JP2006317572A - Optical waveguide and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive optical waveguide which can be mounted without using a curved fiber array and can be manufactured in a very simple manner and to provide a method for manufacturing the optical waveguide. <P>SOLUTION: The optical waveguide is characterized in that varied refractive index difference is formed depending on the location by using a polysilane material containing a photosensitizer. The method of manufacturing the optical waveguide is characterized in that the polysilane material 200 containing the photosensitizer is applied on a substrate 80 having ultraviolet transmissivity, a mask 230 provided with a predetermined pattern on the front surface of the coating film or both the front and the bottom surfaces of the coating film is arranged, and an ultraviolet laser beam 250 is radiated to generate the varied refractive index difference depending on the location. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical waveguide and a manufacturing method thereof, and more preferably to a refractive index control type optical waveguide formed of a polysilane material containing a photosensitizer and a manufacturing method thereof.

With the recent increase in the Internet subscriber population, it is desired to provide a broadband service at a low price. Conventionally, as a material for forming an optical waveguide for optical communication, an inorganic material mainly composed of quartz glass is promising from the viewpoint of environmental resistance and reliability and has been put into practical use.
However, since the optical waveguide manufacturing process has a process exceeding 1000 degrees Celsius, a special specification manufacturing apparatus is required, and since fine processing is required, a vacuum etching apparatus is required, which increases capital investment. It was a huge expense. In order to reduce the price of the optical waveguide chip, it may be possible to pack as many optical waveguides as possible in the wafer to improve the yield, but in order to embed the optical waveguide at a high density, an optical waveguide with an extremely small radius of curvature is designed. There is a need (see, for example, Patent Document 1).

  For this purpose, it is effective to increase the difference in refractive index between the core and the cladding, but on the input / output side, the connection with the optical fiber is easy, and the connection loss is low and the reflection of the optical waveguide signal is extremely low. As a result, the mounting form of the optical waveguide module is determined.

FIG. 9 is a plan view showing an outline of a conventional optical signal distribution optical waveguide module, and shows a 1 × 8 splitter mounting form. The illustrated optical signal distribution optical waveguide module includes an optical waveguide 120 that branches input light into a plurality of paths, and an input-side optical fiber cord 150A is connected to the input side of the optical waveguide 120 via a bare fiber 140A. The fiber array 130A is connected, and the output side fiber cord 150B is connected to the output side of the optical waveguide 120 via the bare fiber 140B. It is housed and protected.
A connector 160A for connecting to another optical fiber is attached to the input side optical fiber cord 150A. Similarly, each of the branched output side fiber cords 150B is attached to the connector 160B. At the connection point 170A between the fiber array 130A and the optical waveguide 120 and at the connection point 170B between the fiber array 130B and the optical waveguide 120, it is necessary to align the cores and connect them to each other, and the fiber arrays 130A and 130B are extremely strict. High pitch accuracy was required. (For example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 11-14846 (paragraph numbers “0051” and “FIG. 4”) JP 2002-174747 A (paragraph numbers “0011” and “FIG. 3”)

In the case of such a conventional optical waveguide module structure, it is necessary to produce bare fibers 140A and 140B for connection to the optical fiber arrays 130A and 130B, and such fiber arrays 130A and 130B. As mentioned later, there was a problem that it was very expensive.
Further, the bare fibers 140A and 140B between the fiber arrays 130A and 130B and the optical fiber cords 150A and 150B have a problem that they are easily broken due to the occurrence of microcracks. In particular, the bare fiber 140B of the eight-core fiber array 130B on the output side has a problem that it is easy to break due to the adjustment of the pitch of the optical waveguide 120 and the pitch of the optical fiber cord 150B and is very dangerous.
Furthermore, at the connecting portion 170A between the fiber array 130A and the optical waveguide 120 and at the connecting portion 170B between the fiber array 130B and the optical waveguide 120, the cores must be aligned, and the pitch accuracy of the array is extremely precise (for example, It is very expensive to manufacture within 0.5 μm), and the alignment while passing the laser beam has a problem that time and high technology are required for connection work.

  Accordingly, an object of the present invention is to solve the above-described problems and to provide an optical waveguide that can be mounted without using a bent fiber array, which has been conventionally required, and a method for manufacturing the same. It is another object of the present invention to provide such an optical waveguide module at a low price, and to provide an optical waveguide that can be manufactured very simply and a method for manufacturing the same.

