JP2001296438A - Photo-breaching waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photo-breaching waveguide having a uniform rectangular cross section shape and the uniform distribution of refractive index. SOLUTION: A core layer 3 having the uniform rectangular cross section shape and the uniform distribution of refractive index is provided by preparing ultraviolet ray absorbing layers 10-1, 10-2 having a ultraviolet ray absorbing function and a clad layer function on upper and rear surfaces of the core layer and side surface clad layers 4-1, 4-2 consisting of photo-breaching polymer. The ultraviolet ray absorbing layers 10-1, 10-2 are transparent and small in loss, the refractive index is controlled by the kind and an added quantity of added metallic oxide material, and an absorbing quantity of ultraviolet rays is controlled by the kind and an added quantity of metallic oxide material. Thus, the ultraviolet ray absorbing layers 10-1, 10-2 not only function as the light guiding clad layer of the waveguide, but also keep the shape and the refractive index of the polymer core layer uniform and keep stability for a long period of optical characteristics of the waveguide against the ultraviolet rays from the external part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photobleaching waveguide.

[0002]

2. Description of the Related Art As a waveguide using a polymer material for photobleaching, the present inventor has previously proposed a waveguide shown in FIG. 8 (see Japanese Patent Application Laid-Open No. 10-48443).

FIG. 8 is a sectional view of a waveguide on which the present invention is based.

This waveguide comprises a substrate 1, a lower refractive index lower cladding layer 2 formed on the substrate 1, and a higher refractive index higher than the lower cladding layer 2 and formed on the lower cladding layer 2. Core layer 3 made of a polymer layer for photobleaching with high refractive index, and side cladding layers 4-1 and 4- formed on both sides of the core layer 3 and made of a polymer layer for photobleaching having a lower refractive index than the core layer 3. 2, an upper clad layer 5 having a lower refractive index than the core layer 3 and formed on the core layer 3 and the side clad layers 4-1 and 4-2, and formed on the upper clad layer 5. And an ultraviolet light absorbing layer 6 for absorbing ultraviolet light.

[0005] The feature of this waveguide is that the core layer 3 having a substantially rectangular cross-sectional shape can be formed by a photography step and an ultraviolet light irradiation step without a dry etching step, so that the cost can be reduced by a simple process. And that the surface of the core layer 3 and the side cladding layers 4-1 and 4-2 are flat, so that unnecessary light scattering loss can be reduced.

[0006]

In the waveguide shown in FIG. 8, the core layer 3 and the side cladding layer 4-
It has been found that the following problems occur when the thickness of 1, 4-2 is large (> 8 μm) and when the reflectance of the ultraviolet light in the material of the substrate 1 is high. That is, it was found that the refractive index in the depth direction of the core layer 3 became non-uniform, and the shape of the core layer 3 in the depth direction became non-uniform.

Hereinafter, description will be made with reference to FIGS. 9 (a) to 9 (c).

FIG. 9 (a) is an explanatory view of a method of manufacturing the waveguide shown in FIG. 8, and FIGS. 9 (b) and 9 (c) show the method of manufacturing the waveguide shown in FIG.
It is sectional drawing of the waveguide layer at the time of using the method shown to (a).

[0009] As shown in FIG.
After a lower cladding layer 2 and a photobleaching polymer layer 3 are sequentially formed on a substrate 1, a photomask 7 having a desired pattern shape is arranged on the polymer layer 3, and ultraviolet light is irradiated from above the photomask 7. 8 is applied.
The photomask 7 includes a light transmitting area 7-1 and a light non-transmitting area 7
And the ultraviolet light 8 is irradiated onto the polymer layer 3 through the light transmission region 7-1.

The problem here is that when the thickness of the polymer layer 3 is large, the irradiation power of the ultraviolet light 8 must be increased or the irradiation time must be lengthened. Are reflected in the lower clad layer 2 through the polymer layer 3 or on the surface of the substrate 1 (reflected light of ultraviolet light is indicated by an arrow 9).

For this reason, the core layer 3 which should have a rectangular cross section and a uniform refractive index should have a non-uniform structure as shown in FIG. 9 (b) or 9 (c).
It was found that the refractive index distribution in the depth direction of the core layers 3-1 and 3-2 became non-uniform as well as 1, 3-2. That is, it was found that the reflected light 9 of the ultraviolet light 8 had an adverse effect.

