CN117170024A - Optical path coupling equipment and optical path coupling method - Google Patents

Abstract

The application provides optical path coupling equipment, and belongs to the technical field of laser communication. The light path coupling device comprises a light path coupler, a beam expanding device, a light beam guiding component and a reflecting mirror; the optical path coupler comprises a box body and a hollow optical fiber, wherein the box body is internally provided with a vacuum cavity, the hollow optical fiber is arranged in the vacuum cavity, the side wall of the box body is provided with an incident window and an emergent window, and a channel of the hollow optical fiber faces the incident window; the beam expanding device is movably arranged at one side of the box body so that laser injected into the beam expanding device can pass through the hollow optical fiber; the light beam guiding component is arranged on one side of the box body facing the incident window and comprises a first lens and at least two diaphragms, and the diaphragms are arranged on one side of the first lens facing away from the incident window. The optical path coupling equipment provided by the application can spatially combine the femtosecond laser and the visible laser, so that the coupling success rate of the femtosecond laser and the service life of the vacuum optical fiber are improved.

Description

Optical path coupling equipment and optical path coupling method

Technical Field

The present application relates to the field of laser communications technologies, and in particular, to an optical path coupling device and an optical path coupling method.

Background

In the existing high-energy femtosecond laser coupling process, because the inlet of the end face of the hollow optical fiber is only in the order of hundred micrometers, the inlet position of the hollow optical fiber is difficult to coincide with the focus of the femtosecond laser, and in the adjusting process, the high-energy femtosecond laser is likely to hit the pipe wall of the hollow optical fiber, so that the hollow optical fiber is damaged, the coupling efficiency is reduced and even fails, and if the femtosecond laser is in an invisible wave band, the coupling difficulty is greatly improved.

Disclosure of Invention

In view of the above, the present application aims to overcome the defects in the prior art, and provides an optical path coupling device and an optical path coupling method.

The application provides the following technical scheme: an optical path coupling apparatus comprising:

the optical path coupler comprises a box body and a hollow optical fiber, wherein a vacuum cavity is defined in the box body, the hollow optical fiber is arranged in the vacuum cavity, an incident window and an emergent window are arranged on the side wall of the box body, and a channel of the hollow optical fiber faces the incident window;

the beam expanding device is movably arranged at one side of the box body so that laser injected into the beam expanding device can pass through the hollow optical fiber;

the light beam guiding assembly is arranged on one side of the box body, which faces the incident window, and comprises a first lens and at least two diaphragms, wherein the diaphragms are arranged on one side of the first lens, which faces away from the incident window;

and a reflecting mirror disposed in the vacuum chamber at a side close to the exit window so that the laser light passing through the hollow optical fiber can be reflected by the reflecting mirror and then emitted from the exit window or the laser light reflected by the reflecting mirror can be transmitted through the hollow optical fiber and then emitted from the entrance window.

Further, the beam expanding device is arranged on one side of the diaphragm, which is away from the first lens, and comprises a second lens and a third lens which are arranged at intervals;

the third lens is arranged on one side of the second lens, which is close to the light beam guiding assembly.

Further, the beam expanding device is arranged on one side of the box body, which faces the exit window, and comprises a fourth lens and a fifth lens which are arranged at intervals, and the fifth lens is arranged between the fourth lens and the exit window.

Further, a folding mirror is arranged between the beam expanding device and the beam guiding component;

the folding mirror is arranged at the intersection point of the axis of the beam expanding device and the axis of the beam guiding assembly, so that laser passing through the beam expanding device can pass through the hollow optical fiber after being reflected by the folding mirror and guided by the beam guiding assembly.

Further, the number of the diaphragms is two, and the axes of two adjacent diaphragms coincide.

Further, the optical path coupler comprises a limiting device, an installation channel is defined in the limiting device, and the hollow optical fiber penetrates through the installation channel.

Further, the axis of the hollow optical fiber coincides with the axis of the diaphragm.

Further, one side of the box body is provided with an observation window.

