CN111381329A

CN111381329A - Coupling adapter

Info

Publication number: CN111381329A
Application number: CN202010266760.2A
Authority: CN
Inventors: 伍斌; 阮扬
Original assignee: Wuhan Telecommunication Devices Co Ltd
Current assignee: Wuhan Telecommunication Devices Co Ltd
Priority date: 2020-04-07
Filing date: 2020-04-07
Publication date: 2020-07-07

Abstract

The invention provides a coupling adapter, and relates to the field of optical communication. The coupling adapter includes: the outer sleeve is provided with a first through hole penetrating through a first end and an opposite second end of the outer sleeve, the first end is used for connecting the laser emitting piece, and the second end is used for connecting the optical fiber connector; a ceramic sleeve disposed in the first through hole and having a second through hole coaxial with the first through hole; the ceramic ferrule is arranged in the first through hole and is partially inserted into the second through hole, and the ceramic ferrule is provided with a third through hole coaxial with the first through hole; the space enclosed by the inlet end of the ceramic ferrule close to the first end and the outer sleeve is internally filled with a gradual change film, the gradual change film is in contact with the inlet end of the ceramic ferrule and the inner wall surface of the outer sleeve, and the refractive index of the gradual change film is increased along with the increase of the refractive index of the gradual change film close to the inlet end of the ceramic ferrule. The gradual change film with the changed refractive index is arranged at the inlet end of the ceramic ferrule, so that the divergence angle of the divergent light beam is gradually reduced, the cost is reduced, and the space occupied by the lens is reduced.

Description

Coupling adapter

Technical Field

The invention belongs to the technical field of optical communication, and particularly relates to a coupling adapter.

Background

The coupling adapter is an optical fiber movable connector, the structure of which comprises an outer sleeve, a ceramic sleeve and a ceramic ferrule, is an optical passive device for realizing movable connection between optical fibers, and has the functions of movable connection between the optical fibers, between the optical fibers and active devices, between the optical fibers and other passive devices and between the optical fibers and instruments.

The coupling adapter has an inlet end and an outlet end, the inlet end is connected with the laser, and the outlet end is connected with the optical fiber. The laser emits the optical signal as a transmitting element of the optical signal, which enters an optical fiber inserted in the coupling adapter. Because the light beam emitted by the laser is relatively divergent, the diameter of the formed light spot is relatively large, the numerical aperture of the optical fiber is relatively small, and the numerical aperture of the optical fiber represents the capability of the end face of the optical fiber for receiving light. The smaller the numerical aperture of the fiber, the less light energy can enter the fiber, and the larger spot results in less light energy being able to enter the fiber. Although the related coupling adapter can adopt the laser with the aspheric lens to receive the light beam emitted by the laser so as to trim the spot size adaptive optical fiber, the aspheric lens has high material cost and higher process precision requirement of the chip, the chip refers to a process of adjusting the physical position of the lens by adopting an optical instrument to realize the alignment and fixation of the lens and an optical signal source, and the aspheric lens has longer focal length so as to occupy more space in the coupling adapter.

Disclosure of Invention

In view of the above, the present invention is directed to a coupling adapter, so as to solve the technical problems of reducing the cost and the installation space.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

an embodiment of the present invention provides a coupling adapter, including: the laser transmitter comprises an outer sleeve and a laser transmitting piece, wherein a first through hole penetrating through a first end and an opposite second end of the outer sleeve is formed in the outer sleeve; a ceramic sleeve disposed within the first through-hole and having a second through-hole coaxial with the first through-hole; the ceramic ferrule is arranged in the first through hole and is partially inserted into the second through hole, and the ceramic ferrule is provided with a third through hole coaxial with the first through hole; the inlet end of the ceramic ferrule close to the first end and the space enclosed by the outer sleeve are internally filled with a gradual change film, the gradual change film is in contact with the inlet end of the ceramic ferrule and the inner wall surface of the outer sleeve, and the refractive index of the gradual change film is increased along with the increase of the refractive index of the gradual change film close to the inlet end of the ceramic ferrule.

Furthermore, an optical fiber core and a glass body are adjacently arranged in the third through hole, the glass body is close to the inlet end of the ceramic ferrule relative to the optical fiber core, and the refractive index of the glass body is smaller than that of the optical fiber core.

Furthermore, the glass body is attached to the gradient film, and the refractive index of the glass body is larger than that of the gradient film attached to the glass body.

