JP2012098556A - Optical coupling unit and light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To curb an adverse effect caused by clad mode light on an optical coupling technology capable of coupling laser beam traveling in space to an optical fiber.SOLUTION: An optical coupling unit 100 on which a laser beam L traveling in space is incident from an end surface of one end side of an optical fiber 300 comprises: a unit body 110 in which the optical fiber 300 is disposed and which emits heat externally; a ferrule 130 which holds part of an exposure part without using members susceptible to heat deformation by clad mode light leaked from the optical fiber 300 and adjusts in advance the end surface of the one end side of the optical fiber 300 to a position on which the laser beam L is incident; a high refractive index member 120 which, embedded on a downstream side of the exposure part and attached firmly to the unit body 110, has a high refractive index as high as or higher than a clad 302 of the optical fiber 300.

Description

  The present invention relates to an optical coupling unit in which laser light traveling in space enters from an end face on one end side of an optical fiber, and a light source device including the optical coupling unit.

  When laser light is used, there are many cases in which it is desirable to take a form of output from an optical fiber as a final output form. For example, when irradiating an object with laser light for the purpose of various analysis, treatment, and processing, it is desirable to take the above-described form so that the irradiation position can be freely changed. In such cases, in order to irradiate high-order harmonics with laser light, the crystal is wavelength-converted through the laser light, and the laser light emitted to the space is once emitted into the space. In some cases, it is necessary to couple the laser beam to the optical fiber.

  Therefore, an optical coupling technique for coupling laser light emitted from a laser light source into a space to an optical fiber is known. In such an optical coupling technique, generally, an optical connector (see Patent Document 1) usually used for connecting optical fibers is used as it is. In other words, by placing an optical connector fixed to the end of the optical fiber on the optical path of the laser light emitted from the laser light source, the laser light once emitted into the space is transferred to the optical fiber fixed to the optical connector. I try to guide you.

  Here, as the wavelength of the laser light becomes shorter, the diameter of the core has to be reduced particularly in a single mode optical fiber. The smaller the diameter of the core, the more difficult it is to make the laser light incident on the core when the laser light traveling in the space is incident on the end face on one end side of the optical fiber. As a result, the probability of becoming clad mode light (light passing through the clad) increases.

  After the light is coupled to one end of the optical fiber, if the cladding mode light remains in the laser light emitted from the other end of the optical fiber, the power of the laser light fluctuates, and the desired optical power and beam shape It becomes impossible to obtain the laser beam.

  Further, in an ordinary optical fiber, the outer peripheral surface of the clad is covered with a coating material having a refractive index higher than that of the clad. For this reason, the remaining clad mode light leaks to the coating material, and is absorbed by an adhesive, metal, or the like outside the cover material, and generates heat (see Patent Documents 2 and 3). When the laser light source has a high output, the amount of heat generation increases, the position of the optical fiber varies due to expansion of the metal member, etc., coupling efficiency decreases, and signal light output decreases. As a result of the relatively increased clad mode light, the heat generation amount is further increased, resulting in a negative chain, and eventually the optical fiber may be broken. The output may become unstable until it does not break.

  As a technique for suppressing the negative effects of these clad mode light, a technique for removing the clad mode light by actively absorbing and radiating the clad mode light in an optical fiber laser or an optical fiber amplifier is known. (Patent Document 4).

JP 2009-175545 A JP-A-3-145608 JP 2001-111153 A JP 2008-187100 A

  However, the technique disclosed in Patent Document 4 removes the clad mode light that has traveled through the clad in the optical fiber from the outside of the apparatus. Therefore, this technique is not an optical coupling technique that couples laser light traveling in space to an optical fiber, and does not describe any handling of clad mode light immediately after entering the end face of the optical fiber.

  An object of the present invention is to make it possible to suppress adverse effects caused by clad mode light in an optical coupling technique in which laser light traveling in space is coupled to an optical fiber.

  The present invention employs the following means in order to solve the above problems.

That is, the optical coupling unit of the present invention is
In an optical coupling unit in which laser light traveling in space is incident from an end face on one end side of an optical fiber,
Light in which the optical fiber is disposed in a state having an exposed portion exposed on the outer peripheral surface of the clad on the one end side, absorbs clad mode light leaked from the exposed portion, generates heat, and releases the heat to the outside An absorption heat dissipation member (a member made of a material having high thermal conductivity such as metal);
Positioning that holds a part of the exposed portion without using a member that is thermally deformed by clad mode light leaked from the optical fiber, and pre-positions the end face on the one end side of the optical fiber at a position where the laser light is incident Members,
Of the exposed portion, the downstream side in the light traveling direction from the holding position by the positioning member is embedded, and is provided in close contact with the light absorbing and radiating member, and leaks clad mode light from the exposed portion, A high refractive index member having a refractive index equal to or higher than that of the optical fiber cladding;
It is characterized by providing.

  Here, in “holding a part of the exposed portion without using a member that is thermally deformed by the clad mode light leaked from the optical fiber”, the exposed portion is absorbed by the member that does not deform even if it generates heat by absorbing the clad mode light. When the exposed portion is held by a member that transmits (does not absorb) clad mode light, the exposed portion is held by a member that releases the heat even if the clad mode light is absorbed and generates heat. Includes cases.

  According to the present invention, when laser light traveling in the space is incident on the end face on one end side of the optical fiber, even if it enters the clad and becomes clad mode light, the clad mode light passes from the clad to the high refractive index member. It is absorbed by the light absorbing and radiating member. Therefore, the clad mode light can be removed in the optical coupling unit. The light absorbed by the light absorbing and radiating member is converted into heat, but the light absorbing and radiating member itself can release the heat to the outside and suppress the temperature rise in the unit. Thereby, the malfunction accompanying the difference in the thermal expansion of the various members accompanying a temperature rise, and the linear expansion coefficient of an adjacent member can be suppressed.