In order to solve the above-mentioned problem, the present invention according to claim 1 applies a polysilane material containing a photosensitizer on a substrate having ultraviolet transparency, and is applied to the surface side or the surface side and the bottom side of the coating film. Provided is a method of manufacturing a refractive index control type optical waveguide, characterized in that a mask having a predetermined pattern is arranged and an ultraviolet laser beam is irradiated so as to generate a difference in refractive index depending on a place.
Polysilane, which is a silicon-based polymer material, has a characteristic that its refractive index changes upon exposure to ultraviolet rays. However, polysilanes containing photosensitizers react more sensitively to ultraviolet light than conventional polysilanes, making it easier to form an optical waveguide in the polysilane film, and controlling the intensity of the ultraviolet light in the depth direction (ultraviolet irradiation). Direction) can be easily controlled. As a result, a desired optical waveguide pattern can be easily manufactured at low cost.

In order to solve the above-mentioned problem, the present invention according to claim 2 is the method of manufacturing an optical waveguide according to claim 1, wherein the surface side of the polysilane material containing the photosensitizer applied on the substrate and the substrate An optical waveguide having a different refractive index depending on a place is formed by partially irradiating ultraviolet laser light from the bottom surface side.
An optical waveguide having a difference in refractive index depending on the location is formed by partially irradiating ultraviolet rays onto the coating film of the polysilane material applied on the substrate.

In order to solve the above-mentioned problem, the present invention according to claim 3 is the method of manufacturing an optical waveguide according to claim 1 or 2, wherein the number of times of application of the polysilane material including the photosensitizer applied on the substrate is one. It is characterized by times.
A polysilane material containing a photosensitizer is applied only once on the substrate, and an optical waveguide is formed by arranging a mask and irradiating ultraviolet rays.

  In order to solve the above-mentioned problem, the present invention according to claim 4 is the method for manufacturing an optical waveguide according to any one of claims 1 to 3, wherein the single-mode optical waveguides having different core diameters are arranged in the same coating film. It is characterized by forming in.

In order to solve the above-mentioned problem, the present invention according to claim 5 is the optical waveguide manufacturing method according to any one of claims 1 to 4, wherein the mask has a different transmittance of ultraviolet laser light depending on the location. And is irradiated with ultraviolet laser light using the mask.
Thereby, the core diameter of the core in the incident part and the emission part is formed larger than the core diameter of the core in the branch part, and the cores of the incident part and the emission part gradually changed to a tapered shape according to the core direction of the branch part. An optical waveguide can be manufactured.

  In order to solve the above-mentioned problems, the present invention according to claim 6 is a refractive index control type optical waveguide characterized in that the refractive index difference is different depending on the location by a polysilane material containing a photosensitizer. provide.

  In order to solve the above-mentioned problem, the present invention according to claim 7 is the optical waveguide according to claim 6, wherein an incident portion into which light is incident, a branch portion that branches incident light, and a branch portion are branched. A core diameter that is configured to include an emission part that emits light and that is positioned on the end part side of the incident part and the emission part is formed larger than the core diameter of the branch part, and gradually decreases toward the branch part side. It is formed in a taper shape.

  As described above, according to the present invention, it is possible to provide an optical waveguide in which a branch portion that is an integrated optical waveguide portion and an incident portion and an output portion that are optical waveguide portions that are well matched with an optical fiber coexist. Therefore, the conventionally required complicated optical fiber array is not required, the number of parts is reduced, the mounting process is eliminated, and the price of the optical waveguide module can be greatly reduced. In addition, in the production process of polysilane containing a photosensitizer, the production process can be greatly reduced, and an economic process can be expected.

