JP2011176257A - Plane waveguide type laser device - Google Patents

Plane waveguide type laser device Download PDF

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JP2011176257A
JP2011176257A JP2010118127A JP2010118127A JP2011176257A JP 2011176257 A JP2011176257 A JP 2011176257A JP 2010118127 A JP2010118127 A JP 2010118127A JP 2010118127 A JP2010118127 A JP 2010118127A JP 2011176257 A JP2011176257 A JP 2011176257A
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waveguide
excitation light
temperature
core layer
temperature distribution
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JP5495943B2 (en
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Noriyuki Miyamoto
紀之 宮本
Yosuke Akino
陽介 秋野
Shuhei Yamamoto
修平 山本
Toshiyuki Ando
俊行 安藤
Yoshihito Hirano
嘉仁 平野
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a plane optical waveguide type laser device that has a small decrease in output light power and small deterioration in beam quality due to an increase or decrease in excitation light power, by reducing unevenness of temperature distribution of a core layer of a plane type optical waveguide and suppressing produced thermal lens effect. <P>SOLUTION: The plane waveguide type laser device is equipped with: the core layer 2 which has a plate-like shape and has a waveguide structure in the thickness direction of a section perpendicular to the optical axis 7 of the excitation light; a clad 3 joined to one surface of the core layer 2; a waveguide internal temperature adjusting portion 4 which is joined to one surface side of the clad 3 with a bonding agent, and has small thermal resistance nearby an excitation light irradiation position 8 and has large thermal resistance at a distance from the excitation light irradiation position in the width direction of the section perpendicular to the optical axis 7 of the excitation light; and a cooling device 5 which discharges heat generated in the waveguide through the clad and waveguide internal temperature adjusting portion. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

この発明は、平面光導波路を用いた光増幅器および光発振器を備える平面導波路型レーザ装置に関するものである。   The present invention relates to a planar waveguide laser device including an optical amplifier using a planar optical waveguide and an optical oscillator.

従来、平面型光導波路を用いる光増幅器や光発振器において、コア層、クラッド、ヒートシンク、冷却装置の励起光の光軸に対して垂直な断面の厚さ方向において、各層の厚さが一定の各層からなるものが知られている（例えば、特許文献１参照）。   Conventionally, in an optical amplifier or optical oscillator using a planar optical waveguide, each layer has a constant thickness in the thickness direction of the cross section perpendicular to the optical axis of the excitation light of the core layer, cladding, heat sink, and cooling device (See, for example, Patent Document 1).

特開２００４−２９６６７１号公報JP 2004-296671 A

上述したような従来の平面型光導波路に励起光を入力すると、励起光照射領域における局所的な励起光吸収により、コア層の、励起光進行方向に対して垂直な方向において、励起照射領域近傍と遠方の間で温度分布が生じる。その結果、コア層内の屈折率に不均一性が生じ、熱レンズ効果が発生するが、この熱レンズ効果の大小は、入力励起光パワーに依存して変化する。このため、光増幅器において、励起光と対向して信号光を入力し、導波路内でビームオーバーラップを図る際には、励起光の導波路内ビーム形状が変化し、その結果、固定された光学系では励起光パワー変化時に安定したビームオーバーラップ効率が得られず、出力低下の原因になるという問題があった。   When excitation light is input into a conventional planar optical waveguide as described above, the excitation of the core layer in the direction perpendicular to the excitation light traveling direction is caused by local excitation light absorption in the excitation light irradiation region. A temperature distribution occurs between and far away. As a result, the refractive index in the core layer becomes non-uniform and a thermal lens effect is generated. The magnitude of the thermal lens effect changes depending on the input pumping light power. Therefore, in the optical amplifier, when the signal light is input opposite to the excitation light and the beam overlap is attempted in the waveguide, the beam shape of the excitation light in the waveguide is changed and fixed as a result. The optical system has a problem in that stable beam overlap efficiency cannot be obtained when the pumping light power changes, resulting in a decrease in output.

さらに、光増幅器および光発振器において、出力光をある定点で受光する際には、励起光パワーの増減による熱レンズ効果の変化により、ビームパターンやビーム品質が変化・劣化するという問題があった。   Further, when the output light is received at a certain fixed point in the optical amplifier and the optical oscillator, there is a problem that the beam pattern and the beam quality are changed or deteriorated due to the change of the thermal lens effect due to the increase or decrease of the excitation light power.

この発明は、上述のような課題を解決するためになされたもので、その目的は、平面型光導波路のコア層における温度分布の不均一性を軽減し、発生する熱レンズ効果を抑制することで、励起光パワーの増減に伴う、出力光パワーの低下およびビーム品質の劣化の少ない平面光導波路型レーザ装置を得るものである。   The present invention has been made to solve the above-described problems, and its purpose is to reduce the nonuniformity of the temperature distribution in the core layer of the planar optical waveguide and to suppress the generated thermal lens effect. Thus, a planar optical waveguide laser device in which the output light power is reduced and the beam quality is hardly deteriorated as the pumping light power is increased or decreased is obtained.

この発明に係る平面導波路型レーザ装置は、平板状をなし、励起光の光軸に対し垂直な断面の厚さ方向に導波路構造を有するコア層と、前記コア層の一面に接合されたクラッドと、前記クラッドの一面側に接合剤を介して接合され、励起光の光軸に垂直な断面の幅方向の、励起光照射位置近傍では小さい熱抵抗を有し、励起光照射位置遠方では大きい熱抵抗を有する導波路内温度調整部と、導波路内で発生した熱を前記クラッドと前記導波路内温度調整部を介して排熱する冷却装置とを備えるものである。   The planar waveguide laser device according to the present invention has a flat plate shape, and is joined to a core layer having a waveguide structure in a thickness direction of a cross section perpendicular to the optical axis of excitation light, and one surface of the core layer. The clad is bonded to one side of the clad via a bonding agent and has a small thermal resistance in the vicinity of the excitation light irradiation position in the width direction of the cross section perpendicular to the optical axis of the excitation light, and at a position far from the excitation light irradiation position A temperature adjusting unit in the waveguide having a large thermal resistance, and a cooling device that exhausts heat generated in the waveguide through the cladding and the temperature adjusting unit in the waveguide.

この発明によれば、平面型光導波路のコア層における温度分布の不均一性を軽減し、発生する熱レンズ効果を抑制することで、励起光パワーの増減に伴う、出力光パワーの低下およびビーム品質の劣化の少ない光増幅器および光発振器を得ることができる。   According to the present invention, the nonuniformity of the temperature distribution in the core layer of the planar optical waveguide is reduced and the generated thermal lens effect is suppressed. An optical amplifier and an optical oscillator with little deterioration in quality can be obtained.

この発明の実施の形態１に係る平面導波路型レーザ装置の光増幅器の構成を示す側面図である。It is a side view which shows the structure of the optical amplifier of the planar waveguide type laser apparatus which concerns on Embodiment 1 of this invention. 図１のａ−ａ’断面を励起光入力手段側から見た断面図である。It is sectional drawing which looked at the a-a 'cross section of FIG. 1 from the excitation light input means side. 従来技術における励起時の導波路内温度分布計算結果の一例を示す図である。It is a figure which shows an example of the temperature distribution calculation result in the waveguide at the time of the excitation in a prior art. この発明の実施の形態１における励起時の導波路内温度分布計算結果の一例を示す図である。It is a figure which shows an example of the temperature distribution calculation result in the waveguide at the time of the excitation in Embodiment 1 of this invention. この発明の実施の形態２に係る平面導波路型レーザ装置の光増幅器の構成を示す断面図である。It is sectional drawing which shows the structure of the optical amplifier of the planar waveguide type laser apparatus based on Embodiment 2 of this invention. この発明の実施の形態２における励起時の導波路内温度分布計算結果の一例を示す図である。It is a figure which shows an example of the temperature distribution calculation result in the waveguide at the time of the excitation in Embodiment 2 of this invention. この発明の実施の形態３に係る平面導波路型レーザ装置の光増幅器の構成を示す断面図である。It is sectional drawing which shows the structure of the optical amplifier of the planar waveguide type laser apparatus which concerns on Embodiment 3 of this invention. この発明の実施の形態４に係る平面導波路型レーザ装置の光増幅器の構成を示す側面図である。It is a side view which shows the structure of the optical amplifier of the planar waveguide type laser apparatus based on Embodiment 4 of this invention. 図８のａ−ａ’断面を励起光入力手段側から見た断面図である。It is sectional drawing which looked at the a-a 'cross section of FIG. 8 from the excitation light input means side. この発明の実施の形態４に係る平面導波路型レーザ装置の光増幅器の構成の一例として、導波路のコア層の上部に上部クラッドおよび基板が接合されている場合の構成を示す側面図である。It is a side view which shows a structure in case the upper clad and the board | substrate are joined to the upper part of the core layer of a waveguide as an example of the structure of the optical amplifier of the planar waveguide type laser apparatus concerning Embodiment 4 of this invention. . 従来技術における励起時のコア層内温度分布計算結果の一例を示す図である。It is a figure which shows an example of the temperature distribution calculation result in the core layer at the time of the excitation in a prior art. この発明の実施の形態４における励起時のコア層内温度分布計算結果の一例を示す図である。It is a figure which shows an example of the temperature distribution calculation result in the core layer at the time of the excitation in Embodiment 4 of this invention. この発明の実施の形態５に係る平面導波路型レーザ装置の光増幅器の構成を示す側面図である。It is a side view which shows the structure of the optical amplifier of the planar waveguide type laser apparatus based on Embodiment 5 of this invention. 図１３のａ−ａ’断面を励起光入力手段側から見た断面図である。It is sectional drawing which looked at the a-a 'cross section of FIG. 13 from the excitation light input means side. この発明の実施の形態５に係る平面導波路型レーザ装置の光増幅器の構成の一例として、導波路に上部クラッド、および基板が接合されている場合の構成を示す側面図である。It is a side view which shows a structure in case an upper clad and a board | substrate are joined to a waveguide as an example of a structure of the optical amplifier of the planar waveguide type laser apparatus concerning Embodiment 5 of this invention. 図１５のａ−ａ’断面を励起光入力手段側から見た断面図である。It is sectional drawing which looked at the a-a 'cross section of FIG. 15 from the excitation light input means side. 従来技術における励起時のコア層内温度分布と、基板上面の温度分布との計算例を示す図である。It is a figure which shows the example of calculation of the temperature distribution in the core layer at the time of the excitation in a prior art, and the temperature distribution of a board | substrate upper surface. この発明の実施の形態４における励起時のコア層内温度分布と、基板上面の温度分布との計算例を示す図である。It is a figure which shows the example of calculation of the temperature distribution in the core layer at the time of the excitation in Embodiment 4 of this invention, and the temperature distribution of a board | substrate upper surface.