Further, the bore diameter of the first through bore decreases from the first end to the inlet end of the ferrule.

Further, a reflecting film is coated on the inner wall surface of the outer sleeve close to the first end, so that light rays are reflected by the reflecting film to enter the gradual-change thin film.

Further, the reflective film is in contact with the graded film.

Further, the reflectance of the reflection film is larger than the reflectance of the inner wall surface of the outer sleeve.

Further, the end face, close to the inlet end, of the ceramic ferrule is an inclined face.

Further, the outer sleeve comprises: a first sleeve disposed at the first end for connection to a laser emitting member, the first sleeve having a first cavity; a second sleeve disposed at the second end for connection to an optical fiber connector, the second sleeve having a second cavity; the first sleeve is fixedly connected with the second sleeve, and the first cavity is communicated with the second cavity to form the first through hole.

Further, the first sleeve comprises a first metal piece, an isolating glue and a second metal piece which are fixedly connected in sequence, the first metal piece is arranged at the first end and used for being connected with a laser emitting piece, and the second metal piece is used for being fixedly connected with the second sleeve; coaxial through holes are formed in the first metal piece, the isolating glue and the second metal piece to form the first cavity.

The invention provides a coupling adapter which comprises an outer sleeve, a ceramic sleeve and a ceramic ferrule, wherein a space enclosed by an inlet end of the ceramic ferrule close to a first end and the outer sleeve is internally filled with a gradual change film, the gradual change film is in contact with the inlet end of the ceramic ferrule and the inner wall surface of the outer sleeve, and the refractive index of the gradual change film is increased along with the increase of the refractive index of the gradual change film close to the inlet end of the ceramic ferrule. The space enclosed by the inlet end of the ferrule and the outer sleeve is partially filled with a graded film, and the refractive index of the graded film increases as the graded film approaches the inlet end of the ferrule. The divergence angle of the transversely diffracted diverging light beam passing through the spherical lens can be gradually reduced by utilizing the refractive index gradient of the gradual change film, the light beam is coupled into the optical fiber core, the requirement for trimming the light beam of the laser emitting part is reduced, and the spherical lens can be arranged, so that the cost is reduced, and the space occupied by the lens is reduced.

Drawings

FIG. 1 is a schematic cross-sectional view of a coupling adapter;

FIG. 2 is a schematic cross-sectional view of a coupling adapter according to an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating the optical path of a tapered film of a coupling adapter according to an embodiment of the present invention;

FIG. 4a is a schematic diagram of the optical path operation of the spherical lens;

FIG. 4b is a schematic diagram of the optical path working principle of the aspheric lens;

FIG. 5 is a schematic diagram illustrating a cross-sectional view of a glass body of a coupling adapter in accordance with an embodiment of the present invention;

FIG. 6 is a schematic diagram illustrating the optical path of the glass body of the coupling adapter according to an embodiment of the present invention;

FIG. 7 is a schematic sectional view of a first through hole of a coupling adapter according to an embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a reflective film of a coupling adapter in accordance with an embodiment of the present invention;

FIG. 9 is a schematic diagram illustrating the optical path of the reflective film of the coupling adapter according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of the operation principle of the reflection light path of the ferrule;

FIG. 11 is a schematic diagram illustrating the operation of the reflection optical path of the ferrule of the coupling adapter according to an embodiment of the present invention;

FIG. 12 is a schematic cross-sectional view of an outer sleeve construction of a coupling adapter in accordance with an embodiment of the present invention;

fig. 13 is a schematic cross-sectional view of a first sleeve structure of a coupling adapter according to an embodiment of the present invention.

Description of the reference numerals

1-laser emitting part, 11-laser chip, 12-cap lens, 2-outer sleeve, 21-first through hole, 221-first cavity, 222-first metal part, 223-spacer, 224-second metal part, 23-second sleeve, 231-second cavity, 3-ceramic sleeve, 31-second through hole, 4-ceramic ferrule, 41-third through hole, 5-fiber core, 51-vitreous body, 6-fiber connector, 7-graded film, 81-spherical lens, 82-aspherical lens, 9-reflective film, O '-axis, O' ″ -primary optical axis, focal point of F-spherical lens, focal point of F '-aspherical lens, optical center of P-spherical lens, optical center of P' -aspherical lens, focal length of f-spherical lens, focal length of f' -aspherical lens

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The individual features described in the embodiments can be combined in any suitable manner without departing from the scope, for example different embodiments and aspects can be formed by combining different features. In order to avoid unnecessary repetition, various possible combinations of the specific features of the invention will not be described further.

