CN218886221U - Polarization maintaining optical fiber coupling device - Google Patents

Abstract

The utility model provides a polarization maintaining optical fiber coupling device. The polarization maintaining fiber coupling device comprises: the focusing lens group is arranged in the lens cone, wherein a first light through hole is formed in the fixed seat and corresponds to a light outlet of an external laser; the lens cone is fixedly connected with the fixed seat, and a second light through hole communicated with the first light through hole is formed in the lens cone; the connecting seat is connected with the lens cone and connected with the optical fiber assembly; and the connecting seat is provided with a third light through hole communicated with the second light through hole and a fourth light through hole communicated with the third light through hole, and an included angle gamma is formed between the central axis of the fourth light through hole and the central axis of the third light through hole, so that the fourth light through hole is inclined relative to the third light through hole. The technical scheme of the utility model can reduce the influence of fiber end face reflection to the laser beam.

Description

Polarization maintaining optical fiber coupling device

Technical Field

The utility model relates to an optical fiber technology field particularly, relates to a polarization maintaining optical fiber coupling device.

Background

The polarization maintaining fiber has high extinction ratio and is a special fiber capable of maintaining linear polarization in a certain direction. The polarization maintaining fiber has the advantages of multi-directional direction, linear polarization maintaining capacity and the like. It is widely used in polarization-related fields. The alignment of the principal axes of polarization of the fiber is critical to the transmission of the input polarization state without distortion.

At present, an existing optical fiber coupling device is generally used for coupling a common optical fiber, and includes a lens barrel and a focusing lens group disposed in the lens barrel, central axes of the lens barrel and the focusing lens group both extend along a preset direction, one side of the lens barrel is connected with a light source, the other side of the lens barrel is connected with an optical fiber assembly, and a laser beam emitted from a light outlet of the light source can pass through the focusing lens group along the preset direction and then enter the optical fiber assembly, so that coupling of the optical fiber is achieved. If the existing optical fiber coupling device is adopted to realize the coupling of the polarization-maintaining optical fiber, on one hand, a laser beam emitted by a light source is transmitted along a straight line, the laser beam is emitted at the end face of an optical fiber component, reflected light is directly transmitted to the light source along a preset direction, and a virtual reflection phenomenon is caused, so that the polarized light transmission mode of the polarization-maintaining optical fiber is adversely affected; on the other hand, improper mating between the polarization maintaining fiber and the connector may cause axial displacement of the composite beam and the coupling efficiency may also be reduced.

SUMMERY OF THE UTILITY MODEL

A primary object of the present invention is to provide a polarization maintaining fiber coupling device to solve the problem of polarized light transmission of polarization maintaining fiber caused by the reflection of the laser beam of polarization maintaining fiber at the end surface of the optical fiber assembly in the prior art.

In order to achieve the above object, the present invention provides a polarization maintaining optical fiber coupling device, including: the focusing lens group is arranged in the lens cone, wherein a first light through hole is formed in the fixed seat, and the first light through hole is constructed to be capable of being arranged corresponding to a light outlet of an external laser; the lens cone is provided with a first end and a second end which are arranged oppositely, the first end of the lens cone is fixedly connected with the fixed seat, the lens cone is provided with a second light through hole communicated with the first light through hole, the focusing lens group is positioned in the second light through hole, and the optical axis of the focusing lens group is coaxial with the second light through hole; the connecting seat is provided with a first end and a second end which are oppositely arranged, the first end of the connecting seat is arranged in the second light through hole, the second end of the connecting seat is connected with the second end of the lens cone, and the second end of the connecting seat is constructed to be capable of being connected with the optical fiber assembly; the connecting base is provided with a third light through hole communicated with the second light through hole and a fourth light through hole communicated with the third light through hole, the maximum angle at which the lens barrel can receive light is always smaller than or equal to the maximum angle at which the connecting base can receive light, and an included angle gamma is formed between the central axis of the fourth light through hole and the central axis of the third light through hole, so that the fourth light through hole is inclined relative to the third light through hole.

