JP2004029613A - Three-dimensional optical waveguide - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensional optical waveguide for which even a three-dimensionally bent and refracted optical waveguide is easily manufactured in a plastic material with excellent workability. <P>SOLUTION: The three-dimensional optical waveguide is manufactured by forming an inducing structure part in a three-dimensional shape so as to surround a part where the inducing structure is not formed by the irradiation of a laser whose pulse width is ≤10<SP>-12</SP>second in the plastic material. It is preferable that a refractive index difference between the refractive index of the inducing structure part and the refractive index of the part other than the inducing structure part in the plastic material is ≥0.0005. It is suitable that the plastic material has the transmissivity of ≥10% in the visible light wavelength region of 400-800 nm. Either one of the inducing structure part and the part other than the inducing structure part in the plastic material may be selectively removed by etching action from the outside. <P>COPYRIGHT: (C)2004,JPO

Description

【００７０】
なお、表１中、「第１の方向への移動」とは、照射サンプルＡを初めに照射方向に平行な方向に移動速度：約２０μｍ／秒で移動させた際の方向への移動を意味し、「第２の方向への移動」とは、次に照射方向に垂直な方向に移動速度：約５０μｍ／秒で移動させた際の方向への移動を意味し、「第３の方向への移動」とは、その後、さらに９０°方向を変えた照射方向に垂直な方向に移動速度：約５０μｍ／秒で移動させた際の方向への移動を意味し、「第４の方向への移動」とは、さらにその後、最後に照射方向に平行な方向に移動速度：２０μｍ／秒で移動させた際の方向への移動を意味している。
【００７１】
（実施例２）
基板［光学ガラス（ＢＫ７）；厚さ：２．０ｍｍ］上に、ポリシラン系ポリマー［ポリ（メチルフェニルシラン）］の２０重量％トルエン溶液による溶媒除去、減圧乾燥法（真空乾燥法）で、ポリシラン系ポリマーによる薄膜（膜厚：約３００μｍ）を形成して、基板上の薄膜状サンプル（「照射サンプルＢ」と称する場合がある）を作製した。
【００７２】
図２に示されるような方法で、前記照射サンプルＢのポリシラン系ポリマーによる薄膜の上面から深さが約３００μｍである前記薄膜の底面を焦点にして、チタン・サファイア・フェムト秒パルスレーザー装置及び対物レンズ（倍率：２０倍）を使用して、超短パルスレーザー（照射波長：８００ｎｍ、パルス幅：１５０×１０^−１５秒、繰り返し：２００ｋＨｚ）を、照射エネルギー（平均出力）：２０ｍＷ、照射スポット径：約３μｍの条件で、照射サンプルＢを照射方向に平行な方向（第１の方向）に、移動速度：約２０μｍ／秒で１０秒、次に垂直な方向（第２の方向）に移動速度：約１００μｍ／秒で２秒、最後に、平行な方向（第３の方向）に移動速度：２０μｍ／秒で１５秒移動させながら、照射した。次に、薄膜の底面における前回の照射の開始位置に戻り、直径が２０μｍ（半径が１０μｍ）の円弧上で、且つ前回の照射の開始位置から４μｍ離れた距離の位置を焦点として、前回の照射と同様の移動速度で、前回の照射の終了位置から４μｍ離れた距離の位置で且つ直径が２０μｍ（半径が１０μｍ）の円弧上の位置まで照射することを、計１６回繰り返したところ［照射時間（移動に要した時間）は表２のとおりである。また、各照射開始位置は同一の円弧上にあり、各照射終了位置は同一の円弧上にある。］、図１で示されるような三次元的に屈曲した円筒状の誘起構造部が形成された。前記誘起構造部の内部（中心）には、誘起構造未形成部が存在しており、誘起構造部が、誘起構造未形成部を囲むようにして形成されている。
【００７３】
前記誘起構造部は、超短パルスレーザーの未照射部（誘起構造未形成部）に対して、屈折率が約０．００２高い永久的な屈折率変調を起こしており、屈折率の高い光導波路のクラッド部として利用でき、一方、超短パルスレーザーの未照射部はコア部となり、光導波路として機能した。
【００７４】
【表２】

【００７５】
なお、表２中、「第１の方向への移動」とは、照射サンプルＢを初めに照射方向に平行な方向に移動速度：約２０μｍ／秒で移動させた際の方向への移動を意味し、「第２の方向への移動」とは、次に照射方向に垂直な方向に移動速度：約１００μｍ／秒で移動させた際の方向への移動を意味し、「第３の方向への移動」とは、その後、最後に照射方向に平行な方向に移動速度：２０μｍ／秒で移動させた際の方向への移動を意味している。
【図面の簡単な説明】
【図１】本発明の三次元光導波路の一例を示す概略鳥瞰図である。
【図２】プラスチック材料に光導波路のクラッド部として利用される誘起構造部を形成して三次元光導波路を形成する方法の一例を示す概略鳥瞰図である。
【図３】本発明の三次元光導波路の他の例を示す概略鳥瞰図である。
【符号の説明】
１　三次元光導波路を有するプラスチック構造体
２　プラスチック材料
１ａ　三次元光導波路プラスチック構造体１の上面
１ｂ　三次元光導波路プラスチック構造体１の下面
３　光導波路
４　誘起構造部
ｄ　光導波路３の径（直径又は幅）
５１、５２　誘起構造未形成部
６　超短パルスレーザー
６ａ　レンズ
Ｄ　レーザー６の照射方向
７ａ１，・・，７ａｎ　レーザー６の照射開始位置
７ｂ１、７ｃ１　レーザー６の移動屈曲位置
７ｄ１，・・，７ｄｎ　レーザー６の照射終了位置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional optical waveguide using a plastic material.
[0002]
[Prior art]
In recent years, there has been an increasing demand for highly functional surfaces and interiors of plastic structures (components). In response to such demands for higher functionality, technical support on the material side of polymer structures or composites of plastic structures themselves, and processing that incorporates functional parts and controls the structure according to demands Efforts are being made in two aspects, technical support in terms of aspects. For example, in the functionalization and performance enhancement of the inside (bulk) of plastic structures, electricity and light conductivity, light transmission or blocking properties, moisture and gas transmission or blocking properties, heat, light, and stress In response to various characteristics such as responsiveness to external stimuli or memory characteristics, various technical efforts have been made from both the material and processing surfaces. Specifically, as a method (technique) for forming a structure part different from the structure inside the original plastic inside the plastic structure, by applying heat, phase separation (composition change), recrystallization (density and (Change in crystallinity) and methods that cause thermal reaction, and by applying pressure and stress, molecular orientation (orientation degree, optical / mechanical anisotropy) is promoted, and electrical / optical changes are promoted. And methods for causing photoreaction (electrochemical bond reaction), photocrosslinking (crosslinking and curing), photolysis (bond cleavage), etc. by irradiation with light have been studied. Of these methods (techniques), heat and pressure are often applied to the entire plastic structure, and are limited to an arbitrary location (part) within the plastic structure. It is unsuitable to form a structure different from that inside the body. On the other hand, light is essentially a means suitable for acting anywhere in the plastic structure, and can contribute to the trend of technology for higher functionality and higher performance through finer structure control. There is sex.