In the following description, references to the terms "first", "second", and the like are simply to distinguish between different objects and do not denote the same or a relationship between the two. It should be understood that the references to "above" and "below" are to be interpreted as referring to the orientation during normal use.

It should be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The coupling adapter provided by the embodiment of the invention is mainly used for realizing the optical passive devices which are movably connected among devices, between the devices and instruments, between the devices and optical fibers (or optical cables) and between the optical fibers (or optical cables) in an optical communication system. It should be noted that the type of the application scenario in the present invention is not limited to the present invention.

The working principle of the coupling adapter, which may include an outer sleeve 2, a ferrule 3 and a ferrule 4, is exemplified below in connection with fig. 1. The ceramic sleeve 3 is arranged in the outer sleeve 2, the middle of the ceramic ferrule 4 is provided with a through hole for accommodating an optical fiber core 5, the ceramic ferrule 4 can be partially arranged in the ceramic sleeve 3, the rest part of the ceramic ferrule 4 can be arranged in the outer sleeve 2, and the outer sleeve 2 can play a role in protecting and clamping the ceramic sleeve 3 and the ceramic ferrule 4. The outlet end of the outer sleeve 2 is connected with an optical fiber connector 6, an optical fiber core 5 in the optical fiber connector 6 is inserted into a through hole of the ceramic ferrule 4, the inlet end of the outer sleeve 2 is fixedly connected with a laser emitting piece 1, and the laser emitting piece 1 can be a laser diode. The laser chip 11 of the laser emitting component 1 emits a light beam, the emitted light beam is a divergent light beam, the divergent light beam is transmitted into the tube cap lens 12, the divergent light beam is changed into a convergent light beam through the refraction effect of the tube cap lens 12, the focus of the tube cap lens 12 is positioned at the inlet end of the through hole of the ceramic ferrule 4 when the coupling adapter is designed, the convergent light beam can be transmitted into the inlet end of the optical fiber core 5 in the ceramic ferrule 4, so that the light beam can be continuously transmitted in the optical fiber core 5 and enter the external optical fiber connector 6, and the butt joint of optical paths is realized. The coupling adapter is used for realizing the butt joint of optical fiber lines, so that the light energy of emitted light can be coupled into the receiving optical fiber to the maximum extent, the loss of the light energy is reduced, and the influence on the system caused by the light energy of the emitted light which is introduced into the optical path is reduced as much as possible. It should be noted that the cap lens 12 is selected as an aspheric lens (directly correcting the spot size) or as a spherical lens (with a graded film) according to the embodiment of the present invention.

In an embodiment of the invention, as shown in fig. 2, the coupling adapter comprises an outer sleeve 2, which is provided with a first through hole 21 penetrating a first end and an opposite second end of the outer sleeve 2, the first end being used for connecting the laser emitting element 1, and the second end being used for connecting the optical fiber connector 6. Specifically, the first end of the outer sleeve 2 is an inlet end for receiving the optical signal from the laser emitting element 1, and the second end of the outer sleeve 2 is an outlet end for outputting the optical signal to the optical fiber connector 6. A cavity, i.e. said first through hole 21, is formed inside the outer sleeve 2 through the inlet end and the outlet end of the outer sleeve 2.

As shown in fig. 2, the coupling adapter further includes a ceramic sleeve 3 disposed in the first through hole 21 and having a second through hole 31 coaxial with the first through hole 21. The outer wall surface of the ceramic sleeve 3 is in interference fit with the inner wall surface of the outer sleeve 2, and the ceramic sleeve 3 can be a cylinder. The cavity formed inside the ceramic sleeve 3 penetrates through two opposite end faces of the ceramic sleeve 3, namely the second through hole 31, and is coaxial with the first through hole 21.

