WO2019082347A1 - Light guide device, optical waveguide device, multi-wavelength light source module, and method for manufacturing optical waveguide device - Google Patents

Abstract

This optical waveguide device is provided with: a substrate; an optical waveguide path which is provided on the substrate, has an incidence opening and an emission opening for the light, and guides light from the incidence opening to the emission opening; a first clad layer which is disposed between the optical waveguide path and the substrate, is in contact with the optical waveguide path, and has a smaller refractive index than the optical waveguide path; and a second clad layer which is provided on the opposite side of the first clad layer on the optical waveguide path, is in contact with the optical waveguide path, and has a smaller refractive index than the optical waveguide path. The optical waveguide path extends and is composed of the same material from the incidence opening to the emission opening. In at least a portion of the optical waveguide path, the surface of the optical waveguide path on at least one side in the width direction of the optical waveguide path is in contact with air.

Description

Light guide device, optical waveguide device, multi-wavelength light source module, and method of manufacturing optical waveguide device

The present invention relates to a light guide device for emitting incident light, an optical waveguide device, a multi-wavelength light source module using the light guide device or the optical waveguide device, and a method of manufacturing the optical waveguide device.

Conventionally, laser light of a plurality of wavelengths, such as a projector that emits laser light of three primary colors RGB to display a color image, and a diagnostic device that performs sensing using visible light and infrared light (IR light), is used. There are various devices. In these devices, usually, laser light of a plurality of wavelengths is separately emitted from a laser light source generating light of each wavelength, and is multiplexed using an optical multiplexer (multiplexer) to form a single beam It is output. At this time, an optical waveguide is used to guide the incident light to a position where it is combined and to emit the combined light.

For example, as a light guide, PLC (Planar Lightwave Circuit) using glass material (silicon) as a hollow light guide or a medium, etc. are mentioned. The PLC can be formed, for example, using a known semiconductor manufacturing process on a silicon substrate. In such an optical waveguide, there is known a technique in which a mirror member such as aluminum is provided in a deflection part in which the direction of the optical waveguide changes so that the incident laser light is totally reflected (Patent Document 1).

JP 2017-129744 A

In the above configuration, it is necessary to provide a mirror surface member at the bent portion, which complicates the device configuration and complicates the manufacturing process. In addition, there is also a case where the laser beam does not necessarily totally reflect and a part leaks from the bent portion.

Therefore, according to the present invention, when emitting incident light with a new configuration different from the above configuration, even if there is a deflecting unit in which the direction of the path changes in the light route, the light leaks in the deflecting unit. An object of the present invention is to provide a method of manufacturing a light guiding device, an optical waveguide device, and an optical waveguide device that can be suppressed.

One embodiment of the present invention is a light guide device that emits incident light. The light guiding device is
With a glass substrate,
It is provided on the glass substrate, has an entrance and an exit for the light, is composed of a single material from the entrance to the exit, and is exposed to an external atmosphere surrounding the light guide, A fiber for guiding light from an entrance to the exit;
An adhesive layer made of an adhesive interposed between a part of the fiber and the glass substrate is provided to fix the entrance and the exit of the fiber at a designated position of the glass substrate. .
When the refractive index of the fiber, the refractive index of the adhesive, and the refractive index of the glass substrate are n1, n2 and n3, respectively, n1> n2 and n1> n3 are satisfied.
The outer diameter of the fiber is, for example, 10 μm or less, and preferably 3 to 5 μm.

The fiber has, in a cut surface of the fiber, two first regions in contact with the adhesive layer, and a second region in contact with the glass substrate and not in contact with the glass substrate. ,
It is preferable that parts other than the said 1st area | region and the said 2nd area | region are in contact with the said external atmosphere.

As the fibers, first and second fibers for guiding two lights are provided on the glass substrate,
The separation distance Δ between the center of the light outlet of the first fiber and the center of the light outlet of the second fiber is the center of the light entrance of the first fiber and the light of the second fiber At least one of the first fiber and the second fiber is curved so as to approach each other as it goes to the exit so that the distance La between the center of the entrance and the center of the entrance is not more than 1/100
When the separation distance between the entrance and exit of the first fiber or the separation between the entrance and exit of the second fiber is Lb, the distance between the separation La and the separation Lb is The ratio Lb / La is preferably 1.0 or less.
In addition, the separation distance Δ between the center of the light emission port of the first fiber and the center of the light emission port of the second fiber is 1 times the outer diameter of the first fiber and the second fiber. It is preferable to make the distance larger by 1.5 times or less. When the outer diameter of the first fiber and the second fiber is, for example, 5 μm, the separation distance Δ can be 5 μm to 7.5 μm.
In the light guiding device, at least three of the fibers are provided on the glass substrate, and the three fibers are brought close to each other so that light beams emitted from the respective light emission ports overlap to form substantially one light beam. Is preferred.