  Preferred embodiments of an optical waveguide and a method for manufacturing the same according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a plan view showing a first embodiment of an optical waveguide according to the present invention. The illustrated optical waveguide 1 is a 1 × 8 optical waveguide circuit that branches incident light into eight systems. The purpose of this optical waveguide is to evenly distribute the light propagated by one optical fiber to eight systems and send it out to the eight optical fibers. The illustrated optical waveguide 1 incorporates all the functions of the input side optical fiber cord 150A, bare fibers 140A and 140B, output side optical fiber cord 150B, and fiber arrays 130A and 130B in the conventional optical waveguide 120 shown in FIG. An optical waveguide integrated with an optical fiber. In FIG. 1, reference numeral 10 denotes a photosensitizer-containing polysilane film formed from a polysilane material containing a photosensitizer, and includes an incident portion 20, a branch portion 30, and an output portion 40, and the incident portion 20, the branch portion 30, The exit portions 40 have different refractive index differences between the core and the clad.
Here, the refractive index difference Δ is calculated by the following equation.
Δ = 100 × (core refractive index−cladding refractive index) / core refractive index (%)

  The branch portion 30 has a refractive index distribution that is high in the refractive index at the center of the optical waveguide 1 and becomes lower toward the end of the optical waveguide in order to form the branch portion optical waveguide 50, and the refractive index difference between the core and the clad is 1 ˜2%, core width and core depth are 2 to 5 μm. Specifically, the refractive index of the core is 1.57 (0.633 μm), the refractive index of the cladding is 1.547 (0.633 μm), and the refractive index difference is about 1.5%. . Each of the optical waveguide portions branched into eight is formed such that the refractive index of the cladding gradually decreases toward the upper and lower sides in the height direction and both end sides in the width direction.

  The refractive index difference between the core and the clad of the incident part optical waveguide 60 of the incident part 20 and the outgoing part optical waveguide 70 of the outgoing part 40 is the same as the power distribution of the single mode optical fiber. .3%, the core width and the core depth are 7 to 10 μm, and the optical waveguide has a refractive index distribution. Here, it is treated as a single-mode optical waveguide for a long-distance optical communication wavelength 1.55 μm band, but in the case of short-distance optical communication and in-home optical wiring, it is a 0.85 μm band and functions as a multimode optical waveguide.

  In the present embodiment, the incident portion optical waveguide 60 and the emission portion optical waveguide 70 are connected to a single mode optical fiber, and the core diameter on the side connected to the branching portion optical waveguide 50 side that is an integrated portion is gradually reduced. It is formed to change in a tapered shape. As a result, the single mode condition can be maintained. Further, since it is possible to manufacture a single mode optical waveguide having a large core diameter between the incident portion optical waveguide 60 and the output portion optical waveguide 70, it is possible to reduce the connection loss with the single mode optical fiber. The single mode optical fiber has a 9 μm diameter core and a 125 μm diameter cladding. The incident portion optical waveguide 60 has a core width and depth of 7 to 10 μm, the branch portion optical waveguide 50 has a core width and core depth of 2 to 5 μm, and the output portion optical waveguide 70 has a single mode optical waveguide core width and core depth. Is 7 to 10 μm.

  2A is a conceptual diagram of the refractive index of the optical waveguide 1 shown in FIG. 1, and FIG. 2B is an optical waveguide 1 shown in FIG. 2A and an optical fiber optically connected to both sides thereof. It represents the power distribution of light propagating through. The incident part 20, the emitting part 40, and the branch part 30 have different refractive index differences between the core and the clad. A polysilane under-cladding layer 90, a core layer 100, and an over-cladding layer 110 containing a photosensitizer are sequentially formed on a substrate having ultraviolet transparency, preferably a substrate 80 having high ultraviolet transmittance (eg, quartz glass). It has a deposited structure. Polysilane containing a photosensitizer reacts more sensitively to ultraviolet light than conventional polysilanes, so it is easy to form an optical waveguide perpendicular to the polysilane film, and the refractive index can be changed in the depth direction by controlling the intensity of ultraviolet light. Become. Here, as the photosensitizer, for example, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone (“BTTB” (trade name of NOF Corporation) and the like are used. It adjusts so that it may contain in the ratio of 1 to 20 weight% with respect to polysilane material.

  The power distribution 190 of the optical fiber and the power distribution 191 of the incident portion 20 are designed to be equal to the power distribution 192 of the optical fiber and the power distribution 193 of the emission portion 40. The refractive index difference of the branch part 30 is 1 to 2%, which is higher than the refractive index difference of the incident part 20 and the output part 40, and the core width and thickness are also 2 to 5 μm. Compared with the power distribution of the incident part 20 and the output part 40, the power distribution 194 is concentrated in the core region. On the other hand, the refractive index difference between the core and the clad of the incident portion 20 and the emission portion 40 is set to 0.25 to 0.3% as in the optical fiber connected to both ends, and the core width and thickness are 7 to 10 μm. It is.