Further, a telescopic piece is arranged in the vacuum cavity, and the reflecting mirror is connected with the output end of the telescopic piece;

the moving direction of the reflecting mirror is parallel to the axis of the hollow optical fiber.

Some embodiments of the present application provide an optical path coupling method, using the optical path coupling apparatus, including:

obtaining visible laser, injecting the visible laser into a beam expanding device along a preset direction, and adjusting the incidence angle of the visible laser, the position of the beam expanding device, the position of a beam guiding assembly and the position of a box body so that the visible laser passing through the beam expanding device can pass through a hollow optical fiber after being focused by the beam guiding assembly;

the position of the reflector is regulated so that the visible laser is emitted through the emergent window after being reflected by the reflector;

the method comprises the steps of obtaining femtosecond laser, removing a beam expanding device, adjusting the incidence direction and the incidence angle of the femtosecond laser, and completing spatial beam combination of the femtosecond laser and visible laser when the femtosecond laser passes through a beam guiding assembly so as to realize that the femtosecond laser passes through a hollow optical fiber.

Embodiments of the present application have the following advantages: the optical path coupling equipment provided by the application can spatially combine the femtosecond laser and the visible laser to enable the femtosecond laser to be coupled on the end surface of the hollow optical fiber in the vacuum cavity, and the visible laser passes through the hollow optical fiber to enable the femtosecond laser after beam combination to pass through the hollow optical fiber; the coupling success rate of the femtosecond laser can be effectively improved by observing the facula and the energy of the femtosecond laser after the hollow optical fiber, and the possibility that the hollow optical fiber is damaged by the high-energy femtosecond laser is greatly reduced, thereby improving the success rate of the laser in the coupling process with the hollow optical fiber in the vacuum cavity and the service life of the vacuum optical fiber.

In order to make the above objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural view of a view angle of a first embodiment of an optical path coupling apparatus according to some embodiments of the present application;

fig. 2 is a schematic structural view of another view of the first embodiment of the optical path coupling apparatus according to some embodiments of the present application;

FIG. 3 shows a cross-sectional view of section A-A of FIG. 2;

FIG. 4 is a schematic diagram of the optical path of a femtosecond laser in an optical path coupling apparatus according to some embodiments of the present application;

fig. 5 is a schematic structural view of a view angle of a second embodiment of an optical path coupling apparatus according to some embodiments of the present application;

fig. 6 is a schematic structural view of another view of a second embodiment of an optical path coupling apparatus according to some embodiments of the present application;

FIG. 7 shows a cross-sectional view of section B-B of FIG. 6;

FIG. 8 shows an enlarged view of section C of FIG. 7;

fig. 9 is a flow chart illustrating an optical path coupling method according to some embodiments of the present application.

Description of main reference numerals:

a 100-optical coupler; 110-a box body; 120-hollow fiber; 111-vacuum chamber; 112-entrance window; 113-an exit window; 200-beam expanding device; 300-a beam steering assembly; 310-a first lens; 320-diaphragm; 400-reflecting mirror; 210-a second lens; 220-a fifth lens; 230-a third lens; 240-fourth lens; 500-limiting devices; 600-fold mirror.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the application.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.

In the present application, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.

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

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the templates herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

As shown in fig. 1, 3, 5 and 7, some embodiments of the present application provide an optical path coupling device, which is mainly applied to improving the success rate in the coupling process of laser and hollow fiber, improving the service life of the hollow fiber, reducing the experimental cost, and improving the experimental efficiency.

The optical path coupling apparatus includes an optical path coupler 100, a beam expanding device 200, a beam guiding assembly 300, and a reflecting mirror 400.

Specifically, the optical path coupler 100 includes a box 110 and a hollow fiber 120, the box 110 defines a vacuum cavity 111 inside, the hollow fiber 120 is disposed in the vacuum cavity 111, and a limiting device 500 is disposed in the box 110, so that the limiting device 500 forms a limiting and fixing function on the hollow fiber 120, so as to improve the stability of the hollow fiber 120 in the box 110.

