JP2005228987A - Laser apparatus and laser working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive laser apparatus which is manufactured easily with a high power. <P>SOLUTION: The light emitted from the emitting surface 102 of the light generated by the optical amplifying medium 103 of each optical amplifier 10<SB>n</SB>is incident on the incident/emitting end 311<SB>n</SB>of an optical coupling part 31. The light incident on the incident/emitting end 311<SB>n</SB>is outputted from the common incident/emitting end 312 of the optical coupling part 31 through optical couplers 313<SB>1</SB>-313<SB>7</SB>, and is incident on a diffraction grating part 40. The part of the light of the specific wavelength is selectively reflected by this diffraction grating part 40, returned to the optical amplifying medium 103 of each optical amplifier 10n through an optical path reverse to an optical path so far, and reflected by the reflecting surface 211 of the optical amplifier 10<SB>n</SB>. A laser resonator constituted between the reflecting surfaces 101 of the optical amplifiers 20<SB>1</SB>-20<SB>8</SB>, and the diffraction grating part 40 performs a laser oscillation. An optical waveguide in each incident/emitting end 311<SB>n</SB>of the optical coupling part 31 is a multi-mode, and an optical waveguide in the diffraction grating part 40 is a single mode. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a laser device and a laser beam machine.

  A laser device generally has an optical amplification medium between a reflection surface and an emission surface, and a laser resonator is configured between the reflection surface and the emission surface. When the bandwidth of light generated in the optical amplification medium is wide, the laser device outputs an optical amplification unit having the optical amplification medium between the reflection surface and the emission surface, and the output surface of the optical amplification unit. A diffraction grating part that selectively Bragg-reflects a part of the light of a specific wavelength among transmitted light and transmits the remaining part, and constitutes a laser resonator between the reflection surface of the optical amplification part and the diffraction grating part (See Patent Document 1 and Patent Document 2). The bandwidth of the laser beam output from the laser device having such a diffraction grating portion is about the Bragg reflection bandwidth of the diffraction grating portion.

In order to increase the power of the output laser beam, a plurality of laser devices including the diffraction grating portion as described above are used, and the Bragg reflection wavelengths of the respective diffraction grating portions are different from each other. Multi-wavelength laser light output from the diffraction grating portion is multiplexed by AWG (Arrayed-Waveguide Grating) (see Patent Document 3).
Japanese Patent No. 3412584 JP-A-11-289130 JP 2001-267684 A

  However, since the configuration described in Patent Document 3 includes many diffraction grating portions and AWGs, the wavelength of the output laser light (that is, the Bragg reflection wavelength of each diffraction grating portion) is managed with high accuracy. Is necessary and expensive.

  Furthermore, the configuration described in Patent Document 3 requires high-precision optical axis adjustment to enhance optical coupling between the end face of the optical waveguide and the incident end face of the AWG in each diffraction grating portion. Therefore, the production yield is poor and the production cost is increased. In particular, when the wavelength is short, since the mode field diameter of the optical waveguide is small, a more accurate optical axis adjustment is required.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a high-power laser device that is inexpensive and easy to manufacture.

  The laser apparatus according to the present invention is generated by (1) N optical amplifying units each having an optical amplifying medium between a reflecting surface and an emitting surface, and (2) an optical amplifying medium of each of the N optical amplifying units. A diffraction grating part that selectively Bragg-reflects a part of light of a specific wavelength out of light and transmits the remainder of the light of the specific wavelength, and (3) one-to-one correspondence with N light amplification parts N input / output ends optically coupled to the output surface and a common input / output end optically coupled to the diffraction grating portion, and input to the N input / output ends. And an optical coupling unit that outputs the light input to the common input / output end in N branches and outputs it from N input / output ends. Furthermore, in the laser device according to the present invention, the optical waveguide at each of the N input / output ends of the optical coupling unit is a multimode optical waveguide at a specific wavelength, and the optical waveguide at the diffraction grating unit is a single mode optical waveguide at a specific wavelength. There is a feature that a laser resonator is formed between the reflection surface of each of the N optical amplification units and the diffraction grating unit. However, N is an integer of 2 or more. The “optical waveguide” includes both the optical waveguide and the optical fiber formed on the substrate.

  The laser device according to the present invention operates as follows. Of the light generated in the optical amplifying medium of each of the N optical amplifying units, the light emitted to the outside from the emission surface enters the corresponding incident / exit end of the optical coupling unit. The light incident on each of the N input / output ends of the optical coupling unit is output from the common input / output end of the optical coupling unit and enters the diffraction grating unit. A part of the light having a specific wavelength out of the light incident on the diffraction grating part is selectively reflected by the diffraction grating part, and returns to the optical amplifying medium of each optical amplifying part by following the reverse optical path. The light is reflected by the reflection surface of the light amplification unit. In this way, by returning light to the optical amplifying medium, stimulated radiation is generated in the optical amplifying medium, and in the laser resonator configured between the reflecting surface of each of the N optical amplifying parts and the diffraction grating part. Laser oscillation. A part of the oscillated laser beam is transmitted through the diffraction grating and emitted to the outside.

  In this laser apparatus, stimulated radiation is generated in the optical amplifying medium of each of the plurality of optical amplifying units arranged in parallel, so that it is possible to increase the power of the output laser light. In addition, since it is only necessary to provide one diffraction grating part on one side of the laser resonator, the cost is low, and the wavelength of the output laser light (that is, the Bragg reflection wavelength of the diffraction grating part) can be easily managed. . In addition, since the optical waveguide at each input / output end of the optical coupling portion is multimode at the output laser light wavelength, it is easy to adjust the optical axis to enhance optical coupling between each input / output end of the optical coupling portion and the optical amplification portion. Thus, the manufacturing yield can be improved and the manufacturing cost can be reduced. Further, since the optical waveguide in the diffraction grating portion is single mode at the output laser light wavelength, the waveguide mode and the reflectance are stable in this diffraction grating portion, and the operation is also stable.

  In the laser apparatus according to the present invention, the optical coupling unit includes (N−1) 2-input 2-output 3 dB optical couplers connected in a tree shape, and one unconnected terminal of each 3 dB optical coupler has A non-reflective terminal is preferred. Alternatively, it is preferable that the optical coupling unit includes an N-input N-output equi-branching optical coupler, and (N−1) non-connected terminals of the N outputs have non-reflective terminations. Alternatively, it is preferable that the optical coupling unit includes a plurality of equally branched optical couplers connected in a tree shape, and a non-connected terminal of each equally branched optical coupler is a non-reflective terminal. In any of these cases, it is convenient to configure a laser resonator between the reflecting surface of each of the N optical amplification units and the diffraction grating unit.

  In the laser apparatus according to the present invention, it is preferable that the optical coupling unit includes (N−1) two-input one-output branched optical couplers connected in a tree shape. Alternatively, the optical coupling unit preferably includes one N-input / one-output branching optical coupler. Alternatively, the optical coupling unit preferably includes a plurality of multi-input one-output branch optical couplers connected in a tree shape. In any of these cases, it is convenient to configure a laser resonator between the reflecting surface of each of the N optical amplification units and the diffraction grating unit.