以下、この発明の実施の形態について、添付の図面に従って説明する。なお、以降では、各図中、同一符号は同一または相当部分を示す。   Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following, in each figure, the same reference numerals indicate the same or corresponding parts.

実施の形態１．
図１と図２は、この発明の実施の形態１に係る平面導波路型レーザ装置の光増幅器の構成を示す図であり、図１は側面図であり、図２は図１のａ−ａ’断面を励起光入力手段１側から見た断面図である。 Embodiment 1 FIG.
1 and 2 are diagrams showing the configuration of an optical amplifier of a planar waveguide laser device according to Embodiment 1 of the present invention, FIG. 1 is a side view, and FIG. 2 is aa in FIG. 'A cross-sectional view of the cross section viewed from the excitation light input means 1 side.

図１と図２に示される本実施の形態１に係る光増幅器は、励起光入力手段１と、励起光進行方向を表す光軸７に対し垂直な断面の厚さ方向に導波路構造を有する平面状のコア層２と、コア層２の下側に接合されたクラッド３と、コア層２の下面に接合されたクラッド３の下面に接合された導波路内温度調整部４と、導波路内温度調整部４の下面に接して配置されている冷却装置５とを備えている。   The optical amplifier according to the first embodiment shown in FIGS. 1 and 2 has a waveguide structure in the thickness direction of the cross section perpendicular to the excitation light input means 1 and the optical axis 7 representing the traveling direction of the excitation light. A planar core layer 2, a clad 3 bonded to the lower side of the core layer 2, an in-waveguide temperature adjusting unit 4 bonded to the lower surface of the clad 3 bonded to the lower surface of the core layer 2, and a waveguide And a cooling device 5 disposed in contact with the lower surface of the inner temperature adjusting unit 4.

ここで、励起光入力手段１としては、半導体レーザまたは半導体レーザを集光させる構成を用いることができる。なお、励起光入力手段１としては、励起光をコア層２に入力させる機能を持つものであれば、どのような構成を用いても良い。   Here, as the excitation light input means 1, a semiconductor laser or a configuration for condensing the semiconductor laser can be used. The excitation light input means 1 may have any configuration as long as it has a function of inputting excitation light to the core layer 2.

また、信号光入力手段６としては、ファイバレーザまたはファイバレーザを集光させる構成を用いることができる。なお、信号光入力手段６としては、信号光をコア層２に入力させる機能を持つものであれば、どのような構成を用いても良い。   Further, as the signal light input means 6, a fiber laser or a configuration for condensing the fiber laser can be used. The signal light input means 6 may have any configuration as long as it has a function of inputting signal light to the core layer 2.

コア層２は、光軸７に垂直な断面が典型的には、ｙ軸方向の厚さが数〜数十μｍ、ｘ軸方向の幅が数百μｍ〜数ｍｍの大きさを有し、コア層２の材質は、励起光１０を吸収して、信号光１１を増幅させるためのレーザ媒質である。これにより、励起光１０がコア層２を伝搬する際に励起光１０が吸収されて、信号光１１がコア層２を伝搬する際に信号光１１が増幅される。   The core layer 2 typically has a cross section perpendicular to the optical axis 7 having a thickness in the y-axis direction of several to several tens of μm and a width in the x-axis direction of several hundreds of μm to several mm. The material of the core layer 2 is a laser medium for absorbing the excitation light 10 and amplifying the signal light 11. Thus, the excitation light 10 is absorbed when the excitation light 10 propagates through the core layer 2, and the signal light 11 is amplified when the signal light 11 propagates through the core layer 2.

クラッド３は、コア層２に比べて小さな屈折率を有し、コア層２のｘｚ平面に平行な一つの面に接合される。   The clad 3 has a refractive index smaller than that of the core layer 2 and is bonded to one surface parallel to the xz plane of the core layer 2.

クラッド３と導波路内温度調整部４との間は、金属半田や光学接着剤、熱伝導接着剤などの接合剤で接合しても良い。また、クラッド３のコア層２が接合されている面に対向した面（図１，２のクラッド３の下面）は、接合剤との接合強度を上げるため、メタライズを行っても良い。   The clad 3 and the waveguide temperature adjustment unit 4 may be joined with a joining agent such as a metal solder, an optical adhesive, or a heat conductive adhesive. Further, the surface of the clad 3 facing the surface to which the core layer 2 is bonded (the lower surface of the clad 3 in FIGS. 1 and 2) may be metallized in order to increase the bonding strength with the bonding agent.

導波路内温度調整部４は、熱抵抗の異なる複数種の材料（熱抵抗の低い材料から順に４ａ、４ｂ、４ｃ、・・・とする）で構成され、光軸７に垂直な断面の幅方向（ｘ方向）に多層構造をなし、クラッド３と接合される。   The in-waveguide temperature adjusting unit 4 is composed of a plurality of types of materials having different thermal resistance (4a, 4b, 4c,... In order from the material having the lowest thermal resistance), and the width of the cross section perpendicular to the optical axis 7 A multilayer structure is formed in the direction (x direction) and is joined to the clad 3.

すなわち、導波路内温度調整部４は、励起光１０の光軸７に垂直な断面の幅方向であるｘ方向の、励起光照射位置（励起光照射領域）８の近傍では小さい熱抵抗を有し、励起光照射位置８の遠方では大きい熱抵抗を有するもので、励起光照射位置８の近傍から遠方になるにつれて、熱伝導率が徐々に低い材料となるように材料を並べ、光軸７に垂直な断面の幅方向（図２のｘ方向）に対し多層構造を有する。   That is, the waveguide temperature adjusting unit 4 has a small thermal resistance in the vicinity of the excitation light irradiation position (excitation light irradiation region) 8 in the x direction, which is the width direction of the cross section perpendicular to the optical axis 7 of the excitation light 10. However, it has a large thermal resistance far from the excitation light irradiation position 8, and the materials are arranged so that the thermal conductivity becomes gradually lower from the vicinity of the excitation light irradiation position 8, and the optical axis 7. 2 has a multilayer structure in the width direction (x direction in FIG. 2) of the cross section perpendicular to the cross section.

冷却装置５は、導波路内温度調整部４のクラッド３が接合されている面に対向した面（図１，２の導波路内温度調整部４の下面）のｘｚ平面に平行な面に接して配置され、典型的には、水冷およびペルチェ素子を用いることができる。なお、冷却装置５としては、コア層２に励起光１０が吸収される際に発生する熱を、クラッド３および導波路内温度調整部４を介して排熱するものであれば、どのような構成を用いても良い。   The cooling device 5 is in contact with a surface parallel to the xz plane of the surface (the lower surface of the waveguide temperature adjusting unit 4 in FIGS. 1 and 2) facing the surface to which the cladding 3 of the waveguide temperature adjusting unit 4 is bonded. Typically, water cooling and Peltier elements can be used. Any cooling device 5 may be used as long as the heat generated when the excitation light 10 is absorbed by the core layer 2 is exhausted through the cladding 3 and the waveguide temperature adjustment unit 4. A configuration may be used.

コア層２で発生した熱は、クラッド３および導波路内温度調整部４を介して冷却装置５と接することにより排熱される。   The heat generated in the core layer 2 is exhausted by coming into contact with the cooling device 5 via the clad 3 and the waveguide temperature adjusting unit 4.

次に、この実施の形態１に係る平面型光導波路のコア層内温度分布について図面を参照しながら説明する。なお、実施の形態１の導波路内温度調整部４として、励起光の光軸７に対して垂直な断面の幅方向に対し、２材料３層から成る場合を例として示す。   Next, the temperature distribution in the core layer of the planar optical waveguide according to the first embodiment will be described with reference to the drawings. As an example, a case where the waveguide temperature adjusting unit 4 of the first embodiment is composed of two layers of three materials in the width direction of the cross section perpendicular to the optical axis 7 of the excitation light will be described.

図３に、従来技術における励起時の導波路内温度分布の数値計算結果の一例を示す。導波路内温度分布の数値計算は以下の方法で得ることができる。   FIG. 3 shows an example of a numerical calculation result of the temperature distribution in the waveguide at the time of excitation in the prior art. Numerical calculation of the temperature distribution in the waveguide can be obtained by the following method.

ある物質内の２次元の熱伝導方程式は、物質の温度θ［Ｋ］、物質のｘ方向、ｙ方向それぞれの熱伝導率λｘ，λｙ［Ｗ／ｍ・Ｋ］、発生熱量［Ｗ／ｍ３］、物質の密度［ｋｇ／ｍ３］、物質の比熱［Ｊ／ｋｇ・Ｋ］を用いて、次の式（１）で表される。 A two-dimensional heat conduction equation in a material is expressed as follows: material temperature θ [K], material x-direction and y-direction thermal conductivity λx, λy [W / m · K], generated heat quantity [W / m 3 ], The density of the substance [kg / m 3 ], and the specific heat of the substance [J / kg · K], are expressed by the following formula (1).