Meanwhile, the side wall of the box 110 is provided with an incident window 112 and an exit window 113, and it should be noted that the incident window 112 and the exit window 113 are respectively disposed at two sides of the box 110, and the channel of the hollow optical fiber 120 faces the incident window 112, so that when the laser is injected into the vacuum cavity 111 from the incident window 112, the laser can pass through the channel of the hollow optical fiber 120, so as to realize the coupling between the laser and the hollow optical fiber 120. That is, the incident window 112 covers the hollow optical fiber 120 along the projection in the axial direction of the hollow optical fiber 120, thereby ensuring that the laser light transmitted through the incident window 112 can pass through the hollow optical fiber 120.

The hollow fiber 120 has a hollow cylindrical structure.

The beam expander 200 is movably disposed at one side of the case 110, so that the laser beam incident into the beam expander 200 can pass through the hollow optical fiber 120, and the beam expander 200 can provide a beam expanding effect on the laser beam incident into the beam expander 200, so as to expand the diameter of the laser beam, reduce the divergence angle of the laser beam, and make the laser beam focused by the beam expander 200 smaller, thereby making the light spot of the laser smaller and improving the collimation characteristic of the laser beam.

In some embodiments, the beam expander 200 is disposed on the side of the case 110 facing the incident window 112 or the beam expander 200 is disposed on the side of the case 110 facing the exit window 113, which may be specifically set according to practical situations.

The light beam guiding assembly 300 is disposed on a side of the case 110 facing the incident window 112, the light beam guiding assembly 300 includes a first lens 310 and at least two diaphragms 320, the diaphragms 320 are disposed on a side of the first lens 310 facing away from the incident window 112, and it is understood that the number of diaphragms 320 may be two or more of any number.

It should be noted that, by setting at least two diaphragms 320, and overlapping the axes of any two diaphragms 320, the two diaphragms 320 can form a limiting effect on the light beam, that is, the two diaphragms 320 spaced apart can play a role in collimating the light beam, so that the accuracy of the incident angle of the light beam can be ensured.

Preferably, in the present embodiment, the number of the diaphragms 320 is two, and the axes of the two diaphragms 320 are coincident, so that not only the position of the light beam can be defined, but also the cost of the optical path coupling device can be reduced.

The first lens 310 is a convex lens, so that the laser passing through the first lens 310 is focused, and the size of the spot is further reduced, so that the laser focused by the first lens 310 can be focused on the end face of the hollow optical fiber 120, that is, the outer diameter of the laser beam focused by the first lens 310 is smaller than the inner diameter of the hollow optical fiber 120, so that the laser beam can effectively pass through the hollow optical fiber 120, and contact between the laser beam and the inner wall of the hollow optical fiber 120 can be avoided, the service life of the hollow optical fiber 120 can be prolonged, and the success rate of the coupling process of the laser and the hollow optical fiber 120 in the vacuum cavity 111 can be improved.

The aperture 320 is an entity that limits the light beam in the optical system. It may be the edge of a lens, a frame or a specially arranged perforated screen. Its effect can be in two ways, limiting the beam or limiting the size of the field of view (imaging range).

A mirror 400 is provided in the vacuum chamber 111 at a side close to the exit window 113 to provide a reflecting effect on the laser light entering the vacuum chamber 111 by the mirror 400 so that the laser light can be reflected to the exit window 113 by the effect of the mirror 400 and emitted from the exit window 113, thereby guiding the laser light out of the vacuum chamber 111 through the exit window 113.

Specifically, the reflecting mirror 400 is disposed at the intersection point of the extension line of the axis of the hollow optical fiber 120 and the extension line of the axis of the exit window 113, so that the laser light irradiated to the reflecting mirror 400 through the entrance window 112 can be reflected to the exit window 113 through the reflecting mirror 400 and emitted from the exit window 113, or the laser light irradiated to the reflecting mirror 400 through the exit window 113 can be reflected to the entrance window 112 through the reflecting mirror 400 and emitted from the entrance window 112. The laser light entering the vacuum chamber 111 can pass through the hollow optical fiber 120.