  In the laser device according to the present invention, it is preferable that the core size of the multimode optical waveguide at each of the N input / output ends of the optical coupling unit is 10 times or more of the specific wavelength, or N optical coupling units It is preferable that the relative refractive index difference of the core of the multi-mode optical waveguide at each of the light input and output ends is 0.2% or more. In any of these cases, the optical coupling between each input / output end of the optical coupling unit and the optical amplification unit can be made highly efficient.

In laser apparatus according to the present invention, a multimode optical waveguide and a single mode optical waveguide are fusion spliced together, the core size of multimode optical waveguide and a _1, a core size of single mode optical waveguide and a ₂ It is preferable that the relational expression of “0.9 ≦ a ₁ / a ₂ ≦ 1.0” or “0.9 ≦ a ₂ / a ₁ ≦ 1.0” is satisfied. In this case, the connection loss at the connection position between the multimode optical waveguide and the single mode optical waveguide can be reduced.

  In the laser apparatus according to the present invention, it is preferable that the exit surface of each of the N optical amplifying units is inclined at an angle of greater than 0 degree and less than or equal to 10 degrees with respect to the reflection surface. Further, it is also preferable that the end faces of the N input / output ends of the optical coupling portion are inclined at an angle of 80 degrees or more and less than 90 degrees with respect to the optical axis of the optical waveguide of the optical coupling section in the vicinity of the end face. is there. In these cases, it is convenient to improve the resonance efficiency in the laser resonator.

  The laser apparatus according to the present invention is provided between the exit surface of each of the N optical amplifiers and the N entrance / exit ends of the optical coupling unit, and condenses the light emitted from the exit surface to enter / exit the light. It is preferable to further include N coupling lenses that are incident on the end and collect the light emitted from the incident / exit end and make the light incident on the exit surface. It is also preferable that a coupling lens is integrally formed on the exit surface of each of the N optical amplification units, and the light emitted from the coupling lens is condensed and incident on the incident / exit end. In addition, it is preferable that a reflection reducing film is formed on the surface of the coupling lens. It is also preferable that a reflection reducing film is formed on each of the N input / output ends of the optical coupling portion. It is also preferable that a reflection reducing film is formed on the exit surface of the optical amplification unit. These cases are also advantageous for improving the resonance efficiency of the laser resonator.

  In the laser apparatus according to the present invention, the optical path lengths from the reflecting surface to the diffraction grating portion of each of the N optical amplifiers are different from each other, and the optical path length ratio is in the range of 0.5 to 2.0 (except for 1). ). This is also advantageous in improving the resonance efficiency of the laser resonator.

  In the laser apparatus according to the present invention, it is preferable that each of the N optical amplifiers includes a semiconductor light emitting element. Further, it is preferable that the N optical amplifying units are arranged in a one-dimensional or two-dimensional array and integrated. Further, the laser device according to the present invention is provided between the exit surface of each of the N optical amplification units and the N input / output ends of the optical coupling unit, and condenses the light emitted from the exit surface. The optical system further includes N coupling lenses that are incident on the incident / exit end and collect the light emitted from the incident / exit end and enter the exit surface, and the N coupled lenses are arrayed in a one-dimensional or two-dimensional array. It is preferred that they are arranged and integrated. In these cases, it is possible to reduce the size and price, and it is easy to adjust the temperature with a Peltier element or the like.

  In the laser apparatus according to the present invention, it is preferable that the optical amplifying medium of each of the N optical amplifying units generates light having any wavelength included in the wavelength range of 200 nm to 900 nm. In this case, the processing efficiency is excellent when the metal is processed by irradiating the output laser beam.

  In the laser device according to the present invention, it is preferable that the branching portion in the optical coupling portion is composed of an optical waveguide that is single mode at a specific wavelength. In this case, the waveguide mode is stable and the operation is stable.

  In the laser apparatus according to the present invention, it is preferable that the diffraction grating portion is composed of an optical waveguide formed on the substrate. In this case, since there is no flexibility, the mode is stable, and stable operation is possible by adjusting the temperature.

  In the laser apparatus according to the present invention, it is preferable that the diffraction grating portion is formed of an optical fiber. In this case, the characteristics are good and inexpensive.

  In the laser device according to the present invention, it is preferable that the branching portion in the optical coupling portion is constituted by an optical waveguide formed on the substrate. It is also preferable to further include temperature adjusting means for adjusting the temperature of the optical coupling portion. It is also preferable that the optical waveguide is of an over clad type. In this case, when the number of cores is large, the price can be reduced and the size can be reduced.

  A laser processing machine according to the present invention includes the above-described laser device according to the present invention and an irradiation optical system that irradiates a processing object with laser light output from the laser device. The irradiation optical system preferably collects the laser beam output from the laser device and irradiates the object to be processed, and condenses the laser beam output from the laser device to a beam diameter of 20 μm or less. Is more preferred.

  The laser device according to the present invention can output a high-power laser beam, can be made inexpensive, and wavelength management is easy.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, a first embodiment of a laser apparatus according to the present invention will be described. FIG. 1 is a configuration diagram of a laser apparatus 1 according to the first embodiment. The laser apparatus 1 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 31, and a diffraction grating unit 40.

Each optical amplifying unit 10 _n has the same configuration, and has an optical amplifying medium between the reflecting surface and the emitting surface. The optical amplifying medium emits light in a predetermined wavelength region and is guided. Radiation can occur. Here, n is an arbitrary integer from 1 to 8.

The optical coupling unit 31 has eight incident / exit ends 311 _{1 to} 311 ₈ and one common incident / exit end 312, and the light input to the _eight incident / exit ends 311 _{1 to} 3118 is a common input / output end. While being output from 312, the light input to the common input / output end 312 is branched into _eight and output from _eight input / output ends 311 _{1 to} 311 ₈ .

The entrance / exit end 311 _n of the optical coupling unit 31 is optically coupled to the exit surface of the optical amplification unit 10 _n via the coupling lens 20 _n . That is, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplifying unit 10 _n , collects the light, and makes it incident on the incident / exit end 311 _n of the optical coupling unit 31, and the optical coupling unit The light emitted from the 31 entrance / exit end 311 _n is input, and the light is collected and incident on the exit surface of the optical amplifying unit 10 _n . Alternatively, the coupling lens on the exit surface of the optical amplifying section 10 _n is integrally formed, also suitable for causing incident light emitted from the coupling lens on the condenser to input and output end 311 _n.

  The common input / output end 312 of the optical coupling unit 31 is optically coupled to the diffraction grating unit 40. That is, the light emitted from the common input / output end 312 of the optical coupling unit 31 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 312 of the optical coupling unit 31.

Optical coupling portion 31 includes a 3dB optical coupler ₃₁₃ 1-313 ₇ 7 connected in a tree-like two-input and two outputs. As shown in the drawing, two input terminals of each of the _four optical couplers 313 _{1 to} 313 ₄ are connected to _eight incident / exit ends 311 _{1 to} 3118 in a _one-to-one relationship. Two input terminals of each of the two optical couplers 313 ₅ and 313 ₆ are connected to one output terminal of each of the _four optical couplers 313 _{1 to} 313 _{4 on} a one-to-one basis. Two input terminals of the optical coupler 313 ₇ are connected to one output terminal of each of the two optical couplers 313 ₅ and 313 _{6 in} a one-to-one relationship. One output terminal of the optical coupler 313 ₇ is connected to the common input and output end 312. When the seven optical couplers 313 _{1 to} 313 ₇ are connected in a tree shape in this way, each of the seven optical couplers 313 _{1 to} 313 ₇ has one non-connected terminal, and this non-connected terminal is a non-reflective terminal. .

