagated to the second polarization reflector 204, and is reflected by the second polarization reflector 204 to the polarization beam splitting combiner 202 and returned. The polarization state changes perpendicular to its initial polarization state; The first polarization state optical signal whose polarization state is changed is reflected through the polarization beam splitting coupler 202, and the second polarization state optical signal whose polarization state is changed is projected through the polarization beam splitting combiner 202, and two An open optical signal is formed, propagated to the optical signal receiving unit 206 via the light transmitting area 2072 of the diaphragm 207, and is received.

When used to emit an outgoing optical signal, the optical signal transmission unit 205 emits an outgoing optical signal containing at least one wavelength, and the outgoing optical signal has a single polarization state; When the optical signal transmission unit 205 is located on one side of the first polarization reflector 203, the output optical signal sequentially passes through the first polarization reflector 203 and the polarization beam splitting combiner 202 to the input/output terminal 201. projected up to; When the optical signal transmission unit 205 is located on one side of the second polarization reflector 204, the outgoing optical signal passes through the second polarization reflector 204 and is projected to the polarization beam splitting combiner 202, and the polarization beam splitting combiner ( 202) and is reflected to the input/output terminal 201 and then output.

When used to block the crosstalk signal, when the outgoing optical signal is projected or reflected to the input/output terminal 201 via the polarization beam splitting combiner 202, a portion of the outgoing optical signal is transferred to the functional surface 2022 of the polarization beam splitting combiner 202. The first crosstalk optical signal 210 is formed and propagates toward the optical signal receiving unit 206, and is blocked by the internal light-shielding region 2071 of the diaphragm 207.

An embodiment of the present invention includes one input/output terminal, one polarization beam splitting combiner, one first polarization reflector, one second polarization reflector, at least one optical signal transmission unit, one optical signal reception unit, and one diaphragm. A low-crosstalk single-core bidirectional optical assembly comprising: a diaphragm is provided with an internal light-shielding region for blocking a crosstalk optical signal reflected or projected by a polarization beam splitting coupler to an optical signal receiving unit, so that the crosstalk optical signal is converted into an optical signal. By preventing the optical signal from reaching the receiving unit, the quality of the signal received by the optical signal receiving unit is effectively improved, realizing bidirectional transmission of optical signals of the same wavelength or near wavelength with a high signal-to-noise ratio.

Example 2

This embodiment is implemented based on Embodiment 1, and as shown in FIG. 8 , this embodiment provides a low-crosstalk single-core bidirectional optical assembly 300. The difference from the low-crosstalk single-core bidirectional optical assembly 200 shown in FIG. 2 is that the included angle between the normal of the incident end face 2011 of the input/output end 201 and the output optical signal is greater than 0 degrees and less than 82 degrees, , the included angle between the normal of the incident end surface 2021 of the polarization beam splitting coupler 202 and the outgoing optical signal is greater than 0 degrees and less than 82 degrees.

In a specific application, the included angle between the normal of the incident end face 2011 of the input/output terminal 201 and the outgoing optical signal is greater than 8 degrees and less than 82 degrees, and the angle of incidence of the incident end face 2021 of the polarization beam splitting combiner 202 The included angle between the normal and the outgoing light signal is greater than 8 degrees and less than 82 degrees.

Based on Embodiment 1, the working principle when the low-crosstalk single-core bidirectional optical assembly 200 provided in this embodiment blocks a crosstalk signal further includes the following.

When the outgoing optical signal is projected to the input/output terminal 201 via the polarization beam splitting combiner 202, some of the outgoing optical signal is transmitted to the incident end surface 2021 of the polarization beam splitting coupler 202 or the incident end surface of the input/output terminal 201 ( 2011) to form a second crosstalk optical signal 2012, and the outgoing light of the normal of the incident end surface 2021 of the polarization beam splitting combiner 202 and the normal of the incident end surface 2011 of the input/output terminal 201 Since the angle with respect to the signal is greater than 8 degrees and less than 90 degrees, the second crosstalk optical signal 2012 propagates at an angle greater than 16 degrees in a reverse direction away from the outgoing optical signal, and does not cause interference with the incident optical signal.

As shown in FIG. 8 , a propagation path of the second crosstalk optical signal 2012 is illustrated as an example.

In one embodiment, the incident end surface 2011 of the input/output terminal 201 and the incident end surface 2021 of the polarization beam splitting coupler 202 are directly bonded and connected by a refractive index matching adhesive.