It will be appreciated that the laser light passing through the hollow optical fiber 120 can be reflected by the reflecting mirror 400 and then emitted from the exit window 113, or the laser light reflected by the reflecting mirror 400 can be transmitted through the hollow optical fiber 120 and then emitted from the entrance window 112.

Specifically, as shown in fig. 1 and 4, in the present embodiment, by injecting visible laser light (for example, helium-neon laser light with power of 1 mW) into the beam expander 200, the helium-neon laser light is expanded by the beam expander 200 to reduce the divergence angle of the helium-neon laser light, and simultaneously, the helium-neon laser light is focused, and by adjusting the incidence angle of the helium-neon laser light, the helium-neon laser light can pass through the hollow optical fiber 120 after being focused by the beam guide assembly 300. Because the helium-neon laser is visible light, and even if the helium-neon laser is injected into the surface of the hollow optical fiber 120 in the beam expanding process, the hollow optical fiber 120 is not affected, and the coupling of the helium-neon laser to the hollow optical fiber 120 is realized by observing the helium-neon laser spot behind the hollow optical fiber 120. Then, the beam expander 200 is removed, and the femtosecond laser and the helium-neon laser are spatially combined (it should be noted that, when the helium-neon laser passes through the beam guide assembly 300 and the hollow fiber 120, the beam expander 200 is removed, and then the incident angle of the femtosecond laser is adjusted so that the femtosecond laser can pass through the beam guide assembly 300 and the hollow fiber 120, thereby implementing the spatial beam combination of the femtosecond laser and the helium-neon laser), so that the femtosecond laser is coupled onto the end surface of the hollow fiber 120 in the vacuum cavity 111, and the combined femtosecond laser can also pass through the hollow fiber 120 because the helium-neon laser passes through the hollow fiber. By observing the light spot and energy of the femtosecond laser after the hollow optical fiber 120 to optimize, the coupling success rate of the femtosecond laser can be effectively improved, and the possibility that the hollow optical fiber 120 is damaged by the high-energy femtosecond laser is greatly reduced, thereby improving the success rate of the laser in the coupling process with the hollow optical fiber 120 in the vacuum cavity 111 and the service life of the vacuum optical fiber.

As shown in fig. 1 to 3, in some embodiments of the present application, the beam expander 200 is disposed on a side of the diaphragm 320 facing away from the first lens 310, so as to expand the laser entering the vacuum cavity 111 through the incident window 112 by the beam expander 200, so as to focus the laser, reduce the divergence angle of the laser, and improve the collimation of the laser entering the vacuum cavity 111.

The beam expander 200 includes a second lens 210 and a third lens 230 disposed at intervals, the third lens 230 is disposed on a side of the second lens 210 near the beam guiding assembly 300, and an axis of the third lens 230 and an axis of the second lens 210 are coincident. Further, the axis of the third lens 230 and the axis of the beam steering assembly 300 are both on the same plane.

As shown in fig. 1 and 3, in some embodiments of the present application, a folding mirror 600 is disposed between the beam expander 200 and the beam guiding assembly 300, and the folding mirror 600 is disposed at an intersection point of an axis of the beam expander 200 and an axis of the beam guiding assembly 300, so that the laser light passing through the beam expander 200 can pass through the hollow optical fiber 120 after being reflected by the folding mirror 600 and guided by the beam guiding assembly 300, wherein the axis of the beam guiding assembly 300 coincides with the axis of the hollow optical fiber 120.

The normal line of the folding mirror 600, the axis of the beam expander 200 and the axis of the beam guiding assembly 300 are all located on the same plane, so that the laser light passing through the beam expander 200 can be injected into the beam guiding assembly 300 after being reflected by the folding mirror 600.

In some embodiments, the fold mirror 600 is replaced with a dichroic mirror.