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

In the laser device 1, a laser resonator is configured between the reflection surface of each of the _eight optical amplifying units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

FIG. 2 is a detailed view of the configuration of the light amplifying unit 10 _n , the coupling lens 20 _n, and the incident / exit end 311 _n of the optical coupling unit 31. The optical amplifying unit 10 _n includes an optical amplifying medium 103 between the reflecting surface 101 and the emitting surface 102, and the optical amplifying medium 103 emits light in a predetermined wavelength region and can generate induced radiation. it can. At the wavelength of light generated in the optical amplification medium 103, the reflectance of the reflecting surface 101 is high, for example, 99% or more, and the reflectance of the emitting surface 102 is low, for example, 1% or less. The optical amplifying part 10 _n is preferably a laser diode (semiconductor light emitting element), preferably a high reflection film is formed on the reflection surface 101, and a reflection reducing film is formed on the emission surface 102. Preferably it is formed.

The coupling lens 20 _n receives the light emitted from the emission surface 102 of the optical amplification unit 10 _n , collects the light, and causes the light to enter the incident / exit end 311 _n of the optical coupling unit 31. The light emitted from the light incident / exit end 311 _n is input, and the light is collected and incident on the light exit surface 102 of the optical amplifying unit 10 _n . It is preferable that a reflection reducing film is also formed on the surface of the coupling lens 20 _n . In addition, it is preferable that a reflection reducing film is also formed on the incident / exit end 311 _n of the optical coupling portion 31. By doing so, the resonance efficiency in the laser resonator is improved.

When each of the optical amplifying units 10 ₁ to 10 ₈ is a laser diode, it is easy to reduce the size, and it is also easy to adjust the temperature with a Peltier element or the like. In addition, it is preferable that the optical amplifying units 10 ₁ to 10 ₈ are integrated in a one-dimensional or two-dimensional array. Furthermore, it is preferable that the coupling lenses 20 _{1 to} 20 ₈ are also integrated by being arranged in a one-dimensional or two-dimensional array. By integrating in this way, the assembly of the apparatus becomes easy and the cost can be reduced.

Moreover, it is preferable that each of the optical amplification media 103 of the optical amplification units 10 ₁ to 10 ₈ generate light having any wavelength included in the wavelength range of 200 nm to 900 nm. In this case, the processing efficiency is excellent when the metal is processed by irradiating the output laser beam.

The optical path lengths from the respective reflecting surfaces of the optical amplification units 10 ₁ to 10 ₈ to the diffraction grating unit 40 are different from each other, and the optical path length ratio is in the range of 0.5 to 2.0 (excluding 1). Is preferred. That is, when the optical path length from the reflecting surface 101 of the optical amplification unit 10 _n to the diffraction grating unit 40 is expressed as L _n , “L _n1 ≠ L _n2 ” and “1 <L _n1 / L _n2 <2” or “1 <L _n2 / L _n1 <2”. However, the subscripts n1 and n2 are arbitrary integers of 1 to 8, and are different from each other. This also improves the resonance efficiency in the laser resonator.

FIG. 3 is a detailed view of another configuration of the light amplifying unit 10 _n , the coupling lens 20 _n, and the incident / exit end 311 _n of the optical coupling unit 31. As shown in this figure, it is preferable that the exit surface 101 of the optical amplifying unit 10 _n is inclined with respect to the reflecting surface 102 at an angle greater than 0 degree and less than 10 degrees. In addition, it is preferable that the end face of the incident / exit end 311 _n is inclined at an angle of 80 degrees or more and less than 90 degrees with respect to the optical axis of the optical waveguide of the optical coupling portion 31 in the vicinity of the end face. This also improves the resonance efficiency in the laser resonator.

FIG. 4 is an explanatory diagram of an optical waveguide structure between the incident / exit end 311 _n of the optical coupling portion 31 and the diffraction grating portion 40. In the Bragg reflection wavelength of the diffraction grating portion 40, the optical waveguide in the input and output end 311 _n of the optical coupling portion 31 is a multi-mode optical waveguide at the diffraction grating portion 40 is a single mode. The boundary between the multi-mode optical waveguide A and the single-mode optical waveguide B is at any position C along the longitudinal direction of the optical waveguide between each input / output end 311 _{n of the} optical coupling section 31 and the diffraction grating section 40. Exists.

The multimode optical waveguide A and the single mode optical waveguide B may be fusion-connected at the boundary position C. In this case, when the core size of the multimode optical waveguide A is a ₁ and the core size of the single mode optical waveguide B is a ₂ at the boundary position C, “0.9 ≦ a ₁ / a ₂ It is preferable that the relational expression of “≦ 1.0” or “0.9 ≦ a ₂ / a ₁ ≦ 1.0” is satisfied. Here, when the optical waveguide is an optical fiber, the core size is the core diameter, and when the optical waveguide is an optical waveguide formed on the substrate, the core size is the core width. By doing in this way, the connection loss in this connection position C can be reduced.

  Alternatively, the core size of the optical waveguide may be continuously changed along the longitudinal direction, and the multimode and the single mode may be switched at a position C in the middle of the continuous change of the core size.

The core size of the multimode optical waveguide A at each input / output end 311 _n of the optical coupling portion 31 is preferably 10 times or more the Bragg wavelength of the diffraction grating portion 40. In addition, it is preferable that the relative refractive index difference of the core of the multimode optical waveguide A at each incident / exit end 311 _n of the optical coupling portion 31 is 0.2% or more. By doing in this way, the optical coupling between each input / output end 311 _n of the optical coupling part 31 and the optical amplification part 10 _n can be made highly efficient.

In the optical coupling unit 31, each of the optical couplers 313 _{1 to} 313 ₇ may be composed of any of the multimode optical waveguide A and the single mode optical waveguide B. However, each of the optical couplers 313 _{1 to} 313 ₇ is preferably composed of a single mode optical waveguide B. By doing so, the waveguide mode is stable and the operation is also stable. .

The laser device 1 according to this embodiment operates as follows. Of the light generated in the optical amplifying medium 103 of each optical amplifying unit 10 _n, the light emitted to the outside from the emission surface 102 is collected by the coupling lens 20 _{n and} is applied to the incident / exit end 311 _n of the optical coupling unit 31. Incident. The light incident on the eight input and output end ₃₁₁ 1-311 ₈ each of the optical coupling portion 31 via the optical coupler ₃₁₃ 1-313 _7, is output from the common input and output end 312 of the optical coupling portion 31, a diffraction grating Incident on the portion 40. A part of the light having a specific wavelength out of the light incident on the diffraction grating unit 40 is selectively reflected by the diffraction grating unit 40 and follows the reverse optical path so far, so that the optical amplification of each optical amplification unit 10 _n is performed. It returns to the medium 103 and is reflected by the reflecting surface 101 of the optical amplifying unit _10n . By the light is fed back to the thus optical amplification medium 103, stimulated emission is occurring in the optical amplifier media 103, configured between the optical amplifying portions 20 ₁ to 20 ₈ each reflecting surface 101 and the diffraction grating portion 40 The laser resonator oscillates. A part of the oscillated laser beam is transmitted through the diffraction grating portion 40 and emitted to the outside.