Accordingly, an object of the present invention is to solve the above problems and to provide a photobleaching waveguide having a uniform rectangular cross-sectional shape and a uniform refractive index distribution.

[0013]

In order to achieve the above object, a photobleaching waveguide according to the present invention comprises an ultraviolet light absorbing layer for absorbing ultraviolet light, and a photobleaching layer formed on the ultraviolet light absorbing layer. A core layer having a substantially rectangular cross-sectional shape having a higher refractive index than the ultraviolet light absorbing layer and a refractive index higher than the ultraviolet light absorbing layer formed on both side surfaces of the core layer and having a lower refractive index than the core layer. It has a side cladding layer and another ultraviolet light absorbing layer formed on the core layer and the side cladding layer and having a lower refractive index than the side cladding layer.

In addition to the above structure, the photobleaching waveguide of the present invention may have an ultraviolet light absorbing layer formed on a substrate.

In addition to the above structure, the photobleaching waveguide of the present invention may use, as a substrate, a film made of a polymer material including an ultraviolet light absorbing layer.

In the photobleaching waveguide of the present invention, in addition to the above-described structure, the core layer is formed so as to keep at least two desired intervals, and even if side cladding layers are formed on both side surfaces of each core layer. Good.

In the photobleaching waveguide according to the present invention, in addition to the above structure, the ultraviolet light absorbing layer has a thickness of at least 2 μm.
m is preferred.

In the photobleaching waveguide according to the present invention, in addition to the above-described structure, the ultraviolet light absorbing layer may be formed by laminating at least two layers having different refractive indexes.

In addition to the above configuration, the photobleaching waveguide of the present invention may have an ultraviolet light absorbing layer formed on the light input end face and the light output end face of the core layer.

In addition to the above configuration, the photobleaching waveguide of the present invention may have an ultraviolet light absorbing layer having a different refractive index formed on the light input end face and the light output end face of the core layer.

In addition to the above configuration, in the photobleaching waveguide of the present invention, the light input end face and the light output end face of the core layer may be formed oblique to the optical axis.

In addition to the above configuration, the photobleaching waveguide of the present invention may be provided with at least one of an electronic circuit, an electronic component, and an optical component on the front surface, the back surface, or inside the substrate.

In addition to the above constitution, the photobleaching waveguide of the present invention comprises a core layer comprising another photobleaching polymer layer on the ultraviolet light absorbing layer formed on the core layer and the side cladding layer. At least one or more side cladding layers and ultraviolet light absorbing layers may be laminated.

According to the present invention, a uniform rectangular shape is provided by providing an ultraviolet light absorbing layer having an ultraviolet light absorbing function and a function of a cladding layer above and below a core layer and a side cladding layer made of a polymer for photobleaching. A core layer having a cross-sectional shape and a uniform refractive index distribution can be provided.

The ultraviolet light absorbing layer is transparent and has low loss, the refractive index can be controlled by the type and amount of the metal oxide material to be added, and the ultraviolet light absorption amount can be controlled by the type of the metal oxide material. It can be controlled by the amount added. For this reason, the ultraviolet light absorbing layer not only functions as a light guide cladding layer of the waveguide, but also functions to make the shape and the refractive index of the photobleaching polymer core layer uniform and to guide external ultraviolet light. And a function of maintaining long-term stability of optical characteristics (loss, refractive index distribution, wavelength characteristics, etc.) of the wave path.

As described above, a low-loss waveguide with low scattering loss can be realized. In addition, since the refractive index distribution on the light input / output end face side can be manufactured with high yield,
Variations in coupling loss characteristics with the optical fiber connected to the input / output end face can be reduced.

[0027]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the photobleaching waveguide of the present invention.

In FIG. 1, reference numeral 1 denotes a substrate, which is made of glass (quartz, multi-component), ceramics, semiconductor (Si,
GaAs, InP, etc.), plastics (polyimide, polyphenylene sulfide, polyester, Eval, polyvinylidene chloride, polypropylene, etc.), sapphire, LiNbO ₃ , LiTaO _{5 and the} like can be used.

The ultraviolet light absorbing layer 10-1 is formed on the substrate 1 with a thickness of at least several μm. This ultraviolet light absorbing layer 10-1 is made of an ultraviolet light (wavelength: 300 to 370n).
Those having sufficient light absorption characteristics for m) are used. For example, using a polymer material to which additives such as benzophenone-based, salicylate-based, and benzotriazole-based additives are added, the refractive index is adjusted by the base polymer material, and the wavelength band of ultraviolet light and its transmittance characteristics are mainly It is adjusted by the type and amount of the above additive.