Further, the angle γ between the third light passing hole and the fourth light passing hole ranges from 6 ° to 10 °.

Furthermore, the connecting seat comprises a seat body and an end cover which are connected, the third light through hole is formed in the seat body, the fourth light through hole is formed in the end cover, and an included angle is formed between the two end faces of the end cover.

Further, polarization maintaining fiber coupling device still includes the first adjustment mechanism of setting between lens cone and fixing base, and first adjustment mechanism can adjust the axiality between first light passing hole and the second light passing hole, and first adjustment mechanism includes: at least three first connection holes arranged on the lens barrel at intervals in a circumferential direction of the lens barrel; the at least three adjusting threaded holes are arranged in one-to-one correspondence to the first connecting holes and are arranged at intervals along the circumferential direction of the fixed seat; and each adjusting screw penetrates through the first connecting hole and then is in threaded connection with the corresponding adjusting threaded hole.

Further, polarization maintaining fiber coupling device still includes a plurality of elastic components of setting between lens cone and fixing base, and a plurality of elastic components set up with a plurality of adjusting screw one-to-one to every elastic component is established in the periphery of the adjusting screw that corresponds, the one end of elastic component and the terminal surface butt of lens cone, the other end of elastic component and the terminal surface butt of fixing base.

Further, the lens cone includes that lens cone body and the first annular of setting on the outer peripheral face of lens cone body one end are protruding, a plurality of first connecting holes are all seted up on first annular is protruding, a plurality of first locking screw holes have still been seted up on the first annular is protruding, a plurality of first locking screw holes and a plurality of first connecting hole are along the bellied circumference interval arrangement of first annular, first adjustment mechanism still includes a plurality of fine setting screws, every fine setting screw passes behind a first locking screw hole with the terminal surface butt of fixing base, in order to finely tune the axiality of fixing base and lens cone.

Further, the polarization maintaining fiber coupling device further comprises a locking structure for connecting the lens barrel and the connecting seat, and the locking structure comprises: the two first focusing threaded holes are arranged on the lens barrel at intervals, extend along the radial direction of the lens barrel and are communicated with the second light through hole; the two grooves are arranged on the connecting seat at intervals, the two grooves are respectively in one-to-one correspondence with the two first focusing threaded holes, and the central axes of the two grooves form an included angle; and each first focusing screw penetrates through the first focusing threaded hole and then is abutted against the groove bottom of the corresponding groove.

Further, the two grooves are spaced apart by 90 ° in the circumferential direction of the connecting socket.

Furthermore, the polarization maintaining optical fiber coupling device further comprises an optical fiber connector connected with the connecting seat, a positioning clamping groove is formed in the optical fiber connector, and the central axis of the positioning clamping groove is parallel to the central axis of the fourth light hole.

Further, the external screw thread that can with outside frock threaded connection is still seted up to the surface of fixing base.

By applying the technical scheme of the utility model, the laser beam emitted from the light outlet of the external laser can sequentially pass through the first light through hole, the second light through hole, the focusing lens group, the third light through hole and the fourth light through hole and then enter the optical fiber assembly, and the laser beam can be transmitted along the preset direction because the optical axes of the first light through hole, the second light through hole, the focusing lens group and the third light through hole are coaxially arranged (namely all extend along the preset direction); because an included angle γ is formed between the central axis of the third light passing hole and the central axis of the fourth light passing hole (i.e. the fourth light passing hole is obliquely arranged relative to the third light passing hole), most of the light beams are directly coupled into the optical fiber core in the process that the laser beams enter the fourth light passing hole from the third light passing hole. The rest part of light is reflected at the end face of the optical fiber, the light beam collides with a wall body forming the fourth light hole, and the collided light is reflected and then enters the cladding of the optical fiber assembly, so that the reflected light can be prevented from being directly reflected back to the light source along an incident path, the virtual reflection can be reduced, and the problem that the polarized light transmission is influenced due to the fact that the laser beam is reflected at the end face of the optical fiber assembly is avoided.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a cross-sectional view of an embodiment of a polarization maintaining fiber coupling device according to the present invention;

fig. 2 shows a cross-sectional view of another embodiment of a polarization maintaining fiber coupling device according to the present invention;

