CN219871874U - Single-fiber bidirectional device with high reflection return loss and optical module - Google Patents

Abstract

The utility model provides a single-fiber bidirectional device and an optical module with high reflection return loss, which integrate an optical filter and a detector through an optical filter support, ensure that the optical axes of the optical filter and the detector coincide, synchronously deflect the detector and the optical filter at a preset angle, and couple the deflected detector into an optical receiving end of a tube body, thereby ensuring that reflected light generated when incident light passes through the optical filter cannot be transmitted along a receiving optical path, improving the reflection return loss index, and ensuring the coupling index and the coupling efficiency between the optical signal and the detector after the optical signal passes through the optical filter because the optical filter always coincides with the optical axis of the detector.

Description

Single-fiber bidirectional device with high reflection return loss and optical module

Technical Field

The utility model relates to the field of optical modules, in particular to a single-fiber bidirectional device with high reflection return loss and an optical module.

Background

In the prior art, before the detector receives the optical signal, the optical signal needs to pass through the optical filter, so that the optical signal is screened at a specified wavelength, the optical filter reflects the optical signal in the process of passing through the optical filter, the optical signal is normally vertically incident, the light path of the reflected light coincides with the original receiving light path, the reflection return loss index is low, the reflection return loss index can only meet the level of-14 db to-20 db, and the specified reflection return loss index is difficult to reach; the prior solution comprises the following two methods: the first method is to change the angle of the 45-degree beam splitter on the original light emitting path and the light receiving path, so as to deflect the original light path, thereby reducing the reflection on the 45-degree beam splitter, when the light signal is reflected on the 45-degree beam splitter and the optical filter, the reflected light cannot be transmitted along the original receiving light path, and the reflection return loss index is improved, but at the same time, the 45-degree optical filter is taken as the most important optical component of the main light path, and the change of the angle can affect the coupling index and the efficiency of the laser emission and the detector reception at the same time, so that the insufficient light power margin or the insufficient responsiveness margin can be caused; in the second method, the incident angle of the pin assembly is increased, so that an original light path is deflected, when an optical signal is reflected on the 45-degree beam splitter and the optical filter, reflected light cannot be transmitted along an original receiving light path, and in this way, a return loss index can be improved, but at the same time, the larger the emergent angle of the pin assembly is, the larger the deflection of the light path is, the coupling index and the efficiency of laser emission and detector receiving are affected, and the insufficient optical power margin or the insufficient responsivity margin can be caused.

In view of this, overcoming the drawbacks of the prior art is a problem to be solved in the art.

Disclosure of Invention

The utility model aims to solve the technical problem of improving the reflection loss index of the device on the premise of avoiding too much influence on the coupling efficiency and index of the detector and the laser.

The utility model is realized in the following way:

in a first aspect, a high return loss single fiber bi-directional device is provided, comprising: light filter 1, light filter support 2, detector 3 and body 4, wherein:

the optical filter support 2 is arranged at the position of the circumference of the light receiving port 31 of the detector 3, the optical filter 1 is arranged on the optical filter support 2, and the optical axes of the optical filter 1 and the detector 3 are in the same straight line;

the upper end of the tube body 4 is provided with a light receiving end 41, the detector 3 is coupled in the light receiving end 41 of the tube body 4, and the optical axes of the detector 3 and the optical filter 1 are deflected by a preset angle relative to a receiving optical path in the tube body 4.

Preferably, the light receiving end 41 is in a hollow column shape, and the caliber of the light receiving end 41 is larger than the diameter of the section of the detector 3, so that the detector 3 after being deflected by a preset angle is coupled;

after the detector 3 deflects by a preset angle, the outer side of the detector 3 is adhered to the inner side of the light receiving end 41 by glue.

Preferably, the preset angle is 1-3 °.

Preferably, the filter support 2 is hollow cylindrical, and the filter support 2 includes a bottom end round table 21 and a round groove 22, wherein:

the bottom round table 21 is positioned at the bottom of the optical filter support 2, and the round groove 22 is positioned at the top of the optical filter support 2;

the bottom round table 21 is a hollow circular column, the light receiving port 31 of the detector 3 is in a convex shape, the bottom round table 21 is adhered to the peripheral position of the light receiving port 31, and the light receiving port 31 extends into the optical filter support 2 from the center position of the bottom round table 21;

the center of the circular groove 22 is provided with a light passing hole, the axis of the light passing hole coincides with the axis of the optical filter 1, and the upper surface of the circular groove 22 is used for bonding the optical filter 1 and limiting the optical filter 1.