It should be noted that the arrangement at the intersection point between the axis of the second lens 210 and the axis of the hollow optic fiber 120 allows the laser light sequentially passing through the second lens 210 and the third lens 230 to be reflected to the beam guiding assembly 300 by the folding mirror 600 and to be focused by the beam guiding assembly 300 and then to pass through the hollow optic fiber 120.

Specifically, the folding mirror described in the present embodiment includes a folding frame and a reflecting mirror mounted on the folding frame.

Illustratively, as shown in fig. 1 and 3, when the folding leg is unfolded, at this time, the light beam 1 (i.e., the visible laser light) passing through the beam expander 200 can be reflected to the beam guide assembly 300 by the mirror on the folding leg. When the folding leg is folded, the light beam 2 (i.e., the femtosecond laser) can be directly injected into the light beam guiding assembly 300, so that not only blocking of the light beam 2 by the folding mirror can be avoided, but also the spatial beam combining efficiency of the light beam 1 and the light beam 2 can be improved.

In the present embodiment, the second lens 210 is a concave lens, and the third lens 230 is a convex lens, so that the third lens 230 focuses the laser beam, and improves the collimation of the laser beam (generally, the spot size (about 2 mm) of the he—ne laser beam is smaller than that of the femtosecond laser beam (about 10 mm)), so that the he—ne laser beam is expanded to have the same size as that of the femtosecond laser beam, and thus the size at the focal point can be compared, thereby having better directivity.

In some embodiments, a fluorescent layer is disposed at the edge of the diaphragm 320 to improve the collimation accuracy of the laser.

In addition, as shown in fig. 5 to 7, in some embodiments, the beam expander 200 is disposed on a side of the case 110 facing the exit window 113, the beam expander 200 includes a fourth lens 240 and a fifth lens 220 disposed at intervals, the fifth lens 220 is disposed between the fourth lens 240 and the exit window 113, an axis of the fourth lens 240 and an axis of the fifth lens 220 are coincident, and visible laser light can pass through the fourth lens 240 and the fifth lens 220, then enter the vacuum cavity 111 through the exit window 113, and reflect the visible laser light to a port of the hollow optical fiber 120 through the mirror 400, and exit the entrance window 112 through the hollow optical fiber 120.

It should be noted that, since the visible laser is coupled in the hollow fiber, the incident angle of the visible laser or the position of the mirror 400 may be adjusted according to the position of the visible laser and the hollow fiber 120, so that the visible laser can pass through the hollow fiber 120. Thus, the coupling of the visible laser in the hollow optical fiber 120 is controlled, so that the positions of the reflecting mirror 400 and the beam guiding assembly 300 are adjusted, when the femtosecond laser is emitted into the beam guiding assembly 300 from one side of the beam guiding assembly 300 away from the box 110, the femtosecond laser can enter the hollow optical fiber 120 through the incident window 112, thereby realizing the spatial beam combination of the femtosecond laser and the visible laser, and the coupling of the femtosecond laser and the visible laser can pass through the hollow optical fiber 120, thereby enabling the femtosecond laser to pass through the hollow optical fiber 120, improving the coupling efficiency of the femtosecond laser and the hollow optical fiber 120, and further effectively avoiding the contact of the femtosecond laser and the hollow optical fiber 120, and prolonging the service life of the hollow optical fiber 120.

In the present embodiment, the fourth lens 240 is a concave lens, and the fifth lens 220 is a convex lens, so that the fifth lens 220 focuses the laser beam to improve the collimation of the laser beam.

As shown in fig. 3, 7 and 8, in some embodiments of the present application, the optical coupler 100 includes a limiting device 500, and a mounting channel is defined inside the limiting device 500, and the mounting channel is a linear channel. Wherein, the hollow fiber 120 is disposed through the installation channel.

In some embodiments of the present application, a viewing window (not shown) is provided at one side of the housing 110 to observe the coupling of the laser light in the hollow optic fiber 120 through the viewing window.

In some embodiments, a telescopic member (not shown) is disposed in the vacuum chamber 111 and connected to the housing 110, so as to improve stability of the telescopic member in the housing 110.