In this laser apparatus 1, one non-connected terminal of each of the optical couplers 313 _{1 to} 313 ₇ is a non-reflective terminal, and the terminal that is the non-reflective terminal and the reflective surface 101 of the optical amplifying unit 20 _n. Resonance does not occur between Therefore, high-power laser light is output to the outside through the diffraction grating portion 40. Further, this laser device 1 is inexpensive because it is only necessary to provide one diffraction grating section 40 on one side of the laser resonator, and the wavelength of the output laser light (that is, Bragg reflection of the diffraction grating section 40). Management of wavelength is easy.

Further, the laser device 1, since the optical waveguide is a multi-mode in each input and output end 311 _n of the optical coupling portion 31 in the output laser beam wavelength, the input and output end 311 _n and the optical amplification portion of the optical coupling portion 31 The optical axis adjustment for increasing the optical coupling with 10 _n is easy, the manufacturing yield can be improved, and the manufacturing cost can be reduced. In addition, since the optical waveguide in the diffraction grating section 40 is a single mode at the output laser light wavelength, the laser device 1 has a stable waveguide mode and reflectivity in the diffraction grating section 40 and a stable operation. It becomes.

In particular, in this embodiment, each of the optical coupling part 31 and the diffraction grating part 40 is comprised from the optical fiber. In this case, when the number of cores is relatively small (for example, 2 to 4 cores), it can be manufactured at low cost. The optical fiber preferably operates in a single mode at a specific wavelength, thereby improving the resonance efficiency. In addition, the optical coupling unit 31 is composed of a polarization-maintaining optical fiber, and the polarization maintaining directions at each of the _eight incident / exit surfaces 311 _{1 to} 3118 of the optical coupling unit 31 are on the incident / exit surfaces. It is preferable to adjust so as to coincide with the deflection direction of the incident light. In the case where a multimode waveguide is interposed between each of the incident / exit surfaces 311 _{1 to} 311 ₈ and the branch portion made of the polarization-maintaining optical fiber, the multimode waveguide is constituted by a planar substrate, etc. When the waveguide mode is stabilized, the resonance efficiency is improved.

(Second Embodiment)
Next, a second embodiment of the laser apparatus according to the present invention will be described. FIG. 5 is a configuration diagram of the laser apparatus 2 according to the second embodiment. The laser apparatus 2 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 32, and a diffraction grating unit 42. The eight light amplification units 10 ₁ to 10 ₈ and the eight coupling lenses 20 _{1 to} 20 ₈ are the same as those in the first embodiment.

The optical coupling unit 32 has eight incident / exit ends 321 _{1 to} 321 ₈ and one common incident / exit end 322, and the light input to the _eight incident / exit ends 321 _{1 to} 321 ₈ is a common incident / exit end. In addition to outputting from 322, the light input to the common input / output end 322 is branched into _eight and output from the _eight input / output ends 321 _{1 to} 321 ₈ .

The incident / exit end 321 _n of the optical coupling unit 32 is optically coupled to the emission surface of the optical amplification unit 10 _n via the coupling lens 20 _n . In other words, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplification unit 10 _n , collects the light, and causes the light to enter the incident / exit end 321 _n of the optical coupling unit 32. The light emitted from the 32 incident / exit ends 321 _n is input, and the light is collected and incident on the exit surface of the optical amplifying unit 10 _n .

  The common input / output end 322 of the optical coupling unit 32 is optically coupled to the diffraction grating unit 42. In other words, the light emitted from the common input / output end 322 of the optical coupling unit 32 enters the diffraction grating unit 42, and the light reflected by the diffraction grating unit 42 enters the common input / output end 322 of the optical coupling unit 32.

Optical coupling portion 32 includes a 3dB optical coupler ₃₂₃ 1-323 ₇ 7 connected in a tree-like two-input and two outputs. As shown in the figure, two input terminals of each of the _four optical couplers 323 _{1 to} 323 ₄ are connected to _eight incident / exit ends 321 _{1 to} 321 ₈ in a one-to-one relationship. Two input terminals of each of the two optical couplers 323 ₅ and 323 ₆ are connected to one output terminal of each of the _four optical couplers 323 _{1 to} 323 _{4 on} a one-to-one basis. Two input terminals of the optical coupler 323 ₇ are connected to one output terminal of each of the two optical couplers 323 ₅ and 323 _{6 in} a one-to-one relationship. One output terminal of the optical coupler 323 ₇ is connected to the common input and output end 322. When the seven optical couplers 323 _{1 to} 323 ₇ are connected in a tree shape as described above, each of the seven optical couplers 323 _{1 to} 323 ₇ has one non-connected terminal, and this non-connected terminal is a non-reflective terminal. .

The diffraction grating unit 42 selectively Bragg-reflects part of the light having a specific wavelength among the light generated by the optical amplification media of the _eight optical amplification units 10 ₁ to 10 ₈ , and Make the remainder transparent. More specifically, the diffraction grating portion 42 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

In the laser device 2, a laser resonator is configured between the reflecting surfaces of the _eight optical amplifying units 20 _{1 to} 20 ₈ and the diffraction grating unit 42.

The details of the configuration of the optical amplifying unit 10 _n , the coupling lens 20 _n and the incident / exit end 321 _n of the optical coupling unit 32 are the same as those described in the first embodiment with reference to FIGS. 2 and 3.

The optical waveguide structure between the input / output end 321 _n of the optical coupling portion 32 and the diffraction grating portion 42 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 2, an optical waveguide in each input and output end 321 _n of the optical coupling portion 32 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 42 in the output laser wavelength .

  The laser apparatus 2 according to the present embodiment configured as described above can operate in the same manner as the laser apparatus 1 according to the first embodiment, and achieve the same effects.

  In particular, in the present embodiment, each of the optical coupling part 32 and the diffraction grating part 42 is composed of an optical waveguide formed on a common substrate 320. In this case, when the number of cores is relatively large (for example, when the number is 5 or more), it can be manufactured at low cost. Further, it is convenient for protecting the diffraction grating portion 42.

  It is preferable to further include a temperature adjusting means (for example, a Peltier element) for adjusting the temperature of the substrate 320 on which the optical coupling portion 32 and the diffraction grating portion 42 are formed, and the temperature of the substrate 320 is set to 40 by this temperature adjusting means. It is preferable to maintain the temperature at a predetermined temperature equal to or higher than ° C. By adjusting the temperature in this manner, the characteristics of the optical coupling unit 32 and the diffraction grating unit 42 are stabilized, which is convenient for maintaining the polarization state of the guided light. Further, it is preferable that the optical waveguide in the optical coupling portion 32 is of an over clad type, and in this case, the polarization state of the guided light can be maintained.

(Third embodiment)
Next, a third embodiment of the laser apparatus according to the present invention will be described. FIG. 6 is a configuration diagram of a laser apparatus 3 according to the third embodiment. The laser device 3 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 33, and a diffraction grating unit 40. The eight light amplifying units 10 ₁ to 10 ₈ , the eight coupling lenses 20 _{1 to} 20 ₈ and the diffraction grating unit 40 are the same as those in the first embodiment.