Furthermore, in the present invention, the end face of the optical fiber on the side on which the laser beam is incident is positioned without using a member that is thermally deformed by the cladding mode light leaking from the optical fiber, and the exposed portion where the outer peripheral surface of the cladding is exposed. It is done by holding a part of. Therefore, the cladding mode light immediately after entering the optical fiber end face does not leak from the optical fiber until reaching the high refractive index member, or even if it leaks, there is no problem of thermal deformation, and the displacement of the end face of the optical fiber is suppressed. can do.

  The positioning member may be a ferrule having a fine hole through which the exposed portion is inserted, and only the exposed portion may exist in the fine hole.

  As a result, there is nothing that absorbs light between the exposed portion of the optical fiber and the fine hole of the ferrule, so that a defect caused by the thermal deformation of the inclusion can occur when there is an inclusion between them. Does not occur.

  It is also preferable that the positioning member is a member having a positioning groove into which the exposed portion is fitted and a cover for pressing the exposed portion into the positioning groove.

  Even if such a member is used, the end face on one end side of the optical fiber can be suitably positioned.

  Moreover, the positioning member having the positioning groove and the cover may be the light absorbing and radiating member.

  If such a structure is employ | adopted, the end surface of the one end side of an optical fiber can be positioned with few components.

The light source device of the present invention comprises:
A laser light source;
Any of the above optical coupling units for coupling laser light emitted from the laser light source into the space;
It is characterized by providing.

  According to the light source device of the present invention, in the optical coupling unit, the clad mode light is suitably removed, and the positional deviation of the end face of the optical fiber is suppressed and the quality is maintained. Laser light can be emitted.

  In addition, said each structure can be employ | adopted combining as much as possible.

  As described above, according to the present invention, in the optical coupling technique for coupling laser light traveling in space to an optical fiber, adverse effects due to clad mode light can be suppressed.

FIG. 1 is a schematic configuration diagram of a light source device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of the light source device according to the first embodiment of the invention. FIG. 3 is a schematic cross-sectional view of a light source apparatus according to Embodiment 2 of the present invention. FIG. 4 is a schematic cross-sectional view of a light source device according to Embodiment 3 of the present invention. FIG. 5 is an external view of an optical coupling unit according to Embodiment 4 of the present invention. FIG. 6 is a cross-sectional view of an optical coupling unit according to Embodiment 4 of the present invention. FIG. 7 is an external view showing a state where the cover of the optical coupling unit according to Embodiment 4 of the present invention is removed. FIG. 8 is a cross-sectional view illustrating a state where the cover of the optical coupling unit according to the fourth embodiment of the present invention is removed. 9A and 9B are an external view and a cross-sectional view of a light-absorbing and radiating member (unit main body) according to Example 4 of the present invention. FIG. 10 is an external view of an optical coupling unit according to Embodiment 5 of the present invention. FIG. 11 is an external view of an optical coupling unit according to Embodiment 6 of the present invention. FIG. 12 is a cross-sectional view of an optical coupling unit according to Embodiment 6 of the present invention. 13A and 13B are an external view and a cross-sectional view of a light absorbing and radiating member according to Embodiment 6 of the present invention. FIG. 14 is an external view and a cross-sectional view of an optical coupling unit according to Embodiment 7 of the present invention. FIG. 15 is an external view and a cross-sectional view of an optical coupling unit according to Embodiment 8 of the present invention.

  DETAILED DESCRIPTION Exemplary embodiments for carrying out the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments and examples are intended to limit the scope of the present invention only to those unless otherwise specified. Is not.

  In the following description, among the optical fibers provided in the optical coupling unit, the side on which laser light traveling in the space is incident is referred to as “one end side”, and the opposite side is referred to as “the other end side”.

(Embodiment)
<Configuration of light source device and optical coupling unit>
With reference to FIG. 1, the light source device and optical coupling unit which concern on embodiment of this invention are demonstrated. FIG. 1A shows a schematic configuration of the entire light source device according to the present embodiment. In FIG. 1A, the optical coupling unit is shown in a schematic sectional view. FIG. 1B is a partially enlarged cross-sectional view of the optical coupling unit. For convenience of explanation, the scale of the optical coupling unit in FIG. 1A is different from that of the optical coupling unit in FIG.

  A light source device 200 according to the present embodiment includes a laser light source 210 provided in a case 201, and an optical coupling unit 100 that couples laser light L emitted from the laser light source 210 and traveling in space to an optical fiber 300. I have. Further, the light source device 200 irradiates the laser light L toward a desired position from the lens 220 or the optical fiber 300 for condensing the laser light L emitted from the laser light source 210 toward the optical coupling unit 100. A laser head 310 is also provided.

  The optical coupling unit 100 is a unit main body 110 as a light absorbing and radiating member on which the optical fiber 300 is disposed, a high refractive index member 120, and a positioning member for positioning the end surface 300a on one end side of the optical fiber 300. And a ferrule 130.

  The unit main body 110 is a member that releases heat to the outside, and is made of a metal having high thermal conductivity. As a structure for more efficiently dissipating heat, a configuration in which a plurality of fins or a plurality of holes and protrusions are provided in order to increase the surface area of the unit main body 110 can be employed.

An end of one end side of the optical fiber 300 is disposed inside the unit main body 110. The optical fiber 300 is covered by a predetermined distance from the end surface 300a on one end side toward the other end side.
3 is peeled off and the outer peripheral surface of the clad 302 is exposed. Hereinafter, a portion of the optical fiber 300 where the outer peripheral surface of the clad 302 is exposed is simply referred to as an “exposed portion”.