[0003]
On the other hand, technological progress with respect to laser light sources is remarkable, and in particular, pulsed lasers have nanosecond (10 ^-9 From a pulse width on the order of seconds, picoseconds (10 ^-12 Ultra-short pulses are progressing to pulse widths on the order of seconds, and more recently, femtoseconds (10 ^-15 A pulse laser having a pulse width on the order of seconds) has also been developed. Pulse width is 10 ^-12 Ultra-short pulse lasers or systems that have subseconds (for example, the pulse width is on the order of femtoseconds) or the system has characteristics such as directivity, spatial and temporal coherence, etc. Since the width is extremely narrow, even with the same average output, the electric field strength per unit time and unit space is extremely high. Therefore, an attempt to form a new structure (induced structure) by irradiating a substance with an ultrashort pulse laser using this high electric field strength has been carried out mainly using an inorganic glass material.
[0004]
In addition, amorphous plastics and the like that are polymer materials have a lower glass transition temperature than inorganic glass materials. This is because inorganic glass materials are three-dimensionally bonded by covalent bonds to form an amorphous structure, whereas polymer materials are three-dimensionally linked by one-dimensional covalently linked polymer chains. This is a result of reflecting that an amorphous structure is formed by being entangled with each other. Therefore, when an inorganic glass material is not irradiated with large irradiation energy, an induced structure is not formed. However, in a polymer material, irradiation with high energy may cause deterioration of the material. It is necessary to avoid it.
[0005]
On the other hand, many optical functional parts are used for the purpose of optical path switching, branching / coupling, light wave polarization, amplification, interference, diffraction, and the like in optical applications such as optical communication, optical measurement, and optical recording. These optical functional components are manufactured in advance as functionally imparted components in advance, and a target system is constructed by combining optical components having respective functions. In such an optical application field, as in the electronic application field, it is predicted that the optical device will be directed toward a high-integrated system or a compact system by high-density optical devices or three-dimensional stacking in the future. Therefore, there is a demand for the development of unitized optical modular components and modularization technology. Optical functional parts are generally precision parts made of materials such as inorganic glass, metal oxides, plastic materials, etc., and can be acted on by heat, pressure, reactive gas, etc. in unitization and modularization processes. It is desired to limit the time and space as much as possible. As described above, the processing method using light is essentially a means that is suitable for action on any part, and can be easily processed by using a polymer material (plastic material). There is sex. Specifically, since the polymer material has a characteristic of low thermal conductivity, it tends to store heat easily. In other words, the thermal motion of polymer materials occurs more easily than inorganic glass materials, and the amount of heat required for motion and reaction can be reduced, so that an induced structure is formed even with relatively low irradiation energy compared to inorganic glass materials. There is a possibility. Therefore, the formation of an inductive structure of a polymer material using an ultrashort pulse laser has an advantage that it can be formed at an arbitrary position and in-situ by irradiation with a low-energy laser compared to inorganic glass. Have.
[0006]
[Problems to be solved by the invention]
However, for plastic structures that are polymeric materials, the pulse width is 10 ^-12 Until now, the formation of induced structures by irradiation with ultrashort pulse lasers with a pulse width of the order of femtoseconds or less (for example, the pulse width is on the order of femtoseconds) has not been performed as much as inorganic glass materials.
[0007]
Accordingly, an object of the present invention is to provide a three-dimensional optical waveguide that can be easily and excellently manufactured in a plastic material, even if the optical waveguide is bent and refracted three-dimensionally. .
Another object of the present invention is that the pulse width is 10 ^-12 An object of the present invention is to provide a three-dimensional optical waveguide formed in an arbitrary shape at an arbitrary position in a plastic material by irradiation with an ultrashort pulse laser of seconds or less.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventors have found that the pulse width is 10 ^-12 When an ultrashort pulse laser of less than 1 second is focused on and irradiates a portion inside the plastic material, an induced structure is formed in the portion irradiated by the pulse laser and its peripheral portion inside the plastic material. Furthermore, the inductive structure portion can be easily manufactured even if the inductive structure portion surrounds a portion where the inductive structure is not formed and is bent and refracted three-dimensionally. Has been found to be usable as a cladding portion of a three-dimensional optical waveguide, and the present invention has been completed.
[0009]
That is, the present invention provides a plastic material with a pulse width of 10 ^-12 Provided is a three-dimensional optical waveguide produced by forming a three-dimensionally shaped induction structure so as to surround a portion where no induction structure is formed by laser irradiation for a second or less.
[0010]
The refractive index difference between the refractive index of the induced structure portion and the refractive index of the portion other than the induced structure portion in the plastic material is preferably 0.0005 or more. The plastic material is preferably a plastic material having a transmittance of 10% or more in a visible light wavelength region of 400 to 800 nm.
[0011]
It should be noted that one of the induction structure portion and the portion other than the induction structure portion in the plastic material may be selectively removed by an etching action from the outside.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings as necessary. In addition, about the same member or site | part, the same code | symbol may be attached | subjected.
(Three-dimensional optical waveguide)
FIG. 1 is a schematic bird's-eye view showing an example of the three-dimensional optical waveguide of the present invention. In FIG. 1, 1 is a plastic structure having a three-dimensional optical waveguide (sometimes referred to as “three-dimensional optical waveguide plastic structure”), 2 is a plastic material, 1a is a three-dimensional optical waveguide plastic structure 1 or a plastic material. The upper surface of 2, 1 b is the lower surface of the three-dimensional optical waveguide plastic structure 1 or plastic material 2, 3 is the optical waveguide, 4 is the induction structure portion, 51 is the induction structure unformed portion surrounded by the induction structure portion 4, 52 Is an inductive structure non-formed part not surrounded by the inductive structure part 4.
[0013]
The three-dimensional optical waveguide plastic structure 1 according to FIG. 1 is a substantially rectangular parallelepiped, and the upper surface 1a thereof is parallel to the XY plane (or perpendicular to the Z axis). The three-dimensional optical waveguide plastic structure 1 has a pulse width of 10 on the plastic material 2. ^-12 The induction structure 4 having a three-dimensional shape used as the optical waveguide 3 is formed by irradiation with a laser of less than a second (sometimes referred to as “ultrashort pulse laser”). Specifically, the induction structure portion 4 is formed so as to surround the induction structure non-formation portion 51, and the induction structure non-formation portion 51 is the optical waveguide 3. That is, the optical waveguide 3 is formed using the induction structure portion 4. The induction structure non-formed part 51 is a part where the induction structure is not formed, and the induction structure part 4 formed around the induction structure exhibits a function as an optical waveguide. On the other hand, the induced structure non-formed portion 52 is a portion where an induced structure similar to the induced structure unformed portion 51 is not formed, but usually does not have a function as an optical waveguide. The optical waveguide 3 is formed at a specific portion inside the plastic material 2 from the upper surface 1a to the lower surface 1b, and is not formed by lamination or the like.