As another material of the ultraviolet light absorbing layer 10-1, a material obtained by adding a metal oxide pigment such as titanium dioxide, zinc oxide or iron oxide to a polymer material can be used. In this case, the refractive index can be adjusted by the type and amount of the metal oxide material other than the polymer material, and the wavelength range of ultraviolet light and its transmittance characteristics are mainly determined by the amount of the metal oxide material added. Adjust. As an example, when a UV absorbing hard coat (trade name KP-851) manufactured by Shin-Etsu Chemical Co., Ltd. is used for the ultraviolet light absorbing layer, the wavelength is 300 to 370 nm.
In the band, the transmittance is 10% or less (when the film thickness is 1 μm)
Can be suppressed.

Therefore, when the thickness of the ultraviolet light absorbing layer 10-1 is set to 5 μm or more, the transmittance can be reduced to approximately 1% or less, that is, the ultraviolet light absorptivity of 90% or more can be realized. In order to form the ultraviolet light absorbing layer 10-1 having a thickness of 5 μm or more on the substrate 1, 3
It can be realized by recoating about once. The ultraviolet light absorbing layer 10-1 has a refractive index n _u (wavelength 0.63 μm
Is 1.424 and baking at 250 ° C. has a sufficient heat-resistant temperature.

A core layer 3 made of a polymer material for photobleaching and side cladding layers 4-1 and 4-2 are formed on the ultraviolet light absorbing layer 10-1. The refractive index n _{p of the} core layer 3 is set higher than the refractive index n _u of the ultraviolet light absorbing layer 10-1 and higher than the refractive index n _b of the side cladding layers 4-1 and 4-2. For this reason, the core layer 3 is not irradiated with ultraviolet light or is irradiated with a small amount.

The side cladding layer 4-
Since the refractive indices n _b of 1, 4-2 must be approximately the same as the refractive index n _u of the ultraviolet light absorbing layer 10-1, they are formed by sufficiently irradiating ultraviolet light.

Examples of the material for the polymer layer for photobleaching include polysilane, a silicone resin containing a nitrone compound, and polymethyl methacrylate containing DMAPN {(4-N, N-dimethylaminophenyl) -N-phenylnitrone}. , Dye polymer, and a polyimide resin or an epoxy resin containing a nitrone compound.

Here, when, for example, polysilane is used as the material of the ultraviolet light absorbing layer 101-, the refractive index can be adjusted to about 1.475 to 1.43 according to the irradiation amount of the ultraviolet light. This polysilane is first coated with hexamethyldisilazane on the ultraviolet light absorbing layer 10-1,
After baking at 20 ° C. for 30 minutes to make it hydrophobic, spin-coating with polysilane dissolved in toluene at a concentration of 10% by weight, baking at 120 ° C. for 30 minutes, and after baking, forming a desired pattern on the obtained film. The side cladding layers 4-1 and 4-2 whose refractive index has been reduced by arranging a drawn photomask and irradiating ultraviolet light from above the photomask, and the refractive index does not decrease or slightly decreases Core layer 3 obtained.

The core layer 3 and the side cladding layers 4-1 and 4-
The ultraviolet light absorbing layer 10-2 is formed on the substrate 2. The thickness of the core layer 3 and the side cladding layers 4-1 and 4-2 is preferably in the range of 10 μm to several tens μm for multi-mode transmission, and 2 μm to 10 μm for single mode transmission. A range of several μm is preferred. The relative refractive index difference between the refractive index n _p of the core layer 3 and the refractive index n _b of the side cladding layers 4-1 and 4-2 (or the refractive index n _u of the ultraviolet light absorbing layer 10-1) is 0.2. % To several%.

The core layer 3 and the side cladding layers 4-1 and 4-
By providing the ultraviolet light absorbing layer 10-1 under 2
UV light can be prevented from reaching the surface of the substrate 1 and the substrate 1
Of the core layer 3 and the side cladding layers 4-1 and 4-2, and the refractive index of the core layer 3 and the side cladding layers 4-1 and 4-2. The distribution can be made uniform. That is,
Problems such as those shown in FIGS. 9B and 9C can be avoided.