As shown in fig. 2, the coupling adapter further includes a ferrule 4 disposed in the first through hole 21 and partially inserted into the second through hole 31, and the ferrule 4 is opened with a third through hole 41 coaxial with the first through hole 21. The outer diameter of the ferrule 4 is substantially the same as the diameter of the second through hole 31, a part of the ferrule 4 extends into the ferrule 3, the outer wall surface of the ferrule 4 is in interference fit with the inner wall surface of the ferrule 3, and the other part of the ferrule extends into the first through hole 21 of the outer sleeve 2 and is in interference fit with the inner wall surface of the outer sleeve 2. The outer sleeve 2, the ceramic sleeve 3, and the ferrule 4 are tightly fitted to each other to form a firm connection. A third through hole 41 is formed through the ferrule 4 from one end to the opposite end thereof, the third through hole being coaxial with the first through hole 21, and adapted to receive the optical fiber core 5, and a diameter of the third through hole 41 is determined by a diameter of the optical fiber core 5. The ceramic materials of the ceramic ferrule 4 and the ceramic sleeve 3 are well matched with the quartz material of the optical fiber core 5 in heat, the physical and chemical properties are stable, and good communication quality can be ensured.

As shown in fig. 2, the coupling adapter further includes a graded membrane 7 that fills a portion of the space enclosed by the inlet end of the ferrule 4 and the outer sleeve 2. The graded film 7 is in contact with both the entrance end of the ferrule 4 and the inner wall surface of the outer sleeve 2, and the refractive index of the graded film 7 increases as it approaches the entrance end of the ferrule 4.

As shown in fig. 3, the graded film 7 is a film having a non-uniform refractive index whose refractive index has a tendency to gradually increase along the main optical axis O ' as approaching the entrance end of the ferrule 4, it being noted that the main optical axis O ' and the axis O ' are collinear. The inner surface 71 of the graded diaphragm 7 is the surface that is closer to the inlet end of the ferrule 4, and the outer surface 72 of the graded diaphragm 7 is the surface that is farther from the inlet end of the ferrule 4. It has been mentioned in the foregoing principle part of the coupling adapter that the cap lens can converge and transmit the light beam emitted by the laser chip to the entrance end of the ferrule 4, but the light has the property of a wave, which has a diffraction phenomenon during transmission, which causes the light beam to expand laterally during propagation, it being noted that the lateral direction refers to the direction perpendicular to the main optical axis O' ″. This part of the laterally expanded light beam becomes a diverging light beam having a divergence angle, which is to be noted as the acute angle the light beam makes with the main optical axis O'. The light beam with the excessively large divergence angle cannot enter the optical fiber core 5 in the ferrule 4, and the light energy of the divergent light beam which does not enter the optical fiber core 5 is directly lost and dissipated without being utilized, so that the loss of the light energy is caused to a certain extent. The graded film 7 is provided in the last optical path of the light beam entering the entrance end of the optical fiber core 5 of the ferrule 4, the divergent light beam enters the outer surface 72 of the graded film 7, the refractive index of the graded film 7 is larger than that of air, the incident divergent light beam is deflected in a direction close to the main optical axis O ' ″, the deflected light beam is continuously deflected to a side close to the main optical axis O ' ″ as the refractive index of the graded film 7 gradually increases from the outer surface 72 to the inner surface 71 in the direction of the main optical axis O ' ″, thereby gradually closing the divergent angle of the divergent light beam and becoming a closed light beam before exiting the inner surface 71 of the graded film 7, and the graded film 7 can gradually adjust the divergent light beam before entering into the closed light beam at the time of exit to enter the optical fiber core 5 of the ferrule 4.

As shown in fig. 4a, the optical path of the parallel light emitted from the laser emitting element after passing through the spherical lens is changed. It should be noted that the spherical lens refers to a lens having a constant curvature from the center to the edge of the lens. The spherical lens 81 causes a poor focus due to the presence of spherical aberration, which means that the light beams are different in convergence ability in the central region and the edge region of the lens, and the positions of the actual image point and the ideal image point are deviated from each other not at the same point as the intersection point of the main optical axis O' ″ after passing through the lens. The poor focusing causes a large light spot (i.e. an imaging point is not a point but an area with a certain area) to be formed when the light beam converges, and the optical fiber numerical aperture of the optical fiber core 5 is relatively small, which means the ability of the end face of the optical fiber core 5 to receive light. The smaller the numerical aperture of the fiber, the less light energy can enter the fiber core 5, and the less light energy of the larger light spot can enter the fiber core 5.