Another aspect of the present invention is an optical waveguide device for emitting incident light. The optical waveguide device is
A substrate,
An optical waveguide provided on the substrate, having an entrance and an exit for the light, and guiding the light from the entrance to the exit;
A first cladding layer stacked between the optical waveguide and the substrate and in contact with the optical waveguide, the first cladding layer having a smaller refractive index than the refractive index of the optical waveguide;
A second cladding layer in contact with the optical waveguide and having a smaller refractive index than the refractive index of the optical waveguide is provided on the side opposite to the first cladding layer with respect to the optical waveguide.
The optical waveguide extends continuously with the same material from the entrance to the exit,
In at least a part of the optical waveguide, the surface of the optical waveguide on at least one side in the width direction of the optical waveguide parallel to the surface of the substrate and orthogonal to the extension direction of the optical waveguide uses air as a cladding element It is in contact with the air clad layer.

And a third cladding layer in contact with the optical waveguide on one side in the width direction and having a smaller refractive index than the refractive index of the optical waveguide,
The optical waveguide device according to claim 4, wherein the optical waveguide has a portion that is in continuous contact with the first cladding layer, the second cladding layer, and the third cladding layer.

It is preferable that the portion is provided in a linear portion extending in a straight line of the optical waveguide.

The optical waveguide includes a corner portion that bends the traveling direction of light on the substrate,
It is preferable that the optical waveguide is in contact with the third cladding layer inside the corner at the corner portion and is in contact with the air cladding layer outside the corner.

It is preferable that the side surface outside the corner of the light guide is a flat surface.

The optical waveguide device includes, as the optical waveguide, a first optical waveguide and a second optical waveguide for guiding two lights,
The first optical waveguide and the second optical waveguide have different entrances, respectively.
The optical waveguide device includes a junction where the first optical waveguide and the second optical waveguide merge with each other on the substrate, and a common exit of the first optical waveguide and the second optical waveguide. Is preferred.

It is preferable that an inclination angle between the first optical waveguide and the second optical waveguide at the junction is 5 degrees or less. The inclination angle is more preferably 2 degrees or less, and particularly preferably 1 degree or less.

The optical waveguide device includes, as the optical waveguide, at least a first optical waveguide that guides at least three lights, a second optical waveguide, and a third optical waveguide.
The first optical waveguide, the second optical waveguide, and the third optical waveguide have different entrances, respectively.
The optical waveguide device includes a joining portion where the first optical waveguide, the second optical waveguide, and the third optical waveguide join together on the substrate, the first optical waveguide, the second optical waveguide, and the optical waveguide device. It is preferable to have a common exit of the third optical waveguide.

The entrances of the first optical waveguide, the second optical waveguide, and the third optical waveguide are respectively provided along the first side of the substrate,
The emission ports of the first optical waveguide, the second optical waveguide, and the third optical waveguide are provided along the second side facing the same direction as the incident port and facing the first side.
At least each of the second optical waveguide and the third optical waveguide among the first optical waveguide, the second optical waveguide, and the third optical waveguide has a corner portion that bends the traveling direction of the light on the substrate. Two widthwise side walls provided at two places and provided with the corner part are in contact with the third cladding layer inside the corner in the corner part and in contact with the air clad layer outside the corner,
The side wall outside the corner is composed of a plane,
It is preferable that the merging portion be located on the side of the exit with respect to the location of the corner portion of each of the second optical waveguide and the third optical waveguide.

A separation distance between the entrance of the first optical waveguide, the second optical waveguide, and the entrance of the third optical waveguide and the exit along the direction of the entrance is L, and the first optical waveguide is The ratio L / D is preferably 3.0 or less when the center-to-center distance D between adjacent entrances among the entrances of the second optical waveguide and the third optical waveguide is set to D. . The ratio L / D can be, for example, up to 1.0 or less.

The first optical waveguide linearly extends from the entrance of the first optical waveguide to the exit.
Each of the second optical waveguide and the third optical waveguide, as a path, extends from the entrance of each of the second optical waveguide and the third optical waveguide and extends parallel to the first optical waveguide. A straight portion; a first corner portion for deflecting light passing through the first straight portion toward the first optical waveguide; and light passing through the first corner portion approaching the first optical waveguide A second straight portion guiding light to be guided, a second corner portion deflecting light passing through the second straight portion toward the merging portion, and the merging portion light passing through the second corner portion And a third straight portion for guiding light to reach the distance.

In the merging portion, the second optical waveguide and the third optical waveguide merge from a direction inclined with respect to the first optical waveguide,
It is preferable that the inclination angles of the second optical waveguide and the third optical waveguide with respect to the first optical waveguide at the merging portion be 5 degrees or less. The inclination angle is more preferably 2 degrees or less, and particularly preferably 1 degree or less.

Yet another aspect of the present invention is a method of manufacturing an optical waveguide device having a lower cladding layer, an optical waveguide, and an upper cladding layer. The manufacturing method is
A laminated structure in which a lower cladding film serving as the element of the lower cladding layer, a waveguide film serving as the element of the optical waveguide, and an upper cladding film serving as the element of the upper cladding layer are sequentially stacked from the surface side of the substrate. Forming steps,
Forming the optical waveguide with the side surfaces on both sides exposed to the outside by etching so that the side surface of the waveguide film is exposed using the first resist mask in the outermost layer of the laminated structure .