[0014]
In the present invention, the optical waveguide has a pulse width of 10 ^-12 This is an induced structure non-formed part (part where no induced structure is formed) surrounded by a three-dimensional shaped induced structure part formed by laser irradiation for less than a second. That is, the induction structure portion is a clad portion of the optical waveguide, and the induction structure unformed portion surrounded by the induction structure portion is a core portion. Thus, the optical waveguide has a pulse width of 10 ^-12 It is formed by using a three-dimensionally shaped inductive structure formed by laser irradiation for less than a second as a cladding of an optical waveguide, and has a pulse width of 10 ^-12 It consists of an induced structure non-formed part surrounded by a three-dimensional shaped induced structure part formed by laser irradiation for less than a second.
[0015]
In FIG. 1, the optical waveguide 3 is formed from one surface of the three-dimensional optical waveguide plastic structure 1 to the other surface, but may be formed only inside, or any surface. It may be formed in a form exposed only to the surface.
[0016]
The induction structure has a pulse width of 10 inside the plastic material. ^-12 It can be formed by irradiating with a specific method while focusing an ultrashort pulse laser of less than a second. For example, the inducing structure 4 shown in FIG. 1 irradiates the plastic material 2 with the ultrashort pulse laser while moving the focal point from one surface to the other surface (for example, the lower surface 1b to the upper surface 1a). Can be formed. That is, the induction structure portion 4 is a laser irradiation portion irradiated with an ultrashort pulse laser (laser focused). The induced structure non-formed portions (51, 52) are laser non-irradiated portions that are not irradiated with the ultrashort pulse laser (the laser is not focused) and are not affected by the laser irradiation. It is a part where the induced structure is not formed and retains its original state or form.
[0017]
In the optical waveguide 3, the size (for example, diameter or width) and shape of the optical waveguide (for example, the shape in the longitudinal direction in which the optical waveguide is formed, the cross-sectional shape in the cross section of the surface perpendicular to the longitudinal direction, etc.) There is no particular limitation. The diameter (or width) d of the optical waveguide can be selected from a range of, for example, about 0.1 to 1000 μm, preferably 0.1 to 100 μm, and more preferably about 0.5 to 30 μm. In addition, when the optical waveguide is composed of an induction structure non-formed part surrounded by the induction structure part, the diameter (diameter or width) d of the optical waveguide is 5 μm or more as shown below. is important.
[0018]
The shape of the optical waveguide in the longitudinal direction may be linear, may be bent or refracted, and is a combination of linear and bent or refracted shapes. It may be. The length in the longitudinal direction of the optical waveguide is not particularly limited.
[0019]
Among the cross-sectional shapes of the optical waveguide, the cross-sectional shape in the cross section of the surface perpendicular to the longitudinal direction in which the optical waveguide is formed is, for example, a substantially circular shape or a substantially polygonal shape (for example, a substantially rectangular shape). May be. The substantially circular shape may be a circular shape, and examples thereof include a circular shape such as a perfect circle shape or an elliptical shape, or a shape similar thereto (such as an elliptical shape having a distortion such as an egg shape). It is done. In addition, the arc in the substantially circular shape may have an uneven shape such as a wave shape or a saw shape. Further, the substantially polygonal shape may be a polygonal shape, and examples thereof include a substantially rectangular shape, a substantially hexagonal shape, and a substantially octagonal shape. The substantially quadrangular shape includes, for example, a square shape, a rectangular shape, a trapezoidal shape, a quadrangular shape such as a quadrangular shape whose opposing sides are not parallel to each other, or a similar shape (such as a distorted square shape). . Note that the corners of the substantially polygonal shape may be angular or rounded, and the plurality of corners may have different shapes. In addition, the angle of the corner (inner angle) in the substantially polygonal shape is not particularly limited. For example, in the case of a substantially rectangular shape, each angle of the corner may be a right angle, an acute angle or an obtuse angle. . Furthermore, the sides in a substantially polygonal shape (such as a substantially square shape) may each be a straight shape, or may be an uneven shape such as a wave shape or a sawtooth shape. In addition, as a cross-sectional shape in the cross section of the surface perpendicular | vertical with respect to the longitudinal direction of an optical waveguide, it is preferable that it is a substantially circular shape.
[0020]
In the present invention, as long as the optical waveguide is formed continuously, its size and shape may be different in each part. Further, in one three-dimensional waveguide plastic structure, the number of optical waveguides is not particularly limited, and may be singular or plural. A plastic structure having a plurality of optical waveguides inside may have a laminated structure in which optical waveguides are laminated at an appropriate interval. In the case where a plurality of optical waveguides are provided inside one plastic structure, the interval between the optical waveguides can be arbitrarily selected. The interval between the optical waveguides is preferably 5 μm or more. If the distance between the optical waveguides provided in the plastic structure is less than 5 μm, the optical waveguides may be fused at the time of producing the optical waveguide, and it may not be possible to form a plurality of independent optical waveguides.
[0021]
(Induction structure forming method)
In the present invention, an ultra-short pulse laser is focused on a plastic material from outside (for example, on the surface or inside of the plastic material), and the focal position is moved to irradiate the clad of the optical waveguide. The induction structure part used as a part is formed. FIG. 2 is a schematic bird's-eye view showing an example of a method of forming a three-dimensional optical waveguide by forming an induction structure portion used as a cladding portion of an optical waveguide in a plastic material. Specifically, FIG. 2 is a view showing an example of a method for producing the three-dimensional optical waveguide plastic structure according to FIG. 1, and FIG. 2 (a) is a three-dimensional optical waveguide plastic according to FIG. An overall schematic bird's-eye view of the method for manufacturing the structure is shown, FIG. 2 (b) shows an enlarged view of the main part of the lower surface 1b, and FIG. 2 (c) shows an enlarged view of the main part of the upper surface 1a. 2, reference numerals 1, 1a, 1b, 2, 3, 4, 51, 52 are the same as those in FIG. Reference numeral 6 denotes an ultrashort pulse laser (sometimes simply referred to as “laser”), 6 a denotes a lens, and D denotes an irradiation direction of the laser 6. The plastic material 2 is a material for producing the three-dimensional optical waveguide plastic structure 1. An inductive structure 4 used as a clad of the optical waveguide 3 is formed in the plastic material 2 to form a three-dimensional optical waveguide plastic structure 1.
[0022]
In FIG. 2, the laser 6 irradiates the plastic material 2 with one light flux in the direction of the irradiation direction D (that is, in a direction parallel to the Z axis). The laser 6 can be focused by using the lens 6a. Therefore, when it is not necessary to focus the laser 6 by focusing, the lens 6a need not be used.