Figure 2011176257
Figure 2011176257

ここで、励起光入力手段１がＣＷ動作の場合、式（１）の時間微分項は０となる。また、簡単のため、物質のｘ方向、ｙ方向それぞれの熱伝導率が等しいとし、λｘ＝λｙ＝λとすると、熱伝導方程式は次のラプラス方程式（２）となる。   Here, when the excitation light input unit 1 is in the CW operation, the time differential term of the equation (1) is zero. Further, for the sake of simplicity, assuming that the thermal conductivities of the substance in the x direction and y direction are equal, and λx = λy = λ, the heat conduction equation is the following Laplace equation (2).

Figure 2011176257
Figure 2011176257

式（２）の離散化を考えると、例えばｘ方向の微分は微小区間Δｘでのθの差分となるので、次の式（３）となる。   Considering the discretization of the equation (2), for example, the differentiation in the x direction is the difference of θ in the minute section Δx, and therefore, the following equation (3) is obtained.

Figure 2011176257
Figure 2011176257

式（３）を２次元に拡張して用いると、式（２）は次の式（４）で表される。   When Expression (3) is extended to two dimensions and used, Expression (2) is expressed by the following Expression (4).

Figure 2011176257
Figure 2011176257

式（４）のように、物質の境界を除く内部の各点の温度θ（ｘ，ｙ）は、物質を微小な格子点に分割した場合の、ｘ方向、ｙ方向それぞれの隣接する4点の温度、θ（ｘ＋Δｘ,ｙ）、θ（ｘ−Δｘ，ｙ）、θ（ｘ，ｙ＋Δｙ）、θ（ｘ，ｙ−Δｙ）と、励起領域に相当する範囲の格子点に発熱密度Ｑ［Ｗ／ｍ３］を与えることで得られることが分かる。 As shown in equation (4), the temperature θ (x, y) of each internal point excluding the substance boundary is the four adjacent points in the x and y directions when the substance is divided into fine lattice points. , Θ (x + Δx, y), θ (x−Δx, y), θ (x, y + Δy), θ (x, y−Δy), and a heat generation density Q [ It can be seen that it is obtained by giving W / m 3 ].

物質の境界では、式（３）の離散化では、隣接する格子点が存在しないため、式（４）を用いて温度分布を求めることはできない。そのため、物質外部との接触条件に応じて、境界面温度固定、断熱境界面、境界面熱流速付与、線形熱伝達などの境界条件を与えることで物質内全体の温度分布θ（ｘ，ｙ）を得る。   At the boundary of the material, in the discretization of Equation (3), there is no adjacent lattice point, and therefore the temperature distribution cannot be obtained using Equation (4). Therefore, the temperature distribution θ (x, y) of the whole substance is given by giving boundary conditions such as interface temperature fixation, heat insulation interface, interface heat flow rate, and linear heat transfer according to contact conditions with the outside of the material. Get.

以上の手順で、２階常微分方程式（２）は、（分割格子点数−境界格子点数）個の式（４）で表す方程式、および境界格子点数個の境界条件を表す式での連立方程式に変換される。   By the above procedure, the second-order ordinary differential equation (2) is expressed as a simultaneous equation with an equation represented by (number of divided grid points−number of boundary grid points) and an equation representing the boundary condition of the number of boundary grid points. Converted.

実際の計算方法としては、初期条件として、全格子点にある温度θ０を与えておき、順番に式（４）または境界条件式を解くことで、全点の温度分布はθ１に更新される。初期に与えた温度分布は適当なものなので、更新された温度分布θ１とθ０には差が生じる。そして、更新された温度分布θ１を用いて、再度全点の温度分布を、式（４）と境界条件式を用いて解くと、さらに更新された温度分布θ２となり、温度分布θ２とθ１の差は、温度分布θ１とθ０の差に比べて小さくなる。これを繰り返すと、更新される前の温度分布θｎと更新後の温度分布θｎ＋１がほぼ変わらなくなり、この時の温度分布は、全点で式（４）を満たしており、連立方程式の解となる。 As an actual calculation method, the temperature θ 0 at all lattice points is given as an initial condition, and the temperature distribution at all points is updated to θ 1 by solving Equation (4) or the boundary condition equation in order. The Since the initial temperature distribution is appropriate, there is a difference between the updated temperature distributions θ 1 and θ 0 . Then, using the updated temperature distribution θ 1 , if the temperature distribution of all points is solved again using the equation (4) and the boundary condition equation, the updated temperature distribution θ 2 is obtained , and the temperature distribution θ 2 difference theta 1 is smaller than the difference of temperature distribution theta 1 and theta 0. If this is repeated, the temperature distribution θ n before the update and the temperature distribution θ n + 1 after the update are almost unchanged, and the temperature distribution at this time satisfies the equation (4) at all points, and the solution of the simultaneous equations It becomes.

図３に示した、従来技術における励起時の導波路内温度分布例は、上記の計算方法において、温度分布を計算する物質としてコア層２にＮｄ：ＹＶＯ４（Ｎｄは１ａｔ％）として熱伝導率１１．２［Ｗ／Ｋ・ｍ］、発生熱量Ｑ［Ｗ／ｍ３］の領域・強度として、励起光１０に対応した値である、発光波長８０８．５［ｎｍ］、ｂビーム径（１／ｅ２）１５０×１２ｕｍ2、励起光密度１．６１×１０１２［Ｗ／ｍ３］、境界条件として、コア層２の下面のクラッド３に接合された面には、理想的に冷却装置５の温度として１５℃の固定温度を与え、コア層２の下面のクラッド３に接合された面以外の全面は、理想的に室温として２５℃の固定温度を与え計算した結果である。 FIG. 3 shows an example of temperature distribution in the waveguide at the time of excitation in the prior art. In the above calculation method, the thermal conductivity is calculated as Nd: YVO 4 (Nd is 1 at%) in the core layer 2 as a material for calculating the temperature distribution. As the region / intensity of 11.2 [W / K · m] and generated heat quantity Q [W / m 3 ], the emission wavelength is 808.5 [nm], the b beam diameter (1 / E 2 ) 150 × 12 um 2 , excitation light density 1.61 × 10 12 [W / m 3 ], and as a boundary condition, an ideal cooling device is provided on the surface joined to the clad 3 on the lower surface of the core layer 2. The result is calculated by giving a fixed temperature of 15 ° C. as the temperature of 5 and giving the fixed temperature of 25 ° C. as the ideal room temperature for the entire surface other than the surface bonded to the cladding 3 on the lower surface of the core layer 2.

図４に、実施の形態１の場合での励起時の導波路内温度分布の計算結果の一例を示す。ここで、コア層２の下面のクラッド３に接合された面において、ｘ方向に熱抵抗の異なる３層構造を有することを再現するため、上記境界条件でコア層２のクラッド３に接合された面に与える固定温度を、励起領域近傍で０℃、遠方で２５℃の異なる温度を与えることで再現した。その他の、温度分布を計算する物質、発生熱量、コア層２の下面のクラッド３に接合された面以外の全面の条件は、図３の場合と同じである。   FIG. 4 shows an example of the calculation result of the temperature distribution in the waveguide at the time of excitation in the case of the first embodiment. Here, in order to reproduce that the surface bonded to the clad 3 on the lower surface of the core layer 2 has a three-layer structure having different thermal resistance in the x direction, the core layer 2 was bonded to the clad 3 of the core layer 2 under the above boundary conditions. The fixed temperature applied to the surface was reproduced by applying different temperatures of 0 ° C. in the vicinity of the excitation region and 25 ° C. in the distance. The other conditions other than the material for calculating the temperature distribution, the amount of heat generated, and the surface joined to the cladding 3 on the lower surface of the core layer 2 are the same as those in FIG.

この結果、励起領域における導波路内温度Ｔｎｅａr［Ｋ］と非励起領域における導波路内温度Ｔfａr［Ｋ］の差が、従来技術導波路での温度差に比べて小さくなっていることが分かる。 As a result, the difference between the waveguide temperature T near [K] in the excitation region and the waveguide temperature T far [K] in the non-excitation region is smaller than the temperature difference in the prior art waveguide. I understand.

ここで、導波路内に、励起領域中心から等方的に温度分布ｎ（ｒ）が存在する場合に生じる熱レンズの焦点距離ｆ［ｍ］は、物質の厚さｔ［ｍ］、励起光の光軸方向の物質の長さＬ［ｍ］、物質の屈折率の温度依存性ｄｎ／ｄＴ［１／Ｋ］、導波路内の励起領域と非励起領域での温度差ΔＴ＝Ｔｎｅａr−Ｔfａr［Ｋ］を用いて次の式（５）で表される。 Here, the focal length f [m] of the thermal lens generated when the temperature distribution n (r) isotropically exists from the center of the excitation region in the waveguide is the thickness t [m] of the substance, the excitation light The length L [m] of the material in the optical axis direction, the temperature dependence of the refractive index of the material dn / dT [1 / K], and the temperature difference ΔT = T near − between the excitation region and the non-excitation region in the waveguide It is represented by the following formula (5) using T far [K].

Figure 2011176257
Figure 2011176257

式（５）より熱レンズの焦点距離ｆ［ｍ］は、導波路内の励起領域と非励起領域での温度差ΔＴが小さいほど長くなるので、導波路内温度分布を抑えることで熱レンズの影響を軽減できることがわかる。   From equation (5), the focal length f [m] of the thermal lens becomes longer as the temperature difference ΔT between the excitation region and the non-excitation region in the waveguide becomes smaller. Therefore, by suppressing the temperature distribution in the waveguide, It can be seen that the impact can be reduced.

よって、実施の形態１の場合、従来技術に比べて導波路内温度分布の不均一性を軽減することで、熱レンズ効果を抑制することができ、その結果、励起光パワー増減時のビームオーバーラップの変化やビーム品質の劣化の影響の少ない光増幅器を得ることができる。   Therefore, in the case of the first embodiment, the thermal lens effect can be suppressed by reducing the non-uniformity of the temperature distribution in the waveguide as compared with the prior art, and as a result, the beam over when the pumping light power is increased or decreased. It is possible to obtain an optical amplifier that is less affected by wrap changes and beam quality degradation.