Preferably, the filter 1 is a 0 ° filter.

Preferably, the tube body 4 includes: laser 5, pin assembly 6 and beam splitter 43, wherein:

the pin assembly 6 is arranged at one end of the pipe body 4, the other end of the pipe body 4 is a light emitting end 42, the laser 5 is coupled in the light emitting end 42, and the laser 5 and the pin assembly 6 are positioned at the same optical axis;

the beam splitter 43 is disposed between the laser 5 and the pin assembly 6, and is located on the optical axis of the laser 5 and the optical axis of the detector 3.

Preferably, the light receiving end 41 is located at the upper end of the tube body 4, and the light receiving end 41 is oriented perpendicularly to the optical axis of the pin assembly 6.

Preferably, the light splitting piece 43 forms an angle of 45 ° with the optical axis of the laser 5, and the light splitting piece 43 forms an angle of 45 ° with the light emitting end 42.

Preferably, the tube body 4 further comprises: an isolator 44, wherein:

the isolator 44 is disposed between the laser 5 and the beam splitter 43, and is used for isolating the retro-reflection light from entering the laser 5.

In a second aspect, an optical module includes the high reflection loss single fiber bi-directional device.

The embodiment of the utility model provides a single-fiber bidirectional device and an optical module with high reflection return loss, which integrate an optical filter and a detector through an optical filter support, ensure that the optical axes of the optical filter and the detector are coincident, synchronously deflect the detector and the optical filter at a preset angle, and couple the deflected detector into an optical receiving end of a tube body, thereby ensuring that reflected light generated when incident light passes through the optical filter cannot be transmitted along a receiving optical path, improving the reflection return loss index, and ensuring the coupling index and the coupling efficiency between the optical signal and the detector after the optical signal passes through the optical filter because the optical filter is always coincident with the optical axis of the detector.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a cross-sectional view of a high reflection return loss single fiber bi-directional device provided by an embodiment of the present utility model;

FIG. 2 is a schematic diagram of an integrated structure of a detector and an optical filter of a single-fiber bidirectional device with high reflection return loss according to an embodiment of the present utility model;

FIG. 3 is a schematic structural diagram of a detector of a single-fiber bidirectional device with high reflection return loss according to an embodiment of the present utility model;

FIG. 4 is a cross-sectional view of another high reflection return loss single fiber bi-directional device provided by an embodiment of the present utility model;

FIG. 5 is a cross-sectional view of a prior art single fiber bi-directional device provided by an embodiment of the present utility model;

FIG. 6 is a cross-sectional view of a detector of a high reflection loss single fiber bi-directional device according to an embodiment of the present utility model removed;

fig. 7 is a schematic structural diagram of an optical filter support of a single-fiber bidirectional device with high reflection return loss according to an embodiment of the present utility model;

FIG. 8 is a schematic diagram of a structure in which a detector of a single-fiber bidirectional device with high reflection loss is bonded to a filter support according to an embodiment of the present utility model;

FIG. 9 is a schematic diagram of a structure in which an optical filter and an optical filter support of a single-fiber bidirectional device with high reflection loss are bonded;

FIG. 10 is a cross-sectional view of a high reflection return loss single fiber bi-directional device provided by an embodiment of the present utility model;

wherein, the reference numerals in the drawings are as follows:

a filter 1; a filter holder 2; round bench 21; a detector 3; a light receiving port 31; a tube body 4; a light receiving end 41; a light emitting end 42; a light-splitting sheet 43; an isolator 44; a laser 5; pin assembly 6.

Detailed Description

In the description of the present utility model, the terms "inner", "outer", "longitudinal", "transverse", "upper", "lower", "top", "bottom", etc. refer to an orientation or positional relationship based on that shown in the drawings, merely for convenience of describing the present utility model and do not require that the present utility model must be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

The terms "first," "second," and the like herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the present utility model, unless explicitly specified and limited otherwise, the term "connected" is to be construed broadly, and for example, "connected" may be either fixedly connected, detachably connected, or integrally formed; can be directly connected or indirectly connected through an intermediate medium. Furthermore, the term "coupled" may be a means of electrical connection for achieving signal transmission.