FIG. 3 shows a right side view of the polarization maintaining fiber coupling device of FIG. 1;

FIG. 4 is a schematic diagram of a connecting receptacle of the polarization maintaining fiber coupling device of FIG. 1;

figure 5 shows a schematic view of another angle of the connection socket of figure 4; and

fig. 6 shows a cross-sectional view of the coupling receptacle of the polarization maintaining fiber coupling device of fig. 4.

Wherein the figures include the following reference numerals:

10. a fixed seat; 11. an external thread; 12. a first light passing hole; 13. adjusting the threaded hole; 20. an elastic member; 30. a lens barrel; 301. a lens barrel body; 32. a first annular projection; 321. a first locking threaded hole; 322. a first connection hole; 33. a second light passing hole; 34. a second focusing threaded hole; 36. a first focus adjustment screw hole; 40. a focusing lens group; 50. a connecting seat; 501. a base body; 502. an end cap; 53. a third light passing hole; 54. a second annular projection; 541. a second locking threaded hole; 542. a second connection hole; 55. a fourth light aperture; 57. a groove; 58. an optical fiber connector; 581. positioning the clamping groove; 60. an adjusting screw; 70. fine adjustment of screws; 80. fastening screws; 90. a second focus screw.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It should be noted that α in fig. 1 is the maximum angle at which the connecting base 50 can receive the laser beam, and β is the maximum angle at which the lens barrel 30 can receive the laser beam.

It should be noted that, the polarization maintaining fiber coupling device of the present invention can be applied to the coupling of multimode fiber and single mode fiber, wherein, when the fiber is single mode fiber, the polarization maintaining fiber coupling device can couple the linearly polarized laser beam into the single mode polarization maintaining fiber with a very small core diameter (for example, the core diameter range is (2.8 ± 0.5) μm to (4.5 ± 0.5) μm)).

As shown in fig. 1 to 6, an embodiment of the present invention provides a polarization maintaining fiber coupling device. The polarization maintaining fiber coupling device comprises: the laser focusing lens system comprises a fixed seat 10, a lens barrel 30, a connecting seat 50 and a focusing lens group 40 arranged in the lens barrel 30, wherein the fixed seat 10, the lens barrel 30 and the connecting seat 50 are sequentially connected and have coincident central axes, a first light through hole 12 is formed in the fixed seat 10, and the first light through hole 12 is constructed to be capable of being arranged corresponding to a light outlet of an external laser; the lens cone 30 is provided with a first end and a second end which are oppositely arranged, the first end of the lens cone 30 is fixedly connected with the fixed seat 10, a second light through hole 33 communicated with the first light through hole 12 is formed in the lens cone 30, the focusing lens group 40 is positioned in the second light through hole 33, and the optical axis of the focusing lens group 40 is coaxially arranged with the second light through hole 33; the connecting holder 50 has a first end and a second end disposed oppositely, the first end of the connecting holder 50 is disposed in the second light passing hole 33, the second end of the connecting holder 50 is connected with the second end of the lens barrel 30, and the second end of the connecting holder 50 is configured to be connectable with an optical fiber assembly; the connecting seat 50 is provided with a third light passing hole 53 communicated with the second light passing hole 33 and a fourth light passing hole 55 communicated with the third light passing hole 53, the maximum angle at which the lens barrel 30 can receive light is always smaller than or equal to the maximum angle at which the connecting seat 50 can receive light, and an included angle gamma is formed between the central axis of the fourth light passing hole 55 and the central axis of the third light passing hole 53, so that the fourth light passing hole 55 is inclined relative to the third light passing hole 53.