  The ferrule 130 is, for example, a cylindrical member, and is provided with a fine hole 130a through which an exposed portion of the optical fiber 300 is inserted. As shown in FIG. 1B, by making the hole diameter of the minute hole 130a slightly larger (for example, about 1 μm larger) than the outer diameter (for example, 125 μm) of the clad 302 in the optical fiber 300, the minute hole 130a. Thus, a part of the exposed portion can be held, and the end face 300a on one end side of the optical fiber 300 can be positioned with high accuracy so that the laser light L is incident.

  Here, in the present embodiment, a member that is not thermally deformed based on the clad mode light is used when positioning the end surface 300a on one end side of the optical fiber 300 by holding a part of the exposed portion of the optical fiber 300. . Specifically, (1) the exposed portion is held by a member that does not deform even if it absorbs clad mode light and generates heat, or (2) the exposed portion is held by a member that transmits (does not absorb) clad mode light. (3) Even if the clad mode light is absorbed to generate heat, the exposed portion is held by a member that releases the heat to the outside.

  In the case of (1), for example, the ferrule 130 may be made of a material that does not deform even when it generates heat by absorbing clad mode light. In the case of (2), for example, the ferrule 130 may be made of a material that transmits (does not absorb) clad mode light. In the case of (3), for example, even if the ferrule 130 absorbs the cladding mode light and generates heat, it may be made of a material that releases the heat to the outside.

  Further, in the example shown in FIG. 1B, only the exposed portion of the optical fiber 300 exists in the minute hole 130a. Accordingly, since there is no light absorbing member between the exposed portion and the fine hole 130a, there is no problem with the thermal deformation of the inclusion that may occur when the inclusion is present between them.

  The high refractive index member 120 is provided on the downstream side in the light traveling direction from the position where the ferrule 130 holds the exposed portion of the optical fiber 300. The high refractive index member 120 is made of a material having a refractive index equal to or higher than that of the clad 302 of the optical fiber 300. The high refractive index member 120 is provided so as to be in close contact with the inner wall surface of the unit main body 110. Further, the high refractive index member 120 is configured such that a part of the exposed portion of the optical fiber 300 is embedded.

  The high refractive index member 120 is formed, for example, by forming a space portion in the unit main body 110 and placing the optical fiber 300, and then filling the space portion with a high refractive index resin material in a flowing state. Then, it can obtain by hardening this resin material. In addition, although the high refractive index member 120 is provided adjacent to the ferrule 130 in FIG. 1B, there may be a gap (space) between the high refractive index member 120 and the ferrule 130. Absent. Further, FIG. 1B shows a case where only the exposed portion of the optical fiber 300 is embedded in the high refractive index member 120, but not only the exposed portion but also a part of the coating 303 in the optical fiber 300. May be buried. In the exposed portion of the optical fiber 300, the range in the longitudinal direction (the length direction of the optical fiber 300) embedded by the high refractive index member 120 is usually about several centimeters.

  In addition, the surface of the space inner wall 110a in the unit main body 110 is roughened to form a plurality of minute irregularities 110b. Thereby, it is possible to suppress the light that has passed through the high refractive index member 120 from being reflected by the inner wall surface of the unit body 110 and returning to the optical fiber 300.

  The high refractive index member 120 also exhibits a function of fixing the optical fiber 300 to the unit main body 110 by embedding a part of the optical fiber 300 therein.

<Functions of light source device and optical coupling unit>
The laser light L emitted from the laser light source 210 into the space is condensed by the lens 220 and is incident on the end surface 300 a on one end side of the optical fiber 300. At this time, the light L1 incident on the core 301 of the optical fiber 300 is totally reflected at the interface with the cladding 302, and thus travels through the core 301 without leaking from the core 301.

  On the other hand, the light incident on the clad 302 of the optical fiber 300 becomes the clad mode light L2. The clad mode light L2 leaks from the partial clad 302 and is reflected by the outer surface of the partial clad 302 to return. In the case of the example shown in FIG. 1B, the clad mode light L <b> 2 is repeatedly reflected on the outer surface of the clad 302 and proceeds without leaking from the optical fiber 300. Then, the clad mode light L2 reaching the high refractive index member 120 leaks out to the high refractive index member 120 and is then absorbed by the space inner wall 110a of the unit body 110. The light absorbed by the unit main body 110 is converted into heat, and the converted heat is transmitted through the unit main body 110 and released to the outside.

<Excellent points of light source device and optical coupling unit according to this embodiment>
According to the present embodiment, when the laser light L traveling in the space is incident on the end surface 300a on the one end side of the optical fiber 300, the clad mode light L2 is incident on the clad 302 and becomes the clad mode light L2. The light is absorbed into the space inner wall 110a of the unit main body 110 from the clad 302 through the high refractive index member 120. Therefore, the clad mode light L2 can be removed in the optical coupling unit 100. Further, in the present embodiment, since the minute unevenness 110b is formed on the surface of the space inner wall 110a in the unit main body 110, the light that has passed through the high refractive index member 120 passes through the space inner wall 110a of the unit main body 110. Reflecting on the surface and returning to the optical fiber 300 can be suppressed.

  Moreover, although the light absorbed in the unit main body 110 is converted into heat, as described above, since the heat can be radiated from the outer surface of the unit main body 110, the temperature rise in the optical coupling unit 100 can be suppressed. it can. Thereby, the malfunction etc. accompanying the difference in the thermal expansion of the various members in the optical coupling unit 100 accompanying temperature rising, or the linear expansion coefficient of an adjacent member can be suppressed.

  Further, the positioning of the end face 300a of the optical fiber 300 is performed by holding a part of the exposed portion where the outer peripheral surface of the clad 302 is exposed without using a member that is thermally deformed by the leaked clad mode light. . Accordingly, the cladding mode light L2 immediately after entering the end face 300a of the optical fiber 300 does not leak from the optical fiber 300 until reaching the high refractive index member 120, or even if it leaks, there is no problem of thermal deformation, and the optical fiber 300 The positional deviation of the end face 300a can be suppressed.