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Example 1:

embodiment 1 of the present utility model provides a single-fiber bidirectional device with high reflection return loss, as shown in fig. 1-3, including: light filter 1, light filter support 2, detector 3 and body 4, wherein:

as shown in fig. 2 and 3, the optical filter support 2 is disposed at a position around the light receiving port 31 of the detector 3, the optical filter 1 is disposed on the optical filter support 2, and the optical axes of the optical filter 1 and the detector 3 are in the same straight line; as shown in fig. 1, the upper end of the tube body 4 is provided with a light receiving end 41, the detector 3 is coupled into the light receiving end 41 of the tube body 4, and the optical axes of the detector 3 and the optical filter 1 are deflected by a preset angle with respect to a receiving optical path in the tube body 4.

As shown in fig. 4, the structure of this embodiment is a single-fiber bidirectional device, where the single-fiber bidirectional device includes a light emitting end 42, a light receiving end 41, a tube body 4 and a pin assembly 6, where the tube body 4 is a housing of the single-fiber bidirectional device, and the tube body 4 is provided with the light emitting end 42 and the light receiving end 41, where the light emitting end 42 is used TO set a laser 5, and the light receiving end 41 is used TO set a detector 3, and in this embodiment, the laser 5 is a laser TO-CAN, and the detector 3 is a detector TO-CAN; the pin assembly 6 is used for being connected with other components, transmitting the optical signals from the laser 5 to the other components, and receiving the optical signals from the other components and transmitting the optical signals to the detector 3; in this embodiment, the tube body 4 may be a round square tube body.

Wherein, the optical signal is emitted from the laser 5 and emitted from the pin assembly 6, namely an emergent light path; the pin module 6 receives the optical signal from other components, and after passing through the beam splitter 43, the optical signal is received by the detector 3, and the received optical path represents the optical path between the beam splitter and the optical filter.

In this embodiment, the optical filter 1 is a 0 ° optical filter, the optical filter 1 is disposed on a receiving optical path in front of the detector 3, optical signals transmitted to the detector 3 need to be received by the detector 3 after passing through the optical filter 1, and the optical filter 1 is used for screening optical signals with specified wavelengths to enter the detector 3.

As shown in fig. 2, the filter support 2 is configured to fix the filter 1 to the detector 3, and it is required to ensure that the filter 1 and the detector 3 are located on the same optical axis, so that when the optical axis deflection is performed on the detector 3, the filter 1 and the detector 3 are relatively fixed, and therefore, the filter 1 and the detector 3 synchronously perform the optical axis deflection at the same angle; as shown in fig. 5, in most of the prior art single-fiber bidirectional device structures, in most of the cases, the optical signal is incident perpendicularly to the surface of the optical filter 1, so that the surface of the optical filter 1 reflects the optical signal, the reflected optical path is consistent with the original receiving optical path, thereby affecting the original incident optical signal and leading to lower reflection loss of the receiving end, in this embodiment, the optical filter 1 is arranged on the detector 3, and the detector 3 and the optical filter 1 are synchronously deflected by a preset angle, so that the original receiving optical path is not perpendicularly incident to the surface of the optical filter 1, but reflected by the preset angle, the incident light on the optical filter 1 is ensured not to coincide with the reflected light, the reflection loss index is improved, meanwhile, because the detector 3 and the optical filter 1 synchronously deflect, the optical signal is coupled into the detector 3 with the same deflection angle after passing through the optical filter 1 with the deflection angle, so that the coupling index and the efficiency received by the detector 3 are not greatly affected; wherein the preset angle is adjusted by a person skilled in the art according to actual conditions; in this embodiment, the preset angle is 1 ° to 3 °.