Fig. 4b shows the optical path change of the parallel light emitted by the laser emitting element after passing through the aspheric lens. The aspherical lens is a lens in which the curvature changes continuously from the center to the edge of the lens. The aspherical lens 82 changes the radius of curvature of the surface of the aspherical lens 82 in accordance with the distance of the spherical surface from the main optical axis O ', and maintains good spherical aberration correction, and the light beams passing through the lens form a spot having a small diameter at the same point as the intersection point of the main optical axis O ', i.e., the intersection point F ' of the aspherical lens. However, the focal length f' of the aspheric lens 82 is determined to be greater than the focal length f of the spherical lens 81 due to the property of the aspheric lens 82, in the length direction, the larger focal length inevitably occupies a larger design space, which brings a certain limit to the design of the coupling adapter, and the aspheric lens 82 has high requirements on the precision of the placement, and the material price is expensive.

In the case of the ball lens 81, the gradation film 7 is provided in cooperation. On one hand, the diverging light beam which is transversely diffracted after passing through the ball lens 81 can gradually converge the divergence angle of the light beam through the refractive index gradient of the gradual change film 7 to form a smaller light spot, so that the coupling efficiency of the optical power is improved, the light spot is not required to be reduced by designing a longer focal length, the design space is saved, and meanwhile, the requirement on the precision of the patch is also reduced.

As shown in fig. 3, the inner surface 71 of the graded film 7 is in full contact with the end face of the entrance end of the ferrule 4, the end face of the optical fiber core 5, and the inner wall surface of the outer sleeve 2 which are in contact with each other. The perfect adhesion means that the inner surface 71 of the graded film 7 is in complete contact with the end face of the entrance end of the ferrule 4, the end face of the optical fiber core 5, and the inner wall surface of the outer sleeve 2. On one hand, firm and reliable connection can be formed by complete attachment, and light receiving failure caused by falling of the gradual change film 7 in the use process of the coupling adapter is avoided; on the other hand, if the graded film 7 is partially attached to the end faces of the ferrule 4 and the optical fiber core 5, and there is a gap in the non-attached region, since the gap is filled with air, the refractive index of the air is lower than that of the graded film 7, the light beam with the divergence angle being closed by the graded film 7 enters the air segment, the divergence angle of the light beam with the divergence angle being closed is expanded, so that the light beam which can be received into the optical fiber core 5 is reduced, and the coupling efficiency of the optical power is reduced.

The embodiment of the invention is characterized in that the space enclosed by the inlet end of the ceramic ferrule 4 and the outer sleeve 2 is internally filled with the gradual-change film 7, and the refractive index of the gradual-change film 7 is increased along with the approach of the inlet end of the ceramic ferrule 4. The divergence angle of the transversely diffracted diverging light beam passing through the spherical lens can be gradually reduced by utilizing the refractive index gradient of the gradual change film 7, and the diverging light beam is coupled into the optical fiber core 5, so that the cost and the space occupied by the lens are reduced.

In some embodiments, as shown in FIG. 5, the optical fiber core 5 and the glass body 51 are disposed adjacent to each other in the third through hole 41, the glass body 51 is disposed adjacent to the inlet end of the ferrule 4 relative to the optical fiber core 5, and the refractive index of the glass body 51 is smaller than that of the optical fiber core 5.

Specifically, as shown in fig. 6, the end surface of the glass body 51 close to the optical fiber core 5 is bonded to the entrance end surface of the optical fiber core 5, and the refractive index of the optical fiber core 5 is larger than the refractive index of the glass body 51. The light beam emitted from the glass body 51 enters the optical fiber core 5 to be deflected, the light beam from the glass body 51 is further folded and converged, the divergence angle of the light beam is reduced, the capability of the light beam to be coupled into the optical fiber core 5 is improved by further folding the divergence angle of the light beam, and the coupling efficiency of the optical power is further improved.

In some embodiments, as shown in fig. 5, a glass body 51 is attached to graded film 7, and the refractive index of glass body 51 is greater than the refractive index of graded film 7 where glass body 51 is attached. Specifically, as shown in fig. 6, the end face of the glass body 51 near the graded film 7 is bonded to the graded film 7, the refractive index of the glass body 51 is larger than the refractive index of the graded film 7, and the refractive index of the optical fiber core 5 is larger than the refractive index of the glass body 51. The light beam emitted from the graded film 7 enters the glass body 51 to be deflected, the light beam from the graded film 7 is further converged and converged, the divergence angle of the light beam is reduced, the light beam emitted from the glass body 51 enters the optical fiber core 5 to be deflected, the light beam from the glass body 51 is further converged and converged, and the divergence angle of the light beam is reduced. Compared with the case that the light beam directly enters the optical fiber core 5 from the graded film 7, the glass body 51 is additionally arranged on the inlet end face of the optical fiber core 5, so that the effect of converging the divergence angle of the light beam is better. The ability of the light beam to couple into the fiber core 5 is improved by continuously folding the divergence angle of the light beam, thereby improving the coupling efficiency of the optical power.