One aspect of this embodiment is one input/output terminal, one polarization beam splitting combiner, one first polarization reflector, one second polarization reflector, at least one optical signal transmission unit, one optical signal reception unit, and one diaphragm. Provided is a low-crosstalk single-core bidirectional optical assembly comprising: a diaphragm, wherein an internal light-shielding region for blocking a crosstalk optical signal reflected or projected by a polarization beam splitting coupler to an optical signal receiving unit is provided, so that the crosstalk optical signal is transmitted to the optical signal receiving unit; not reach the signal receiving unit; The included angle between the normal of the incident cross section of the input/output terminal and the outgoing optical signal is greater than 0 degree and less than 82 degrees, and the included angle between the normal of the incident cross section of the polarization beam splitting coupler and the incident optical signal is greater than 0 degree and less than 82 degrees, The crosstalk optical signal reflected by the input/output end or the incident end face of the polarization beam splitting combiner is allowed to deviate from the propagation path, effectively improving the quality of the optical signal transmitted and received by the low-crosstalk single-core bidirectional optical assembly, resulting in the same wavelength with a high signal-to-noise ratio. Alternatively, bidirectional transmission of near-wavelength optical signals is implemented.

Example 3

As shown in FIG. 9 , this embodiment provides a low-crosstalk single-core bi-directional optical assembly 400, including one input/output terminal 201, one polarization beam splitting combiner 202, and one first A polarization reflector 203 and one second polarization reflector 204, at least one optical signal transmission unit 205 and one optical signal reception unit 206 are included, and the incident end face 2011 of the input/output terminal 201 is included. ) The included angle between the normal and the outgoing optical signal is greater than 0 degrees and less than 82 degrees, and the included angle between the normal of the incident end face 2021 of the polarization beam splitting coupler 202 and the outgoing optical signal is greater than 0 degrees and less than 82 degrees.

The structure of the low-crosstalk single-core bidirectional optical assembly 400 provided in this embodiment is similar to the structure of the low-crosstalk single-core bidirectional optical assembly 300 of Example 2, but the structure of the low-crosstalk single-core bidirectional optical assembly 300 The difference is that the diaphragm 207 is not included.

In a specific application, the included angle between the normal of the incident end face 2011 of the input/output terminal 201 and the outgoing optical signal is greater than 8 degrees and less than 82 degrees, and the angle of incidence of the incident end face 2021 of the polarization beam splitting combiner 202 The included angle between the normal and the outgoing light signal is greater than 8 degrees and less than 82 degrees.

The operation principle of the low-crosstalk single-core bidirectional optical assembly 400 provided in this embodiment when receiving an incident optical signal, emitting an outgoing optical signal, and blocking a crosstalk optical signal is as follows.

When used for receiving an incident optical signal, the input/output end 201 receives an incident optical signal comprising at least one wavelength, and couples the incident optical signal to the polarization beam splitting coupler 202; an incident optical signal is decomposed into a first polarization state optical signal and a second polarization state optical signal perpendicular to each other by the polarization beam splitting combiner 202; The first polarization state optical signal is projected through the polarization beam splitting combiner 202, propagates to the first polarization reflector 203, and is reflected back to the polarization beam splitting combiner 202 by the first polarization reflector 203; The polarization state changes perpendicular to its initial polarization state; The second polarization state optical signal is reflected through the polarization beam splitting combiner 202 and propagated to the second polarization reflector 204, and is reflected by the second polarization reflector 204 to the polarization beam splitting combiner 202 and returned. The polarization state changes perpendicular to its initial polarization state; The first polarization state optical signal whose polarization state is changed is reflected through the polarization beam splitting coupler 202, and the second polarization state optical signal whose polarization state is changed is projected through the polarization beam splitting coupler 202, and two An individual optical signal is formed, propagated to the optical signal receiving unit 206, and received.

When used to emit an outgoing optical signal, the optical signal transmission unit 205 emits an outgoing optical signal containing at least one wavelength, and the outgoing optical signal has a single polarization state; When the optical signal transmission unit 205 is located on one side of the first polarization reflector 203, the output optical signal sequentially passes through the first polarization reflector 203 and the polarization beam splitting combiner 202 to the input/output terminal 201. projected up to; When the optical signal transmission unit 205 is located on one side of the second polarization reflector 204, the outgoing optical signal passes through the second polarization reflector 204 and is projected to the polarization beam splitting combiner 202, and the polarization beam splitting combiner ( 202) and is reflected to the input/output terminal 201 and then output.