  Further, the ferrule 130 is made of a material that transmits the clad mode light, a material that does not deform due to heat even if the clad mode light is absorbed, or a material that releases the heat even if it absorbs the clad mode light and generates heat. In order to suppress the leakage of the clad mode light L2 and the heat generated by the leakage as much as possible, the distance from the end surface 300a on the one end side of the optical fiber 300 to the high refractive index member 120 is shortened as much as possible. Is desirable.

As described above, according to the light source device 200 according to the present embodiment, the cladding mode light L2 is suitably removed in the optical coupling unit 100, and the misalignment of the end face 300a of the optical fiber 300 is suppressed. The end beam quality is maintained. Therefore, according to the light source device 200 according to the present embodiment, the laser light L can be stably emitted over a long period of time.

<Others>
As described above, the refractive index of the high refractive index member 120 is the same as or higher than the refractive index of the cladding 302 so that the cladding mode light L2 passing through the cladding 302 leaks to the high refractive index member 120. Is set to However, if the refractive index of the high-refractive index member 120 is too high, the angle at which the cladding mode light L2 enters the high-refractive index member 120 becomes steep, and is reflected by the space inner wall 110a and returned into the optical fiber 300. The possibility increases. Therefore, it is desirable that the refractive index of the high refractive index member 120 be as close as possible to the refractive index of the clad 302. However, since the refractive index has temperature dependency, the refractive index may be reversed between two materials depending on the temperature. Therefore, the refractive index S of the high-refractive index member 120 and the refractive index T of the clad 302 are maintained so that the relationship of S ≧ T is always maintained at the environmental temperature under the condition where the optical coupling unit 100 is used. It is necessary to choose the material. In the present embodiment, the environmental temperature is set to an arbitrary temperature range of 0 to 50 ° C. This is because the actual use environment may be, for example, 5 to 30 ° C. or 15 to 45 ° C., and may not be determined in a certain pattern.

  In addition, the optical fiber 300 in the present embodiment may be a single mode optical fiber or a multimode optical fiber. In the present embodiment, as described above, even if the clad mode light L2 is generated without being incident on the core 301, the clad mode light L2 can be suitably removed. Therefore, the present invention can also be suitably applied to a single mode optical fiber whose core diameter must be reduced.

  Further, in the light source device 200 according to the present embodiment, the wavelength of light incident on the optical coupling unit 100 is not particularly limited. Even in the case where the wavelength of such light is 700 nm or less and the core diameter of the optical fiber 300 must be reduced, in the present embodiment, there is no problem because the clad mode light L2 can be suitably removed as described above. .

  Further, even if the power of the output light of the light source device is high output of 0.5 W or more, as described above, the temperature rise in the optical coupling unit 100 can be suppressed. Therefore, even a high output light source can be suitably used.

  Hereinafter, some more specific examples of the light source device and the optical coupling unit according to the present embodiment will be described.

(Example of light source device)
Example 1
With reference to FIG. 2, the light source device according to the first embodiment of the present invention will be described. FIG. 2 is a schematic cross-sectional view of the light source device according to the first embodiment of the invention. In addition, the same code | symbol is attached | subjected about the same component as the light source device 200 which concerns on embodiment mentioned above, and the description is abbreviate | omitted suitably.

  The light source device 200a according to the present embodiment includes a solid-state laser unit 211 provided in the case 201, a wavelength conversion unit 212 that converts the wavelength of the laser light L emitted from the solid-state laser unit 211, and the optical coupling unit 100. It has. The wavelength conversion unit 212 includes a nonlinear optical crystal 212a therein, and the nonlinear optical crystal 212a is arranged on the optical path of the laser light L, so that the laser light is transmitted when light passes through the crystal. The wavelength of L can be converted to 1 / integer (for example, 1/2, 1/3).

  The solid-state laser unit 211 is directly fixed to the case 201, and the wavelength conversion unit 212 is fixed to the first stage 230 fixed to the case 201 in a state in which the position of the solid-state laser unit 211 is adjusted. ing. Further, the optical coupling unit 100 is fixed to the second stage 231 fixed to the first stage 230 in a state where the position adjustment with the wavelength conversion unit 212 is performed. Further, the lens 220 is fixed to the third stage 232 fixed to the second stage 231 in a state where the position of the wavelength conversion unit 212 and the optical coupling unit 100 is adjusted. The optical fiber 300 outside the case 201 is connected to the optical fiber 300 in the case 201 by an optical connector 320.

  According to the light source device 200a according to the present embodiment configured as described above, the laser light L emitted from the solid-state laser unit 211 is wavelength-converted by the wavelength conversion unit 212. Then, the wavelength-converted laser beam L is coupled to the optical fiber 300 in the optical coupling unit 100. Since the optical coupling unit 100 is as described in the above embodiment, the description thereof is omitted.

(Example 2)
With reference to FIG. 3, a light source device according to Embodiment 2 of the present invention will be described. FIG. 3 is a schematic cross-sectional view of a light source apparatus according to Embodiment 2 of the present invention. In the light source device according to the first embodiment, the case where the wavelength conversion unit is provided on the downstream side of the solid-state laser unit (downstream side in the light traveling direction) is shown. However, in this embodiment, the wavelength conversion unit is provided. The case where there is not will be described. Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  In the light source device 200b according to the present embodiment, a solid-state laser unit 213 is provided in a case 201. This solid-state laser unit 213 is a type that does not require a wavelength conversion unit. However, a wavelength conversion unit may be provided inside the solid-state laser unit 213.