As shown in fig. 5, in most of the single-fiber bidirectional device structures in the prior art, before the detector receives the optical signal, the optical signal needs to pass through the optical filter, so that the optical signal is screened at a specified wavelength, the optical filter table reflects the optical signal in the process of passing through the optical filter, the optical signal is normally vertically incident, the optical path of the reflected light coincides with the original receiving optical path, so that the reflection loss index is lower, and in such a situation, the reflection loss index can only meet the level of-14 db to-20 db, and the required reflection loss index is difficult to reach; the prior solution comprises the following two methods: the first method is to change the angle of the 45-degree beam splitter on the original light emitting path and the light receiving path, so as to deflect the original light path, thereby reducing the reflection on the 45-degree beam splitter, when the light signal is reflected on the 45-degree beam splitter and the optical filter, the reflected light cannot be transmitted along the original receiving light path, and the reflection return loss index is improved, but at the same time, the 45-degree optical filter is used as an important optical component in the main light path, and the change of the angle can affect the coupling index and the efficiency of the laser emission and the detector reception at the same time, so that the insufficient light power margin or the insufficient responsivity margin can be caused; in the second method, the incident angle of the pin assembly is increased, so that an original light path is deflected, when an optical signal is reflected on the 45-degree beam splitter and the optical filter, reflected light cannot be transmitted along an original receiving light path, and in this way, the reflection return loss index can be improved, but at the same time, the larger the emergent angle of the pin assembly is, the larger the deflection of the light path is, the coupling index and the efficiency of the laser emission and the detector receiving are affected, and the insufficient optical power allowance or the insufficient responsivity allowance can be possibly caused.

In this embodiment, the optical filter 1 and the detector 3 are integrated through the optical filter support 2, and it is ensured that the optical axes of the optical filter 1 and the optical axis of the detector 3 are coincident, the detector 3 and the optical filter 1 are synchronously deflected by a preset angle, and the deflected detector 3 is coupled into the light receiving end 41 of the tube body 4, so that it is ensured that reflected light generated when incident light passes through the optical filter 1 is not transmitted along a receiving light path, and therefore, the reflection loss index is improved, and meanwhile, as the optical axes of the optical filter 1 and the optical filter 3 are always coincident, after the optical signal passes through the optical filter 1, the coupling index and the coupling efficiency between the optical signal and the detector 3 can be ensured.

Since the detector 3 and the optical filter 1 need to be coupled to the light receiving end 41 after being deflected, the port of the light receiving end 41 needs to provide a space for inserting and deflecting the detector 3, and thus the present embodiment also relates to a preferable design:

as shown in fig. 6, the light receiving end 41 is in a hollow column shape, and the caliber of the light receiving end 41 is larger than the diameter of the cross section of the detector 3, so that the detector 3 after being deflected by a preset angle is coupled; after the detector 3 deflects by a preset angle, the outer side of the detector 3 is adhered to the inner side of the light receiving end 41 by glue.

As shown in fig. 6, the light receiving end 41 is hollow and cylindrical, and is led into the tube body 4, the detector 3 is inserted into the light receiving end 41 after being adjusted to a specified deflection angle, and the outer side of the detector 3 is bonded with the inner side of the light receiving end 41 through glue, wherein the caliber of the light receiving end 41 is larger than the diameter of the cross section of the detector 3, so that the detector 3 can be inserted into the light receiving end 41 in a deflection manner of a certain angle, or the movement adjustment in the horizontal direction or the vertical direction is performed in the light receiving end 41.

In this embodiment, the method for deflecting the detector 3 by a predetermined angle and coupling with the light receiving end 41 is as follows: the detector 3 is clamped by the holder clamp, the detector 3 is deflected by a preset angle by the holder clamp, after the deflection by the preset angle is completed, the detector 3 is clamped by the holder clamp and inserted into the light receiving end 41, and corresponding four glue is respectively arranged on the outer side of the detector 3 and the inner side of the light receiving end 41, so that the detector 3 is adhered to the inside of the light receiving end 41.

When the optical filter 1 is integrated on the detector 3, since the optical filter 1 needs to pass through an optical signal, and in order to ensure that the optical filter 1 can complete screening of an optical signal with a specified wavelength, the optical filter 1 needs to keep a certain distance from the light receiving port 31 of the detector 3, so that the optical filter 1 cannot be directly adhered to the detector 3, the present embodiment achieves the above condition by providing the optical filter support 2 between the optical filter 1 and the detector 3, and therefore the present embodiment relates to the following design:

as shown in fig. 7, the filter support 2 is hollow cylindrical, and the filter support 2 includes a bottom end truncated cone 21 and a circular groove 22, wherein:

as shown in fig. 7, the bottom end circular table 21 is located at the bottom of the filter support 2, and the circular groove 22 is located at the top end of the filter support 2; as shown in fig. 3 and 8, the bottom circular table 21 is a hollow circular column, the light receiving opening 31 of the detector 3 is convex, the bottom circular table 21 is adhered to the peripheral position of the light receiving opening 31, and the light receiving opening 31 extends into the filter support 2 from the center position of the bottom circular table 21; as shown in fig. 8 and 9, the center of the circular groove 22 is provided with a light passing hole, the axis of the light passing hole coincides with the axis of the optical filter 1, and the upper surface of the circular groove 22 is used for bonding the optical filter 1 and limiting the optical filter 1.