In some embodiments, as shown in FIG. 7, the aperture of the first through-hole 21 decreases from the first end to the inlet end of the ferrule 4. Specifically, the aperture of the first through hole 21 at the inlet end of the outer sleeve 2 is gradually reduced to be approximately the same as the outer diameter of the ferrule 4, so that the outer sleeve 2 can clamp the ferrule 4. The aperture of the first through hole 21 decreases progressively from the first end to the inlet end of the ferrule 4, which can facilitate the insertion of the ferrule 4 or other assembly components, avoid interference during the insertion process, and optimize the assembly design.

In some embodiments, as shown in figure 8, the inner wall surface of the outer sleeve 2 near the first end is coated with a reflective film 9 so that light is reflected by the reflective film 9 into the graded film 7. Specifically, as shown in fig. 9, a part of the light beam from the tube cap ball lens directly enters the gradient film 7, and a part of the light beam is limited by the incident angle and the incident height and cannot directly enter the gradient film 7, and the part of the light beam cannot directly enter the light beam of the gradient film 7, and a part of the light beam cannot enter the first through hole 21 of the outer sleeve 2 due to an excessively large divergence angle or an excessively high incident height and directly dissipates and is directly incident on the inner wall surface of the first through hole 21 at various incident angles, and is influenced by the manufacturing process and the material properties, the inner wall surface of the outer sleeve 2 has a certain roughness rather than an absolutely smooth inner wall surface, and the inner wall surface can absorb or transmit most of the incident light entering the inner wall surface, a small amount of the incident light can be reflected on the inner wall surface, and if the reflected light is reflected to the inner wall surface again, there is still the possibility of absorption or transmission, and finally only a very small amount of light can enter the graded film 7 by continuous reflection, that is, the light beams directly incident on the inner wall surface of the first through hole 21 at various incidence angles are mostly not coupled into the fiber core and directly lost, resulting in great waste of light energy. The inner wall surface is coated with the reflecting film 9, when light beams directly enter the reflecting film 9 on the inner wall surface at various incident angles, most of the light beams can be continuously reflected on the surface of the reflecting film 9, enter the gradual change film 7 and finally enter the optical fiber core in a coupling mode, the utilization rate of light is improved, and meanwhile light energy which can be coupled into the optical fiber core is also improved.

In some embodiments, as shown in fig. 8, the reflective film 9 is in contact with the graded film 7. Specifically, as shown in fig. 9, if there is a gap at the joint of the reflective film 9 and the gradual change film 7, when the light beam is reflected by the reflective film 9, some light beam may be reflected into the gap during the reflection process, and since the gap is the inner wall surface of the first through hole 21, the inner wall surface can absorb or transmit the light beam reflected to the wall surface, so that the light beam cannot be reflected into the gradual change film 7, which results in waste of light energy. The joint of the reflecting film 9 and the gradual change film 7 should ensure good contact without a gap, so as to ensure that the light beam can enter the gradual change film 7 effectively finally after being reflected continuously on the reflecting film 9.

In some embodiments, the reflectivity of the reflective film 9 is greater than the reflectivity of the inner wall surface of the outer sleeve 2. Specifically, the reflective film 9 may be a highly reflective film, and the highly reflective film refers to an optical thin film that can reflect most or almost all of incident light energy. The high-reflection film can improve the effective reflectivity, so that the light beam can be finally and effectively incident to the gradual-change film 7 and coupled into the fiber core after being continuously reflected on the reflection film 9, and the utilization rate of light energy is improved.

In some embodiments, as shown in FIG. 8, the end face of the ferrule 4 near the inlet end is beveled. Specifically, as shown in fig. 10, when the end face of the ferrule 4 is parallel to the radial cross section of the ferrule 4, when incident light enters the end face of the ferrule 4, the incident light is easily reflected at the end face of the ferrule 4, and the reflected light returns to the laser emitter along the original path, so as to interfere with the emitted light signal of the laser emitter, thereby affecting the performance of the laser. As shown in fig. 11, when the end face of the ferrule 4 has a certain inclination angle with respect to the cross section of the ferrule 4 in the radial direction, the reflected light reflected by the end face of the ferrule 4 does not return along the original path, and does not interfere with the optical signal of the laser transmitter.