実施の形態２．
次に、この実施の形態２に係る平面型光導波路のコア層内温度分布について図面を参照しながら説明する。なお、実施の形態２としての導波路内温度調整部４として、励起光の光軸７に対して垂直な断面の幅方向に対し、３材料５層から成る場合を例として示す。 Embodiment 2. FIG.
Next, the temperature distribution in the core layer of the planar optical waveguide according to the second embodiment will be described with reference to the drawings. As an example, a case where the waveguide temperature adjusting unit 4 according to the second embodiment is composed of five layers of three materials in the width direction of the cross section perpendicular to the optical axis 7 of the excitation light will be described.

この実施の形態２に係る平面型光導波路のコア層内温度分布の基本的な計算方法については実施の形態１に係る平面型光導波路のコア層内温度分布計算と同様なので、重複する説明を省略する。   The basic calculation method of the temperature distribution in the core layer of the planar optical waveguide according to the second embodiment is the same as the calculation of the temperature distribution in the core layer of the planar optical waveguide according to the first embodiment. Omitted.

図５は、この発明の実施の形態２に係る平面導波路型レーザ装置の光増幅器の構成を示す断面図である。なお、図５は、図１のａ−ａ’断面を励起光入力手段１側から見た状態に相当する断面図である。   FIG. 5 is a cross-sectional view showing the configuration of the optical amplifier of the planar waveguide laser device according to Embodiment 2 of the present invention. FIG. 5 is a cross-sectional view corresponding to a state in which the a-a ′ cross section of FIG. 1 is viewed from the excitation light input unit 1 side.

図６に、実施の形態２の場合での励起時の導波路内温度分布の計算結果の一例を示す。ここでは、コア層２の下面のクラッド３に接合された面において、ｘ方向に励起領域近傍、励起領域端、励起領域遠方の順に熱抵抗が順に増大する５層構造を有することを再現するため、計算時境界条件に、コア層２のクラッド３に接合された面に与える固定温度を、順に高くなるよう異なる温度（０℃、１０℃、２５℃）を与えることで再現した。   FIG. 6 shows an example of the calculation result of the temperature distribution in the waveguide at the time of excitation in the case of the second embodiment. Here, in order to reproduce that the surface joined to the cladding 3 on the lower surface of the core layer 2 has a five-layer structure in which the thermal resistance increases in the order of the vicinity of the excitation region, the end of the excitation region, and the distance from the excitation region in the x direction. The fixed temperature given to the surface joined to the clad 3 of the core layer 2 was reproduced by giving different temperatures (0 ° C., 10 ° C., 25 ° C.) in order to increase the boundary conditions at the time of calculation.

同様に、導波路内温度調整部４の、励起光の光軸７に対し垂直な断面の幅方向（ｘ方向）に、励起領域中心から遠方になるにつれて、徐々に熱抵抗の高い物質が並ぶ多層構造を用いることで、従来技術よりも導波路内温度分布の不均一性が抑えられた光増幅器が得られることに加え、高次収差の少ない温度分布が得られる。   Similarly, substances having higher thermal resistance gradually line up in the width direction (x direction) of the cross section perpendicular to the optical axis 7 of the excitation light in the waveguide temperature adjusting unit 4 as the distance from the excitation region center increases. By using the multilayer structure, an optical amplifier in which the non-uniformity of the temperature distribution in the waveguide is suppressed as compared with the prior art, and a temperature distribution with less high-order aberrations can be obtained.

実施の形態３．
次に、この実施の形態３に係る平面型光導波路のコア層内温度分布について図面を参照しながら説明する。 Embodiment 3 FIG.
Next, the temperature distribution in the core layer of the planar optical waveguide according to the third embodiment will be described with reference to the drawings.

この実施の形態３に係る平面型光導波路のコア層内温度分布の基本的な計算方法については上記の実施の形態１に係る平面型光導波路のコア層内温度分布計算と同様なので、重複する説明を省略する。   The basic calculation method of the temperature distribution in the core layer of the planar optical waveguide according to the third embodiment is the same as the calculation of the temperature distribution in the core layer of the planar optical waveguide according to the first embodiment, and thus overlaps. Description is omitted.

図７は、この発明の実施の形態３に係る平面導波路型レーザ装置の光増幅器の構成を示す断面図である。なお、図７は、図１のａ−ａ’断面を励起光入力手段１側から見た状態に相当する断面図である。   FIG. 7 is a cross-sectional view showing the configuration of an optical amplifier of a planar waveguide laser device according to Embodiment 3 of the present invention. 7 is a cross-sectional view corresponding to a state in which the a-a ′ cross section of FIG. 1 is viewed from the excitation light input means 1 side.

この実施の形態３の場合、導波路内温度調整部４の、励起光の光軸７に対し垂直な断面の幅方向（ｘ方向）に、励起領域近傍と遠方で異なる熱抵抗を持たせる手段として、導波路内温度調整部４の厚さを変化させている。図７では、導波路内温度調整部４の厚さが連続的（円形状）に変化する例を示したが、これは、励起光照射位置８の近傍のみ薄い矩形状の厚さ変化など、励起光照射位置８の近傍で低い熱抵抗、遠方では高い熱抵抗を与えられるものであれば、どのような形状でもよい。   In the case of the third embodiment, means for giving different thermal resistances in the width direction (x direction) of the cross section perpendicular to the optical axis 7 of the excitation light in the waveguide temperature adjusting unit 4 in the vicinity and far from the excitation region. As described above, the thickness of the temperature adjusting section 4 in the waveguide is changed. FIG. 7 shows an example in which the thickness of the waveguide temperature adjustment unit 4 changes continuously (circular shape). This is because the thickness of the rectangular shape is thin only in the vicinity of the excitation light irradiation position 8. Any shape may be used as long as it can provide a low thermal resistance in the vicinity of the excitation light irradiation position 8 and a high thermal resistance in the distance.

この結果、導波路内温度調整部４に１種類の物質のみを用いた場合でも、実施の形態１と同様の効果を実現可能となる。   As a result, even when only one type of substance is used for the waveguide temperature adjustment unit 4, the same effect as in the first embodiment can be realized.

実施の形態４．
図８と図９は、この発明の実施の形態４に係る平面導波路型レーザ装置の構成を示す図であり、図８は側面図であり、図９は図８のａ−ａ’断面を励起光入力手段１側から見た断面図である。 Embodiment 4 FIG.
8 and 9 are views showing a configuration of a planar waveguide laser device according to Embodiment 4 of the present invention, FIG. 8 is a side view, and FIG. 9 is a cross-sectional view taken along line aa ′ of FIG. It is sectional drawing seen from the excitation light input means 1 side.

図８と図９に示される本実施の形態４による平面導波路型レーザ装置は、励起光入力手段１と、励起光進行方向を表す光軸７に対し垂直な断面の厚さ方向（図８のｙ方向）に導波路構造を有する平面状のコア層２と、コア層２の下側に接合された下部クラッド３と、下部クラッド３の下面に接合されたヒートシンク２６と、ヒートシンク下面に接触した導波路内温度分布調整部２５と、励起光入力手段および励起光をモニターする励起光モニター部２０と、信号処理部（信号演算部）２１とを備えている。なお、導波路の構成は、実施の形態１と同様であり、重複する説明を省略する。   The planar waveguide laser device according to the fourth embodiment shown in FIGS. 8 and 9 has the thickness direction of the cross section perpendicular to the excitation light input means 1 and the optical axis 7 representing the excitation light traveling direction (FIG. 8). The planar core layer 2 having a waveguide structure in the y direction), the lower cladding 3 bonded to the lower side of the core layer 2, the heat sink 26 bonded to the lower surface of the lower cladding 3, and the lower surface of the heat sink The waveguide temperature distribution adjustment unit 25, the excitation light input unit and the excitation light monitor unit 20 for monitoring the excitation light, and a signal processing unit (signal calculation unit) 21 are provided. The configuration of the waveguide is the same as that of the first embodiment, and a duplicate description is omitted.

下部クラッド３とヒートシンク２６との間は、必要であれば、金属半田や光学接着剤、熱伝導接着剤などの接合剤で接合しても良い。また、下部クラッド３のコア層２が接合されている面に対向した面は、接合剤との接合強度を上げるため、メタライズを行っても良い。   If necessary, the lower clad 3 and the heat sink 26 may be bonded with a bonding agent such as a metal solder, an optical adhesive, or a heat conductive adhesive. Further, the surface of the lower cladding 3 facing the surface to which the core layer 2 is bonded may be metallized in order to increase the bonding strength with the bonding agent.

導波路内温度分布調整部２５は、複数の調整手段２５ａ，２５ｂを有している。調整手段２５ａ，２５ｂは、励起光照射位置８の近傍箇所と遠方箇所とで、機能的または物質的に独立しており、異なる温度設定可能な物質で構成され、励起光の光軸７に垂直な断面の幅方向に多層構造（ｘ方向に並べられた構造）をなし、ヒートシンク２６下面に接触および接合される。また、調整手段２５ａ，２５ｂは、ヒートシンク２６との接触部分の温度が、外部から入力された信号によって設定された温度となるように排熱する。なお、調整手段２５ａ，２５ｂには、例えばペルチェ素子による電子冷却器等を用いることができる。   The waveguide temperature distribution adjusting unit 25 includes a plurality of adjusting units 25a and 25b. The adjusting means 25a, 25b are functionally or materially independent at a location near and far from the excitation light irradiation position 8, and are composed of materials that can be set at different temperatures, and are perpendicular to the optical axis 7 of the excitation light. A multi-layered structure (structure arranged in the x direction) is formed in the width direction of a simple cross section, and is in contact with and bonded to the lower surface of the heat sink 26. Further, the adjusting means 25a and 25b exhaust heat so that the temperature of the contact portion with the heat sink 26 becomes a temperature set by a signal input from the outside. As the adjusting means 25a and 25b, for example, an electronic cooler using a Peltier element can be used.