When used to block the crosstalk signal, when the outgoing optical signal is projected to the input/output terminal 201 via the polarization beam splitting coupler 202, a portion of the outgoing optical signal passes through the polarization beam splitting coupler 202 to the first incident end face 2021 Alternatively, it is reflected by the second incident end face 2011 of the input/output terminal 201 to form a second crosstalk optical signal 2012, and the normal line of the first incident end face 2021 of the polarization beam splitting coupler 202 and the input/output Since the angle of the normal of the second incident end face 2011 of the stage 201 to the outgoing optical signal is greater than 8 degrees and less than 82 degrees, the second crosstalk optical signal 2012 is 16 degrees away from the outgoing optical signal in the reverse direction. Since it propagates at a large angle, it cannot reach the optical signal receiving unit and does not cause interference to the incident optical signal.

In one embodiment, the included angle between the outgoing optical signal 209 and the normal of the functional surface 2022 of the polarization beam splitting combiner 202 is not 45 degrees, for example, 34 degrees to 44 degrees or 46 degrees to 56 degrees. The included angle between the first crosstalk optical signal 210 in front of the optical signal receiving unit 206 and the incident optical signal 213 is greater than 0 degrees, so that the first crosstalk optical signal 210 is formed by the incident light. The influence of the first crosstalk optical signal 201 deviating from the direction of the signal is reduced.

This embodiment is a low-crosstalk single unit including one input/output terminal, one polarization beam splitting combiner, one first polarization reflector, one second polarization reflector, at least one optical signal transmission unit and one optical signal reception unit. A core bi-directional optical assembly is provided, wherein the included angle between the normal of the incident surface of the input and output terminals and the output optical signal is greater than 0 degrees and less than 82 degrees, and the included angle between the normal of the incident surface of the polarization beam splitting coupler and the output optical signal is less than 0 degrees. The light transmitted and received by the low-crosstalk single-core bi-directional optical assembly is made larger than 82 degrees and the crosstalk optical signal reflected by the polarization beam splitting coupler or the input and output end faces of the polarization beam splitting coupler deviates from the propagation path. By effectively improving signal quality, bidirectional transmission of optical signals of the same wavelength or near wavelength with a high signal-to-noise ratio is realized.

The above content does not limit the present invention to the relatively preferred embodiments of the present invention, and all modifications, equivalent replacements and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (15)