In the above technical solution, the laser beam emitted from the light outlet of the external laser can enter the optical fiber assembly through the first light passing hole 12, the focusing lens group 40, the second light passing hole 33, the third light passing hole 53 and the fourth light passing hole 55, and since the optical axes of the first light passing hole 12, the second light passing hole 33, the focusing lens group 40 and the third light passing hole 53 are all coaxially arranged, that is, all extend along the preset direction, the laser beam can be transmitted along the preset direction; because an included angle γ is formed between the central axis of the third light passing hole 53 and the central axis of the fourth light passing hole 55, that is, the fourth light passing hole 55 is obliquely arranged relative to the third light passing hole 53, most of the laser beams are directly coupled into the fiber core in the process of entering the fourth light passing hole 55 from the third light passing hole 53.

Through the setting, when the laser beam got into fiber assembly, partial light took place to reflect at the fiber end face, and the reflected beam bumps with the wall body that forms fourth unthreaded hole, and the light after the collision jets into fiber assembly covering after the reflection in, can avoid reflected light directly to reflect back to light source department along incident path like this, can reduce the ghost, avoids leading to influencing the problem of polarized light transmission because of the laser beam takes place to reflect at fiber assembly's terminal surface.

According to the test result, adopt the utility model discloses a polarization maintaining fiber coupling device, the return loss of light can be more than or equal to 60dB.

In an embodiment of the present invention, the fixing base 10, the lens barrel 30 and the connecting base 50 are made of materials with thermal expansion coefficients close to that of the focusing lens group 40 (for example, the metal portions of the fixing base 10, the lens barrel 30 and the connecting base 50 are made of invar steel, and the glass portions are made of fused quartz glass), so as to reduce the influence of heat on the propagation of the light beam.

In the embodiment of the present invention, the angle range of the included angle γ between the third light passing hole 53 and the fourth light passing hole 55 is 6 ° to 10 °.

In the above technical solution, the included angle γ between the third light passing hole 53 and the fourth light passing hole 55 is preferably 8 °, because the optical fiber adopts APC form (i.e. angle physical contact, specifically, optical fiber end face grinding technology for grinding the end face of the optical fiber to an angle of 8 °), the end face of the optical fiber is usually inclined by 8 °, thus, γ is set to 8 °, the return loss of the optical fiber is maximum, and the reflected light has the least influence on the beam mode. The included angle gamma between the third light passing hole 53 and the fourth light passing hole 55 is set to be the same as the inclination angle of the end face of the FC/APC optical fiber, so that the connecting seat 50 is matched with the FC/APC optical fiber, the axial displacement of the synthesized light beam can be avoided, and the coupling efficiency of the device is ensured.

As shown in fig. 4 to fig. 6, in the embodiment of the present invention, the connection seat 50 includes a seat body 501 and an end cover 502 connected to each other, the third light passing hole 53 is formed on the seat body 501, the fourth light passing hole 55 is formed on the end cover 502, and an included angle is formed between two end surfaces of the end cover 502.

In the above technical solution, the end surfaces of the first end and the second end of the seat body 501 are parallel to each other, and an included angle between the end surfaces of the first end and the second end of the end cap 502 is the same as an angle γ. Therefore, the end cap 502 is conveniently provided with the fourth light hole 55 meeting the requirement, and the end cap 502 is conveniently provided with the optical fiber connector 58.

In another embodiment of the present invention, as shown in fig. 1, two end surfaces of the end cap 502 may be disposed parallel to each other.

As shown in fig. 2 and 4, in the embodiment of the present invention, the polarization maintaining fiber coupling device further includes a first adjusting mechanism disposed between the lens barrel 30 and the fixing base 10, the first adjusting mechanism can adjust the coaxiality between the first light passing hole 12 and the second light passing hole 33, and the first adjusting mechanism includes: at least three first connection holes 322 arranged on the lens barrel 30 at intervals in a circumferential direction of the lens barrel 30; at least three adjusting threaded holes 13, which are arranged in one-to-one correspondence with the first connecting holes 322, and the adjusting threaded holes 13 are arranged at intervals along the circumferential direction of the fixing base 10; and at least three adjusting screws 60, wherein each adjusting screw 60 is in threaded connection with the corresponding adjusting threaded hole 13 after passing through the first connecting hole 322.