In this embodiment, as shown in fig. 3, the front end of the conventional detector 3 is convex, that is, the light receiving port 31 of the detector 3 is used for directly receiving the light signal, so the light filter support 2 cannot cover the light receiving port 31 of the detector 3, and therefore the light filter support 2 needs to be in a hollow column shape, and a hollow portion in the middle is used for passing through a light receiving path; as shown in fig. 7-9, the bottom end of the filter support 2 is used for being connected with the detector 3, the top end of the filter support 2 is used for being connected with the filter 1, the bottom end of the filter support 2, that is, the bottom end round table 21, is framed around the light receiving opening 31, in this embodiment, the bottom surface of the bottom end round table 21 is bonded with the light receiving opening 31 by means of glue or welding, the top end of the filter support 2 is provided with a circular groove 22, a light passing hole in the center of the circular groove 22 is used for passing through a receiving light path, the aperture of the light passing hole is smaller than the diameter of the filter support 2, so that the circular groove 22 provides a supporting surface for bonding the filter 1, in this embodiment, the filter 1 is square, therefore, the diameter of the circular groove 22 should be greater than the diagonal length of the filter 1, when the filter 1 is actually bonded, the glue is only coated on four corners of the filter 1, and the four corners of the filter 1 are bonded on the supporting surface of the filter 22, so that the passing through the center of the filter 1 is not affected; the height of the filter support 2 is set according to the distance between the filter 1 and the detector 3.

In this embodiment, in order to ensure that the optical signals of the optical transmitting end 42 and the optical receiving end 41 both pass through the pin assembly 6, the present embodiment further relates to the following design:

as shown in fig. 10, the pipe body 4 includes: laser 5, pin assembly 6 and beam splitter 43, wherein:

the pin assembly 6 is disposed at one end of the tube body 4, the other end of the tube body 4 is a light emitting end 42, the laser 5 is coupled in the light emitting end 42, and the laser 5 and the pin assembly 6 are located on the same optical axis. The beam splitter 43 is disposed between the laser 5 and the pin assembly 6, and is located on the optical axis of the laser 5 and the optical axis of the detector 3. The light receiving end 41 is located at the upper end of the tube body 4, and the light receiving end 41 is oriented perpendicularly to the optical axis of the pin assembly 6.

As shown in fig. 10, the beam splitter 43 forms an angle of 45 ° with the optical axis of the laser 5, and the beam splitter 43 forms an angle of 45 ° with the light emitting end 42.

As shown in fig. 10, the pipe body 4 further includes: an isolator 44, wherein:

the isolator 44 is disposed between the laser 5 and the beam splitter 43, and is used for isolating the retro-reflection light from entering the laser 5.

Example 2:

the embodiment 2 of the utility model provides a single-fiber bidirectional device with high reflection return loss on the basis of the embodiment 1, and the structure and the light path of the single-fiber bidirectional device with high reflection return loss are shown in a specific situation.

The present embodiment employs a 0 ° filter and a 45 ° spectroscopic plate 43, in which:

the optical filter 1 is adhered to the optical filter support 2 through glue, so that the optical filter 1, the optical filter support 2 and the detector 3 are integrated, and the optical axes of the optical filter 1 and the detector 3 are ensured to coincide; then coupling the contact pin assembly 6, the laser 5 and the detector 3 into the pipe body 4, clamping the detector 3 through a holder clamp when the detector 3 is coupled, deflecting the detector 3 by 3 degrees through the holder clamp, arranging four glues on the outer side of the detector 3 and the inner side of the light receiving end 41 after the deflection of 3 degrees is completed, clamping the detector 3 by the holder clamp to be inserted into the light receiving end 41, and bonding the detector 3 into the light receiving end 41; the original optical filter 1 is vertically reflected on the optical path of the detector 3, and the optical path of the reflected light coincides with the receiving optical path, so that the index of reflection return loss is lower under the condition, but in the embodiment, the optical filter 1 and the detector 3 are synchronously deflected by 3 degrees, so that the optical filter 1 has the angle deflection of 3 degrees when the light is incident, the return loss on the reflecting surface of the optical filter 1 is increased, the index of reflection return loss of a device is further improved, and meanwhile, the optical filter 1 and the detector 3 are connected together, so that the coupling efficiency and the influence of the index caused by the angle deflection are reduced to the greatest extent.