Wherein the reflecting mirror 400 is connected to the output end of the telescopic member, so that the reflecting mirror 400 is controlled to move by the output end of the telescopic member, and when laser light is incident on the reflecting mirror 400, the position of the reflecting mirror 400 is adjusted by the telescopic member, so that the position of the laser light reflected by the reflecting mirror 400 at the exit window 113 is adjusted, thereby enabling the reflected laser light to be guided out of the exit window 113.

The moving direction of the reflecting mirror 400 is parallel to the axis of the hollow optical fiber 120.

In addition, in some embodiments, a driving device (not shown) is disposed at one side of the case 110, so that the position of the case 110 is adjusted by the driving device, so that the axis of the hollow optical fiber 120, the axis of the diaphragm 320, and the axis of the first lens 310 in the case 110 can be completely overlapped, thereby achieving the optical path adjustment of the optical path coupling apparatus.

Specifically, the driving device can adjust the position of the case 110 in the horizontal direction and the vertical direction. The driving device comprises a first hydraulic rod, a second hydraulic rod and a third hydraulic rod, the axes of the first hydraulic rod, the second hydraulic rod and the third hydraulic rod are mutually perpendicular, the axes of the first hydraulic rod and the second hydraulic rod are all located on the same horizontal plane, and the output ends of the first hydraulic rod, the second hydraulic rod and the third hydraulic rod are all connected with the box body, so that the position of the box body can be adjusted through the driving device.

As shown in fig. 9, some embodiments of the present application provide an optical path coupling method, using the optical path coupling apparatus described in any one of the above embodiments, the optical path coupling method including:

step S100, obtaining visible laser, injecting the visible laser into a beam expanding device along a preset direction, and adjusting the incidence angle of the visible laser, the position of the beam expanding device, the position of a beam guiding assembly and the position of a box body so that the visible laser passing through the beam expanding device can pass through the hollow optical fiber after being focused by the beam guiding assembly.

The preset direction refers to the axial direction of the beam expander 200. Specifically, the visible laser is sequentially emitted onto the folding mirror 600 through the second lens 210 and the third lens 230 along the axis direction of the beam expanding device 200, reflected by the folding mirror 600, and then emitted into the beam guiding assembly 300, and the visible laser is emitted into the vacuum cavity 111 through the beam guiding assembly 300 and the incident window 112, so that a worker can observe the positional relationship between the visible laser emitted into the vacuum cavity 111 and the hollow optical fiber 120 through the observation window of the box 110, and the coupling between the visible laser and the hollow optical fiber 120 is realized by adjusting the position of the folding mirror 600, the position of the beam guiding assembly 300 or the incident angle of the visible laser, so that the visible laser can pass through the hollow optical fiber 120 in the vacuum cavity 111.

Since there are at least two diaphragms 320 in the beam guiding assembly 300, and the axes of any two diaphragms 320 coincide, the diaphragms 320 can provide guiding and limiting effects on the visible laser light, so that the visible laser light can completely pass through the beam guiding assembly 300. It will be appreciated that when the visible laser light passes completely through the beam steering assembly 300 and the hollow optic 120, the axis of the beam steering assembly 300 and the axis of the hollow optic 120 in the housing 110 coincide.

In step S200, the position of the mirror is adjusted so that the visible laser light is emitted through the exit window after being reflected by the mirror.

Specifically, the visible laser light passing through the hollow optical fiber 120 is incident on the mirror 400 in the vacuum chamber 111, and is reflected by the mirror 400 to be emitted from the exit window 113.

The distance between the reflecting mirror 400 and the hollow optical fiber 120 is adjusted so that the laser light passing through the hollow optical fiber 120 can be reflected by the reflecting mirror 400 and then emitted from the exit window 113, thereby guiding the laser light out of the vacuum chamber 111.

Step S300, obtaining the femtosecond laser, removing the beam expanding device, adjusting the incidence direction and the incidence angle of the femtosecond laser, and completing spatial beam combination of the femtosecond laser and the visible laser when the femtosecond laser passes through the beam guiding assembly so as to realize that the femtosecond laser passes through the hollow optical fiber.