In the above technical solution, the lens barrel 30 includes a lens barrel body 301 and a first annular protrusion 32 disposed on an outer peripheral surface of one end of the lens barrel body 301, three first connection holes 322 are disposed on the first annular protrusion 32, three first locking screw holes 321 are further disposed on the first annular protrusion 32, the three first locking screw holes 321 and the three first connection holes 322 are circumferentially spaced along the first annular protrusion 32, and the first locking screw holes 321 and the first connection holes 322 are alternately disposed along a circumferential direction of the first annular protrusion 32, the first adjusting mechanism further includes three fine adjustment screws 70, each fine adjustment screw 70 passes through one first locking screw hole 321 and then abuts against an end surface of the fixing base 10, so as to perform fine adjustment on coaxiality of the fixing base 10 and the lens barrel 30.

Through the above arrangement, the adjusting screw 60 is in threaded fit with the first connecting hole 322 and the adjusting threaded hole 13, on one hand, the lens barrel 30 and the fixing seat 10 can be fixedly connected, and on the other hand, the coaxiality of the first light passing hole 12 and the second light passing hole 33 can be adjusted by rotating the adjusting screw 60.

As shown in fig. 2, in the embodiment of the present invention, the polarization maintaining fiber coupling device further includes a plurality of elastic members 20 disposed between the lens barrel 30 and the fixing base 10, the plurality of elastic members 20 and the plurality of adjusting screws 60 are disposed in a one-to-one correspondence, each elastic member 20 is disposed at the periphery of the corresponding adjusting screw 60, one end of the elastic member 20 abuts against the end surface of the lens barrel 30, and the other end of the elastic member 20 abuts against the end surface of the fixing base 10.

With the above arrangement, the elastic element 20 passes through the adjusting screw 60, and the elastic element 20 is used to change the relative posture (Rx, ry, rz, i.e. the degree of freedom of the lens barrel 30 relative to the fixing base 10 in the three directions x, y, z as shown in fig. 1) of the lens barrel 30 relative to the fixing base 10, so as to assist in adjusting the coaxiality of the first light passing hole 12 and the second light passing hole 33, thereby achieving the degree of freedom adjustment of the polarization maintaining optical fiber coupling device. Compare the scheme of adopting the rubber circle to assist in adjusting the axiality among the prior art, the utility model discloses an elastic component can reduce because the ageing problem that influences the coupling device performance of rubber circle.

As shown in fig. 1 and fig. 4 to fig. 6, in the embodiment of the present invention, the polarization maintaining fiber coupling device further includes a locking structure for connecting the lens barrel 30 and the connecting seat 50, and the locking structure includes: two first focusing screw holes 36 arranged on the lens barrel 30 at intervals, the first focusing screw holes 36 extending along the radial direction of the lens barrel 30 and communicating with the second light through holes 33; the two grooves 57 are arranged on the connecting seat 50 at intervals, the two grooves 57 are respectively arranged in one-to-one correspondence with the two first focusing threaded holes 36, and the central axes of the two grooves 57 form an included angle; and each first focusing screw passes through the first focusing threaded hole 36 and then abuts against the bottom of the corresponding groove 57.

In the above technical solution, the first end of the connecting seat 50 extends into the second light through hole 33 and is connected to the second end of the lens barrel 30, and the distance between the focusing lens set 40 and the optical fiber assembly can be adjusted by adjusting the length of the first end of the connecting seat 50 extending into the second light through hole 33, so as to achieve the effect of adjusting the focal length of the polarization maintaining optical fiber coupling device. Moreover, when the first end of the connecting seat 50 is located at any position in the second light passing hole 33, the maximum angle of the lens barrel 30 that can receive light is smaller than or equal to the maximum angle of the connecting seat 50 that can receive light, so as to ensure that the laser beam emitted by the external laser can completely irradiate the optical fiber assembly.