導波路内温度分布調整部２５における励起光照射位置８の近傍箇所の調整手段２５ａでは任意の設定温度Ｔ１とし、導波路内温度分布調整部２５における励起光照射位置８の遠方箇所の調整手段２５ｂでは設定温度Ｔ２(＞Ｔ１)として、異なる温度に設定することによって、励起時の導波路内温度分布を軽減することが可能となる。   The adjustment means 25a in the vicinity of the excitation light irradiation position 8 in the temperature distribution adjustment unit 25 in the waveguide is set to an arbitrary set temperature T1, and the adjustment means 25b in the position far from the excitation light irradiation position 8 in the temperature distribution adjustment part 25 in the waveguide. Then, by setting the set temperature T2 (> T1) to a different temperature, the temperature distribution in the waveguide at the time of excitation can be reduced.

コア層２で発生した熱は、下部クラッド３およびヒートシンク２６を介して、導波路内温度分布調整部２５の調整手段２５ａ，２５ｂによって排熱される。   The heat generated in the core layer 2 is exhausted by the adjusting means 25 a and 25 b of the waveguide temperature distribution adjusting unit 25 through the lower clad 3 and the heat sink 26.

なお、導波路において、必要に応じて、コア層２の上部に多層構造物質が接合されていても良い。   In the waveguide, a multilayer structure material may be bonded to the upper portion of the core layer 2 as necessary.

図１０は、この発明の実施の形態４に係る平面導波路型レーザ装置の構成の一例として、導波路のコア層２の上部に上部クラッド２２、および基板２３が接合されている場合の構成を示す側面図である。   FIG. 10 shows, as an example of the configuration of the planar waveguide laser device according to the fourth embodiment of the present invention, a configuration in which an upper clad 22 and a substrate 23 are bonded to the upper portion of the core layer 2 of the waveguide. FIG.

図１０において、上部クラッド２２は、コア層２に比べて小さな屈折率を有し、コア層２のｘｚ平面に平行な面のうち、下部クラッド３が接合されている面の対向側の面（図１０のコア層２のｚ上面）に接合される。   In FIG. 10, the upper cladding 22 has a refractive index smaller than that of the core layer 2, and is a surface on the opposite side of the surface parallel to the xz plane of the core layer 2 to which the lower cladding 3 is bonded ( Bonded to the z upper surface of the core layer 2 in FIG.

基板２３は、主に強度を上げることを目的として、上部クラッド２２のｘｚ平面のうち、コア層２が接合されている面に対向する面（図１０の上部クラッド２２の上面）に接合される。   The substrate 23 is bonded to a surface (upper surface of the upper cladding 22 in FIG. 10) facing the surface to which the core layer 2 is bonded in the xz plane of the upper cladding 22 mainly for the purpose of increasing the strength. .

次に、この実施の形態４に係る平面導波路型レーザ装置の光増幅器において、励起光パワー変化時の熱レンズ効果変動の制御について説明する。   Next, in the optical amplifier of the planar waveguide laser device according to the fourth embodiment, control of fluctuations in the thermal lens effect when the pumping light power changes will be described.

励起光モニター部２０は、励起光入力手段１および励起光１０の状態をモニターする。   The excitation light monitoring unit 20 monitors the states of the excitation light input unit 1 and the excitation light 10.

励起光モニター部２０がモニターする対象としては、例えば、励起光１０のパワー、励起光入力手段１の駆動電流、または信号光１１の励起波長に整合させるために各励起光パワーで設定される励起光入力手段１の駆動温度などである。なお、励起光モニター部２０がモニターする対象は、ある励起光状態において一意に決まる物理量であれば、どのようなものもモニターの対象とすることができる。   For example, the pump light monitoring unit 20 monitors the pump light 10, the drive current of the pump light input unit 1, or the pump light set for each pump light power to match the pump wavelength of the signal light 11. This is the driving temperature of the light input means 1. Note that any object to be monitored by the excitation light monitoring unit 20 can be monitored as long as it is a physical quantity that is uniquely determined in a certain excitation light state.

信号処理部２１には、各励起光状態（パワー、駆動電流、整合温度など）において、一意に決まる、調整手段２５ａ，２５ｂに出力するそれぞれの温度Ｔ１，Ｔ２（＞Ｔ１）のマップが予め設定されている。信号処理部２１は、励起光モニター部２０がモニターした励起光状態に対応して温度Ｔ１，Ｔ２（Ｔ１）の信号を出力する。   The signal processing unit 21 is preset with a map of each temperature T1, T2 (> T1) output to the adjusting means 25a, 25b, which is uniquely determined in each excitation light state (power, driving current, matching temperature, etc.). Has been. The signal processing unit 21 outputs signals of temperatures T1 and T2 (T1) corresponding to the excitation light state monitored by the excitation light monitoring unit 20.

なお、信号処理部２１には、例えば、ＡＤＣ（Ａｎａｌｏｇ Ｄｉｇｉｔａｌ Ｃｏｎｖｅｒｔｅｒ）、ＤＳＰ（Ｄｉｇｉｔａｌ Ｓｉｇｎａｌ Ｐｒｏｃｅｓｓｏｒ）、ＤＡＣ（Ｄｉｇｉｔａｌ Ａｎａｌｏｇ Ｃｏｎｖｅｒｔｅｒ）などの信号処理システムを用いることができるが、励起光モニター部２０がモニターした励起光状態に対して一意に決まる温度Ｔ１，Ｔ２を出力できるものであればどのような構成でも良い。   For example, a signal processing system such as an ADC (Analog Digital Converter), a DSP (Digital Signal Processor), or a DAC (Digital Analog Converter) can be used as the signal processing unit 21, but the excitation light monitoring unit 20 monitors the signal processing unit 21. Any configuration may be used as long as it can output temperatures T1 and T2 that are uniquely determined for the excited light state.

ここで、図１１に、従来技術の導波路における励起時のコア層２内温度分布計算結果例を示す。図１１に示した、従来技術における励起時のコア層２内温度分布計算例は、コア層２にＮｄ：ＹＶＯ４(Ｎｄは１．０ａｔ％)として熱伝導率１１．２[Ｗ／ｍ・Ｋ]および厚さ４０[μｍ]、下部クラッド３にＴａ２Ｏ５として熱伝導率０．１５[Ｗ／ｍ・Ｋ]および厚さ０．７[μｍ]、ヒートシンク２６にＳｉとして熱伝導率１４８[Ｗ／ｍ・Ｋ]および厚さ５００[μｍ]、上部クラッド２２にＳｉＯ２として熱伝導率１．１８[Ｗ／ｍ・Ｋ]および厚さ０．７[μｍ]、基板２３にＹＶＯ４として熱伝導率１１．５[Ｗ／ｍ・Ｋ]および厚さ５００[μｍ]、導波路内温度分布調整部２５を一様物質とし、冷却温度１５℃とした場合の、励起光１０として発光波長８０８．５[ｎｍ]、ビーム半径（１／ｅ２）１００×１２μｍ２をコア層２の中心部に入射した場合の計算結果である。 Here, FIG. 11 shows an example of the temperature distribution calculation result in the core layer 2 at the time of excitation in the waveguide of the prior art. In the example of calculating the temperature distribution in the core layer 2 at the time of excitation in the prior art shown in FIG. 11, the thermal conductivity of 11.2 [W / m · Nd: YVO 4 (Nd is 1.0 at%) in the core layer 2 is shown. K] and thickness 40 [μm], the lower clad 3 has Ta 2 O 5 as thermal conductivity 0.15 [W / m · K] and thickness 0.7 [μm], and the heat sink 26 has thermal conductivity as Si. 148 [W / m · K] and a thickness of 500 [μm], the upper clad 22 as SiO 2 with a thermal conductivity of 1.18 [W / m · K] and a thickness of 0.7 [μm], and the substrate 23 with YVO 4 As the excitation light 10 when the thermal conductivity is 11.5 [W / m · K], the thickness is 500 [μm], the temperature distribution adjusting unit 25 in the waveguide is a uniform material, and the cooling temperature is 15 ° C. wavelength 808.5 [nm], the field incident beam radius (1 / e 2) 100 × 12μm 2 at the center of the core layer 2 Which is the calculation result.

図１２に、実施の形態４の実施例として、導波路の構成および入射する励起光状態は、従来技術における温度分布計算時と同様とし、調整手段２５ａの範囲をｘ方向中心から±５００μｍ、設定温度Ｔ１を０℃、調整手段２５ｂの範囲を調整手段２５ａ以外の全域とし、設定温度Ｔ２を４０℃とした場合の、コア層２内のｘ方向の温度分布計算結果を示す。   In FIG. 12, as an example of the fourth embodiment, the configuration of the waveguide and the incident excitation light state are the same as those in the temperature distribution calculation in the prior art, and the range of the adjusting means 25a is set to ± 500 μm from the center in the x direction. The temperature distribution calculation result in the x direction in the core layer 2 when the temperature T1 is 0 ° C., the range of the adjusting means 25b is the entire area other than the adjusting means 25a, and the set temperature T2 is 40 ° C. is shown.

この図１２によれば、図１１の従来技術の導波路に比べて、励起時のコア層内温度分布を軽減し、熱レンズ効果を抑制できていることがわかる。   As can be seen from FIG. 12, the temperature distribution in the core layer at the time of excitation is reduced and the thermal lens effect can be suppressed as compared with the waveguide of the prior art of FIG.