The thickness and the refractive index of the ultraviolet light absorbing layer 10-2 are selected to have the same values as those of the ultraviolet light absorbing layer 10-1. It should be noted that as the thickness of the ultraviolet light absorbing layers 10-1 and 10-2 increases, the ultraviolet light can be more strongly absorbed. Therefore, it is preferable to increase the thickness within the allowable range.

FIG. 2 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

The difference from the embodiment shown in FIG. 1 is that the substrate is removed.

That is, the present photobleaching waveguide is composed of an ultraviolet light absorbing layer 10-1 for absorbing ultraviolet light and a polymer layer for photobleaching formed on the ultraviolet light absorbing layer 10-1. A core layer 3 having a substantially rectangular cross section having a higher refractive index than the light absorbing layer 10-1; and a refractive index higher than the refractive index of the ultraviolet light absorbing layer 10-1 formed on both side surfaces of the core layer 3 and higher than the refractive index of the core layer 3. Low side cladding layer 4-
1, 4-2, core layer 3 and side cladding layers 4-1 and 4,
-2 and an ultraviolet light absorbing layer 10-2 formed on the substrate.

In this photobleaching waveguide, a polyimide resin, an acrylic resin, an epoxy resin, or the like is used as the polymer material for the ultraviolet light absorbing layer 10-1, and the benzophenone described above is used as the polymer resin. -Based, salicylate-based, benzotriazole-based additives or additives of metal oxide pigments such as titanium dioxide, zinc oxide, iron oxide, etc. can be used to realize thick plastic film waveguides. be able to.

FIG. 3 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

The difference from the embodiment shown in FIG. 1 is that a plurality of ultraviolet light absorbing layers are provided on the ultraviolet light absorbing layer 10-2 on the core layer 3 and the side cladding layers 4-1 and 4-2. 10-
3 and 10-4.

That is, the present waveguide comprises a substrate 1 and a substrate 1
An ultraviolet light absorbing layer 10 formed thereon for absorbing ultraviolet light
-1 and a photobleaching polymer layer formed on the ultraviolet light absorbing layer 10-1.
A core layer 3 having a substantially rectangular cross section having a refractive index higher than 0-1;
Side cladding layers 4-1 and 4-2 formed on both side surfaces of the core layer 3 and having a refractive index higher than the ultraviolet light absorbing layer 10-1 and lower than the refractive index of the core layer 3;
-1, UV light absorbing layer 10-2 formed on 4-2
And a plurality of (but not limited to two in the figure) ultraviolet light absorbing layers 1 formed on the ultraviolet light absorbing layer 10-2.
0-3 and 10-4.

These ultraviolet light absorbing layers 10-2, 10-
The film thicknesses and refractive indices of 3, 10-4 may be equal or different. For example, the thickness of the ultraviolet light absorbing layer 10-2 is small and the refractive index n _b2 is low, the thickness of the ultraviolet light absorbing layers 10-3 and 10-4 on the ultraviolet light absorbing layer 10-2 is large, and When the refractive indices n _b3 and n _b4 are higher than the refractive index n _b2 , the confinement of light in the core layer 3 can be enhanced.

FIG. 4 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

The difference from the embodiment shown in FIG. 1 is that the substrate 1 is removed and a plurality of ultraviolet light absorbing layers 10-
1, 10-2, 10-3, and 10-5 are stacked.

That is, the present photobleaching waveguide comprises an ultraviolet light absorbing layer 10-1 for absorbing ultraviolet light, an ultraviolet light absorbing layer 10-5 formed on the ultraviolet light absorbing layer 10-1, and an ultraviolet light absorbing layer 10-5. The photo-bleaching polymer layer is formed on the light-absorbing layer.
And a side cladding layer 4 formed on both sides of the core layer 3 and having a refractive index higher than the refractive index of the ultraviolet light absorbing layer 10-5 and lower than the refractive index of the core layer 3. -1, 4-2, core layer 3 and side cladding layer 4-
A plurality (two, but not limited to, two layers in the figure) of the ultraviolet light absorbing layers 10-2 and 10-3 laminated on the first and the fourth 4-2.
It is composed of

In this photobleaching waveguide, the mode field diameter can be adjusted by varying the thickness and refractive index of the ultraviolet light absorbing layers 10-1, 10-2, 10-3, and 10-5. An optical fiber (not shown) connected to the end face of the waveguide to adjust the power distribution of the propagating light.
Or the coupling loss characteristic of the coupling can be adjusted. In particular, the confinement of light in the core layer 3 is enhanced by making the refractive index of the ultraviolet light absorbing layers 10-2 and 10-5 sufficiently lower than the refractive index of the ultraviolet light absorbing layers 10-1 and 10-3. can do.

