JP7127268B2 - optical coupler - Google Patents

Description

The present invention relates to an optical coupling device for condensing laser light from a laser light source with a lens and coupling it to an optical fiber.

As a conventional optical coupling device of this type, for example, a laser treatment device described in Patent Document 1 is known. This laser treatment apparatus introduces laser light generated from a laser light source into a light guide fiber from one end thereof, and passes the introduced laser light through a handpiece provided on the output side of the light guide fiber to treat a diseased part of a living body. Treatment is performed by irradiating the

The cross-sectional shape of the core member having the light propagation function of the light guide fiber is polygonal, and the grip member is configured at the other end of the light guide fiber to form the handpiece.

According to this optical coupling device, the laser light incident on the optical waveguide fiber is repeatedly totally reflected by the four walls, resulting in a uniform energy distribution that spreads across the cross section of the rectangular fiber, and the output of the optical waveguide fiber. emitted from the end. Therefore, it is possible to obtain a laser treatment apparatus with good transmission efficiency.

As described above, in an optical fiber having a rectangular core with a rectangular cross section, the near-field pattern of laser light (the beam pattern near the output end of the laser light source) has a uniform intensity distribution.

Japanese Patent Publication No. 3-49591

However, in an optical fiber having a core with a circular cross section, the intensity distribution in the near-field pattern of emitted laser light becomes a Gaussian distribution.

Therefore, it has been desired to make the intensity of the near-field pattern of laser light emitted from an optical fiber including a circular core uniform.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical coupling device capable of making the near-field pattern of laser light emitted from an optical fiber including a circular core uniform in intensity.

Claim 1 of the optical coupling device according to the present invention has a laser light source for emitting laser light, a condenser lens for condensing the laser light emitted from the laser light source, a polygonal core, and the light condensing device a first optical fiber for generating a homogenized polygonal beam by injecting laser light focused by a lens into said polygonal core; and a circular core for homogenizing from said first optical fiber. and a second optical fiber for inputting the polygonal beam into the circular core, the second optical fiber moving in the optical axis direction of the optical coupling device, and the profile of the polygonal beam at the incident end face to the second optical fiber being the above. an optical element for adjusting the size of the polygonal beam so as to form a polygon circumscribing the circular core, and for making the near-field pattern of the laser light emitted from the second optical fiber uniform in intensity; It is characterized by being arranged between the first optical fiber and the second optical fiber.

Moreover, in claim 2 , the polygonal core is composed of a rectangular core.

According to the present invention, the polygonal core of the first optical fiber generates a homogenized polygonal beam, moves along the optical axis of the optical coupler, and multiplies the beam at the entrance end face to the second optical fiber. Optics for adjusting the size of the polygonal beam so that the profile of the rectangular beam is a polygon circumscribing the circular core, and for making the near-field pattern of the laser light emitted from the second optical fiber uniform in intensity. An element is positioned between the first optical fiber and the second optical fiber and the homogenized polygonal beam from the optical element is launched into the circular core of the second optical fiber so that the second light is A near-field pattern of laser light emitted from the fiber can be made uniform in intensity.

1 is a configuration diagram of an optical coupling device according to Example 1 of the present invention; FIG. FIG. 4 is a diagram showing a near-field pattern at the output end of the optical fiber having the rectangular core of the optical coupling device of Example 1 of the present invention; It is a figure which shows the rectangular beam in the optical fiber entrance plane which has a circular core of the optical coupling apparatus of Example 1 of this invention, and a circular fiber core outline. FIG. 4 is a diagram showing a near-field pattern at the output end of an optical fiber having a circular core of the optical coupling device according to Example 1 of the present invention; FIG. 2 is a configuration diagram of an optical coupling device according to Example 2 of the present invention; FIG. 10 is a diagram showing the outer shape of a pentagonal core and a circular fiber core on the incident surface of an optical fiber having a circular core of the optical coupling device according to Example 2 of the present invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, optical coupling devices according to embodiments of the present invention will be described in detail with reference to the drawings.

(Example 1)
FIG. 1 is a configuration diagram of an optical coupling device according to Example 1 of the present invention. The optical coupling device of Example 1 includes a laser light source 1 , a lens 2 , an optical fiber 3 , a lens 4 and an optical fiber 5 .

A laser light source 1 emits a laser beam, and is composed of a semiconductor laser, a solid-state laser, or the like. The lens 2 corresponds to the condensing lens of the present invention, converges the laser light emitted from the laser light source 1 and guides it to the rectangular core of the optical fiber 3 .

The optical fiber 3 corresponds to the first optical fiber of the present invention and, as shown in FIG. 2(a), comprises a square core 3a and a clad 3b covering the square core 3a.

The optical fiber 3 enters the laser light condensed by the lens 2 into a rectangular core 3a to generate a homogenized rectangular beam (rectangular beam BM).