With the above arrangement, the first focusing screw can fixedly connect the lens barrel 30 and the connecting base 50, and by providing the two grooves 57, the lens barrel 30 and the connecting base 50 can be fixed at two positions in the circumferential direction of the lens barrel 30 at the same time, thereby further limiting the relative displacement between the lens barrel 30 and the connecting base 50.

As shown in fig. 4 and 5, in the embodiment of the present invention, the two grooves 57 are spaced by 90 ° in the circumferential direction of the connecting socket 50.

With the above arrangement, the two grooves 57 are perpendicular to each other in the positions, so as to achieve the effect of locking and fixing the lens barrel 30 and the connecting base 50 in two directions.

As shown in fig. 1 and fig. 2, in the embodiment of the present invention, the laser coupling device further includes a second adjusting mechanism disposed between the lens barrel 30 and the connecting seat 50, and the second adjusting mechanism can adjust the axial position and the coaxiality of the connecting seat 50 relative to the lens barrel 30.

In the above technical solution, the second end of the connecting seat 50 is provided with the second annular protrusion 54, three second connecting holes 542 are arranged at intervals along the circumferential direction of the second annular protrusion 54, the end face of the second end of the lens barrel 30 is provided with three second focusing threaded holes 34 arranged at intervals, the three second focusing threaded holes 34 are respectively arranged in one-to-one correspondence with the three second connecting holes 542, and the second adjusting mechanism further includes three second focusing screws 90.

With the above arrangement, each second focusing screw 90 passes through one second connecting hole 542 and then is connected with the corresponding second focusing threaded hole 34, so that the lens barrel 30 and the connecting base 50 can be fixedly connected on one hand, and on the other hand, the coaxiality of the lens barrel 30 and the connecting base 50 can be adjusted by rotating the second focusing screw 90.

As shown in fig. 1 and fig. 2, in the embodiment of the present invention, three second locking threaded holes 541 are further disposed on the second annular protrusion 54, and the three second locking threaded holes 541 and the three second connecting holes 542 are disposed at intervals along the circumference of the second annular protrusion 54. The second adjusting mechanism further includes three fastening screws 80, and each fastening screw 80 passes through the second locking screw hole 541 and abuts against an end surface of the second end of the lens barrel 30, so as to further lock and connect the lens barrel 30 and the connecting base 50.

As shown in fig. 4 to fig. 6, in the embodiment of the present invention, the polarization maintaining fiber coupling device further includes a fiber connector 58 connected to the connecting seat 50, a positioning card slot 581 is disposed on the fiber connector 58, and a central axis of the positioning card slot 581 is parallel to a central axis of the fourth light hole 55.

Through the above arrangement, the second end of the connection seat 50 is provided with the optical fiber connector 58, the optical fiber connector 58 is used for connecting the optical fiber assembly and the connection seat 50, the positioning card slot 581 is in the same direction as the groove 57 and is axially aligned with the fourth light-passing hole 55, and the positioning card slot 581 is used for being connected with the bayonet fitting of the connector of the optical fiber assembly, meanwhile, because the central axis of the positioning card slot 581 is parallel to the central axis of the fourth light-passing hole 55, the positioning card slot 581 can also position and align the polarization maintaining optical fiber polarization axis with the incident hole of the optical fiber assembly, so as to ensure that the light emitted by the polarization maintaining optical fiber coupling device can enter the optical fiber assembly.

As shown in fig. 1 and fig. 2, in the embodiment of the present invention, the outer surface of the fixing base 10 is further provided with an external thread 11 capable of being connected with an external tool thread.