また、各励起光状態（パワーなど）に応じて、調整手段２５ａ，２５ｂの設定温度Ｔ１，Ｔ２を変化させることによって、上記のコア層２内温度分布を一定あるいは変動の小さい状態に保つことにより、励起光状態が変化した場合でも、熱レンズ効果の変動を小さく抑えることができる。従って、出力光パワーの変動およびビーム品質の変動の少ない光増幅器および光発振器を得ることができる。   Further, by changing the set temperatures T1 and T2 of the adjusting means 25a and 25b according to each excitation light state (power, etc.), the temperature distribution in the core layer 2 is kept constant or in a state of small fluctuation. Even when the excitation light state changes, the fluctuation of the thermal lens effect can be suppressed to a small level. Accordingly, it is possible to obtain an optical amplifier and an optical oscillator with little fluctuation in output optical power and little fluctuation in beam quality.

実施の形態５．
次に、この実施の形態５に係る平面導波路型レーザ装置の光増幅器を用いた光増幅器において、励起光パワー変化時の熱レンズ効果変動の制御について、図面を参照しながら説明する。 Embodiment 5 FIG.
Next, in the optical amplifier using the optical amplifier of the planar waveguide laser device according to the fifth embodiment, control of thermal lens effect fluctuation when the pumping light power changes will be described with reference to the drawings.

図１３と図１４は、この発明の実施の形態５に係る平面導波路型レーザ装置の光増幅器の構成を示す図であり、図１３は側面図であり、図１４は図１３のａ−ａ’断面を励起光入力手段１側から見た断面図である。   13 and 14 are diagrams showing the configuration of the optical amplifier of the planar waveguide laser device according to the fifth embodiment of the present invention, FIG. 13 is a side view, and FIG. 14 is aa of FIG. 'A cross-sectional view of the cross section viewed from the excitation light input means 1 side.

導波路を構成するコア層２、下部クラッド３、導波路内温度分布調整部２５およびヒートシンク２６については、上記の実施の形態４に係る平面導波路型レーザ装置と同様なので、重複する説明を省略する。   Since the core layer 2, the lower clad 3, the in-waveguide temperature distribution adjusting unit 25, and the heat sink 26 that constitute the waveguide are the same as those of the planar waveguide laser device according to the fourth embodiment described above, redundant description is omitted. To do.

実施の形態５に係る平面導波路型レーザ装置の光増幅器は、第１および第２の温度モニター部２４ａ，２４ｂ（以下、総称として「温度モニター部２４」ともいう。）と信号処理部２１とを用いて、調整手段２５ａ，２５ｂに出力する温度Ｔ１，Ｔ２を決定する。   The optical amplifier of the planar waveguide laser device according to the fifth embodiment includes first and second temperature monitoring units 24a and 24b (hereinafter, also collectively referred to as “temperature monitoring unit 24”) and a signal processing unit 21. Is used to determine the temperatures T1 and T2 to be output to the adjusting means 25a and 25b.

図１１に示すように、従来技術のような各層の厚みが一定な導波路では、励起光照射位置８の近傍と励起光照射位置８から離れた位置では、コア層２内に温度分布が発生する。   As shown in FIG. 11, in a waveguide with a constant thickness of each layer as in the prior art, temperature distribution occurs in the core layer 2 in the vicinity of the excitation light irradiation position 8 and at a position away from the excitation light irradiation position 8. To do.

温度モニター部２４ａは、コア層２上部のｘ方向に関して中心付近、また、ｚ方向に関して、励起光１０の入射側端面付近に接触されており、励起時のコア層２内の温度上昇の著しい部分の温度をモニターする。   The temperature monitor 24a is in contact with the vicinity of the center in the x direction above the core layer 2 and in the vicinity of the end face on the incident side of the excitation light 10 with respect to the z direction, and the temperature rise in the core layer 2 during excitation is significant. Monitor the temperature.

温度モニター部２４ｂは、コア層２上部のｘ方向に関して端付近、また、ｚ方向に関して、励起光１０の入射側端面付近に接触されており、励起時のコア層２内の温度上昇の少ない部分の温度をモニターする。   The temperature monitoring unit 24b is in contact with the vicinity of the end in the x direction on the core layer 2 and in the vicinity of the end surface on the incident side of the excitation light 10 with respect to the z direction, and the temperature rise in the core layer 2 during excitation is small. Monitor the temperature.

コア層２の温度分布は、ｘ方向中心および励起光１０の入射側端面で最大となるため、温度モニター部２４ａの接触位置もその位置が望ましいが、ｘ方向中心から外れた位置、および励起光１０の入射側端面からｚ軸方向に奥まった位置でも、温度分布のモニターは可能である。同様に、温度モニター部２４ｂの励起光１０の入射側端面からｚ方向にずれても温度モニターは可能である。   Since the temperature distribution of the core layer 2 is maximized at the center in the x direction and the end face on the incident side of the excitation light 10, the contact position of the temperature monitor 24 a is desirable, but the position away from the center in the x direction and the excitation light The temperature distribution can be monitored even at a position deeper in the z-axis direction than the 10 incident side end face. Similarly, temperature monitoring is possible even when the temperature monitoring unit 24b is shifted in the z direction from the incident side end face of the excitation light 10.

実施の形態５の信号処理部２１は、温度モニター部２４ａと温度モニター部２４ｂとからのモニター値を読み取り、その差が減少するように、極端にいえば、０となるように、調整手段２５ａ，２５ｂにそれぞれ温度Ｔ１，Ｔ２（＞Ｔ１）の信号を与える。   The signal processing unit 21 according to the fifth embodiment reads the monitor values from the temperature monitoring unit 24a and the temperature monitoring unit 24b and adjusts the adjustment unit 25a so that the difference is reduced. , 25b are given signals of temperatures T1, T2 (> T1), respectively.

この結果、各励起光状態（パワーなど）に応じて、時々刻々と調整手段２５ａ，２５ｂの設定温度Ｔ１，Ｔ２を変化させることが可能となり、励起光状態が変化した場合でも、熱レンズ効果の変動を小さく抑えることができる。他の信号処理部２１の構成は、実施の形態４と同様である。   As a result, the set temperatures T1 and T2 of the adjusting means 25a and 25b can be changed from moment to moment according to each excitation light state (power, etc.), and even when the excitation light state changes, the thermal lens effect is improved. Variations can be kept small. The configuration of the other signal processing unit 21 is the same as that of the fourth embodiment.

なお、導波路は、必要に応じて、コア層２の上部にも、多層構造の物質が接合されていても良い。   Note that the waveguide may have a multilayered material bonded to the upper portion of the core layer 2 as necessary.

図１５と図１６は、この発明の実施の形態５に係る平面導波路型レーザ装置の光増幅器の構成の一例として、導波路に上部クラッド２２、および基板２３が接合されている場合の構成を示す図であり、図１５は側面図であり、図１６は図１５のａ−ａ’断面を励起光入力手段１側から見た断面である。なお、上部クラッド２２、および基板２３が接合されている場合の導波路の構成は、実施の形態４に係る平面導波路型レーザ装置の光増幅器と同様なので、重複する説明を省略する。   15 and 16 show an example of the configuration of the optical amplifier of the planar waveguide laser device according to the fifth embodiment of the present invention, in the case where the upper cladding 22 and the substrate 23 are joined to the waveguide. FIG. 15 is a side view, and FIG. 16 is a cross section of the cross section aa ′ of FIG. 15 viewed from the excitation light input means 1 side. Note that the configuration of the waveguide when the upper cladding 22 and the substrate 23 are bonded is the same as that of the optical amplifier of the planar waveguide laser device according to the fourth embodiment, and therefore redundant description is omitted.

コア層２の上部に、上部クラッド２２および基板２３が存在する場合においても、励起光１０の入射時のコア層２内温度分布を推定することができる。   Even in the case where the upper clad 22 and the substrate 23 exist above the core layer 2, the temperature distribution in the core layer 2 when the excitation light 10 is incident can be estimated.

多層構造物質の内層に、励起光吸収による発熱がある場合の、物質上端面（図１４の基板２３の上面に対応）と発熱の存在する層（図１４のコア層２の中心に対応）の温度分布の関係を以下に示す。   When the inner layer of the multilayer structure material has heat generation due to absorption of excitation light, the upper end surface of the material (corresponding to the upper surface of the substrate 23 in FIG. 14) and the layer with heat generation (corresponding to the center of the core layer 2 in FIG. 14) The relationship of temperature distribution is shown below.

ポアソン方程式の解、つまり各層の温度をＴｉ（ｘ，ｙ）とすると、Ｔｉ（ｘ，ｙ）は、次の式（６）のフーリエ級数展開で表せ、βｉ，ｎおよびγｉ，ｎを、境界条件を満足するように求めれば温度分布が得られる。 Assuming that the solution of the Poisson equation, that is, the temperature of each layer is T i (x, y), T i (x, y) can be expressed by the Fourier series expansion of the following equation (6), and β i, n and γ i, If n is determined so as to satisfy the boundary condition, a temperature distribution can be obtained.

Figure 2011176257
Figure 2011176257

ただし、この式（６）におけるｋｎ＝２πｎ／Ｂであり、ｎは整数である。
なお、導波路のｘ方向の対称性より、ｓｉｎ（ｋｎ・ｘ）項は発生しない。 However, in this formula (6), k n = 2πn / B, and n is an integer.
Incidentally, from the x-direction of the symmetry of the waveguide, sin (k n · x) term is not generated.

コア層２内の励起光１０の入射中心よりも下側の半分を第１層とし、下側に向かって順に下部クラッド３を第３層とし、ヒートシンク２６を第５層として、奇数層に定義すると、ヒートシンク２６層は、第（２ｂ−１）層と表すことができる。   The lower half of the incident center of the excitation light 10 in the core layer 2 is defined as the first layer, the lower clad 3 is defined as the third layer in order toward the lower side, and the heat sink 26 is defined as the fifth layer, which is defined as an odd layer. Then, the heat sink 26 layer can be expressed as the (2b-1) layer.