The optical coupling unit 33 has eight input / output ends 331 _{1 to} 331 ₈ and one common input / output end 332, and the light input to the _eight input / output ends 331 _{1 to} 331 ₈ is the common input / output end. In addition to outputting from 332, the light input to the common input / output end 332 is branched into _eight and output from the _eight input / output ends 331 _{1 to} 331 ₈ .

The incident / exit end 331 _n of the optical coupling unit 33 is optically coupled to the emission surface of the optical amplification unit 10 _n via the coupling lens 20 _n . That is, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplification unit 10 _n , collects this light, and makes it incident on the incident / exit end 331 _n of the optical coupling unit 33, and the optical coupling unit The light emitted from the incident / exit end 331 _{n of} 33 is input, and this light is collected and incident on the emission surface of the optical amplifying unit 10 _n .

  The common incident / exit end 332 of the optical coupling unit 33 is optically coupled to the diffraction grating unit 40. That is, the light emitted from the common input / output end 332 of the optical coupling unit 33 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 332 of the optical coupling unit 33.

Optical coupling portion 33 includes a 3dB optical coupler ₃₃₃ 1-333 ₇ 7 connected in a tree-like two-input and two outputs. As shown in the figure, two input terminals of each of the _four optical couplers 333 _{1 to} 333 ₄ are connected to _eight incident / exit ends 331 _{1 to} 331 ₈ in a one-to-one relationship. Two input terminals of each of the two optical couplers 333 ₅ and 333 ₆ are connected to one output terminal of each of the _four optical couplers 333 _{1 to} 333 _{4 on} a one-to-one basis. Two input terminals of the optical coupler 333 ₇ are connected to one output terminal of each of the two optical couplers 333 ₅ and 333 _{6 on} a one-to-one basis. One output terminal of the optical coupler 337 ₇ is connected to the common input / output end 332. When the seven optical couplers 333 _{1 to} 333 ₇ are connected in a tree shape as described above, each of the seven optical couplers 333 _{1 to} 333 ₇ has one non-connected terminal, and this non-connected terminal is a non-reflective terminal. .

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

The laser device 3 constitutes a laser resonator between the reflecting surfaces of the _eight light amplifying units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

The details of the configuration of the light amplifying unit 10 _n , the coupling lens 20 _n, and the light incident / exit end 331 _n of the optical coupling unit 33 are the same as those described with reference to FIGS. 2 and 3 in the first embodiment.

The optical waveguide structure between the input / output end 331 _n of the optical coupling portion 33 and the diffraction grating portion 40 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 3, an optical waveguide in each input and output end 331 _n of the optical coupling portion 33 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 40 in the output laser wavelength .

  The laser apparatus 3 according to the present embodiment configured as described above can operate in the same manner as the laser apparatus 1 according to the first embodiment, and achieve the same effects.

  In particular, in this embodiment, the optical coupling part 33 is comprised from the optical waveguide formed on the board | substrate, and the diffraction grating part 40 is comprised from the optical fiber. In this case, when the number of cores is relatively large (for example, when the number of cores is 5 or more), the optical coupling portion 33 can be manufactured at low cost. Moreover, the diffraction grating part 40 comprised from an optical fiber can also be produced cheaply.

  It is preferable to further include a temperature adjusting means (for example, a Peltier element) for adjusting the temperature of the substrate on which the optical coupling portion 33 is formed, and the temperature of the substrate is maintained at a predetermined temperature of 40 ° C. or more by this temperature adjusting means. It is preferable to do this. By adjusting the temperature in this way, the characteristics of the optical coupling unit 33 are stabilized, which is convenient for maintaining the polarization state of the guided light. Further, it is preferable that the optical waveguide in the optical coupling portion 33 is of an over clad type, and in this case, the polarization state of the guided light can be maintained.

(Fourth embodiment)
Next, a fourth embodiment of the laser apparatus according to the present invention will be described. FIG. 7 is a configuration diagram of a laser device 4 according to the fourth embodiment. The laser apparatus 4 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 34, and a diffraction grating unit 40. The eight light amplifying units 10 ₁ to 10 ₈ , the eight coupling lenses 20 _{1 to} 20 ₈ and the diffraction grating unit 40 are the same as those in the first embodiment.

The optical coupling unit 34 has eight incident / exit ends 341 _{1 to} 341 ₈ and one common incident / exit end 342, and the light input to the _eight incident / exit ends 341 _{1 to} 341 ₈ is the common incident / exit end. In addition to being output from 342, the light input to the common input / output end 342 is branched into _eight and output from the _eight input / output ends 341 _{1 to} 341 ₈ .

The incident / exit end 341 _n of the optical coupling unit 34 is optically coupled to the emission surface of the optical amplification unit 10 _n via the coupling lens 20 _n . That is, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplification unit 10 _n , collects the light, and causes the light to enter the incident / exit end 341 _n of the optical coupling unit 34, and the optical coupling unit. The light emitted from the incident / exit end 341 _{n of} 34 is input, and this light is collected and incident on the emission surface of the optical amplifying unit 10 _n .

  The common input / output end 342 of the optical coupling unit 34 is optically coupled to the diffraction grating unit 40. In other words, the light emitted from the common input / output end 342 of the optical coupling unit 34 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 342 of the optical coupling unit 34.

The optical coupling unit 34 includes one 8-input 8-output equi-branching optical coupler 343. As shown in the drawing, the eight input terminals of the optical coupler 343 are connected to the _eight incident / exit ends 341 _{1 to} 341 ₈ on a one-to-one basis. One output terminal of the optical coupler 343 is connected to the common input / output end 342. The other seven unconnected output terminals of the optical coupler 343 are non-reflective terminations.

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

In the laser device 4, a laser resonator is configured between the reflection surfaces of the _eight optical amplification units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

The details of the configuration of the optical amplifying unit 10 _n , the coupling lens 20 _n, and the incident / exit end 341 _n of the optical coupling unit 34 are the same as those described with reference to FIGS. 2 and 3 in the first embodiment.

Further, the optical waveguide structure between the input and output end 341 _n of the optical coupling portion 34 and the diffraction grating portion 40 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 4, an optical waveguide in each input and output end 341 _n of the optical coupling portion 34 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 40 in the output laser wavelength .

  The laser device 4 according to the present embodiment configured as described above can operate in the same manner as the laser device 1 according to the first embodiment, and achieve the same effects.

(Fifth embodiment)
Next, a fifth embodiment of the laser apparatus according to the present invention will be described. FIG. 8 is a configuration diagram of a laser apparatus 5 according to the fifth embodiment. The laser apparatus 5 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 35, and a diffraction grating unit 40. The eight light amplifying units 10 ₁ to 10 ₈ , the eight coupling lenses 20 _{1 to} 20 ₈ and the diffraction grating unit 40 are the same as those in the first embodiment.

The optical coupling unit 35 has eight input / output ends 351 _{1 to} 351 ₈ and one common input / output end 352, and the light input to the _eight input / output ends 351 _{1 to} 351 ₈ is the common input / output end. In addition to outputting from 352, the light input to the common input / output end 352 is branched into _eight and output from _eight input / output ends 351 _{1 to} 351 ₈ .