FIG. 5A is a side view showing another embodiment of the photobleaching waveguide of the present invention.
5B is a top view of FIG. 5A, and FIG.
FIG. 3B is a sectional view taken along line AA of FIG.

The features of this photobleaching waveguide are that a plurality of (six) core layers are arranged in an array, that the light input / output end face is formed obliquely, and that the input / output end face has ultraviolet rays. The point is that the light absorption layers 11a and 11b are formed.

That is, the present photobleaching waveguide comprises an ultraviolet light absorbing layer 10-1 and an ultraviolet light absorbing layer 10-.
1 formed of a polymer layer for photobleaching and having a substantially rectangular cross-sectional shape having a higher refractive index than the ultraviolet light absorbing layer 10-1 (the number is not limited to six in the figure).
Core layers 3-1 to 3-6, and the respective core layers 3-1 to 3-3
-6, side cladding layers 4-1 to 4-7, which are formed on both side surfaces of -6 and are higher than the refractive index of the ultraviolet light absorbing layer 10-1 and lower than the refractive indexes of the core layers 3-1 to 3-6. -1 to 3-6
And a laminated body composed of the ultraviolet light absorbing layer 10-2 formed on the side clad layers 4-1 to 4-7, and both end faces of all the core layers 3-1 to 3-6 of the laminated body. The laminated body is formed in a substantially trapezoidal shape so as to be exposed on the slope, and is constituted by ultraviolet light absorbing layers 11a and 11b formed on both slopes.

In this photobleaching waveguide, when light is incident from below the ultraviolet light absorbing layer 10-1 into, for example, the core layer 3-4 in the direction of arrow 12a, the light is reflected by the ultraviolet light absorbing layer 11a. Thus, the light can propagate through the core layer 3-4 in the direction of arrow 12b, be reflected by the ultraviolet light absorbing layer 11b, and be emitted in the direction of arrow 12c. The other core layer 3
Light can be similarly propagated in -1 to 3-3, 3-5 and 3-6. Incidentally, the ultraviolet light absorbing layers 11a, 1
The input / output end face on which 1b is formed has angles θ1 and θ2 of approximately 45
It is processed diagonally so that it becomes °.

FIG. 6A is a side view showing another embodiment of the photobleaching waveguide of the present invention.
FIG. 6B is a top view of FIG. 6A, and FIG.
It is a BB sectional view taken on the line of (b).

In the present photobleaching waveguide, multilayer (though not limited in the figure, three layers) ultraviolet light absorbing layers 11c and 11d are formed on the light input / output end faces, and a plurality of (6) light absorbing layers are formed.
Core layers 3-1 to 3-6 are arranged in an array, and the inclination angle θ3 of the input / output end face is set in a range of 2 to 8 °.

That is, the present photobleaching waveguide comprises an ultraviolet light absorbing layer 10-1 and an ultraviolet light absorbing layer 10-
1 formed of a polymer layer for photobleaching and having a substantially rectangular cross-sectional shape having a higher refractive index than the ultraviolet light absorbing layer 10-1 (the number is not limited to six in the figure).
Core layers 3-1 to 3-6 and core layers 3-1 to 3-
6, side cladding layers 4-1 to 4-7 higher than the refractive index of the ultraviolet light absorbing layer 10-1 and lower than the refractive indexes of the core layers 3-1 to 3-6. And a laminated body composed of an ultraviolet light absorbing layer 10-2 formed on the side cladding layers 4-1 to 4-7 and all the core layers 3-1 to 3- of the laminated body. 6 is formed of a multilayered ultraviolet light absorbing layer 11c and 11d on both slopes of the laminate formed in a substantially trapezoidal shape so that both end faces are exposed to the slope, and the inclination angles θ3 and θ4 are 2 to 8 ° is set.

The photo-bleaching waveguide has an optical signal from the side of the ultraviolet light absorbing layer 11c on the light input end face to the arrow 12
The light is incident in the direction d, propagates in the core layer (for example, the core layer 3-4) in the direction of arrow 12e, and is output in the direction of arrow 12f from the ultraviolet light absorbing layer 11d side of the light output end face.

FIG. 7 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

The difference from the embodiment shown in FIG. 1 is that a plurality of waveguide layers are stacked.