  This solid-state laser unit 213 is also directly fixed to the case 201 as in the case of the first embodiment. In this embodiment, the optical coupling unit 100 is fixed to the first stage 233 fixed to the case 201 in a state where the position of the optical coupling unit 100 is adjusted with the solid-state laser unit 213. Further, the lens 220 is fixed to the second stage 234 fixed to the first stage 233 in a state where the positions of the solid-state laser unit 213 and the optical coupling unit 100 are adjusted. Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

(Example 3)
With reference to FIG. 4, the light source device which concerns on Example 3 of this invention is demonstrated. FIG. 4 is a schematic cross-sectional view of a light source device according to Embodiment 3 of the present invention. In the light source device according to the first embodiment, the case where the solid laser unit is used as the laser light source is shown, but in this embodiment, the case where the fiber laser unit is used as the laser light source is shown. Since other configurations and operations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

In the light source device 200 c according to the present embodiment, a fiber laser unit 214 is provided in the case 201. In the light source device 200c according to the present embodiment, an optical fiber 215 having one end connected to the fiber laser unit 214 by the optical connector 216 and the other end connected to the wavelength conversion unit 212 by the optical connector 217 is provided. Yes. With this optical fiber 215, the laser light L from the fiber laser unit 214 is guided to the wavelength conversion unit 212. Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

(Example of optical coupling unit)
Example 4
With reference to FIGS. 5-9, the optical coupling unit which concerns on Example 4 of this invention is demonstrated. FIG. 5 is an external view of an optical coupling unit according to Embodiment 4 of the present invention. (A) is a plan view, (b) is a front view, (c) is a rear view, (d) is a rear view, and (e) is a rear view. It is a side view. FIG. 6 is a cross-sectional view of an optical coupling unit according to Embodiment 4 of the present invention, and is a cross-sectional view along AA in FIG. FIG. 7 is an external view showing a state where the cover of the optical coupling unit according to Embodiment 4 of the present invention is removed. The figure (a) is a top view, The figure (b) is a front view. FIG. 8 is a cross-sectional view illustrating a state where the cover of the optical coupling unit according to the fourth embodiment of the present invention is removed, and is a cross-sectional view taken along the line AA in FIG. FIG. 9A is a plan view of a light absorbing and radiating member (unit main body) according to Embodiment 4 of the present invention, and FIG. 9B is a cross-sectional view thereof (AA cross-sectional view in FIG. 9A). is there. In addition, the same code | symbol is attached | subjected about the optical coupling unit 100 which concerns on embodiment mentioned above, and the same component, The description is abbreviate | omitted suitably.

  The optical coupling unit 100a according to the present embodiment is for positioning the unit main body 111 as a light absorbing and radiating member on which the optical fiber 300 is disposed, the high refractive index member 121, and the end face on one end side of the optical fiber 300. And a ferrule 131 as a positioning member. Further, in the optical coupling unit 100a according to the present embodiment, a ferrule 140 that positions the other end side of the optical fiber 300 and a cover 112 that closes the opening of the space in the unit main body 111 are provided.

<< Unit body (light absorption and heat dissipation member) >>
The unit main body 111 according to the present embodiment is made of a metal having high thermal conductivity (for example, pure metal such as gold, silver, copper, aluminum, iron, zinc, nickel, or alloys containing any of these metals (aluminum alloy). , Brass, stainless steel, etc.)) (for example, a rectangular parallelepiped having a length of 44 mm, a width of 60 mm, and a height of about 26 mm). The unit main body 111 is provided with a plurality of fins 111a over substantially the entire area of the upper surface side and the lower surface side, and has a heat dissipation structure that efficiently releases heat to the outside.

  In addition, the unit body 111 is provided with a space that allows one end of the optical fiber 300 to be inserted in the center in the width direction. More specifically, a groove-shaped (groove shape having a length of about 30 mm) space K in which the high refractive index member 121 is disposed, and an insertion hole K1 that is connected to the space K and in which the ferrule 131 is mounted, Similarly, there is provided an insertion hole K2 that communicates with the space K and into which the ferrule 140 is mounted (see in particular FIG. 9B). In addition, a first opening hole 111b that communicates with the space part K and a second opening hole 111c that also communicates with the space part K are provided in the upper part of the space part K (particularly, refer to FIG. 9A). ).

  In addition, the inner wall surface forming the space K is roughened with a file or the like to suppress reflection of light toward the optical fiber 300 due to specular reflection, thereby forming minute irregularities. It has become a state. Furthermore, the surface of the inner wall that forms the space K is subjected to a surface treatment such as black alumite or black plating to further suppress light reflection.

  Further, the unit main body 111 is provided with a screw hole 111d of a screw 151 for fixing the cover 112 and a screw hole 111e of a screw 152 for fixing the ferrules 131 and 140.

  The cover 112 is fixed to the unit main body 111 with four screws 151, so that the first opening hole 111b and the second opening hole 111c are closed. Note that the cover 112 may not be provided if the first opening hole 111b and the second opening hole 111c do not need to be closed due to the usage of the optical coupling unit 100a.

<< High refractive index member >>
The high refractive index member 121 is a member constituted by an optical resin made of, for example, a UV curable resin or a silicone elastomer. As described in the above embodiment, the high refractive index member 121 is made of a material having a refractive index equal to or higher than that of the clad of the optical fiber 300.

  The high refractive index member 121 is obtained by pouring a high refractive index resin material in a fluidized state into the above-described space portion K and then curing it. More specifically, first, the optical fiber 300 is held in the unit main body 111 by the ferrules 131 and 140. In this embodiment, in order to hold the optical fiber 300 more reliably, the optical fiber 300 is fixed by attaching an adhesive 160 to the upstream end of the ferrule 140 on the other end side. The operation of applying the adhesive 160 can be performed through the second opening hole 111c (see FIG. 7A). After fixing with the adhesive 160, the space K is filled with a certain amount of high refractive index resin material through the first opening 111b. Thereafter, the high refractive index member 121 can be obtained by curing the resin material by a method according to the characteristics of the resin material, such as ultraviolet irradiation or standing at room temperature.