[0023]
Moreover, the plastic material 2 is a substantially rectangular parallelepiped, and the upper surface thereof is a plane parallel to the XY plane (perpendicular to the Z axis). In addition, although the rectangular parallelepiped is used as the plastic material 2, what kind of shape may be sufficient and the magnitude | size is not restrict | limited in particular.
[0024]
In FIG. 2, reference numeral 7a1 denotes an initial position or a center position (which may be referred to as an “irradiation start position”) when the laser 6 starts to be irradiated. Reference numerals 7b1 and 7c1 denote focal positions at which the focal point of irradiation of the laser 6 or the central position of the laser 6 moves or a central position thereof (which may be referred to as a “moving bending position”). Reference numeral 7d1 denotes a final position where the focus is obtained when the irradiation of the laser 6 is finished or a center position thereof (sometimes referred to as an "irradiation end position"). The irradiation start position 7a1 is a position on the lower surface 1b of the plastic material 2, and the irradiation end position 7d1 is a position on the upper surface 1a of the plastic material 2. Reference numerals 7a2 and 7d2 denote an irradiation start position and an irradiation end position, respectively. Thus, 7an is an irradiation start position and 7dn is an irradiation end position.
[0025]
In FIG. 2, the plastic material 2 is irradiated while moving the focal point of the laser 6 so that the cylindrical induction structure 4 bent in three dimensions is formed. Specifically, in the irradiation method performed while moving the focal point from one surface to the other surface, the irradiation end position on the upper surface 1a from the irradiation start position 7a1 on the lower surface 1b, through the moving bending position 7b1 and the moving bending position 7c1. Laser irradiation is performed while continuously moving the focal position of the laser 6 to 7d1, and, similarly, the laser is irradiated from the irradiation start position 7a2 on the lower surface 1b to the irradiation end position 7d2 on the upper surface 1a through the moving bending position. Laser irradiation is performed while continuously moving the focal position of 6, and further, the focal position of the laser 6 is continued from the irradiation start position 7 an on the lower surface 1 b to the irradiation end position 7 dn on the upper surface 1 a through the moving bending position. Cylindrical induction structure having an inner diameter d by repeating laser irradiation while moving By forming the can to form an optical waveguide 3 consisting of inducing structure unformed portion 51. That is, the diameter of the inductive structure non-forming portion 51 or the optical waveguide 3 is d.
[0026]
As described above, the irradiation performed while moving the focal point from the part adjacent to the irradiation start position at the previous irradiation to the part adjacent to the irradiation end position at the previous irradiation is almost all the irradiation start positions or all the irradiation end positions. By making it circular or substantially polygonal, the induced structure part can be formed so as to surround the induced structure non-formed part, and the induced structure non-formed part surrounded by the induced structure part is defined as an optical waveguide. can do. In addition, it is desirable that the portion adjacent to the irradiation start position at the previous irradiation is in a range of less than 5 μm (for example, 0.1 μm or more and less than 5 μm, preferably 1 to 3 μm) from the irradiation start position at the previous irradiation. If the distance between the part adjacent to the irradiation start position at the previous irradiation and the irradiation start position at the previous irradiation is 5 μm or more, the induced structure obtained by the two irradiations may not be fused. is there.
[0027]
As described above, in the present invention, by irradiating a plastic material with a laser, an inductive structure can be formed in the plastic material at each focal position on the locus of the focal position of the laser and its peripheral part (near part). it can. In addition, since the focal position is continuously moved during laser irradiation, the portion where the plastic material induction structure is formed also moves continuously in accordance with the movement of the focal position and extends in the moving direction. Thus, an inductive structure portion composed of a portion where the inductive structure is formed is formed. That is, a three-dimensional shape induction structure is formed by irradiating while moving the focal point of the laser, and in the same manner, the three-dimensional shape induction structure formed by the previous irradiation is fused. By forming such an induction structure portion and forming a cylindrical induction structure portion, an optical waveguide having the induction structure portion as a cladding portion can be formed.
[0028]
The moving direction of the focal position of the laser 6 is not particularly limited and may be any direction. For example, a direction perpendicular to the irradiation direction L of the laser 6, a parallel direction (the same direction as or opposite to the irradiation direction of the laser 6), an oblique direction, and the like can be given. The focal position of the laser 6 can be moved linearly only in any direction, or can be moved in a curved manner in various directions. Further, the focal position of the laser 6 can be moved continuously or intermittently.
[0029]
The speed (movement speed) for moving the focal position of the laser 6 is not particularly limited, and can be appropriately selected according to the material of the plastic material, the magnitude of the irradiation energy of the laser 6, and the like. In addition, it is also possible to control the size of the inducing structure portion by controlling the moving speed.
[0030]
Further, the ultrashort pulse laser may be used singly or in plural. That is, when irradiating an ultrashort pulse laser, a method of irradiating with one light beam or a method of irradiating with multi-beam interference can be employed. In addition, the method of irradiating with multi-beam interference means a method of irradiating using a plurality of lasers from multiple directions and using light interference that forms an induction structure at or near the intersection. The method of irradiating with one light beam means a method of irradiating with a single laser (single light source) without using the light interference as described above. For example, as a method of irradiating a laser with two-beam interference, a method of irradiating with two lasers or a beam splitter (for example, a half mirror, a prism, a grating, etc.) to split light from one laser. Then, a method of irradiating can be employed.
[0031]
In the present invention, the induction structure portion may be, for example, a structure change portion due to a structure change, or may be a hole formed by forming a hole (cavity portion). Note that the structure change portion and the hole can be arbitrarily formed not only two-dimensionally but also three-dimensionally.
[0032]
When the induced structure part is a structure change part, the change in the structure mainly includes a change in structure due to phase separation (for example, phase transition due to crystallization, etc.). Physical and / or chemical structural changes such as structural changes, structural changes due to cross-linking reactions or curing reactions, structural changes due to decomposition reactions, and the like can be mentioned. As the structural change, a plurality of the structural changes illustrated above may be combined. For example, a structural change according to another form may be used together with a structural change due to phase separation. Further, the degree of change in structure may be uniform or non-uniform. Therefore, the induced structure portion may have a structure in which the structure is changed so that the degree of change is uniform, and the induced structure portion may be formed from the end on the induced structure non-formed portion side to the inside or the focal point. The structure may be such that the structure is changed so that the degree of change gradually and continuously increases toward the position or the center thereof. Therefore, the interface (or boundary) between the induced structure portion and the induced structure-unformed portion may be clear or unclear.
[0033]
When the inducing structure is a hole, for example, a method of forming a hole by focusing from a surface (surface) in contact with the atmosphere of the plastic material and starting to irradiate a laser can be employed. When focusing from the surface in this way, it is inferred that the focused site is vaporized and removed, and a hole is formed.
[0034]
In the present invention, the induced structure portion and the induced structure are induced by an external etching action by utilizing the difference in characteristics and characteristics between the induced structure portion and the portion other than the induced structure portion in the plastic material (the portion where the induced structure is not formed). It is also possible to selectively remove any part of the structure-unformed part and selectively leave a necessary part as a connection part. For example, by selectively removing the induction structure portion, a cavity portion, a groove portion, or the like can be formed. Moreover, the site | part consisting only of the induction structure part formed in various shapes or forms can be formed by selectively removing the induction structure non-formation part. As an etching action from the outside, a chemical action such as acid, alkali, or organic solvent, or a thing using a high energy action such as plasma or ultraviolet light can be employed.