Through the above arrangement, the external thread 11 is used for fixedly connecting the polarization maintaining optical fiber coupling device with the external laser device, so that the central axis of the light outlet of the external laser device coincides with the central axis of the first light through hole 12 of the fixing seat 10, and the polarization maintaining optical fiber coupling device is aligned with the polarization axis of the laser beam, so that the light is emitted into the polarization maintaining optical fiber coupling device. Meanwhile, the mode of threaded connection is adopted, so that the installation is convenient, and the connection stability of the fixed seat 10 and an external laser can be enhanced.

As shown in fig. 1 and fig. 2, in the embodiment of the present invention, a positioning installation groove is disposed in the second light-passing hole 33, and the focusing lens group 40 is installed in the positioning groove, so that the focusing lens group 40 can be accurately positioned and fixedly connected to the lens barrel 30.

In the embodiment of the present invention, the inner wall of the optical fiber connector 58 is also polished at an angle and provided with an anti-reflection coating to reduce the reflection of light on the inner wall of the optical fiber connector 58, so that the problem of influencing the mode emitted by the external laser due to the reflection and the problem of influencing the interference signal of the laser beam can be avoided. The antireflection coating may be formed by electroplating or the like.

From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: light rays emitted by a light outlet of the external laser can enter the optical fiber assembly after passing through the first light through hole, the second light through hole, the focusing lens group, the third light through hole and the fourth light through hole in sequence, and because an included angle gamma is formed between the central axis of the third light through hole and the central axis of the fourth light through hole, when the light rays enter the optical fiber assembly, part of light is reflected at the end face of the optical fiber, and the reflected light can be reflected to the cladding of the optical fiber assembly, so that the reflected light can be prevented from being directly reflected to the light source along an incident path, the virtual reflection can be reduced, and the problem that the transmission of polarized light is influenced due to the interference of the reflected light and the incident light emitted by the light source is avoided. The first adjusting mechanism can adjust the coaxiality of the first light through hole and the second light through hole, and the elastic piece can assist in adjusting the coaxiality of the first light through hole and the second light through hole; the locking mechanism can fixedly connect the lens cone and the connecting seat, and can constantly maintain the focal length of the polarization maintaining optical fiber coupling device through threaded connection; the second adjusting mechanism can adjust the relative position and the coaxiality of the connecting seat and the lens cone in the axial direction, and through the adjustment of the structure, the alignment of the optical fiber polarization main shaft can be guaranteed, so that the stability of light transmission is guaranteed.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A polarization maintaining optical fiber coupling device is characterized by comprising a fixed seat (10), a lens cone (30), a connecting seat (50) and a focusing lens group (40) arranged in the lens cone (30), wherein the fixed seat, the lens cone (30) and the connecting seat are sequentially connected and the central axes of the fixed seat, the lens cone and the connecting seat are superposed, the focusing lens group is arranged in the lens cone (30),

a first light through hole (12) is formed in the fixed seat (10), and the first light through hole (12) is constructed to be arranged corresponding to a light outlet of an external laser;

the lens cone (30) is provided with a first end and a second end which are arranged oppositely, the first end of the lens cone (30) is fixedly connected with the fixed seat (10), a second light through hole (33) communicated with the first light through hole (12) is formed in the lens cone (30), the focusing lens group (40) is positioned in the second light through hole (33), and the optical axis of the focusing lens group (40) is coaxially arranged with the second light through hole (33);

the connecting base (50) has a first end and a second end which are oppositely arranged, the first end of the connecting base (50) is arranged in the second light through hole (33), the second end of the connecting base (50) is connected with the second end of the lens barrel (30), and the second end of the connecting base (50) is configured to be connected with an optical fiber assembly; the lens barrel is characterized in that the connecting seat (50) is provided with a third light through hole (53) communicated with the second light through hole (33) and a fourth light through hole (55) communicated with the third light through hole (53), the maximum angle of the lens barrel (30) capable of receiving light is always smaller than or equal to the maximum angle of the connecting seat (50) capable of receiving light, and an included angle gamma is formed between the central axis of the fourth light through hole (55) and the central axis of the third light through hole (53), so that the fourth light through hole (55) is inclined relative to the third light through hole (53).