In some embodiments, as shown in fig. 12, the outer sleeve 2 comprises a first sleeve 22 arranged at a first end for connecting the laser emitting element 1, the first sleeve 22 having a first cavity 221; a second sleeve 23 arranged at a second end for connection to the fiber connector 6, the second sleeve 23 having a second cavity 231; the first sleeve 22 is fixedly connected with the second sleeve 23, and the first cavity 221 is communicated with the second cavity 231 to form a first through hole 21. Specifically, compared with the integrated outer sleeve 2, the assembled outer sleeve 2 has greater convenience in installation and disassembly, and is easy to produce in quantity.

In some embodiments, as shown in fig. 13, the first sleeve 22 includes a first metal piece 222, a release glue 223 and a second metal piece 224 which are fixedly connected in sequence, the first metal piece 222 is disposed at a first end for connecting the laser emitting element 1, and the second metal piece 224 is fixedly connected with the second sleeve 23; the first metal piece 222, the isolation glue 223 and the second metal piece 224 are all provided with coaxial through holes to form a first cavity. Specifically, the first metal 222 is used to form the inlet end of the outer sleeve 2, the second metal 224 can fix and clamp the ferrule 4 and the second sleeve 23, and the isolation glue 223 serves to bond the first metal 222 and the second metal 224 to form the first sleeve 22.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A coupling adapter, comprising:

the laser transmitter comprises an outer sleeve and a laser transmitting piece, wherein a first through hole penetrating through a first end and an opposite second end of the outer sleeve is formed in the outer sleeve;

a ceramic sleeve disposed within the first through-hole and having a second through-hole coaxial with the first through-hole;

the ceramic ferrule is arranged in the first through hole and is partially inserted into the second through hole, and the ceramic ferrule is provided with a third through hole coaxial with the first through hole;

the inlet end of the ceramic ferrule close to the first end and the space enclosed by the outer sleeve are internally filled with a gradual change film, the gradual change film is in contact with the inlet end of the ceramic ferrule and the inner wall surface of the outer sleeve, and the refractive index of the gradual change film is increased along with the increase of the refractive index of the gradual change film close to the inlet end of the ceramic ferrule.

2. The coupling adapter of claim 1, wherein an optical fiber core and a glass body are adjacently disposed within the third through hole, the glass body being proximate to the entrance end of the ferrule relative to the optical fiber core, the glass body having a refractive index less than a refractive index of the optical fiber core.

3. The coupling adapter of claim 2, wherein the glass body is bonded to the graded film, the glass body having an index of refraction that is greater than an index of refraction of the graded film where the glass body is bonded.

4. The coupling adapter of claim 1, wherein the aperture of the first through-hole decreases from the first end to the inlet end of the ferrule.

5. The coupling adapter of claim 4 wherein an inner wall surface of the outer sleeve proximate the first end is coated with a reflective film to reflect light into the graduated film through the reflective film.

6. The coupler adapter of claim 5, wherein the reflective film is in contact with the graded film.

7. The coupling adapter of claim 5 wherein the reflective membrane has a reflectivity greater than a reflectivity of an inner wall surface of the outer sleeve.

8. The coupling adapter of claim 1, wherein an end face of the ferrule proximate the inlet end is beveled.

9. The coupler adapter of claim 1, wherein the outer sleeve comprises:

a first sleeve disposed at the first end for connection to a laser emitting member, the first sleeve having a first cavity;

a second sleeve disposed at the second end for connection to an optical fiber connector, the second sleeve having a second cavity;

the first sleeve is fixedly connected with the second sleeve, and the first cavity is communicated with the second cavity to form the first through hole.

10. The coupling adapter of claim 9, wherein the first sleeve comprises a first metal piece, an isolating glue and a second metal piece which are fixedly connected in sequence, the first metal piece is arranged at the first end and used for connecting a laser emitting piece, and the second metal piece is used for fixedly connecting with the second sleeve; coaxial through holes are formed in the first metal piece, the isolating glue and the second metal piece to form the first cavity.