[0035]
In the present invention, in one plastic material, the number of inductive structures is not particularly limited, and may be singular or plural. In a plastic material in which a plurality of induction structure portions are formed, a laminated structure in which induction structure portions are stacked at an appropriate interval may be used. In the case where a plurality of induction structures are provided inside one plastic material, the interval between the induction structures can be arbitrarily selected. The distance between the induction structure parts (between induction structure parts formed so as to surround the induction structure non-formed part) is preferably 5 μm or more. When the interval between the induction structure parts provided in the plastic material is less than 5 μm, the induction structure parts may be fused together at the time of producing the induction structure part, so that a plurality of independent induction structure parts cannot be obtained. is there. Therefore, the diameter or width of the optical waveguide composed of the induced structure non-formed part surrounded by the induced structure part is 5 μm or more.
[0036]
In the present invention, the size and shape of the induced structure, the degree of structural change, etc. are the laser irradiation time, the moving direction and speed of the focal position of the laser, the type of plastic material, and the pulse width of the laser. It can be appropriately adjusted depending on the size of the irradiation energy, the numerical aperture of the lens for adjusting the focus of the laser, the magnification, and the like.
[0037]
In this way, the ultrashort pulse laser is focused by using a lens, and is irradiated to any part (or part) of the plastic material, and the focal position (or irradiation position) of the laser is moved. Thus, the induction structure portion can be provided at an arbitrary site (particularly an internal site). The focal position of the laser can be moved by moving the relative position between the laser and the lens and the plastic material, for example, by moving the laser and the lens and / or the plastic material. Specifically, for example, a plastic material (irradiated sample) is placed on a stage that can be moved precisely in two-dimensional or three-dimensional directions, and an ultrashort pulse laser generator and a lens are focused on the plastic material. Are fixed so that they match each other (can be an arbitrary part), and the stage can be moved to move the focal position, whereby an induction structure having a desired shape can be produced at an arbitrary part of the plastic material. Note that laser irradiation can be arbitrarily performed with two- or three-dimensional continuity by controlling the moving speed, moving direction, moving time, and the like of the stage.
[0038]
As described above, in the present invention, the inductive structure portion can be smoothly induced in an arbitrary portion (inside, etc.) of the plastic material by a simple operation of irradiating the ultrashort pulse laser with the focus reduced and moving the focal position. Can be formed. Then, an optical waveguide can be formed in which the induction structure portion is a cladding portion, and the induction structure non-formed portion surrounded by the induction structure portion is a core portion.
[0039]
Specifically, for example, when a plastic material is irradiated with an ultrashort pulse laser, the irradiated portion irradiated with the laser in the plastic material and the vicinity of the irradiated portion are chemically and physically generated such as plasma generation. It is in a high temperature state locally while receiving the action, and then the irradiated irradiation unit and its irradiation with the end of irradiation or the movement of the irradiation unit (for example, two-dimensional movement or three-dimensional movement) The vicinity is usually returned to room temperature. By this irradiation, an induction structure part in which an induction structure is formed at an arbitrary site and an induction structure non-formation part in which no induction structure is formed are formed.
[0040]
In the present invention, for example, when the inductive structure is formed inside a plastic material, the width of the inductive structure (structure change portion, hole, etc.) is 1 mm or less (preferably 500 μm or less). May be. When the inductive structure portion is a hole, the diameter (or width) of the hole is, for example, in the range of about 0.1 to 1000 μm, preferably about 0.1 to 100 μm, and more preferably about 0.5 to 30 μm. You can choose from. Thus, even if the size of the induction structure portion is extremely small, the induction structure portion can be precisely controlled by using an ultrashort pulse laser as the laser.
[0041]
[Plastic materials]
Plastic materials are composed of various polymer components such as organic polymers and inorganic polymers. The polymer components may be used alone or in combination of two or more. The organic polymer is not particularly limited, and various organic resins such as a thermoplastic resin, a thermosetting resin, and an ultraviolet curable resin can be used. As the organic polymer, a thermoplastic resin, in particular, a thermoplastic resin material having two or more glass transition temperatures (glass transition points) can be suitably used. When the plastic material is a thermoplastic resin material having two or more glass transition temperatures (glass transition points), phase separation occurs due to irradiation with an ultrashort pulse laser to form an induced structure part whose structure has changed. can do. The thermoplastic resin material having two or more glass transition temperatures includes a material system including two or more components having different thermal motility and incompatible with each other. Such material systems include blends of two or more dissimilar materials (eg, blends of two or more homopolymers and / or random copolymers, blends of two or more block copolymers, etc.) Examples thereof include a block copolymer composed of two or more different components.
[0042]
When the plastic material has a glass transition temperature of room temperature (for example, 23 ° C.) or less, the plastic material has sufficient flexibility at a temperature near room temperature. Therefore, in a material system of a blend including a plastic material having a glass transition temperature of room temperature (for example, 20 to 25 ° C., particularly 23 ° C.) or less as an incompatible component, by adjusting the component ratio of each plastic material The flexibility can be arbitrarily adjusted at room temperature, and the handling can be facilitated.
[0043]
In addition, for example, in a material system having two glass transition temperatures composed of two or more different components, a glass transition temperature (T _g1 ) (T) _g1 In the case where the component) is a component showing the glass transition temperature on the low temperature side, the component showing the glass transition temperature on the high temperature side (T _g2 Component glass transition temperature (T) _g2 ) Above temperature (T ₃ ), The temperature T _g2 Near T _g2 The ingredients solidify with reduced mobility, while T _g1 The component is cooled to room temperature (for example, 20 to 25 ° C., particularly 23 ° C.) while still having sufficient mobility. At this time, in particular, the temperature T _g1 And T ₃ Are constant, the two glass transition temperatures (T _g1 , T _g2 ) Temperature difference (T _g2 -T _g1 ) Is larger, T _g2 The component solidifies faster, and in the cooling process to room temperature, the component (T _g2 Component (T) showing glass transition temperature on the low temperature side in a state where component) is solidified _g1 The exercise period of only the component) becomes longer. In particular, the glass transition temperature T on the low temperature side _g1 In the process of being cooled to room temperature, that is, T _g2 ~ T in the normal temperature range, T _g1 A phase-separated structure is formed and an induced structure is formed while maintaining sufficient mobility and relaxation properties due to the components. In this case, if the plastic material contains a plurality of components (polymer components) in a form having a gradient in composition ratio, the plastic material (covered material) can be used even if there is a slight variation in the energy of the ultrashort pulse laser. As a result, it becomes easy to control the size of the induced structure obtained by irradiation. Therefore, even if the energy of the ultrashort pulse laser varies, the induced structure is controlled to a constant or almost constant size by reducing the width of the variation of the size (thickness, length, etc.) of the induced structure. It is also possible to form a part.