It should be noted that, in this step, the folding mirror 600 is removed to avoid the beam expander 200 and the folding mirror 600 blocking the incident angle of the femtosecond laser, so as to ensure that the femtosecond laser can be effectively injected into the beam guide assembly 300.

Specifically, after the femtosecond laser is obtained, the folding mirror 600 is removed, the incident direction and the incident angle of the femtosecond laser are adjusted, so that the femtosecond laser can be directly emitted into the beam guide assembly 300, namely, the femtosecond laser can sequentially pass through the two diaphragms 320 and the first lens 310, the incident light intensity, the incident angle and the incident shape of the femtosecond laser are adjusted through the two diaphragms 320, the laser is focused through the first lens 310, so that the light spot of the laser is further reduced, the space beam combination of the femtosecond laser and the visible laser is realized, the light spot of the laser which enters the vacuum cavity 111 through the incident window 112 can be aligned with and passes through the hollow fiber 120, the femtosecond laser can pass through the hollow fiber 120, the coupling efficiency can be further optimized by observing the light spot and the power of the femtosecond laser which passes through the hollow fiber 120, the time for the femtosecond laser pair coupling into the vacuum hollow fiber 120 is reduced, and the service life of the hollow fiber 120 is effectively prolonged.

It should be noted that, in step S100, by adjusting the positions of the beam guiding assembly 300 and the box 110 so that the visible laser passes through the beam guiding assembly 300 (here, the visible laser passes through the first lens 310 and the at least two diaphragms 320 in sequence, that is, the axis of the visible laser, the axis of the first lens and the axis of each diaphragm coincide) and the hollow optical fiber 120 in the box 110, the accuracy of adjusting the relative position between the beam guiding assembly 300 and the box 110 is achieved, and since the visible laser can be seen, not only the adjustment efficiency and the accuracy of adjusting the optical path coupling device are improved, but also the hollow optical fiber can be effectively prevented from being damaged, thereby ensuring the service life of the hollow optical fiber.

Therefore, when the visible laser can sequentially pass through the beam guiding assembly 300 and the hollow optical fiber 120, the incident angle of the femtosecond laser is adjusted, and when the femtosecond laser passes through the beam guiding assembly 300, the femtosecond laser can also pass through the hollow optical fiber 120 to realize the space coupling of the femtosecond laser and the visible laser, so that the contact between the femtosecond laser and the hollow optical fiber 120 can be avoided, the coupling success rate of the femtosecond laser can be improved, the possibility that the hollow optical fiber is damaged by the high-energy femtosecond laser can be greatly reduced, and the success rate of the laser and the hollow optical fiber in the vacuum cavity in the coupling process and the service life of the vacuum optical fiber can be improved.

In some embodiments of the application, the femtosecond laser is an 800nm femtosecond laser.

Since the power of the helium-neon laser is only about 1mW, there is no problem of deterioration in the process of adjusting the coupling of the helium-neon laser to the hollow optical fiber 120. And secondly, because the helium-neon laser and the high-energy 800nm femtosecond laser are spatially combined through the same two diaphragms 320, once the helium-neon laser passes through the hollow optical fiber 120, the high-energy 800nm femtosecond laser can also directly pass through the hollow optical fiber 120, so that the coupling difficulty is reduced, and the hollow optical fiber 120 is effectively protected.

According to the optical path coupling method provided by the application, under the condition that the wavelength of the femtosecond laser is in an invisible wave band (such as 1030nm femtosecond laser), the visible laser and the femtosecond laser are combined to form the effect of indicating light through the incident path of the visible laser to the femtosecond laser, so that the invisible femtosecond laser is coupled to the hollow optical fiber 120 in the vacuum cavity 111, the coupling efficiency and the coupling accuracy of the femtosecond laser in the hollow optical fiber 120 are improved, the damage to the hollow optical fiber 120 caused by the femtosecond laser can be avoided, and the service life of the hollow optical fiber 120 is prolonged.