<< Optical fiber and ferrule >>
The optical fiber 300 according to the present embodiment is a single mode optical fiber having a core diameter of 10 μm or less. In this example, the outer peripheral surface of the cladding is exposed at one end of the optical fiber 300 as described in the above embodiment. In this embodiment, the range of X in FIG. 6 is the exposed portion. In addition, the range of Y in the figure is a part where the primary coating is exposed, and Z in the figure is a part where the secondary coating is exposed. As can be seen from the figure, in this embodiment, the coating is provided on the optical fiber 300 from the position embedded in the high refractive index member 121. Thereby, the optical fiber 300 is stably bonded by the adhesive 160. In the case where an adhesive having a good compatibility with the cladding is used, for example, a range indicated by Y in the figure may be the exposed portion of the optical fiber 300.

  Ferrules 131 and 140 for holding and fixing the optical fiber 300 to the unit main body 111 are fixed by screws 152 while being inserted into the insertion holes K1 and K2 of the unit main body 111, respectively.

  In particular, the ferrule 131 is fixed to the unit main body 111 only by a mechanical method, and there is no member such as a resin or an adhesive that is deformed by heat. Thereby, the position shift of the ferrule 131 accompanying the thermal deformation by clad mode light can be suppressed.

  As these ferrules 131 and 140, those having a low coefficient of thermal expansion and high heat resistance, those having high light transmittance, and those having high heat conductivity are suitable. For example, in addition to a zirconia ferrule and an electroformed nickel ferrule, a metal ferrule made of SUS or the like, a glass ferrule, and an SMA ferrule can be used. A resin ferrule having low heat resistance and low thermal conductivity is inappropriate.

With respect to the ferrule 131 that positions one end of the optical fiber 300, as described in the above embodiment, the end surface 300a on one end of the optical fiber 300 is positioned by holding a part of the exposed portion of the optical fiber 300. Yes. One end side of the optical fiber 300 is cleaved in the direction perpendicular to the fiber axis in the vicinity of the end face of the ferrule 131 to form an end face 300a.

  Here, in the case where a zirconia ferrule or an electroformed nickel ferrule having excellent microscopic hole dimensional accuracy is employed as the ferrule 131, the optical fiber 300 can be positioned with high accuracy. Thereby, clad mode light can be suppressed.

  Further, when a metal ferrule having high thermal conductivity is adopted as the ferrule 131, the heat converted by the ferrule 131 can be efficiently conducted to the unit body 111.

  Furthermore, when a glass ferrule with high cladding mode light permeability is employed as the ferrule 131, the light incident on the ferrule 131 can be transmitted and radiated to the surroundings. Therefore, since the ferrule 131 does not absorb light, there is an advantage that heat generation due to light absorption and expansion deformation due to heat generation do not occur.

  Further, the ferrule 131 is set to have a total length of, for example, about 10.5 mm, so that the distance from the end face 300a of the optical fiber 300 to the high refractive index member 121 is set as much as possible while sufficiently positioning the optical fiber 300. Can be shortened. Thereby, the bad influence of the clad mode light before reaching the high refractive index member 121 can be minimized.

  With the optical coupling unit 100a configured as described above, the same effects as those of the optical coupling unit 100 according to the above-described embodiment can be obtained. Further, in the optical coupling unit 100a according to the present embodiment, a plurality of fins 111a are provided over substantially the entire area of the upper surface side and the lower surface side of the unit main body 111, and symmetrical with respect to the optical fiber 300 in the vertical direction. A configuration is adopted in which a plurality of fins 111a are provided symmetrically on the right and left sides. Therefore, the heat distribution can be made uniform during heat radiation, and heat can be efficiently radiated.

(Example 5)
With reference to FIG. 10, the optical coupling unit which concerns on Example 5 of this invention is demonstrated. FIG. 10 is an external view of an optical coupling unit according to Embodiment 5 of the present invention. The figure (a) is a top view, The figure (b) is a front view. In the fourth embodiment, the case where the fin is not provided in the cover is shown. However, in this embodiment, the case where the fin is also provided in the cover will be described. Since other configurations and operations are the same as those of the fourth embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  In the optical coupling unit 100b according to the present embodiment, the cover 113 is also provided with a plurality of fins 113a. In the case of the optical coupling unit 100a according to Example 4, since the fins are not provided in the cover 112, the fins are not symmetrically arranged in the vertical direction in the vicinity of the optical fiber 300. On the other hand, in this embodiment, since the cover 113 is provided with a plurality of fins 113a, the symmetry of the fins with respect to the vertical direction of the optical fiber 300 can be further enhanced.

(Example 6)
With reference to FIGS. 11-13, the optical coupling unit which concerns on Example 6 of this invention is demonstrated. FIG. 11 is an external view of an optical coupling unit according to Embodiment 6 of the present invention. (A) is a plan view, (b) is a front view, (c) is a rear view, (d) is a rear view, and (e) is a rear view. It is a side view and the figure (f) is an enlarged view of the site | part shown by P in the figure (b). FIG. 12 is a cross-sectional view of an optical coupling unit according to Embodiment 6 of the present invention, which is a cross-sectional view along AA in FIG. FIG. 13A is a plan view of a light absorbing and radiating member (unit body) according to Embodiment 6 of the present invention, and FIG. 13B is a cross-sectional view thereof (AA cross-sectional view in FIG. 13A). is there.

  In the said Example 4, the case where a ferrule was used as a positioning member for positioning the end surface of the one end side of the optical fiber 300 was shown. On the other hand, in a present Example, the case where the member which has a positioning groove | channel and a cover is used as the said positioning member, and the said member is a unit main body is shown. Since other configurations and operations are the same as those in the fourth embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  The optical coupling unit 100c according to the present embodiment includes a unit main body 115 as a light absorbing and radiating member on which the optical fiber 300 is disposed, and a high refractive index member 122.