[0044]
Among these material systems, blends of different materials can be structured in the form of domains, cylinders, layers, and co-continuous by changing the ratio of each component to be blended and changing the dispersion processing conditions. Various incompatible forms such as shapes can be created. On the other hand, in block copolymers and blends thereof (blends of two or more types of block copolymers), the incompatibility of the block-bonded polymer chains is responsible for the incompatibility of the entire system. Therefore, examples of the structural form include the incompatible forms exemplified above, and the incompatible form can be made finer than the blend.
[0045]
In this way, when the plastic material is irradiated with the ultrashort pulse laser, the microdomain thermal melting once occurs in the irradiated portion of the ultrashort pulse laser, and the phase separation structure is again formed by the end of irradiation or movement of the irradiated portion. In this case, if a cross-linking (curing) reaction or the like occurs in parallel during the regeneration of the phase separation structure, the phase separation is further promoted, and the completed phase separation structure has a domain structure or the like rather than the original phase separation structure. Dimensions and forms may be large. Therefore, it is preferable that the inductive structure portion is formed by changing the structure so that the size or form of the microphase separation structure is increased.
[0046]
In particular, the induced structure part is formed by selectively containing a specific component, causing cross-linking (curing), photoisomerization, etc. to cause a chemical change that is different from the original component or its structure. In some cases, changes (modulation) may occur in physical characteristics such as refractive index. If the refractive index of the domain structure part in the induced structure part differs by 0.0005 or more from the refractive index of the domain structure part in the induced structure non-formed part where the induced structure is not formed (that is, each of the above parts) If the difference in refractive index is 0.0005 or more), there is a possibility that it can be used as an optical waveguide. Therefore, in the present invention, it is preferable that the induction structure portion is formed so that the difference in refractive index between the induction structure portion and the induction structure non-formation portion is 0.0005 or more. The difference between the refractive index of the induced structure portion and the refractive index of the portion where the induced structure is not formed is preferably 0.0005 or more (preferably 0.0008 or more, more preferably 0.001 or more). . Further, when the refractive index difference is 0.005 or more (particularly 0.01 or more), it can be used more effectively as an optical waveguide.
[0047]
As such a plastic material, various polymer materials can be used in combination. Therefore, in the present invention, such a large number of combinations can be used, which is a very useful method. Various characteristics such as compatibility of the polymer material and glass transition temperature are described in, for example, a polymer handbook. The plastic material may be compatible or incompatible.
[0048]
Specifically, phase separation can be caused by irradiation with an ultrashort pulse laser, and among the combinations of two or more polymer materials that express a glass transition temperature, for example, the glass transition temperature on the low temperature side is normal temperature. (For example, 20 to 25 ° C., particularly 23 ° C.) As an amorphous component having optical transparency, for example, polydienes such as polyisoprene and polybutadiene; polyalkenes such as polyisobutylene; polybutyl acrylate, Polyacrylic acid esters such as polyethyl acrylate; Polyvinyl esters such as polybutoxymethylene; Polyurethanes; Polysiloxanes; Polysulfides; Polyphosphazenes; Polytriazines; Polycarboranes and the like. Of these, polydienes, polyalkenes, polyacrylates, polysiloxanes, and the like are widely used as constituents of pressure-sensitive adhesives because of their low glass transition temperature.
[0049]
In addition, as a material having a glass transition temperature on the high temperature side and high optical transparency, polycarbonate (PC); methacrylate resin such as polymethyl methacrylate (PMMA); polyester resin such as polyethylene terephthalate (PET); Polyethersulfone (PES) (polyethersulfone); Polynorbornene; Epoxy resin; Polyaryl; Polyimide; Polyetherimide (PEI); Polyamideimide; Polyesterimide; Polyamide; Polystyrene, Acrylonitrile-styrene copolymer (AS resin) ), Styrene resin such as acrylonitrile-butadiene-styrene copolymer (ABS resin); polyarylene ether such as polyphenylene ether; polyarylate; polyacetal; polyphenylene sulfi ; Polysulfones (polysulfone); polyether ketones such as polyether ether ketone and polyether ketone ketones; polyvinyl alcohol; polyvinyl pyrrolidone.
[0050]
A block copolymer having two or more glass transition temperatures by microphase separation of a polymer chain of a block copolymer composed of two or more blocks is a component that develops a glass transition temperature on the low temperature side, What is necessary is just to copolymerize by suitably combining with the component which expresses a glass transition temperature on the high temperature side, and superposing | polymerizing (copolymerization) so that it may become a block copolymer. The polymerization method (copolymerization method) is not particularly limited, and for example, a known living polymerization method such as a living anion polymerization method, a living cation polymerization method, or a living radical polymerization method can be employed.
[0051]
In addition, as long as the glass transition temperature of such a thermoplastic resin material is two or more, two may be sufficient and three or more may be sufficient. As the thermoplastic resin material, a polymer having two glass transition temperatures is preferable, and a polymer composed of a block copolymer having two glass transition temperatures is particularly preferable.
[0052]
In addition, fluorine resins such as vinylidene fluoride resin, hexafluoropropylene resin, and hexafluoroacetone resin can also be used.
[0053]
Furthermore, a polysilane polymer such as polysilane may be blended. If the plastic material contains a polysilane-based polymer, the mechanical properties of the plastic material can be improved, and the induction structure can be formed with excellent workability. In addition, the polysilane polymer has a structure in which a silicon-silicon bond (Si-Si bond) is cut by light irradiation, and a siloxane bond (Si-O-Si bond) or a silanol group (Si-OH) is generated. It has characteristics such as a large change in refractive index (for example, a decrease) and generation of radicals, and is useful as a composite material. The polysilane polymer is a polymer composed of a main chain having a silicon-silicon bond. The substituent that is substituted on the silicon atom of the main chain is not particularly limited, and examples thereof include a hydrogen atom, an organic group, and a halogen atom. The polysilane polymer may be a homopolymer or a copolymer. Specifically, examples of the polysilane-based polymer include polysilane; poly (dimethylsilane), poly (methylethylsilane), poly (methylpropylsilane), poly (methylbutylsilane), poly (methylhexylsilane), poly (Dihexylsilane), poly (alkylalkylsilane) such as poly (didodecylsilane); poly (alkylcycloalkylsilane) such as poly (methylcyclohexylsilane); poly (methylphenylsilane), poly (ethylphenylsilane), Poly (alkylarylsilane) such as poly (propylphenylsilane), poly (isopropylphenylsilane), poly (butylphenylsilane), poly (hexylphenylsilane); poly (arylarylsilane) such as poly (diphenylsilane); Polyphenylsilin Homopolymers such as a silicon atom-containing polymer having a three-dimensional structure of silicon atoms such as polymethylsiline (having a structure in which silicon atoms are three-dimensionally bonded), poly (dimethylsilane-methylcyclohexylsilane), poly ( And a copolymer such as (dimethylsilane-methylphenylsilane).