  Next, the method for manufacturing the optical waveguide 1 having the above structure will be described, and the description of the optical waveguide 1 will be supplemented. FIG. 3 is a basic conceptual diagram for performing refractive index control in the method of manufacturing an optical waveguide according to the present invention. When polysilane is irradiated with ultraviolet light, the refractive index decreases due to the photobleaching effect. Since the incidence part 20 and the emission part 40 require a cladding layer having a refractive index slightly lower than the refractive index of the core, as shown in FIG. 3, the refractive index difference is Δn2 (0.25 to 0.3%). Ultraviolet light is irradiated so as to have a clad refractive index of 2 as shown. On the other hand, in the case of the branch part 30, the ultraviolet light is irradiated so that the refractive index difference becomes Δn1 (1 to 2%) and the clad refractive index is 1 longer than that.

  The optical waveguide 1 is manufactured based on the above refractive index design. FIG. 4 is a cross-sectional explanatory view of the optical waveguide in each step of the method of manufacturing an optical waveguide according to the present invention. However, this drawing is for explaining the manufacturing process and does not show an actual cross section of the optical waveguide 1. The same applies to FIGS. 5 and 6. First, as shown in FIG. 4A, a polysilane precursor 200 containing a photosensitizer is spin-coated on a substrate having ultraviolet transparency, preferably a substrate 80 having high ultraviolet transmittance, to have a film thickness of 10 to 20 μm. It is made to deposit so that it may become the range of. Then, pre-baking is performed in a temperature range of about 100 to 130 ° C. for about 30 minutes, and a positive type 1 × 8 splitter mask 230 on which a 1 × 8 splitter pattern is drawn is disposed on the top of the coating film. Here, the “polysilane precursor” refers to polysilane in a material state before baking by baking. Then, the ultraviolet laser beam 250 is irradiated from above the mask 230 by an ultraviolet laser beam irradiation device (not shown). Then, the ultraviolet laser beam 250 was irradiated except for the shielded portion 201 where the irradiation of the ultraviolet laser beam 250 was blocked by the 1 × 8 splitter pattern 231 drawn on the mask 230 in the polysilane precursor 200. The refractive index of the part is lower than the refractive index of the shielded part 201. This indicates that the pattern is formed vertically by using the ultraviolet laser beam 250. Here, the ultraviolet laser beam 250 is preferably a laser beam having a wavelength suitable for the absorption characteristics of the polysilane precursor 200. In this experiment, a He—Cd laser having a wavelength of 325 nm close to the absorption peak of polysilane was used. The irradiation time of the ultraviolet laser beam 250 is set to an irradiation time such that the clad refractive index is 2 shown in FIG.

  Next, as shown in FIG. 4B, the ultraviolet laser beam 250 is irradiated from below the substrate 80. When the ultraviolet laser beam 250 is irradiated from below the substrate 80, the refractive index on the lower surface side of the shielded part 201 having a high refractive index is lowered to become the clad 202. In other words, the refractive index of the lower side (substrate 80 side) of the shielded portion 201 in the height direction decreases, but the change in the refractive index decreases toward the upper side, and the refractive index on the upper side does not change. That is, a gradient index optical waveguide is thereby formed, and an optical waveguide having a small refractive index difference from the core is formed.

  Next, the polysilane precursor 200 on the substrate 80 is post-baked. At that time, it is necessary to select the selected temperature according to the desired refractive index. It is usually preferable to bake at 200 to 360 ° C. for 10 to 30 minutes. In this embodiment, the refractive index difference between the core and the clad of the incident portion 20 and the emission portion 40 is set to 0.25 to 0.3%. Thereby, the under clad layer 90 is formed.