コア層２内の励起光１０の入射中心よりも上側の半分を第２層とし、上側に向かって順に上部クラッドを第４層とし、基板２３を第６層として、偶数層に定義すると、基板２３層は、第２ａ層と表すことができる。   When the upper half of the incident center of the excitation light 10 in the core layer 2 is defined as the second layer, the upper clad is defined as the fourth layer in order toward the upper side, and the substrate 23 is defined as the sixth layer. The 23th layer can be expressed as a 2a layer.

導波路外周面のうち、導波路内温度分布調整部２５に接する面以外は、空気と接しているため、導波路内温度分布調整部２５による排熱に比べて、断熱面と近似することができる。   Of the outer peripheral surface of the waveguide, since the surface other than the surface in contact with the temperature distribution adjusting unit 25 in the waveguide is in contact with air, it can be approximated to a heat insulating surface as compared with the heat exhausted by the temperature distribution adjusting unit 25 in the waveguide. it can.

導波路と空気との間の面を断熱面と近似すると、境界条件は次の式（７），（８）となる。   When the surface between the waveguide and air is approximated as a heat insulating surface, the boundary conditions are expressed by the following equations (7) and (8).

Figure 2011176257
Figure 2011176257

ただし、Ｂは導波路のｘ方向の幅である。   Where B is the width of the waveguide in the x direction.

また、導波路内温度分布調整部２５による放熱が理想的であると仮定すれば、ヒートシンク２６下部の、導波路内温度分布調整部２５に接する面での境界条件は、次の式（９）となる。   Assuming that the heat dissipation by the temperature distribution adjusting unit 25 in the waveguide is ideal, the boundary condition on the surface in contact with the temperature distribution adjusting unit 25 in the lower part of the heat sink 26 is expressed by the following equation (9). It becomes.

Figure 2011176257
Figure 2011176257

式（７）〜（９）の各境界条件の温度Ｔに、式（６）のフーリエ級数展開を代入し、励起光１０を入射するコア層２内での温度分布の連続性を用いて、係数γに対して次の式（１０）〜（１３）の関係が得られる。   Substituting the Fourier series expansion of Equation (6) for the temperature T of each boundary condition of Equations (7) to (9), and using the continuity of the temperature distribution in the core layer 2 where the excitation light 10 is incident, The following expressions (10) to (13) are obtained with respect to the coefficient γ.

Figure 2011176257
Figure 2011176257

ただし、λｉはｉ番目の層の熱伝導率[Ｗ／ｍ・Ｋ]を示し、ｔｉはｉ番目の層の厚み[ｍ]を示す。 However, lambda i is the thermal conductivity of the i th layer indicates [W / m · K], t i denotes the thickness of the i-th layer [m].

また、これと同様に、式（６）の係数βに対して、次の式（１４）〜（１８）の関係が得られる。   Similarly to this, the following expressions (14) to (18) are obtained with respect to the coefficient β of the expression (6).

Figure 2011176257
Figure 2011176257

ただし、Ａ[ｍ]は、励起光照射位置（励起光入射領域）８のｘ方向の幅を表し、Ｂ[ｍ]は、導波路のｘ方向の幅を表し、Ｊは、コア層２内の中心の発熱のｘｚ平面方向の熱流束[Ｗ／ｍ２]を表す。 However, A [m] represents the width of the excitation light irradiation position (excitation light incident region) 8 in the x direction, B [m] represents the width of the waveguide in the x direction, and J is in the core layer 2. The heat flux [W / m 2 ] in the xz plane direction of the heat generation at the center of is shown.

以上、式（１０）〜式（１８）から、ある層の温度分布がわかれば、導波路内層の温度分布が逐次的に計算できることがわかる。   As described above, it can be understood from the equations (10) to (18) that if the temperature distribution of a certain layer is known, the temperature distribution of the waveguide inner layer can be calculated sequentially.

図１７に示した、従来技術における励起時のコア層２内温度分布とモニターする基板２３上面の温度分布との計算例は、上記の計算方法において、コア層２にＮｄ：ＹＶＯ４(Ｎｄは１．０ａｔ％)として熱伝導率１１．２[Ｗ／ｍ・Ｋ]および厚さ４０[μｍ]、下部クラッド３にＴａ２Ｏ５として熱伝導率０．１５[Ｗ／ｍ・Ｋ]および厚さ０．７[μｍ]、ヒートシンク２６にＳｉとして熱伝導率１４８[Ｗ／ｍ・Ｋ]および厚さ４５０[μｍ]、上部クラッド２２にＳｉＯ２として熱伝導率１．１８[Ｗ／ｍ・Ｋ]および厚さ０．７[μｍ]、基板２３にＹＶＯ４として熱伝導率１１．５[Ｗ／ｍ・Ｋ]および厚さ５００[μｍ]、導波路内温度分布調整部２５を一様物質とし、冷却温度１５℃とした場合の、励起光１０として発光波長８０８．５[ｎｍ]、ビーム半径（１／ｅ２）１００×１２μｍ２をコア層２の中心部に入射した場合の計算結果である。 The calculation example of the temperature distribution in the core layer 2 at the time of excitation and the temperature distribution on the upper surface of the substrate 23 to be monitored shown in FIG. 17 in the prior art is calculated by adding Nd: YVO 4 (Nd is Nd: 1.0 at%) with a thermal conductivity of 11.2 [W / m · K] and a thickness of 40 [μm], and the lower cladding 3 has Ta 2 O 5 with a thermal conductivity of 0.15 [W / m · K] and Thickness 0.7 [μm], thermal conductivity 148 [W / m · K] and thickness 450 [μm] as Si for heat sink 26, thermal conductivity 1.18 [W / m as SiO 2 for upper clad 22 · K] and thickness 0.7 [μm], YVO4 on the substrate 23 as thermal conductivity 11.5 [W / m · K] and thickness 500 [μm], uniform temperature distribution adjustment unit 25 in the waveguide When the material is a cooling temperature of 15 ° C., the excitation light 10 has an emission wavelength of 808.5 [nm], a half beam This is a calculation result when a diameter (1 / e 2 ) of 100 × 12 μm 2 is incident on the central portion of the core layer 2.

図１７によれば、基板２３上面での温度分布は、コア層２内の温度分布に比べ、分布は緩和されているものの、ｘ方向中心付近とｘ方向端付近とで温度分布が発生していることが分かる。   According to FIG. 17, the temperature distribution on the upper surface of the substrate 23 is moderate compared to the temperature distribution in the core layer 2, but a temperature distribution occurs near the center in the x direction and near the end in the x direction. I understand that.

温度モニター部２４ａは、ｘ方向中心付近の温度（図１７の（ア））を読み取り、温度モニター部２４ｂは、ｘ方向端付近の温度（図１７の（イ））を読み取る。両者の温度差が減少するような、あるいは０となるような、調整手段２５ａ，２５ｂのそれぞれの温度Ｔ１，Ｔ２の信号が、信号処理部２１から出力される。   The temperature monitor 24a reads the temperature near the center in the x direction (FIG. 17A), and the temperature monitor 24b reads the temperature near the x direction end (FIG. 17A). The signal processing unit 21 outputs signals of the temperatures T1 and T2 of the adjusting means 25a and 25b so that the temperature difference between the two decreases or becomes zero.

図１８に、コア層２の上部に上部クラッド２２および基板２３が存在する場合における、実施の形態５の計算結果の一例を示す。図１８の計算結果は、調整手段２５ａの範囲を、ｘ方向中心から±５００μｍとし、調整手段２５ａに与える温度Ｔ１として０℃とし、調整手段２５ｂの範囲を調整手段２５ａ以外の全域とし、調整手段２５ｂに与える温度Ｔ２として４０℃とした場合の計算結果である。   FIG. 18 shows an example of the calculation result of the fifth embodiment in the case where the upper clad 22 and the substrate 23 are present on the core layer 2. The calculation results in FIG. 18 show that the range of the adjusting unit 25a is ± 500 μm from the center in the x direction, the temperature T1 given to the adjusting unit 25a is 0 ° C., the range of the adjusting unit 25b is the entire range other than the adjusting unit 25a, This is a calculation result when the temperature T2 given to 25b is 40 ° C.

この図１８によれば、基板２３の上面での、ｘ方向中心付近とｘ方向端付近での温度差が減少すると共に、コア層２内の、ｘ方向中心付近とｘ方向端付近での温度差も減少していることがわかる。   According to FIG. 18, the temperature difference between the vicinity of the center in the x direction and the vicinity of the end in the x direction on the upper surface of the substrate 23 decreases, and the temperature near the center in the x direction and the vicinity of the end in the x direction in the core layer 2. It can be seen that the difference is also decreasing.

励起光１０のパワーが変化した場合、基板２３の上面でのｘ方向中心付近とｘ方向端付近での温度差を０、あるいは一定に保つように信号処理部２１から出力される温度Ｔ１，Ｔ２を操作することによって、各励起光状態において、一定の熱レンズ効果、あるいは変動を抑えた熱レンズ効果を得ることができる。従って、出力光パワーの変動およびビーム品質の変動の少ない光増幅器および光発振器を得ることができる。   When the power of the pumping light 10 changes, the temperatures T1 and T2 output from the signal processing unit 21 so that the temperature difference between the vicinity of the center in the x direction and the end in the x direction on the upper surface of the substrate 23 is zero or constant. By operating the above, it is possible to obtain a constant thermal lens effect or a thermal lens effect with suppressed fluctuations in each excitation light state. Accordingly, it is possible to obtain an optical amplifier and an optical oscillator with little fluctuation in output optical power and little fluctuation in beam quality.