[0054]
The molecular weight (weight average molecular weight, etc.) of the polymer material (polymer) is not particularly limited. The molecular weight (weight average molecular weight, etc.) of the polymer material can be appropriately selected according to the target plastic material, for example, selected from the range of 1,000 or more (preferably about 10,000 to 500,000) can do.
[0055]
In the present invention, the plastic material may be a composite containing another material such as an inorganic compound or a metal compound in a dispersed state, or a laminate containing another material in a layered state. Further, it may contain a crosslinking agent, a lubricant, an antistatic agent, a plasticizer, a dispersant, a stabilizer, a surfactant, an inorganic or organic filler, if necessary.
[0056]
The plastic material preferably has a total light transmittance of 10% or more (preferably 50% or more, more preferably 85% or more) in the visible light wavelength region (for example, 400 nm to 800 nm). Thus, if it has a light transmittance of 10% or more, laser processing can be easily performed by irradiation with an ultrashort pulse laser whose wavelength is in the visible light wavelength region. Accordingly, a colored plastic material that causes significant light absorption or scattering in the visible wavelength region or a plastic material that contains a large amount of scattering particles is not desirable. When the transmittance of the plastic material is 10% or more, focusing can be performed without attenuating the intensity of the ultrashort pulse laser beam in the sample. Further, when the transmittance of the plastic material is 10% or more, the internal state of the plastic material can be visually recognized, so that the irradiation position or focal position of the ultrashort pulse laser, the degree of structural change, and the like are visually recognized. It is possible to effectively irradiate the plastic material with the ultrashort pulse laser.
[0057]
(laser)
As an ultrashort pulse laser used when processing a plastic material, the pulse width is 10 ^-12 If it is 2 seconds or less, there is no particular limitation, and the pulse width is 10 ^-15 A pulse laser of the order of seconds can be suitably used. Pulse width is 10 ^-15 For pulsed lasers on the order of seconds, the pulse width is 1 × 10 ^-15 Second to 1 × 10 ^-12 A pulsed laser that is seconds is included. More specifically, an ultrashort pulse laser has a pulse width of 10 × 10. ^-15 Second to 500x10 ^-15 Seconds (preferably 50 × 10 ^-15 Second to 300x10 ^-15 A pulse laser of about 2 seconds) is preferable.
[0058]
Pulse width is 10 ^-12 For example, an ultrashort pulse laser of less than 2 seconds can be obtained by reproducing and amplifying a laser or dye laser using a titanium / sapphire crystal as a medium.
[0059]
In the ultrashort pulse laser, the wavelength is preferably, for example, a wavelength region of visible light (for example, 400 to 800 nm). In the ultrashort pulse laser, the repetition can be selected from the range of 1 Hz to 80 MHz, for example, and is usually about 10 Hz to 500 kHz.
[0060]
The average output or irradiation energy of the ultrashort pulse laser is not particularly limited, and can be appropriately selected according to the size of the target induced structure part, the type of the structural change, the degree of the change, etc. For example, it can be selected from a range of about 500 mW or less (for example, 1 to 500 mW), preferably 5 to 300 mW, and more preferably about 10 to 100 mW. Thus, the irradiation energy of the ultrashort pulse laser may be low. Therefore, it is possible to suppress or prevent the thermal influence caused by the irradiation of the ultrashort pulse laser onto the plastic material.
[0061]
Further, the irradiation spot diameter of the ultrashort pulse laser is not particularly limited, and the size of the target induced structure, the type of the induced structure or the degree of the induced structure, the size, the numerical aperture, or the magnification of the lens, etc. For example, it can select from the range of about 0.1-10 micrometers.
[0062]
The optical waveguide of the present invention has a linear two-fold shape as shown in FIG. 1 and a straight three-fold shape as shown in FIG. The number of bends is not particularly limited and can be any number, and the bend angle is not particularly limited and can be any angle. Moreover, the form of a curve may be sufficient like a circular arc. FIG. 3 is a schematic bird's-eye view showing another example of the three-dimensional optical waveguide according to the present invention, and the reference numerals in FIG. 3 are the same as those in FIG.
[0063]
Such an optical waveguide can be used by being joined to, for example, an optical switching component, an optical multiplexing / demultiplexing component, a wavelength conversion filter, an optical isolator, an optical circulator, an optical connector, an optical external modulator, or the like.
[0064]
【The invention's effect】
According to the optical waveguide of the present invention, even an optical waveguide bent and refracted three-dimensionally can be easily produced in a plastic material with excellent workability. The pulse width is 10 ^-12 It can be formed in an arbitrary shape in an arbitrary part in a plastic material by irradiation with an ultrashort pulse laser of less than a second. Therefore, it is possible to easily and inexpensively provide a three-dimensional optical waveguide that is advantageous in reducing the number of work steps, increasing the integration density by high-density or three-dimensional stacking, and improving the degree of freedom in designing an engineering device for a compact system.
[0065]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
[0066]
(Example 1)
In a polymerization vessel, butyl acrylate (BA) and ethyl acrylate (EA) as monomer components are put in an equimolar ratio, and ethyl 2-bromoisobutyrate (0% relative to the total amount of the monomer components) is used as a polymerization initiator. .0012 mol%), copper bromide as a polymerization catalyst (0.0012 mol% based on the total amount of the monomer components), and 2,2′-bipyridine derivative as a co-catalyst (0.0036 mol based on the total amount of the monomer components). First, a butyl acrylate / ethyl acrylate random copolymer [poly (BA / EA) random copolymer] having a weight average molecular weight of about 25,000 was prepared by a known living radical polymerization method using the following method.
Subsequently, methyl methacrylate (MMA) was added as a copolymerizable monomer component for producing a block copolymer to the reaction mixture containing the poly (BA / EA) random copolymer, and further living radical polymerization was performed. In this way, polymethyl methacrylate (PMMA) having a weight average molecular weight of about 58,000 is bonded to the poly (BA · EA) random copolymer in a block manner, and PMMA · (poly (BA · EA) Random copolymer) block copolymer [poly (MMA / BA · EA) block copolymer] was obtained. In the poly (MMA / BA · EA) block copolymer (sometimes referred to as “block copolymer A”), the weight average molecular weight of the entire block copolymer is about 83,000, and the ratio of PMMA is 70% by weight (weight average molecular weight ratio).
The block copolymer A is purified using a filter or an ion exchange resin, and then further added with ethyl acetate to make a solution having a concentration of about 30% by weight. By a casting method, a film sample (film thickness: 500 μm) This was sometimes referred to as “irradiated sample A”.