The photobleaching waveguide is provided on the substrate 1
And an ultraviolet light absorbing layer 10-1 formed on the substrate 1 and absorbing ultraviolet light, and a polymer layer for photobleaching formed on the ultraviolet light absorbing layer 10-1. 2 having a substantially rectangular cross section having a refractive index higher than -1
(The number of core layers is not limited) core layers 3a-1, 3a-
2 and higher than the refractive index of the ultraviolet light absorbing layer 10-1 formed on both side surfaces of the core layers 3a-1 and 3a-2.
Side cladding layer 4a- having a lower refractive index than 1, 3a-2
1, 4a-2, 4a-3 and core layers 3a-1, 3a-2
And an ultraviolet light absorbing layer 10-2 formed on the side cladding layers 4a-1, 4a-2 and 4a-3, and a polymer layer for photobleaching formed on the ultraviolet light absorbing layer 10-2. The core layer 3b has a substantially rectangular cross-sectional shape (the number is not limited) having a higher refractive index than the ultraviolet light absorbing layer 10-2, and the refractive index of the ultraviolet light absorbing layer formed on both side surfaces of the core layer 3b. Side cladding layers 4b-1 and 4b-2, which are higher and lower than the refractive index of the core layer 3b, and an ultraviolet light absorbing layer 10-6 formed on the core layer 3b and the side cladding layers 4b-1 and 4b-2. It is composed of

The ultraviolet light absorbing layer 10-1 and the core layer 3
a-1, 3a-2, side cladding layers 4a-1, 4a-
2, 4a-3 and the ultraviolet light absorbing layer 10-2 constitute a first waveguide layer 13a, and the ultraviolet light absorbing layer 10-2, the core layer 3b, the side cladding layers 4b-1, 4b-2, and the ultraviolet light The absorption layer 10-6 forms the second waveguide layer 13b.

Also in such a photobleaching waveguide, it is possible to realize provision of a photobleaching waveguide having a uniform rectangular cross-sectional shape and a uniform refractive index distribution.

In the present photobleaching waveguide, the waveguide layers 13a and 13b have a two-layer structure. However, the present invention is not limited to this, and there are many waveguide layers such as three layers, four layers,. It may be configured as a layer. 1 to 7, each core layer is formed of a linear pattern, a curved pattern, or the like, and includes an optical directional coupling circuit, an optical ring resonance circuit,
Optical signal processing circuits such as an optical star coupler, an optical multiplexing / demultiplexing circuit, an optical filter circuit, an optical array type waveguide grating circuit, and an optical grating filter circuit may be formed.

FIGS. 5A to 5C and FIGS.
In (c), if an ultraviolet light absorbing layer is also provided on the light input / output end face, it is possible to prevent external ultraviolet light from entering from the end face and disturbing the shape and refractive index distribution of the end face. Further, like the photobleaching waveguides shown in FIGS. 5A to 5C, the ultraviolet light absorbing layer provided on the light input / output end face has a function of efficiently entering an optical signal. As in the photobleaching waveguides shown in FIGS. 6A to 6C, the multilayer ultraviolet light absorbing layer provided on the light input / output end face has a function of suppressing unnecessary reflected light on the light input / output end face. Having.

In FIGS. 1, 3 and 7, an electronic circuit (transistor, diode, resistance, capacitance, inductance, electric wiring, etc.), an electronic component (same as above) ) And an optical / electronic hybrid circuit provided with at least one of optical components (laser, light receiving element, lens, filter, attenuator, etc.). Such a mixed optical / electronic circuit,
It is suitable when a semiconductor substrate such as Si, GaAs, InP or the like is used as the substrate, or when a printed substrate is used.

As described above, according to the present invention, (1) it is possible to realize a core layer having a uniform rectangular cross-sectional shape and a uniform refractive index distribution even if the thickness of the core layer and the side cladding layer is large. it can.

(2) The interface between the core layer and the side cladding layer can be made uniform, and a photobleaching waveguide with low scattering loss can be realized. Further, the coupling with the optical fiber connected to the light input / output end face side is facilitated, and a photobleaching waveguide having a good yield of characteristics can be realized.

(3) Since the core layer and the side cladding layer are sandwiched between the ultraviolet light absorbing layers, the penetration of ultraviolet light from the outside into the core layer and the side cladding layer can be prevented. Further, since the ultraviolet light absorbing layers above and below the waveguide layer also function as cladding layers, there is no need to separately form the cladding layers.