なお、実施の形態４，５では、導波路内温度分布調整部２５が、ｘ方向中心付近での調整手段２５ａ、およびそれ以外の領域での調整手段２５ｂの、２種類３層構造の場合を示したが、この層構造はさらに多層構造（２種類以上・３層以上の層構造）となっても良い。すなわち、導波路のｘ方向の中心付近から調整手段２５ａ，２５ｂ，２５ｃ，・・・とし、それぞれに与える設定温度をＴ１，Ｔ２（＞Ｔ１），Ｔ３（＞Ｔ２），・・・と設定することができる。   In the fourth and fifth embodiments, the case where the temperature distribution adjusting unit 25 in the waveguide has a two-type three-layer structure in which the adjusting unit 25a near the center in the x direction and the adjusting unit 25b in other regions is used. Although shown, this layer structure may be a multi-layer structure (two or more types or three or more layers). That is, the adjustment means 25a, 25b, 25c,... Are set from the vicinity of the center in the x direction of the waveguide, and the set temperatures given to the respective means are set as T1, T2 (> T1), T3 (> T2),. be able to.

この場合、層構造を多層（層数がｉ）にし、各調整手段２５ｉの幅を小さくすることで、より詳細で、かつ局所的な温度操作が可能であり、励起光１０のビーム径が変化した場合においても、一定の熱レンズ効果、あるいは変動を抑えた熱レンズ効果を得ることができる。   In this case, the layer structure is multi-layered (the number of layers is i) and the width of each adjusting means 25i is reduced, so that a more detailed and local temperature operation is possible, and the beam diameter of the excitation light 10 changes. Even in this case, a constant thermal lens effect or a thermal lens effect with suppressed fluctuations can be obtained.

なお、実施の形態１〜３では、下部クラッド３の下面に接合された、ｘ方向に異なる熱抵抗値の物質で層構造をなす導波路内温度調整部４を用いた構成について説明した。また、実施の形態４，５では、各励起光パワーに応じてｘ方向中心付近とｘ方向端付近で異なる温度設定可能な調整手段２５ａ，２５ｂを有する導波路内温度分布調整部２５を用いた構成について説明した。しかしながら、これらの例に限定するものではなく、実施の形態１〜３の導波路内温度調整部４と、実施の形態４，５の導波路内温度分布調整部２５とを併せて用いることもできる。   In the first to third embodiments, the configuration using the in-waveguide temperature adjusting unit 4 which is bonded to the lower surface of the lower clad 3 and has a layer structure with substances having different thermal resistance values in the x direction has been described. In the fourth and fifth embodiments, the temperature distribution adjusting unit 25 in the waveguide having the adjusting means 25a and 25b capable of setting different temperatures near the center in the x direction and near the end in the x direction according to each pumping light power is used. The configuration has been described. However, the present invention is not limited to these examples, and the waveguide temperature adjustment unit 4 of the first to third embodiments and the waveguide temperature distribution adjustment unit 25 of the fourth and fifth embodiments may be used in combination. it can.

１ 励起光入力手段、２ コア層、３ クラッド，下部クラッド、４ 導波路内温度調整部、５ 冷却装置、６ 信号光入力手段、７ 励起光の光軸、８ 励起光照射位置、１０ 励起光、１１ 信号光、２０ 励起光モニター部、２１ 信号処理部、２２ 上部クラッド、２３ 基板、２４ 温度モニター部、２４ａ，２４ｂ 第１および第２の温度モニター部、２５ 導波路内温度分布調整部、２５ａ，２５ｂ 調整手段、２６ ヒートシンク。   DESCRIPTION OF SYMBOLS 1 Excitation light input means, 2 Core layer, 3 Clad, Lower clad, 4 Waveguide temperature adjustment part, 5 Cooling device, 6 Signal light input means, 7 Optical axis of excitation light, 8 Excitation light irradiation position, 10 Excitation light 11 signal light, 20 excitation light monitoring unit, 21 signal processing unit, 22 upper clad, 23 substrate, 24 temperature monitoring unit, 24a, 24b first and second temperature monitoring unit, 25 temperature distribution adjusting unit in waveguide, 25a, 25b adjustment means, 26 heat sink.

Claims (5)

平板状をなし、励起光の光軸に対し垂直な断面の厚さ方向に導波路構造を有するコア層と、
前記コア層の一面に接合されたクラッドと、
前記クラッドの一面側に接合剤を介して接合され、励起光の光軸に垂直な断面の幅方向の、励起光照射位置近傍では小さい熱抵抗を有し、励起光照射位置遠方では大きい熱抵抗を有する導波路内温度調整部と、
導波路内で発生した熱を前記クラッドと前記導波路内温度調整部を介して排熱する冷却装置と
を備えることを特徴とする平面導波路型レーザ装置。 A core layer having a plate shape and having a waveguide structure in a thickness direction of a cross section perpendicular to the optical axis of the excitation light;
A clad bonded to one surface of the core layer;
Bonded to one side of the cladding via a bonding agent, and has a small thermal resistance near the excitation light irradiation position in the width direction of the cross section perpendicular to the optical axis of the excitation light, and a large thermal resistance far from the excitation light irradiation position A temperature adjusting unit in the waveguide having:
A planar waveguide laser device comprising: a cooling device that exhausts heat generated in a waveguide through the clad and the waveguide temperature adjustment unit. 請求項１に記載の平面導波路型レーザ装置において、
前記導波路内温度調整部は、励起光照射位置近傍から遠方になるにつれて、熱伝導率が徐々に低い材料となるように材料を並べ、光軸に垂直な断面の幅方向に対し多層構造を有する
ことを特徴とする平面導波路型レーザ装置。 The planar waveguide laser device according to claim 1, wherein
The temperature adjusting section in the waveguide arranges the materials so that the thermal conductivity becomes gradually lower from the vicinity of the excitation light irradiation position, and forms a multilayer structure in the width direction of the cross section perpendicular to the optical axis. A planar waveguide laser device characterized by comprising: 請求項１に記載の平面導波路型レーザ装置において、
前記導波路内温度調整部は、励起光照射位置近傍から遠方になるにつれて厚さを徐々に厚くすることで、異なる熱抵抗を持たせる
ことを特徴とする平面導波路型レーザ装置。 The planar waveguide laser device according to claim 1, wherein
The planar waveguide laser device characterized in that the waveguide temperature adjustment section has different thermal resistances by gradually increasing the thickness from the vicinity of the excitation light irradiation position. 平板状をなし、励起光の光軸に対し垂直な断面の垂直方向に導波路構造を有するコア層と、
前記コア層の一面に接合されたクラッドと、
前記クラッドの一面側に接合されたヒートシンクと、
前記ヒートシンクの一面側に接するように励起光の光軸に垂直な断面の幅方向に並べられ、それぞれ異なる温度設定が可能であり、前記ヒートシンクとのそれぞれの接触部分の温度が、外部から入力された信号によって設定された温度となるように、前記ヒートシンクの熱を排熱する複数の調整手段を有する導波路内温度分布調整部と、
励起光状態をモニターする励起光モニター部と、
前記励起光モニター部からの信号に応じて、予め設定されたマップに従って、前記複数の調整手段のそれぞれに、異なる温度の信号を出力可能な信号処理部と
を備えることを特徴とする平面導波路型レーザ装置。 A core layer having a plate shape and having a waveguide structure in a vertical direction of a cross section perpendicular to the optical axis of the excitation light;
A clad bonded to one surface of the core layer;
A heat sink joined to one side of the cladding;
Arranged in the width direction of the cross section perpendicular to the optical axis of the excitation light so as to be in contact with one surface side of the heat sink, different temperature settings are possible, and the temperature of each contact portion with the heat sink is inputted from the outside. A temperature distribution adjusting unit in the waveguide having a plurality of adjusting means for exhausting the heat of the heat sink so that the temperature is set by the received signal;
An excitation light monitor for monitoring the excitation light state;
A planar waveguide comprising: a signal processing unit capable of outputting a signal at a different temperature to each of the plurality of adjusting means according to a preset map in accordance with a signal from the excitation light monitoring unit Type laser equipment. 平板状をなし、励起光の光軸に対し垂直な断面の垂直方向に導波路構造を有するコア層と、
前記コア層の一面に接合されたクラッドと、
前記クラッドの一面側に接合されたヒートシンクと、
前記ヒートシンクの一面側に接するように励起光の光軸に垂直な断面の幅方向に並べられ、それぞれ異なる温度設定が可能であり、前記ヒートシンクとのそれぞれの接触部分の温度が、外部から入力された信号によって設定された温度となるように、前記ヒートシンクの熱を排熱する複数の調整手段を有する導波路内温度分布調整部と、
前記コア層の他面の導波路中心部の温度と前記コア層の他面の導波路端部の温度とをそれぞれモニターする第１および第２の温度モニター部と、
前記第１および第２の温度モニター部を介して測定した前記コア層の他面の導波路中心部および導波路端部の温度差が０となるようにあるいは減少するように、前記複数の調整手段のそれぞれに、異なる温度の信号を出力可能な信号処理部と
を備えることを特徴とする平面導波路型レーザ装置。 A core layer having a plate shape and having a waveguide structure in a vertical direction of a cross section perpendicular to the optical axis of the excitation light;
A clad bonded to one surface of the core layer;
A heat sink joined to one side of the cladding;
Arranged in the width direction of the cross section perpendicular to the optical axis of the excitation light so as to be in contact with one surface side of the heat sink, different temperature settings are possible, and the temperature of each contact portion with the heat sink is inputted from the outside. A temperature distribution adjusting unit in the waveguide having a plurality of adjusting means for exhausting the heat of the heat sink so that the temperature is set by the received signal;
First and second temperature monitoring units for monitoring the temperature at the center of the waveguide on the other surface of the core layer and the temperature at the end of the waveguide on the other surface of the core layer;
The plurality of adjustments so that the temperature difference between the waveguide center portion and the waveguide end portion on the other surface of the core layer measured through the first and second temperature monitoring portions becomes zero or decreases. Each of the means includes a signal processing unit capable of outputting signals at different temperatures.
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