<< Unit body (light absorption and heat dissipation member) >>
Similarly to the case of the fourth embodiment, the unit main body 115 according to the present embodiment is also a substantially rectangular parallelepiped member made of a metal having high thermal conductivity. The unit main body 115 is provided with a plurality of fins 115a over substantially the entire upper surface side and lower surface side, and has a heat dissipation structure that diffuses heat to the outside.

  Further, the unit main body 115 is provided with a space portion through which one end side of the optical fiber 300 can be inserted at the center in the width direction. More specifically, a groove-shaped space K in which the high refractive index member 122 is disposed is provided. In the case of the unit main body 115 of the present embodiment, the V groove 115c as a positioning groove that leads to the space K and positions and holds one end side of the optical fiber 300, and the other end side are positioned. A holding V-groove 115d is provided. By fixing the V-groove covers 116 and 117 in a state in which the optical fiber 300 is fitted in the V-grooves 115c and 115d, the optical fiber 300 is pressed into the V-grooves 115c and 115d and positioned and held. . Thereby, the exposed part of the optical fiber 300 is held at one end side of the optical fiber 300. The V-groove covers 116 and 117 are also made of a metal having high thermal conductivity, like the unit main body 115. Thus, in this embodiment, the unit main body 115 also serves as a positioning member having the V-groove 115c as the positioning groove and the V-groove cover 116.

  In addition, an opening hole 115 b that communicates with the space K is provided in the upper part of the space K. The point that the inner wall surface forming the space K is roughened and the surface treatment such as black plating is performed is the same as in the case of the fourth embodiment.

  The unit main body 115 is provided with screw holes 115e and 115f for screws 153 and 154 for fixing the V-groove covers 116 and 117, respectively.

<< High refractive index member >>
The high refractive index member 122 is a member made of an optical resin made of, for example, a UV curable resin or a silicone elastomer. As described in the above embodiment, the high refractive index member 122 is made of a material having a refractive index that is the same as or higher than that of the cladding of the optical fiber 300.

The high refractive index member 122 is obtained by pouring a high refractive index resin material in a fluid state into the above-described space portion K and then curing the same as in the case of the fourth embodiment. More specifically, the optical fiber 300 is held in the unit main body 115 by the V-grooves 115 c and 115 d and the V-groove covers 116 and 117. Then, a certain amount of high refractive index resin material is filled into the space K through the opening hole 115b. Thereafter, the high refractive index member 122 can be obtained by curing the resin material by a method according to the characteristics of the resin material, such as ultraviolet irradiation or standing at room temperature.

<< Optical fiber and V-groove >>
The optical fiber 300 according to the present embodiment is also a single mode optical fiber having a core diameter of 10 μm or less as in the case of the fourth embodiment. In this example, the outer peripheral surface of the cladding is exposed at one end of the optical fiber 300 as described in the above embodiment. In this embodiment, the range of X in FIG. 12 is the exposed portion. In addition, the range of Y in the figure is a site | part in which the coating | cover was provided.

  In the present embodiment, the exposed portion on one end side of the optical fiber 300 is fixed in a state of being directly held by the unit main body 115, and there are no members such as resin or adhesive that are deformed by heat. Therefore, the position shift of the optical fiber 300 due to the thermal deformation caused by the clad mode light can be suppressed.

  Also, one end side of the optical fiber 300 is cleaved in the direction perpendicular to the fiber axis in the vicinity of the end face on one end side of the unit body 115 to form an end face 300a.

  In the case of the present embodiment, one end side of the optical fiber 300 is fixed in a state of being directly held by the unit main body 115. Therefore, part of the cladding mode light immediately after incidence leaks and is absorbed by the unit body 115 and the V-groove cover 116 before reaching the high refractive index member 122. However, the unit main body 115 and the V-groove cover 116 have high thermal conductivity, and heat can be efficiently released by the heat dissipation structure (the plurality of fins 115a) provided in the unit main body 115. Therefore, the positional shift of the end surface 300a on the one end side of the optical fiber 300 can be suppressed.

  The V groove 115c is set to have a total length of, for example, about 7 mm, so that the distance from the end surface 300a of the optical fiber 300 to the high refractive index member 122 is shortened as much as possible while sufficiently positioning the optical fiber 300. Can do. Thereby, it is possible to prevent light from leaking from the optical fiber 300 before reaching the high refractive index member 122.

  With the optical coupling unit 100c configured as described above, the same effects as those of the optical coupling unit 100 according to the above-described embodiment and the optical coupling unit 100a according to Example 4 can be obtained. Also in the optical coupling unit 100c according to the present embodiment, as in the case of the fourth embodiment, a plurality of fins 115a are provided over substantially the entire upper surface side and lower surface side of the unit body 115, and an optical fiber is provided. A configuration is adopted in which a plurality of fins 115a are provided symmetrically up and down about 300 and symmetrically on the left and right. Therefore, the heat distribution can be made uniform during heat radiation, and heat can be efficiently radiated.

(Example 7)
With reference to FIG. 14, the optical coupling unit which concerns on Example 7 of this invention is demonstrated. 14A is a plan view of an optical coupling unit according to Embodiment 7 of the present invention, FIG. 14B is a front view thereof, and FIG. 14C is a sectional view thereof (FIG. 14A). ) In FIG.

  In this embodiment, a case where a cover is further attached to the structure shown in the sixth embodiment will be described. Since other configurations and operations are the same as those in the sixth embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  The optical coupling unit 100d according to the present embodiment has a configuration in which a cover 118 for closing the opening hole 115b is further provided in the configuration of the optical coupling unit 100c according to the sixth embodiment. In this embodiment, a configuration is adopted in which the V-groove covers 116 and 117 are fixed together with the cover 118 by four screws 155.

  According to the optical coupling unit 100d configured as described above, in addition to the same function and effect as in the sixth embodiment, it is possible to close the opening hole in the space. Depending on the use environment, either the optical coupling unit 100c according to the sixth embodiment that does not include a cover or the optical coupling unit 100d according to the present embodiment that includes the cover 118 may be used properly.