  Next, as shown in FIG. 4C, the photosensitizer-containing polysilane precursor 210 is deposited on the undercladding layer 90, which is a polysilane optical waveguide layer, to a thickness of 2 to 5 μm, as in the step of FIG. And spin-coating at about 100-130 ° C. for about 30 minutes. Then, the mask 240 is disposed on the polysilane precursor 210, and the ultraviolet laser beam 250 is irradiated from above. The mask 240 has a 1 × 8 splitter portion that is not present in the mask 230. Accordingly, as shown in FIG. 1, the portion of the optical waveguide 50 remains as the core 211 in the branch portion 30, and the other portion has a refractive index corresponding to the cladding. At this time, the clad of the branch portion 30 has a refractive index corresponding to the clad refractive index 1 shown in FIG. 3, the optical waveguide 50 portion has a high refractive index difference of 1 to 2%, and the core diameter is 2 to 5 μm. It should be noted that a precise marker alignment technique is required because a pattern alignment process for the mask 230 and the mask 240 is included. Specifically, accurate alignment is performed by attaching markers to the mask 230 and the mask 240 and performing mask alignment during exposure. Then, after the ultraviolet laser beam 250 irradiation, post-baking is performed at about 200 to 360 ° C. for 10 to 30 minutes, and the core layer having the polysilane optical waveguide core 211 is completed.

  Next, as shown in FIG. 4D, the photosensitizer-containing polysilane precursor 220 is formed on the core layer having the polysilane optical waveguide core 211 in a thickness of about 10 to 20 μm as in the step of FIG. And spin-coating at about 100-130 ° C. for about 30 minutes. Then, the mask 230 is disposed on the polysilane precursor 220, and the ultraviolet laser beam 250 is irradiated from above. As a result, the refractive index of the polysilane precursor 220 other than the core part 221 is higher than that of the core part 221 except for the core part 221 which is a shielded part corresponding to the 1 × 8 splitter pattern written on the mask 230. The clad refractive index becomes 2 as shown in FIG.

  Next, as shown in FIG. 4 (e), unlike FIG. 4 (b), an ultraviolet laser beam 250 is irradiated from above the pre-baked polysilane precursor 220. As a result, the refractive index on the upper side in the height direction decreases and becomes the cladding portion 222, but the change in the refractive index decreases as it goes downward, and the refractive index on the lower side does not change. As a result, a gradient index optical waveguide is formed, and an optical waveguide having a small refractive index difference from the core is formed.

  Next, the polysilane precursor 220 is post-baked at about 300 to 360 ° C. for 10 to 30 minutes. At that time, it is necessary to select the selected temperature according to the desired refractive index. Now, the refractive index difference between the incident portion 20 and the core of the emitting portion 40 is selected to be 0.25 to 0.3%. The over clad layer 110 is formed by the above steps, and a three-layer polysilane 1 × 8 integrated splitter is completed as a whole.

  Next, a second embodiment of the optical waveguide manufacturing method according to the present invention will be described. Compared with the first embodiment described above, this embodiment is characterized in that a polysilane precursor is sufficient. Now, consider making an integrated 1 × 8 splitter similar to the first embodiment. As shown in FIG. 2A, the incidence part 20 and the emission part 40 have a small refractive index difference between the core and the cladding as small as 0.25 to 0.3%, and a large core width and thickness as 7 to 10 μm. On the other hand, the branch part 30 has a structure in which the core width and thickness are as small as 2 to 5 μm and the difference in refractive index is as large as 1 to 2%. In order to manufacture them on the same substrate, as shown in FIG. 5A, a polysilane precursor 260 is formed on a substrate having ultraviolet transparency, preferably a substrate 80 having high ultraviolet transmittance, to a thickness of 30 to 70 μm. Now spin coat and then pre-bake. The prebaking conditions are about 100 to 130 ° C. for 10 to 30 minutes. Next, a positive type 1 × 8 splitter mask 270 is disposed on the polysilane precursor 260. Then, by uniformly irradiating the ultraviolet laser beam 250 from above the mask 270, the mask pattern is transferred into the polysilane precursor 260, and a residual core portion 261 is formed. This indicates that the pattern is formed vertically by using the ultraviolet laser beam 250.

  Next, in order to form a core circuit which is the branching portion 30 of the branching portion optical waveguide 50 shown in FIG. 1, as shown in FIG. 5B, a partial mask 280 concealing the incident portion 20 and the emitting portion 40 is formed. It is disposed on the polysilane precursor 260 and irradiated with ultraviolet laser light 250. The residual core portion 261 of the branching portion 30 is changed into a clad by lowering the refractive index on the upper side due to the irradiation of the ultraviolet laser beam 250 from the upper side, and the residual core portion 262 is formed. However, the refractive index of the residual core part 261 of the incident part 20 and the output part 40 does not change. The partial mask 280 is a mask that only shields the light incident portion 20 and the light emitting portion 40, and therefore has a feature that mask alignment is very simple compared to the first embodiment.