(4) Since an ultraviolet light absorbing layer is previously formed on the substrate, the substrate is exposed to ultraviolet light (300 to 380 nm).
m) may be formed using a material that reflects the light.

(5) The ultraviolet light absorbing layer used as the cladding layer may have the same thickness and the same refractive index or may have different refractive indices. Since the mode field diameter and the optical power distribution can be easily adjusted, the degree of freedom in design can be increased. Further, by forming the ultraviolet light absorbing layer in a multilayer shape, deterioration of optical characteristics due to irradiation of ultraviolet light from the outside can be suppressed, and a stable waveguide can be realized for a long time.

(6) By forming an ultraviolet light absorbing layer also on the light input / output end face, it is possible to stabilize the long-term optical characteristics and to suppress unnecessary reflected light from the end face. Further, the connectivity of optical signals can be improved.

(7) Since a waveguide layer having a circuit for transmitting light and processing an optical signal can be laminated in multiple layers and has a simple structure, a high-density optical mounting circuit can be realized. It can be realized at low cost.

[0075]

In summary, according to the present invention, the following excellent effects are exhibited.

The provision of a photobleaching waveguide having a uniform rectangular cross-sectional shape and a uniform refractive index distribution can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a photobleaching waveguide of the present invention.

FIG. 2 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

FIG. 3 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

FIG. 4 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

5A is a side view showing another embodiment of the photobleaching waveguide of the present invention, FIG. 5B is a top view of FIG. 5A, and FIG. 5C is a top view of FIG. FIG. 3 is a sectional view taken along line AA.

6A is a side view showing another embodiment of the photobleaching waveguide according to the present invention, FIG. 6B is a top view of FIG. 6A, and FIG. 6C is a top view of FIG. It is BB sectional drawing.

FIG. 7 is a sectional view showing another embodiment of the photobleaching waveguide of the present invention.

FIG. 8 is a sectional view of a waveguide on which the present invention is based.

9A is an explanatory diagram of a method of manufacturing the waveguide shown in FIG. 8, and FIGS. 9B and 9C are cross-sectional views of the waveguide layer when the method shown in FIG. It is.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 3 Core layer 4-1 and 4-2 Side cladding layer 10-1, 10-2 Ultraviolet light absorption layer

Claims (11)

[Claims] 1. An ultraviolet light absorbing layer for absorbing ultraviolet light,
A core layer having a substantially rectangular cross-sectional shape formed on the ultraviolet light absorbing layer and comprising a polymer layer for photobleaching and having a higher refractive index than the ultraviolet light absorbing layer; and the ultraviolet light formed on both side surfaces of the core layer. A side cladding layer having a higher refractive index than the light absorbing layer and a lower refractive index than the core layer; and another ultraviolet light absorbing layer formed on the core layer and the side cladding layer and having a lower refractive index than the side cladding layer. And a photobleaching waveguide. 2. The photobleaching waveguide according to claim 1, wherein said ultraviolet light absorbing layer is formed on a substrate. 3. The photobleaching waveguide according to claim 2, wherein a film made of a polymer material including an ultraviolet light absorbing layer is used as said substrate. 4. The photo-sensor according to claim 1, wherein the core layers are formed with at least two desired intervals, and side cladding layers are formed on both side surfaces of each core layer. Bleaching waveguide. 5. The photobleaching waveguide according to claim 1, wherein the thickness of the ultraviolet light absorbing layer is at least 2 μm. 6. The photobleaching waveguide according to claim 1, wherein said ultraviolet light absorbing layer has at least two layers having different refractive indices laminated. 7. The photobleaching waveguide according to claim 1, wherein an ultraviolet light absorbing layer is formed on the light input end face and the light output end face of the core layer. 8. The photobleaching waveguide according to claim 7, wherein an ultraviolet light absorbing layer having a different refractive index is formed on the light input end face and the light output end face of the core layer. 9. The photobleaching waveguide according to claim 1, wherein the light input end face and the light output end face of the core layer are formed obliquely with respect to an optical axis. 10. The photobleaching waveguide according to claim 1, wherein at least one of an electronic circuit, an electronic component, and an optical component is provided on a front surface, a back surface, or inside the substrate. 11. An ultraviolet light absorbing layer formed on the core layer and the side cladding layer, at least a core layer, a side cladding layer, and an ultraviolet light absorbing layer made of another photobleaching polymer layer. The photobleaching waveguide according to any one of claims 1 to 10, wherein one or more layers are stacked.