The incident / exit end 351 _n of the optical coupling unit 35 is optically coupled to the emission surface of the optical amplification unit 10 _n via the coupling lens 20 _n . In other words, the coupling lens 20 _n receives the light emitted from the emission surface of the light amplification unit 10 _n , collects the light, and causes the light to enter the incident / exit end 351 _n of the optical coupling unit 35. The light emitted from the light incident / exit end 351 _{n of} the light 35 is input, and the light is collected and incident on the light emission surface of the light amplifying unit 10 _n .

  The common input / output end 352 of the optical coupling unit 35 is optically coupled to the diffraction grating unit 40. That is, the light emitted from the common input / output end 352 of the optical coupling unit 35 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 352 of the optical coupling unit 35.

The optical coupling unit 35 includes two four-input four-output equal-branching optical couplers 353 ₁ and 353 ₂ and one two-input two-output equal-branching optical coupler 353 ₃ . As shown in the figure, the four input terminals of each of the optical couplers 353 ₁ and 353 ₂ are connected to _eight incident / exit ends 351 _{1 to} 351 ₈ in a one-to-one relationship. Two input terminals of the optical coupler 353 ₃ are connected to one output terminal of each of the optical couplers 353 ₁ and 353 _{2 in} a one-to-one relationship. One output terminal of the optical coupler 353 ₃ is connected to the common input / output end 352. The non-connected output terminals of the optical couplers 353 _{1 to} 353 ₃ are non-reflective terminations.

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

In the laser device 5, a laser resonator is configured between the reflection surfaces of the _eight optical amplification units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

The details of the configuration of the light amplifying unit 10 _n , the coupling lens 20 _n and the light incident / exit end 351 _n of the optical coupling unit 35 are the same as those described in the first embodiment with reference to FIGS. 2 and 3.

Further, the optical waveguide structure between the input and output end 351 _n and the diffraction grating portion 40 of the optical coupling portion 35 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 5, the optical waveguide in the input and output end 351 _n of the optical coupling portion 35 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 40 in the output laser wavelength .

  The laser device 5 according to the present embodiment configured as described above can operate in the same manner as the laser device 1 according to the first embodiment, and achieve the same effects.

(Sixth embodiment)
Next, a sixth embodiment of the laser apparatus according to the present invention will be described. FIG. 9 is a configuration diagram of a laser device 6 according to the sixth embodiment. The laser apparatus 6 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 36, and a diffraction grating unit 40. The eight light amplifying units 10 ₁ to 10 ₈ , the eight coupling lenses 20 _{1 to} 20 ₈ and the diffraction grating unit 40 are the same as those in the first embodiment.

The optical coupling unit 36 has eight input / output ends 361 _{1 to} 361 ₈ and one common input / output end 362, and the light input to the _eight input / output ends 361 _{1 to} 361 ₈ is a common input / output end. In addition to outputting from 362, the light input to the common input / output end 362 is branched into _eight and output from the _eight input / output ends 361 _{1 to} 361 ₈ .

The incident / exit end 361 _n of the optical coupling unit 36 is optically coupled to the emission surface of the optical amplification unit 10 _n via the coupling lens 20 _n . That is, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplifying unit 10 _n , collects the light, and causes the light to enter the incident / exit end 361 _n of the optical coupling unit 36, and the optical coupling unit The light emitted from the light incident / exit end 361 _{n of} 36 is input, and this light is collected and made incident on the light emission surface of the optical amplifying unit 10 _n .

  The common input / output end 362 of the optical coupling unit 36 is optically coupled to the diffraction grating unit 40. That is, the light emitted from the common input / output end 362 of the optical coupling unit 36 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 362 of the optical coupling unit 36.

The optical coupler 36 includes seven 2-input 1-output Y-branch optical couplers 363 _{1 to} 363 ₇ connected in a tree shape. As shown in the drawing, two input terminals of each of the _four optical couplers 363 _{1 to} 363 ₄ are connected to _eight incident / exit ends 361 _{1 to} 361 ₈ in a one-to-one relationship. Two input terminals of each of the two optical couplers 363 ₅ and 363 ₆ are connected to output terminals of the _four optical couplers 363 _{1 to} 363 _{4 on a} one-to-one basis. The two input terminals of the optical coupler 363 ₇ are connected to the output terminals of the two optical couplers 363 ₅ and 363 _{6 on a} one-to-one basis. An output terminal of the optical coupler 363 ₇ is connected to the common input and output end 362.

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

In the laser device 6, a laser resonator is configured between the reflecting surfaces of the _eight optical amplification units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

The details of the configuration of the optical amplifying unit 10 _n , the coupling lens 20 _n, and the incident / exit end 361 _n of the optical coupling unit 36 are the same as those described in the first embodiment with reference to FIGS.

The optical waveguide structure between the input / output end 361 _n of the optical coupling portion 36 and the diffraction grating portion 40 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 6, an optical waveguide in each input and output end 361 _n of the optical coupling portion 36 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 40 in the output laser wavelength .

  The laser device 6 according to the present embodiment configured as described above can operate in the same manner as the laser device 1 according to the first embodiment, and achieve the same effects.

(Seventh embodiment)
Next, a seventh embodiment of the laser apparatus according to the present invention will be described. FIG. 10 is a configuration diagram of a laser apparatus 7 according to the seventh embodiment. The laser apparatus 7 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 37, and a diffraction grating unit 40. The eight light amplifying units 10 ₁ to 10 ₈ , the eight coupling lenses 20 _{1 to} 20 ₈ and the diffraction grating unit 40 are the same as those in the first embodiment.

The optical coupling unit 37 has eight incident / exit ends 371 _{1 to} 371 ₈ and one common incident / exit end 372, and the light input to the _eight incident / exit ends 371 _{1 to} 371 ₈ is a common incident / exit end. In addition to outputting from the 372, the light input to the common input / output end 372 is branched into _eight and output from the _eight input / output ends 371 _{1 to} 371 ₈ .

The incident / exit end 371 _n of the optical coupling unit 37 is optically coupled to the emission surface of the optical amplification unit 10 _n via the coupling lens 20 _n . That is, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplification unit 10 _n , collects the light, and causes the light to enter the incident / exit end 371 _n of the optical coupling unit 37. The light emitted from the light incident / exit end 371 _{n of} the light 37 is input, and the light is collected and incident on the light emission surface of the light amplifying unit 10 _n .

  The common incident / exit end 372 of the optical coupling unit 37 is optically coupled to the diffraction grating unit 40. That is, the light emitted from the common input / output end 372 of the optical coupling unit 37 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 372 of the optical coupling unit 37.

The optical coupler 37 includes one 8-input 1-output Y-branch optical coupler 373. As shown in the drawing, the eight input terminals of the optical coupler 373 are connected to the _eight incident / exit ends 371 _{1 to} 371 ₈ on a one-to-one basis. The output terminal of the optical coupler 373 is connected to the common input / output end 372.