  Next, as shown in FIG. 5C, the same partial mask 280 as in FIG. 5B is used to irradiate the ultraviolet laser beam 250 from the bottom surface side (lower side) of the substrate 80. Then, the upper part side (the part located in the center part of the polysilane precursor 260) of the residual core part 262 of the branch part 30 becomes the core layer 263, and the core layer 263 is formed with a thin thickness in the center part. Of course, the irradiation time of the ultraviolet laser beam 250 is selected so that the refractive index difference between the core layer 263 and the clad is 1 to 2%.

  On the other hand, if two identical partial masks 280 are prepared in advance and arranged on the upper surface side of the polysilane precursor 260 and the lower surface side of the substrate 80, the ultraviolet laser light 250 is irradiated from both above and below, as shown in FIG. Since the process and the process shown in FIG. 5C can be performed at the same time, the manufacturing time can be shortened, and mass production per hour can be expected.

  Next, as shown in FIG. 5D, the partial mask 290 is disposed on the polysilane precursor 260, and the residual core 261 of the incident portion 20 and the emission portion 40 is partially irradiated with the ultraviolet laser light 250. As a result, the refractive index on the upper side of the residual core 261 is lowered. In this case, as in the first embodiment, the refractive index on the upper side in the height direction of the residual core 261 decreases, but the change in the refractive index decreases toward the lower side and the refractive index of the residual core 261 on the lower side. Has not changed. As a result, a residual core 264 in which the upper side of the residual core 261 is clad is formed. At this time, an ultraviolet laser beam having a wavelength and intensity different from those in the case where the core layer 263 of the branch portion 30 is formed is set to a refractive index difference of 0.25 to 0.3%.

  Next, as shown in FIG. 5E, a partial mask 290 is disposed on the bottom surface side of the substrate 80, and the ultraviolet laser light 250 is irradiated from below the incident part 20 and the emission part 40. Then, the refractive index of the lower side (the substrate 80 side) of the residual core 264 in the height direction decreases, but the change in the refractive index decreases toward the upper side, and the refractive index on the upper side does not change. As a result, a gradient index optical waveguide is formed, and an optical waveguide having a small refractive index difference from the core is formed.

On the other hand, if two pieces of the same partial masks 270 and 290 are prepared in advance and appropriately arranged on the upper surface side of the polysilane precursor 260 and the lower surface side of the substrate 80, the ultraviolet laser beam 250 is irradiated from both above and below, as shown in FIG. b) Step and FIG. 5 (c) and FIG. 5 (d) and FIG. 5 (e) can be performed at the same time, so that the production time can be shortened and mass production per hour can be expected.
Finally, post baking is performed at about 200 to 360 ° C. for about 10 to 30 minutes. As a result, an optical waveguide can be manufactured by using a polysilane film containing a single photosensitizer.

  Next, a third embodiment of the optical waveguide manufacturing method according to the present invention will be described. As shown in FIG. 6, in the graded mask 300 used in the manufacturing method according to the present embodiment, the branch part 30 does not transmit ultraviolet light, and the incident part 20 and the output part 40 have ultraviolet light transmittance. It is formed to change in stages. Specifically, as shown in FIG. 7A, the graded mask 300 is formed so that the transmittance of ultraviolet rays changes in a range of 40% to 100% depending on the location. Of course, it may be changed stepwise in this way, or may be formed so as to change continuously between 0 and 100% as in the graded mask 300 shown in FIG. Then, the graded mask 300 formed in this way is arranged on the bottom surface of the substrate 80 in FIG. 4B and irradiated with the ultraviolet laser beam 250, and on the upper side of the polysilane precursor 220 in FIG. 4E. It arrange | positions and irradiates the ultraviolet laser beam 250. FIG. Thus, as best shown in FIG. 8, the optical waveguide 1 in which the core diameters of the incident portion optical waveguide 60 and the emission portion optical waveguide 70 are changed in a tapered shape along the light traveling direction is formed. Is possible. Further, by applying the graded mask 300 to the respective steps shown in FIGS. 5D and 5E, the core diameters of the optical waveguides of the entrance optical waveguide 60 and the exit optical waveguide 70 in FIG. It is possible to form an optical waveguide (see FIG. 8) that is changed in a tapered shape along the traveling direction of light.