2. The polarization maintaining fiber coupling device according to claim 1, wherein the included angle γ between the third light passing hole (53) and the fourth light passing hole (55) is in the range of 6 ° to 10 °.

3. The polarization maintaining fiber coupling device according to claim 1, wherein the connecting base (50) comprises a base body (501) and an end cap (502) connected to each other, the third light passing hole (53) is formed in the base body (501), the fourth light passing hole (55) is formed in the end cap (502), and an included angle is formed between two end faces of the end cap (502).

4. The polarization-maintaining fiber coupling device according to claim 1, further comprising a first adjusting mechanism disposed between the lens barrel (30) and the fixing base (10), the first adjusting mechanism being capable of adjusting the coaxiality between the first light passing hole (12) and the second light passing hole (33), the first adjusting mechanism comprising:

at least three first connection holes (322) arranged on the lens barrel (30) at intervals in a circumferential direction of the lens barrel (30);

at least three adjusting threaded holes (13) which are arranged in one-to-one correspondence with the first connecting holes (322), and the adjusting threaded holes (13) are arranged at intervals along the circumferential direction of the fixed seat (10);

at least three adjusting screws (60), wherein each adjusting screw (60) is in threaded connection with the corresponding adjusting threaded hole (13) after passing through the first connecting hole (322).

5. The polarization-maintaining fiber coupling device according to claim 4, further comprising a plurality of elastic members (20) disposed between the lens barrel (30) and the fixing base (10), wherein the plurality of elastic members (20) are disposed in one-to-one correspondence with the plurality of adjusting screws (60), each elastic member (20) is disposed at an outer periphery of the corresponding adjusting screw (60), one end of the elastic member (20) abuts against an end face of the lens barrel (30), and the other end of the elastic member (20) abuts against an end face of the fixing base (10).

6. The polarization-maintaining fiber coupling device according to claim 4, wherein the lens barrel (30) comprises a barrel body (301) and a first annular protrusion (32) disposed on an outer peripheral surface of one end of the barrel body (301), the first connecting holes (322) are all opened on the first annular protrusion (32), the first annular protrusion (32) is further opened with a plurality of first locking threaded holes (321), the first locking threaded holes (321) and the first connecting holes (322) are circumferentially spaced along the first annular protrusion (32), the first adjusting mechanism further comprises a plurality of fine adjusting screws (70), and each fine adjusting screw (70) passes through one first locking threaded hole (321) and abuts against an end surface of the fixing base (10) to perform fine adjustment on the coaxiality of the fixing base (10) and the lens barrel (30).

7. A polarization maintaining fiber coupling device according to any one of claims 1 to 6, further comprising a locking structure for connecting the lens barrel (30) and the connecting receptacle (50), the locking structure comprising:

two first focusing threaded holes (36) which are arranged on the lens barrel (30) at intervals, wherein the first focusing threaded holes (36) extend along the radial direction of the lens barrel (30) and are communicated with the second light through holes (33);

the two grooves (57) are arranged on the connecting seat (50) at intervals, the two grooves (57) are respectively arranged in one-to-one correspondence with the two first focusing threaded holes (36), and the central axes of the two grooves (57) form an included angle;

and each first focusing screw passes through the first focusing threaded hole (36) and then abuts against the bottom of the corresponding groove (57).

8. Polarization maintaining fiber coupling device according to claim 7, wherein the two grooves (57) are spaced apart by 90 ° in the circumferential direction of the connection receptacle (50).

9. The polarization maintaining fiber coupling device according to any one of claims 1 to 6, further comprising an optical fiber connector (58) connected to the connecting socket (50), wherein a positioning card slot (581) is opened on the optical fiber connector (58), and a central axis of the positioning card slot (581) is parallel to a central axis of the fourth light passing hole (55).

10. The polarization maintaining optical fiber coupling device according to any one of claims 1 to 6, wherein the outer surface of the fixing base (10) is further provided with an external thread (11) capable of being in threaded connection with an external tool.

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