(Example 8)
With reference to FIG. 15, the optical coupling unit which concerns on Example 8 of this invention is demonstrated. FIG. 15A is a plan view of an optical coupling unit according to Embodiment 8 of the present invention, FIG. 15B is a front view thereof, and FIG. 15C is a sectional view thereof (FIG. 15A). ) In FIG. In the seventh embodiment, the case where the fin is not provided in the cover is shown, but in this embodiment, the case where the fin is also provided in the cover will be described. Since other configurations and operations are the same as those of the seventh embodiment, the same reference numerals are given to the same configurations, and descriptions thereof are omitted.

  In the optical coupling unit 100e according to the present embodiment, the cover 119 is also provided with a plurality of fins 119a. In the case of the optical coupling unit 100d according to the seventh embodiment, since the fins are not provided in the cover 118, the arrangement of the fins is not symmetrical in the vertical direction in the vicinity of the optical fiber 300. On the other hand, in this embodiment, since the cover 119 is provided with a plurality of fins 119a, the symmetry of the fins with respect to the vertical direction of the optical fiber 300 can be further enhanced.

(Other)
In each of the above embodiments, as an example of the heat dissipation structure, a structure in which a plurality of fins extending in the longitudinal direction of the optical fiber are provided on the upper and lower surfaces of the unit main body is shown. However, the heat dissipation structure in the present invention has such a structure. It is not limited. Fins may be provided on the side surface of the unit main body, or fins extending in a direction perpendicular to the longitudinal direction of the optical fiber may be provided. In addition to the fins, it is also possible to employ a heat dissipation structure in which a plurality of holes or a plurality of protrusions are provided to increase the surface area and enhance the heat dissipation effect.

  In Examples 6-8, the case where the positioning member which has a positioning groove | channel and a cover is a unit main body which also plays the role as a light absorption heat radiating member was shown. However, it is also possible to adopt a configuration in which the positioning member having the positioning groove and the cover is formed of a member different from the unit main body and the other member is fixed to the unit main body.

  In Examples 6 to 8, although the case of the V-groove is shown as the positioning groove, a groove having a U-shaped cross section or a groove having a rectangular cross section may be used, and the shape of the groove is not limited. In addition, rather than positioning one end side of the optical fiber by a groove provided in the unit main body, the one end side of the optical fiber is inserted into the fine hole by forming a fine hole in the unit main body. It is also possible to adopt a configuration in which the one end side of each is positioned.

In the said Examples 4-8, although the case where a unit main body was comprised with the substantially rectangular parallelepiped member was shown, the shape of a unit main body is not restricted to this. For example, it is also possible to adopt a substantially cylindrical shape as the unit main body (light absorbing / dissipating member). In this case, an optical fiber is disposed so as to pass through the central axis of the substantially cylindrical unit body, a high refractive index member is disposed concentrically therearound, and the longitudinal direction of the optical fiber is disposed on the entire outer peripheral surface of the unit body. It is possible to adopt a configuration in which fins of the same size and shape extending in the same direction are arranged at equal angles (equal intervals). By adopting such a configuration, heat can be released in a radial manner, the heat distribution can be made more uniform, and the heat dissipation efficiency can be further increased.

  In the said embodiment and each Example, although the thing which hardened the resin material of a fluid state was mentioned as an example as a high refractive index member, the material of a high refractive index member is not limited to this. For example, as a material for the high refractive index member, an elastic or flexible material can be used. In addition, a fluid material such as a liquid or a gel can be used. However, in this case, it is necessary to form a sealed space and contain a fluid material in the sealed space. Thereby, the portion of the material having fluidity enclosed in the sealed space corresponds to the high refractive index member.

  100, 100a, 100b, 100c, 100d, 100e ... optical coupling unit, 110, 111 ... unit body, 111a ... fin, 115 ... unit body, 115a ... fin, 115c, 115d ... V groove, 116, 117 ... V groove Cover, 120, 121, 122 ... high refractive index member, 130, 131, 140 ... ferrule, 130a ... fine hole, 200, 200a, 200b, 200c ... light source device, 210 ... laser light source, 300 ... optical fiber, 300a ... End face, 301 ... core, 302 ... cladding, L ... laser light, L2 ... cladding mode light

Claims (5)

In an optical coupling unit in which laser light traveling in space is incident from an end face on one end side of an optical fiber,
Light in which the optical fiber is disposed in a state having an exposed portion exposed on the outer peripheral surface of the clad on the one end side, absorbs clad mode light leaked from the exposed portion, generates heat, and releases the heat to the outside An absorption heat dissipation member;
Positioning that holds a part of the exposed portion without using a member that is thermally deformed by clad mode light leaked from the optical fiber, and pre-positions the end face on the one end side of the optical fiber at a position where the laser light is incident Members,
Of the exposed portion, the downstream side in the light traveling direction from the holding position by the positioning member is embedded, and is provided in close contact with the light absorbing and radiating member, and leaks clad mode light from the exposed portion, A high refractive index member having a refractive index equal to or higher than that of the optical fiber cladding;
An optical coupling unit comprising:   2. The optical coupling unit according to claim 1, wherein the positioning member is a ferrule having a minute hole through which the exposed portion is inserted, and only the exposed portion exists in the minute hole.   The optical coupling unit according to claim 1, wherein the positioning member is a member having a positioning groove into which the exposed portion is fitted and a cover for pressing the exposed portion into the positioning groove.   The optical coupling unit according to claim 3, wherein the positioning member having the positioning groove and the cover is the light absorbing and radiating member. A laser light source;
The optical coupling unit according to any one of claims 1 to 4, wherein the laser light emitted from the laser light source into the space is coupled.
A light source device comprising:

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