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

In the laser device 7, a laser resonator is configured between the reflecting surfaces of the _eight optical amplification units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

The details of the configuration of the optical amplifying unit 10 _n , the coupling lens 20 _n, and the incident / exit end 371 _n of the optical coupling unit 37 are the same as those described with reference to FIGS. 2 and 3 in the first embodiment.

The optical waveguide structure between the input / output end 371 _n of the optical coupling portion 37 and the diffraction grating portion 40 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 7, the optical waveguide in the input and output end 371 _n of the optical coupling portion 37 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 40 in the output laser wavelength .

  The laser apparatus 7 according to the present embodiment configured as described above can operate in the same manner as the laser apparatus 1 according to the first embodiment, and achieve the same effects.

(Eighth embodiment)
Next, an eighth embodiment of the laser apparatus according to the present invention will be described. FIG. 11 is a configuration diagram of a laser device 8 according to the eighth embodiment. The laser apparatus 8 shown in this figure includes eight optical amplification units 10 ₁ to 10 ₈ , eight coupling lenses 20 _{1 to} 20 ₈ , an optical coupling unit 38, and a diffraction grating unit 40. The eight light amplifying units 10 ₁ to 10 ₈ , the eight coupling lenses 20 _{1 to} 20 ₈ and the diffraction grating unit 40 are the same as those in the first embodiment.

The optical coupling unit 38 has eight incident / exit ends 381 _{1 to} 381 ₈ and one common incident / exit end 382, and the light input to the _eight incident / exit ends 381 _{1 to} 381 ₈ is a common incident / exit end. In addition to outputting from 382, the light input to the common input / output end 382 is divided into _eight and output from _eight input / output ends 381 _{1 to} 3818.

Input and output end 381 _n of the optical coupling portion 38 is optically coupled to the exit surface of the optical amplifying section 10 _n via the coupling lens 20 _n. That is, the coupling lens 20 _n receives the light emitted from the emission surface of the optical amplification unit 10 _n , collects the light, and causes the light to enter the incident / exit end 381 _n of the optical coupling unit 38. 38 by entering the light emitted from the input and output end 381 _n of condenses to be incident on the exit surface of the optical amplifying section 10 _n this light.

  The common input / output end 382 of the optical coupling unit 38 is optically coupled to the diffraction grating unit 40. That is, the light emitted from the common input / output end 382 of the optical coupling unit 38 enters the diffraction grating unit 40, and the light reflected by the diffraction grating unit 40 enters the common input / output end 382 of the optical coupling unit 38.

The optical coupling unit 38 includes two 4-input 1-output Y-branch optical couplers 383 ₁ and 383 ₂ , and one 2-input 1-output Y-branch optical coupler 383 ₃ . As shown in the figure, the four input terminals of each of the optical couplers 383 ₁ and 383 ₂ are connected to _eight incident / exit ends 381 _{1 to} 381 ₈ on a one-to-one basis. The two input terminals of the optical coupler 383 ₃ are connected to the output terminals of the optical couplers 383 ₁ and 383 _{2 on a} one-to-one basis. The output terminal of the optical coupler 383 ₃ is connected to the common input / output end 382.

The diffraction grating unit 40 selectively Bragg-reflects a part of light of a specific wavelength among the light generated by the optical amplification media of each of the _eight optical amplification units 10 ₁ to 10 ₈ , and transmits the light of the specific wavelength. Make the remainder transparent. More specifically, the diffraction grating unit 40 is formed by forming a diffraction grating by periodic refractive index modulation in the longitudinal direction in the optical waveguide, and Bragg conditions in the diffraction grating out of the light guided through the optical waveguide. A part of light having a specific wavelength satisfying the above condition is selectively reflected.

The laser device 8 constitutes a laser resonator between the reflecting surfaces of the _eight optical amplification units 20 _{1 to} 20 ₈ and the diffraction grating unit 40.

The details of the configuration of the light amplifying unit 10 _n , the coupling lens 20 _n, and the light incident / exit end 381 _n of the optical coupling unit 38 are the same as those described with reference to FIGS. 2 and 3 in the first embodiment.

Further, the optical waveguide structure between the input and output end 381 _n of the optical coupling portion 38 and the diffraction grating portion 40 is the same as that described with reference to FIG. 4 in the first embodiment. That is, the laser device 8, the optical waveguide at each input and output end 381 _n of the optical coupling portion 38 in the output laser beam wavelength of multimode optical waveguide is a single mode in the diffraction grating portion 40 in the output laser wavelength .

  The laser apparatus 8 according to the present embodiment configured as described above can operate in the same manner as the laser apparatus 1 according to the first embodiment, and achieve the same effects.

(Embodiment of laser processing machine)
Next, an embodiment of a laser beam machine according to the present invention will be described. FIG. 12 is a configuration diagram of the laser beam machine 9 according to the present embodiment. The laser beam machine 9 shown in this figure includes the laser device 1 and the irradiation optical system 50 described above. The irradiation optical system 50 is for irradiating the object to be processed with laser light output from the laser device 1, and includes an optical fiber 51 and a lens 52.

  The optical fiber 51 inputs laser light transmitted through the diffraction grating portion 40 and output from the laser device 1 to one end, guides the laser light, and outputs it from the other end. The lens 52 receives the laser beam output from the other end of the optical fiber 51 and condenses and irradiates the laser beam onto the object to be processed. In this way, by subjecting the object to be processed to condensing and irradiating laser light, the object to be processed is subjected to drilling, soldering, annealing, and the like.

  At this time, when condensing the laser beam by the lens 52, it is preferable that the beam diameter of the condensed laser beam is 20 μm or less. In this case, it is convenient for finely processing the workpiece. is there.

Moreover, in the laser apparatus 1, it is preferable that the optical amplifying medium 103 of each of the optical amplifying units 10 ₁ to 10 ₈ generates light having any wavelength included in the wavelength range of 200 nm to 900 nm. In this case, when the processing object is a metal, the laser light absorption efficiency of the processing object is high, and the processing efficiency is excellent.

Further, in the laser apparatus 1, it is preferable that each of the optical amplification units 10 ₁ to 10 ₈ is a laser diode. In this case, the laser processing machine 9 can be easily downsized, It is also easy to adjust the temperature with a Peltier element or the like.

(Modification)
The present invention is not limited to the above embodiment, and various modifications can be made. In each of the above-described embodiments, the number of each of the light amplifying unit, the coupling lens, and the light incident / exit end of the light coupling unit is eight. However, in general, the number can be two or more in the present invention.

  Further, in each of the fourth to eighth embodiments, the optical coupling portion may be constituted by an optical waveguide formed on the substrate, and the diffraction grating portion may also be formed on the substrate.

  Further, the coupling lens may not be provided, and the optical amplifying unit and the incident / exit end of the optical coupling unit may be directly coupled. However, when the optical amplifying unit and the optical coupling unit are separate, by using a coupling lens, the optical coupling efficiency is excellent and the optical axis adjustment becomes easy.

  Further, in the optical coupling unit, an optical fiber may be provided between two optical couplers optically coupled to each other, or an optical fiber may be provided between the optical coupler and the input / output end. Further, an optical fiber may be provided between the optical coupler and the common input / output end. In these cases, the optical coupling unit including the optical coupler and the optical fiber can be handled. The optical fiber provided between the optical coupler and the incident / exit end may be a multimode optical fiber.