In the low-crosstalk single-core bi-directional optical assembly,
one input/output terminal, one polarization beam splitting combiner, one first polarization reflector, one second polarization reflector, at least one optical signal transmission unit, one optical signal reception unit and one diaphragm; includes one light-transmitting area and one inner light-shielding area;
the input/output end is configured to input and output an optical signal, and the input/output end includes one first incident end face toward one side of the polarization beam splitting coupler;
The diagonal direction of the polarization beam splitting combiner includes one functional plane, and is configured to split one optical signal into two mutually perpendicular polarized signals, and combine two mutually perpendicular polarized signals into one optical signal. Further, the polarization beam splitting coupler includes a second incident end face toward one side of the input/output terminal;
At least one of the first polarization reflector and the second polarization reflector includes a 45 degree Faraday rotator and a sub-wavelength grating polarization reflector, wherein the sub-wavelength grating polarization reflector generates an optical signal of a specific polarization state and project an optical signal perpendicular to the polarization state of the reflected optical signal;
the optical signal transmission unit is configured to emit an exit optical signal, and the optical signal transmission unit includes a focusing lens;
the optical signal receiving unit is configured to receive an incident optical signal, the optical signal receiving unit includes a focusing lens;
the input/output terminal receives an incident optical signal including at least one wavelength, and couples the incident optical signal to the polarization beam splitting combiner; the incident optical signal is decomposed into a first polarization state optical signal and a second polarization state optical signal perpendicular to each other by the polarization beam splitting combiner; The first polarization state optical signal is projected through the polarization beam splitting coupler, propagates to the first polarization reflector, and is reflected back by the first polarization reflector to the polarization beam splitting coupler, and the polarization state is the initial polarization state. turns perpendicular to; The second polarization state optical signal is reflected through the polarization beam splitting combiner and propagated to the second polarization reflector, and is reflected by the second polarization reflector to the polarization beam splitting combiner and returned, and the polarization state is the initial polarization state. turns perpendicular to; The optical signal of the first polarization state whose polarization state is changed is reflected through the polarization beam split coupler, and the optical signal of the second polarization state whose polarization state is changed is projected through the polarization beam split coupler, so that two light beams in the same direction are formed. forming a signal, propagating through the light transmission area of the diaphragm to the optical signal receiving unit, and being received;
the optical signal transmitting unit emits an outgoing optical signal that includes at least one wavelength, and the outgoing optical signal has a single polarization state; When the optical signal transmission unit is located on one side of the first polarization reflector, the outgoing optical signal is sequentially projected to the input/output terminal via the first polarization reflector and the polarization beam splitting coupler; When the optical signal transmission unit is located on one side of the second polarization reflector, the outgoing optical signal is projected to the polarization beam splitting coupler via the second polarization reflector, and to the input/output terminal via the polarization beam splitting coupler. reflected and output;
When the outgoing optical signal is projected or reflected to the input/output terminal via the polarization beam splitting combiner, a part of the outgoing optical signal is reflected or projected by the functional surface of the polarization beam splitting coupler to form a first crosstalk optical signal; propagates toward the optical signal receiving unit;
the diaphragm is configured to confine an optical signal, the diaphragm is positioned between the polarization beam splitting combiner and the optical signal receiving unit, and the light spot of the first crosstalk optical signal is positioned at a position where the light point is smallest; The light blocking region inside the diaphragm is greater than or equal to a size of a light spot formed by propagation of the first crosstalk optical signal to the position of the diaphragm, and blocks the first crosstalk optical signal so that the first crosstalk optical signal does not propagate to the optical signal receiving unit. used to do,
the angle between the outgoing optical signal and the normal to the functional plane of the polarization beam splitting coupler is 34 degrees to 44 degrees or 46 degrees to 56 degrees; The low-crosstalk single-core bi-directional optical assembly, characterized in that the inner light-shielding area of the diaphragm is provided to deviate from the center of the light-transmitting area. According to claim 1,
The angle between the normal of the first incident end face of the input/output terminal and the outgoing optical signal is greater than 0 degrees and less than 82 degrees, and the angle between the normal of the second incident end face of the polarization beam splitting coupler and the incident optical signal is greater than 0 degrees and less than 82 degrees;
When the outgoing optical signal passes through the polarization beam splitting coupler and is projected to the input/output terminal, a part of the outgoing optical signal is reflected by the first or second incident end face to form a second crosstalk optical signal, and the second crosstalk optical signal A low-crosstalk single-core bidirectional optical assembly, characterized in that the signal propagates in a reverse direction away from the output optical signal. According to claim 2,
The angle between the normal of the first incident surface of the input/output terminal and the output optical signal is greater than 8 degrees, and the angle between the normal of the second incident surface of the polarization beam splitting coupler and the output optical signal is greater than 8 degrees. Features a low-crosstalk single-core bi-directional optical assembly. According to claim 2,
A low-crosstalk single-core bidirectional optical assembly, characterized in that the first incident end surface of the input and output terminal and the second incident end surface of the polarization beam splitting coupler are directly bonded by a refractive index matching adhesive. delete According to claim 1,
The low-crosstalk single-core bidirectional optical assembly of claim 1 , wherein the diaphragm further comprises an outer light-blocking region for blocking crosstalk optical signals and spurious optical signals from entering the optical signal receiving unit. According to claim 1,
the sub-wavelength grating polarization reflector includes any one of a total of three gratings: a sub-wavelength non-metal dielectric grating, a sub-wavelength metal grating, or a combination grating of a sub-wavelength non-metallic dielectric and a sub-wavelength metal;
Alternatively, the sub-wavelength grating polarization reflector is made by forming one of the three gratings through a micro-machining process on one light passing surface of the 45 degree Faraday rotator;
At most one of the first polarization reflector and the second polarization reflector is composed of a 1/4 wave plate and a reflective mirror, and the reflective mirror is fixed to one light passing plane of the 1/4 wave plate. formed by plating either a reflective metal film or a highly reflective multilayer dielectric thin film;
Alternatively, at most one of the first polarization reflector and the second polarization reflector is composed of one 45-degree Faraday rotator and one reflective mirror, and the reflective mirror is fixed to one light passing surface of the 45-degree Faraday rotator. A low-crosstalk single-core bidirectional optical assembly formed by plating either a reflective metal film or a highly reflective multilayer dielectric thin film. According to claim 1,
The polarization beam splitting combiner is a multilayer dielectric thin film type polarization beam splitting combiner or a sub-wavelength grating type polarization beam splitting coupler. According to claim 1,
The light blocking region is a light reflection type or light absorption type light blocking region. delete delete delete delete delete delete

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