[0067]
With the method as shown in FIG. 2, focusing on the bottom surface at a depth of about 500 μm from the top surface of the irradiated sample A, a titanium / sapphire / femtosecond pulse laser device and objective lens (magnification: 20 ×) Using an ultrashort pulse laser (irradiation wavelength: 800 nm, pulse width: 150 × 10 ^-15 Second, repetition: 200 kHz), irradiation energy (average output): 20 mW, irradiation spot diameter: about 3 μm, irradiation sample A in a direction parallel to the irradiation direction (first direction), moving speed: about 20 μm / Second for 10 seconds, then moving speed in the vertical direction (second direction): about 50 μm / second for 4 seconds, and further moving direction in the vertical direction (third direction) changed by 90 °: about Irradiation was performed while moving at 50 μm / second for 4 seconds, and finally moving in a parallel direction (fourth direction) at a moving speed of 20 μm / second for 15 seconds. Next, returning to the previous irradiation start position on the bottom surface of the irradiation sample A, focusing on a position on a circular arc with a diameter of 20 μm (radius of 10 μm) and a distance of 4 μm from the previous irradiation start position, When irradiation was performed 16 times in total at a position that is 4 μm away from the end position of the previous irradiation and a position on an arc with a diameter of 20 μm (radius is 10 μm) at the same movement speed as the irradiation of [ The irradiation time (time required for movement) is as shown in Table 1. Each irradiation start position is on the same arc, and each irradiation end position is on the same arc. ], A three-dimensionally bent cylindrical induction structure as shown in FIG. 3 was formed. An induction structure non-formation part exists in the inside (center) of the induction structure part, and the induction structure part is formed so as to surround the induction structure non-formation part.
[0068]
The inductive structure portion causes a permanent refractive index modulation having a refractive index higher by about 0.002 with respect to an unirradiated portion of the ultrashort pulse laser (an induced structure-unformed portion), and an optical waveguide having a high refractive index. On the other hand, the unirradiated part of the ultrashort pulse laser became the core part and functioned as an optical waveguide.
[0069]
[Table 1]

[0070]
In Table 1, “movement in the first direction” means movement in the direction when the irradiation sample A is first moved in a direction parallel to the irradiation direction at a moving speed of about 20 μm / second. The term “movement in the second direction” means movement in the direction when moving at a movement speed of about 50 μm / second in the direction perpendicular to the irradiation direction, and “in the third direction”. The term “movement” means movement in the direction when moving at a movement speed of about 50 μm / second in a direction perpendicular to the irradiation direction after changing the 90 ° direction. “Movement” means the movement in the direction when moving at a moving speed of 20 μm / second in the direction parallel to the irradiation direction.
[0071]
(Example 2)
On a substrate [optical glass (BK7); thickness: 2.0 mm], a polysilane-based polymer [poly (methylphenylsilane)] is removed with a 20 wt% toluene solution and dried under reduced pressure (vacuum drying method). A thin film (thickness: about 300 μm) was formed from a system polymer to prepare a thin film sample (sometimes referred to as “irradiated sample B”) on the substrate.
[0072]
2, a titanium / sapphire / femtosecond pulse laser apparatus and an object are focused on the bottom surface of the thin film having a depth of about 300 μm from the top surface of the thin film made of the polysilane-based polymer of the irradiation sample B. Using a lens (magnification: 20 times), ultrashort pulse laser (irradiation wavelength: 800 nm, pulse width: 150 × 10 ^-15 Second, repetition: 200 kHz), irradiation energy (average output): 20 mW, irradiation spot diameter: about 3 μm, irradiation sample B in a direction parallel to the irradiation direction (first direction), moving speed: about 20 μm / Second for 10 seconds, then the moving speed in the vertical direction (second direction): about 100 μm / second for 2 seconds, and finally the parallel direction (third direction) for moving speed: 15 for 20 μm / second Irradiated while moving for 2 seconds. Next, returning to the start position of the previous irradiation on the bottom surface of the thin film, the previous irradiation is focused on an arc having a diameter of 20 μm (radius is 10 μm) and a distance of 4 μm from the start position of the previous irradiation. When irradiation was performed a total of 16 times at a position at a distance of 4 μm from the end position of the previous irradiation and a position on a circular arc with a diameter of 20 μm (radius is 10 μm) at the same movement speed as in FIG. Table 2 shows (the time required for movement). Each irradiation start position is on the same arc, and each irradiation end position is on the same arc. ], A three-dimensionally bent cylindrical induction structure as shown in FIG. 1 was formed. An induction structure non-formation part exists in the inside (center) of the induction structure part, and the induction structure part is formed so as to surround the induction structure non-formation part.
[0073]
The inductive structure portion causes a permanent refractive index modulation having a refractive index higher by about 0.002 with respect to an unirradiated portion of the ultrashort pulse laser (an induced structure-unformed portion), and an optical waveguide having a high refractive index. On the other hand, the unirradiated part of the ultrashort pulse laser became the core part and functioned as an optical waveguide.
[0074]
[Table 2]

[0075]
In Table 2, “movement in the first direction” means movement in the direction when the irradiation sample B is first moved in a direction parallel to the irradiation direction at a moving speed of about 20 μm / second. The term “movement in the second direction” means movement in the direction when moving at a movement speed of about 100 μm / second in the direction perpendicular to the irradiation direction, and “in the third direction”. The term “movement” means the movement in the direction when moving at a moving speed of 20 μm / sec in the direction parallel to the irradiation direction at the end.
[Brief description of the drawings]
FIG. 1 is a schematic bird's-eye view showing an example of a three-dimensional optical waveguide of the present invention.
FIG. 2 is a schematic bird's-eye view showing an example of a method of forming a three-dimensional optical waveguide by forming an induction structure portion used as a cladding portion of an optical waveguide in a plastic material.
FIG. 3 is a schematic bird's-eye view showing another example of the three-dimensional optical waveguide of the present invention.
[Explanation of symbols]
1. Plastic structure with three-dimensional optical waveguide
2 Plastic materials
1a Top surface of three-dimensional optical waveguide plastic structure 1
1b Three-dimensional optical waveguide plastic structure 1 bottom surface
3 Optical waveguide
4 Induction structure
d Diameter (diameter or width) of the optical waveguide 3
51, 52 Induced structure non-formed part
6 Ultra short pulse laser
6a lens
D Irradiation direction of laser 6
7a1, ..., 7an Irradiation start position of laser 6
7b1, 7c1 Moving and bending position of laser 6
7d1, ..., 7dn End position of laser 6 irradiation

Claims (4)

A plastic material is produced by irradiating a laser with a pulse width of 10 ⁻¹² seconds or less to form a three-dimensional induction structure so as to surround a portion where no induction structure is formed. 3D optical waveguide. The three-dimensional optical waveguide according to claim 1, wherein a refractive index difference between a refractive index of the induction structure portion and a refractive index of a portion other than the induction structure portion in the plastic material is 0.0005 or more. The three-dimensional optical waveguide according to claim 1 or 2, wherein the plastic material is a plastic material having a transmittance of 10% or more in a visible light wavelength region of 400 to 800 nm. The part according to any one of claims 1 to 3, wherein any one part of the induction structure part and the part other than the induction structure part in the plastic material can be selectively removed by an etching action from the outside. Three-dimensional optical waveguide.

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