Example 3:

the embodiment 3 of the utility model provides an optical module on the basis of the embodiment 1, wherein the optical module comprises the single-fiber bidirectional device with high reflection return loss of the embodiment 1; in actual use, other related components can be arranged in a matched manner according to the specific application scene of the optical module. The specific structure of the high reflection loss single-fiber bidirectional device is described in the foregoing, and is not repeated here.

The foregoing description of the preferred embodiments of the utility model is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the utility model.

Claims (10)

1. A high reflection loss single fiber bi-directional device comprising: light filter (1), light filter support (2), detector (3) and body (4), wherein:

the optical filter support (2) is arranged at the circumferential position of the light receiving port (31) of the detector (3), the optical filter (1) is arranged on the optical filter support (2), and the optical axes of the optical filter (1) and the detector (3) are in the same straight line;

the optical fiber optical tube is characterized in that a light receiving end (41) is arranged at the upper end of the tube body (4), the detector (3) is coupled in the light receiving end (41) of the tube body (4), and the optical axes of the detector (3) and the optical filter (1) deflect by a preset angle relative to a receiving light path in the tube body (4).

2. The single-fiber bidirectional device with high reflection loss according to claim 1, wherein the light receiving end (41) is hollow and columnar, and the caliber of the light receiving end (41) is larger than the diameter of the section of the detector (3) and is used for coupling the detector (3) after deflection by a preset angle;

after the detector (3) deflects by a preset angle, the outer side of the detector (3) is bonded with the inner side of the light receiving end (41) through glue.

3. The high return loss single fiber bi-directional device of claim 1, wherein the predetermined angle is 1 ° to 3 °.

4. The high return loss single fiber bi-directional device of claim 1, wherein the filter support (2) is hollow cylindrical, the filter support (2) comprises a bottom end truncated cone (21) and a circular groove (22), wherein:

the bottom end round table (21) is positioned at the bottom of the optical filter support (2), and the round groove (22) is positioned at the top end of the optical filter support (2);

the bottom end round table (21) is a hollow circular column, a light receiving port (31) of the detector (3) is in a convex shape, the bottom end round table (21) is adhered to the peripheral position of the light receiving port (31), and the light receiving port (31) extends into the optical filter support (2) from the center position of the bottom end round table (21);

the center of the circular groove (22) is provided with a light passing hole, the axis of the light passing hole coincides with the axis of the optical filter (1), and the upper surface of the circular groove (22) is used for bonding the optical filter (1) and limiting the optical filter (1).

5. The high return loss single fiber bi-directional device of claim 1 wherein the filter (1) is a 0 ° filter.

6. The high return loss single fiber bi-directional device of claim 1, wherein a laser (5), a pin assembly (6) and a beam splitter (43) are disposed within the tube (4), wherein:

the contact pin assembly (6) is arranged at one end of the pipe body (4), the other end of the pipe body (4) is a light emitting end (42), the laser (5) is coupled in the light emitting end (42), and the laser (5) and the contact pin assembly (6) are located on the same optical axis;

the beam splitting sheet (43) is arranged between the laser (5) and the pin assembly (6) and is positioned on the optical axis of the laser (5) and the optical axis of the detector (3).

7. The high return loss single fiber bi-directional device of claim 6 wherein the light receiving end (41) is located at the upper end of the tube body (4) and the light receiving end (41) is oriented perpendicular to the optical axis of the pin assembly (6).

8. The high return loss single fiber bi-directional device of claim 6 wherein said beam splitter (43) is oriented at a 45 ° angle to the optical axis of said laser (5), said beam splitter (43) being oriented at a 45 ° angle to said light emitting end (42).

9. The high return loss single fiber bi-directional device of claim 6, wherein an isolator (44) is further disposed within the tube (4), wherein:

the isolator (44) is arranged between the laser (5) and the light splitting sheet (43) and is used for isolating the retro-reflection light from entering the laser (5).

10. An optical module comprising the high return loss single fiber bi-directional device of any of claims 1-9.