FIG. 1 is a plan view showing a first embodiment of an optical waveguide according to the present invention. (A) is a conceptual diagram of the refractive index of the optical waveguide 1 shown in FIG. 1, and (b) is a power distribution of light propagating in the optical waveguide shown in (a) and an optical fiber optically connected to both sides thereof. FIG. It is a basic conceptual diagram for performing refractive index control in the optical waveguide manufacturing method according to the present invention. (A)-(e) is sectional explanatory drawing of the optical waveguide in each process of the manufacturing method of the optical waveguide in 1st Embodiment. (A)-(e) is sectional explanatory drawing of the optical waveguide in each process of the manufacturing method of the optical waveguide in 2nd Embodiment. (A), (b) is sectional explanatory drawing of the optical waveguide in each process of the manufacturing method of the optical waveguide in 3rd Embodiment. (A), (b) is explanatory sectional drawing of the mask formed so that the transmittance | permeability of an ultraviolet-ray may change in steps. FIG. 2 is an explanatory perspective view of the optical waveguide of FIG. 1. It is a top view which shows the conventional optical waveguide.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical waveguide 10 Polysilane film | membrane containing a photosensitizer 20 Incident part 30 Branching part 40 Outgoing part 50 Branching part optical waveguide 60 Incident part optical waveguide 70 Outgoing part optical waveguide 80 Substrate 90 Under clad layer 100 Core layer 110 Over clad layer 120 Optical Waveguide 190 Power distribution 191 Power distribution 192 Power distribution 193 Power distribution 194 Power distribution 200 Polysilane precursor 201 Covered portion 202 Cladding 210 Polysilane precursor 211 Polysilane optical waveguide core 220 Polysilane precursor 221 Core portion 222 Cladding portion 230 Mask 231 1 × 8 splitter Pattern 240 Mask 250 Ultraviolet laser beam 260 Polysilane precursor 261 Residual core portion 262 Residual core portion 263 Core layer 264 Residual core 270 1 × 8 splitter mask 280 Partial mask 290 Partial mask 300 graded mask

Claims (7)

A polysilane material containing a photosensitizer is coated on a substrate having ultraviolet transparency, and a mask having a predetermined pattern is disposed on the surface side or the surface side and the bottom surface side of this coating film, and the refractive index difference varies depending on the location. A method of manufacturing a refractive index control type optical waveguide characterized by irradiating ultraviolet laser light so as to generate In the manufacturing method of the optical waveguide according to claim 1,
Forming optical waveguides with different refractive indexes depending on locations by partially irradiating ultraviolet laser light from the surface side of the polysilane material containing the photosensitizer applied on the substrate and the bottom surface side of the substrate A method of manufacturing a refractive index control type optical waveguide characterized by the above. In the manufacturing method of the optical waveguide according to claim 1 or 2,
A method of manufacturing a refractive index control type optical waveguide, wherein the polysilane material containing a photosensitizer applied on the substrate is applied once. In the manufacturing method of an optical waveguide given in any 1 paragraph of Claims 1-3,
A method of manufacturing a refractive index control type optical waveguide, wherein single mode optical waveguides having different core diameters are formed in the same coating film. In the manufacturing method of the optical waveguide given in any 1 paragraph of Claims 1-4,
A method of manufacturing a refractive index control type optical waveguide, wherein the mask is formed so that the transmittance of the ultraviolet laser beam varies depending on the location, and the ultraviolet laser beam is irradiated using the mask. A refractive index control type optical waveguide, characterized in that a refractive index difference is different depending on a location by a polysilane material containing a photosensitizer. The optical waveguide according to claim 6, wherein
An incident part into which light is incident, a branch part that branches the incident light, and an emission part that emits the branched light are configured.
The core diameter located on the end side of the incident part and the emission part is formed larger than the core diameter of the branch part, and is formed in a tapered shape that gradually decreases toward the branch part side. Refractive index control type optical waveguide.

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