A lens 4, corresponding to the optical element of the present invention, is arranged between the optical fibers 3 and 5 and directs the homogenized square beam (rectangular beam BM) from the optical fiber 3 to the circular core of the optical fiber 5. 5a.

The optical fiber 5 corresponds to the second optical fiber of the present invention, and has a circular core 5a and a clad 5b covering the circular core 5a as shown in FIG. The rectangular beam is incident on the circular core 5a through the lens 4. As shown in FIG.

Also, the lens 4 adjusts the size of the rectangular beam BM so that the profile of the rectangular beam BM on the incident end face of the optical fiber 5 becomes a quadrangle circumscribing the core outline D1 of the circular core 5a.

Next, the operation of the optical coupling device of Example 1 configured in this manner will be described with reference to the drawings.

Here, FIG. 2(b) shows a near-field pattern at the output end (position (a) of FIG. 1) of the optical fiber 3 having the rectangular core 3a. FIG. 3 shows a rectangular beam BM and a circular fiber core outline D1 at the optical fiber entrance plane (position (b) in FIG. 1) having a circular core 5a. FIG. 4(b) shows a near-field pattern at the output end of the optical fiber 5 having a circular core 5a (position (c) in FIG. 1).

First, laser light from a laser light source 1 is condensed by a lens 2 and guided to a rectangular core 3a of an optical fiber 3. As shown in FIG. In the optical fiber 3, the laser light is incident on the rectangular core 3a to generate a homogenized rectangular beam (rectangular beam BM). As shown in FIG. 2(b), the near-field pattern in the rectangular core 3a has a uniform intensity.

Next, as shown in FIG. 3, the lens 4 reduces the size of the rectangular beam BM so that the profile of the rectangular beam BM at the incident end face of the optical fiber 5 becomes a quadrangle circumscribing the core outline D1 of the circular core 5a. adjust. Specifically, the position of the lens 4 is moved in the optical axis direction to adjust the size of the rectangular beam BM.

The lens 4 then guides the homogenized rectangular beam (rectangular beam BM) from the optical fiber 3 to the circular core 5a of the optical fiber 5 .

Further, the optical fiber 5 injects the homogenized rectangular beam from the optical fiber 3 through the lens 4 into the circular core 5a.

Thus, according to the optical coupling device of the first embodiment, the rectangular core 3a of the optical fiber 3 generates a homogenized rectangular beam, and the homogenized rectangular beam from the optical fiber 3 is transferred to the circular core of the optical fiber 5. Since the laser light is incident on the core 5a, the near-field pattern of the laser light emitted from the optical fiber 5 can be made uniform in intensity.

(Example 2)
FIG. 5 is a configuration diagram of an optical coupling device according to Embodiment 2 of the present invention. The optical coupling device of Example 2 is characterized in that an optical fiber 30 having a hexagonal core 30a is used instead of the optical fiber 3 having a rectangular core 3a.

Other configurations of the optical coupling device of the second embodiment shown in FIG. 5 are the same as those of the optical coupling device of the first embodiment shown in FIG. are omitted.

The optical fiber 30, as shown in FIG. 6, has a hexagonal core 30a and a clad 30b covering the hexagonal core 30a. Also, as shown in FIG. 6, the lens 4 adjusts the size of the hexagonal beam BM so that the profile of the hexagonal beam at the incident end face to the optical fiber 5 becomes a quadrangle circumscribing the core outline D1 of the circular core 5a. adjust.

Lens 4 then guides the homogenized hexagonal beam from optical fiber 3 to circular core 5 a of optical fiber 5 .

As described above, the optical coupling device of the second embodiment also provides the same effect as the optical coupling device of the first embodiment.

The present invention is not limited to the optical coupling devices of the first and second embodiments. In the optical coupling devices of Examples 1 and 2, the optical fiber has a rectangular core or a hexagonal core, but it may have a polygonal core such as a triangular core or a pentagonal core.

The optical coupling device of the present invention is applicable to laser devices.

1 laser light source 2 lens 3 optical fiber 3a rectangular core 3b clad 4 lens 5 optical fiber 5a circular core 5b clad 30 optical fiber 30a hexagonal core 30b clad BM rectangular beam D1 circular fiber core outline

Claims (2)

a laser light source that emits laser light;
a first condenser lens for condensing the laser beam emitted from the laser light source;
a first optical fiber having a polygonal core, for generating a homogenized polygonal beam by entering the laser light condensed by the first condensing lens into the polygonal core;
a second optical fiber having a circular core and directing the homogenized polygonal beam from the first optical fiber into the circular core;
with
moving in the optical axis direction of the optical coupler and adjusting the size of the polygonal beam so that the profile of the polygonal beam at the incident end face to the second optical fiber becomes a polygon circumscribing the circular core; and an optical element for uniformizing the intensity of the near-field pattern of the laser light emitted from the second optical fiber is arranged between the first optical fiber and the second optical fiber. An optical coupling device characterized by: 2. The optical coupling device according to claim 1, wherein said polygonal core comprises a rectangular core.

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