In addition, the visible laser includes helium neon laser, low power visible light (e.g., continuous 532nm green light or 650nm red light).

Any particular values in all examples shown and described herein are to be construed as merely illustrative and not a limitation, and thus other examples of exemplary embodiments may have different values.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application.

Claims (10)

1. An optical path coupling apparatus, comprising:

the optical path coupler comprises a box body and a hollow optical fiber, wherein a vacuum cavity is defined in the box body, the hollow optical fiber is arranged in the vacuum cavity, an incident window and an emergent window are arranged on the side wall of the box body, and a channel of the hollow optical fiber faces the incident window;

the beam expanding device is movably arranged at one side of the box body so that laser injected into the beam expanding device can pass through the hollow optical fiber;

the light beam guiding assembly is arranged on one side of the box body, which faces the incident window, and comprises a first lens and at least two diaphragms, wherein the diaphragms are arranged on one side of the first lens, which faces away from the incident window;

and a reflecting mirror disposed in the vacuum chamber at a side close to the exit window so that the laser light passing through the hollow optical fiber can be reflected by the reflecting mirror and then emitted from the exit window or the laser light reflected by the reflecting mirror can be transmitted through the hollow optical fiber and then emitted from the entrance window.

2. The optical path coupling apparatus according to claim 1, wherein the beam expanding device is provided on a side of the diaphragm facing away from the first lens, the beam expanding device including a second lens and a third lens provided at a spacing;

the third lens is arranged on one side of the second lens, which is close to the light beam guiding assembly.

3. The light path coupling apparatus according to claim 1, wherein the beam expanding means is provided on a side of the housing facing the exit window, the beam expanding means comprising fourth and fifth lenses provided at a distance, the fifth lens being provided between the fourth lens and the exit window.

4. The optical path coupling apparatus according to claim 2, wherein a folding mirror is provided between the beam expanding device and the beam guiding assembly;

the folding mirror is arranged at the intersection point of the axis of the beam expanding device and the axis of the beam guiding assembly, so that laser passing through the beam expanding device can pass through the hollow optical fiber after being reflected by the folding mirror and guided by the beam guiding assembly.

5. The optical path coupling apparatus according to any one of claims 1 to 4, wherein the diaphragms are two, and axes of two adjacent diaphragms coincide.

6. The optical path coupling apparatus according to any one of claims 1 to 4, wherein the optical path coupler includes a limiting device, an interior of the limiting device defining a mounting passage, the hollow optical fiber passing through the mounting passage.

7. The optical path coupling apparatus according to any one of claims 1 to 4, wherein an axis of the hollow fiber coincides with an axis of the diaphragm.

8. The optical path coupling apparatus according to any one of claims 1 to 4, wherein a side of the case is provided with an observation window.

9. The optical path coupling apparatus according to any one of claims 1 to 4, wherein a telescopic member is provided in the vacuum chamber, and the reflecting mirror is connected to an output end of the telescopic member;

the moving direction of the reflecting mirror is parallel to the axis of the hollow optical fiber.

10. An optical path coupling method characterized by using the optical path coupling apparatus according to any one of claims 1 to 9, comprising:

obtaining visible laser, injecting the visible laser into a beam expanding device along a preset direction, and adjusting the incidence angle of the visible laser, the position of the beam expanding device, the position of a beam guiding assembly and the position of a box body so that the visible laser passing through the beam expanding device can pass through a hollow optical fiber after being focused by the beam guiding assembly;

the position of the reflector is regulated so that the visible laser is emitted through the emergent window after being reflected by the reflector;

the method comprises the steps of obtaining femtosecond laser, removing a beam expanding device, adjusting the incidence direction and the incidence angle of the femtosecond laser, and completing spatial beam combination of the femtosecond laser and visible laser when the femtosecond laser passes through a beam guiding assembly so as to realize that the femtosecond laser passes through a hollow optical fiber.