  In the laser processing machine 9 of the embodiment, any of the laser devices 2 to 8 may be used instead of the laser device 1.

1 is a configuration diagram of a laser apparatus 1 according to a first embodiment. FIG. 4 is a detailed view of the configuration of an optical amplifying unit 10 _n , a coupling lens 20 _n, and an incident / exit end 311 _n of the optical coupling unit 31. FIG. 10 is a detailed view of another configuration of the light amplifying unit 10 _n , the coupling lens 20 _n, and the incident / exit end 311 _n of the optical coupling unit 31. 4 is an explanatory diagram of an optical waveguide structure between an incident / exit end 311 _n of the optical coupling portion 31 and the diffraction grating portion 40. FIG. It is a block diagram of the laser apparatus 2 which concerns on 2nd Embodiment. It is a block diagram of the laser apparatus 3 which concerns on 3rd Embodiment. It is a block diagram of the laser apparatus 4 which concerns on 4th Embodiment. It is a block diagram of the laser apparatus 5 which concerns on 5th Embodiment. It is a block diagram of the laser apparatus 6 which concerns on 6th Embodiment. It is a block diagram of the laser apparatus 7 which concerns on 7th Embodiment. It is a block diagram of the laser apparatus 8 which concerns on 8th Embodiment. It is a block diagram of the laser processing machine 9 which concerns on this embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1-8 ... Laser apparatus, 9 ... Laser processing machine, 10 ... Optical amplification part, 20 ... Coupling lens, 31-38 ... Optical coupling part, 40, 42 ... Diffraction grating part.

Claims (28)

N optical amplifying units having an optical amplifying medium between the reflecting surface and the emitting surface;
A diffraction grating part that selectively Bragg-reflects a part of light of a specific wavelength among light generated in the optical amplification medium of each of the N optical amplification parts, and transmits the remainder of the light of the specific wavelength;
N input / output ends that are provided in one-to-one correspondence with the N optical amplification units and are optically coupled to the output surface, and are optically coupled to the diffraction grating unit. A light that is input to the N input / output ends, is output from the common input / output end, and the light input to the common input / output ends is N-branched to generate the N input / output ends. An optical coupling portion that outputs from the output end;
With
The optical waveguide at each of the N input / output ends of the optical coupling portion is a multimode optical waveguide at the specific wavelength,
The optical waveguide in the diffraction grating portion is a single mode optical waveguide at the specific wavelength,
A laser resonator is configured between the reflection surface of each of the N optical amplification units and the diffraction grating unit.
A laser device (where N is an integer of 2 or more).   The optical coupling unit includes (N−1) 2-input 2-output 3 dB optical couplers connected in a tree shape, and one non-connected terminal of each 3 dB optical coupler is a non-reflective terminal. The laser device according to claim 1.   2. The optical coupling unit includes an N-input N-output equi-branching optical coupler, and (N-1) non-connected terminals of the N outputs are non-reflective terminations. The laser apparatus described.   2. The optical coupling unit includes a plurality of equally branched optical couplers connected in a tree shape, and a non-connected terminal of each equally branched optical coupler is a non-reflective terminal. The laser apparatus described.   2. The laser device according to claim 1, wherein the optical coupling unit includes (N-1) two-input one-output branched optical couplers connected in a tree shape.   The laser device according to claim 1, wherein the optical coupling unit includes one N-input and one-output branch optical coupler.   2. The laser device according to claim 1, wherein the optical coupling unit includes a plurality of multi-input single-output branch optical couplers connected in a tree shape.   2. The laser device according to claim 1, wherein a core size of the multimode optical waveguide at each of the N input / output ends of the optical coupling unit is 10 times or more of the specific wavelength.   2. The laser device according to claim 1, wherein a relative refractive index difference of a core of the multimode optical waveguide at each of the N input / output ends of the optical coupling portion is 0.2% or more. Wherein is a multimode optical waveguide and the single-mode optical waveguide is fusion spliced to each other, the core size of the multimode optical waveguide and a _1, a core size of said single mode optical waveguide is taken as a _{2, 2.} The laser device according to claim 1, wherein the relational expression of “0.9 ≦ a ₁ / a ₂ ≦ 1.0” or “0.9 ≦ a ₂ / a ₁ ≦ 1.0” is satisfied.   2. The laser device according to claim 1, wherein the emission surface of each of the N optical amplification units is inclined at an angle greater than 0 degree and less than or equal to 10 degrees with respect to the reflection surface.   Each of the N input / output ends of the optical coupling portion is inclined at an angle of 80 degrees or more and less than 90 degrees with respect to the optical axis of the optical waveguide of the optical coupling section in the vicinity of the end face. The laser device according to claim 1, characterized in that:   Provided between the exit surface of each of the N light amplification units and the N entrance / exit ends of the optical coupling unit, and condenses the light exiting from the exit surface to the entrance / exit end. The laser apparatus according to claim 1, further comprising N coupling lenses that make the light incident and collect the light emitted from the incident / exit end and make the light incident on the emission surface.   The coupling lens is integrally formed on the exit surface of each of the N light amplification units, and the light emitted from the coupling lens is condensed and incident on the incident / exit end. Laser device.   The optical path lengths from the reflecting surface to the diffraction grating part of each of the N optical amplifiers are different from each other, and the optical path length ratio is in the range of 0.5 to 2.0 (excluding 1). The laser device according to claim 1.   The laser apparatus according to claim 1, wherein each of the N optical amplification units includes a semiconductor light emitting element.   17. The laser apparatus according to claim 16, wherein the N optical amplifying units are arrayed and integrated in a one-dimensional or two-dimensional array. Provided between the exit surface of each of the N light amplification units and the N entrance / exit ends of the optical coupling unit, and condenses the light exiting from the exit surface to the entrance / exit end. And further comprising N coupling lenses for condensing the light emitted from the incident / exit end and making it incident on the exit surface,
These N coupling lenses are arrayed and integrated in a one-dimensional or two-dimensional array.
The laser device according to claim 17.   2. The laser device according to claim 1, wherein the optical amplification medium of each of the N optical amplification units generates light having any wavelength included in a wavelength range of 200 nm to 900 nm.   2. The laser device according to claim 1, wherein the branching portion in the optical coupling portion includes an optical waveguide that is single mode at the specific wavelength.   2. The laser device according to claim 1, wherein the diffraction grating portion is composed of an optical waveguide formed on a substrate.   The laser apparatus according to claim 1, wherein the diffraction grating portion is formed of an optical fiber.   2. The laser device according to claim 1, wherein the branching portion in the optical coupling portion is constituted by an optical waveguide formed on a substrate.   24. The laser device according to claim 23, further comprising temperature adjusting means for adjusting a temperature of the optical coupling unit.   The laser device according to claim 23, wherein the optical waveguide is of an overclad type. A laser device according to any one of claims 1 to 25;
An irradiation optical system for irradiating a workpiece with laser light output from the laser device;
A laser processing machine comprising:   27. The laser beam machine according to claim 26, wherein the irradiation optical system condenses the laser beam output from the laser device and irradiates the object to be processed.   27. The laser beam machine according to claim 26, wherein the irradiation optical system condenses the laser beam output from the laser device to a beam diameter of 20 [mu] m or less.

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