Yet another aspect of the present invention is a method of manufacturing an optical waveguide device having a lower cladding layer, an optical waveguide, and an upper cladding layer. The manufacturing method is
Forming a laminated structure in which a lower cladding film serving as the element of at least the lower cladding layer from the surface side of the substrate and a waveguide film serving as the element of the optical waveguide are sequentially laminated;
Forming the waveguide film in which a portion of the waveguide film is left over the lower cladding film by etching the waveguide film on the outermost layer of the laminated structure using a second resist mask; ,
Forming an upper cladding film serving as the element of the upper cladding layer on the outermost surface of the etched layered structure;
Using the third resist mask having a pattern in which a portion of the remaining waveguide film does not overlap with a portion of the remaining waveguide film on the outermost layer of the stacked structure in which the upper cladding film is formed, the upper cladding film and the above Forming the optical waveguide having a configuration in which one side surface of the optical waveguide is exposed to the outside and the other side is in contact with the upper cladding layer by etching a part of the remaining waveguide film. .

Yet another aspect of the present invention is a method of manufacturing an optical waveguide device having a lower cladding layer, an optical waveguide, and an upper cladding layer. The manufacturing method is
Forming a laminated structure in which a lower cladding film serving as the element of at least the lower cladding layer from the surface side of the substrate and a waveguide film serving as the element of the optical waveguide are sequentially laminated;
A part of the waveguide film is left on the upper layer of the lower cladding film by etching the waveguide film using the second resist mask in the outermost layer of the laminated structure, and the remaining waveguide film Forming a shape of a waveguide film such that the shape comprises two straight portions and a corner portion sandwiched between the straight portions when the shape is viewed from above the substrate;
Forming an upper cladding film serving as the element of the upper cladding layer on the outermost surface of the etched layered structure;
Using the fourth resist mask having a pattern in which a part of the place outside the corner of the corner portion does not overlap with the outermost surface of the laminated structure on which the upper cladding film is formed, the above-mentioned film being a part of the waveguide film Forming an inclined surface inclined with respect to the straight portion on the side surface outside the corner by etching the portion outside the corner.

The inclination angle of the inclined surface with respect to the linear portion is preferably in the range of 45 degrees ± 3 degrees, and can be, for example, 41.5 degrees or more.

Yet another aspect of the present invention is a multi-wavelength light source module. The multi-wavelength light source module is
As the fibers, first to n-th fibers (where n is a natural number of 2 or more) for guiding a plurality of light beams having different wavelengths from the entrance to the exit are provided on the glass substrate. the light guiding device, wherein the n fibers have a configuration in which the light emitting ports approach each other so that the light combined from the light emitting port is emitted;
A plurality of laser light sources for emitting the plurality of lights fixed to the glass substrate such that each of the plurality of lights is incident on the entrance of each of the first fiber to the n-th fiber; Prepare.

Yet another aspect of the present invention is also a multi-wavelength light source module. The multi-wavelength light source module is
The optical waveguide device;
And a plurality of laser light sources for emitting the plurality of lights fixed to the substrate such that each of the plurality of lights having different wavelengths is incident on the entrance of each of the optical waveguides.

The laser light source in the multi-wavelength light source module emits visible light such as RGB three primary colors or non-visible light such as near-infrared light as the plurality of lights.

According to the optical waveguide device, the optical waveguide device, and the multi-wavelength light source module described above, when emitting incident light, even if there is a deflecting unit in which the direction of the path changes in the light path, Leakage can be suppressed. According to the above-described method of manufacturing an optical waveguide device, such an optical waveguide device can be easily manufactured.

(A) is a top view of the light guide device of one embodiment, (b) is an arrow sectional view of A-A 'of the light guide device shown in (a). (A) is a figure which shows an example of the cross section of the optical waveguide apparatus in other one Embodiment, (b) is a figure which shows an example of the laminated structure in the middle of preparation of the optical waveguide apparatus shown to (a). is there. It is a top view which shows another example of the path | route of the optical waveguide in the optical waveguide apparatus of one Embodiment. (A) is a figure which shows an example of the cross section of the optical waveguide apparatus in other one Embodiment, (b), (c) is an example of the laminated structure in the middle of preparation of the optical waveguide apparatus shown to (a). FIG. It is a top view explaining the arrangement | positioning of the optical waveguide in the optical waveguide apparatus of one Embodiment. It is a figure which shows an example of the laminated structure obtained in the middle of preparation of the optical waveguide apparatus of one Embodiment. (A) to (e) are diagrams illustrating an example of the configuration of a laminated structure obtained by the process of the method of manufacturing an optical waveguide device according to an embodiment. It is a top view explaining the arrangement | positioning of the optical waveguide in the optical waveguide apparatus of other one Embodiment.

Hereinafter, the light guide device, the optical waveguide device, the multi-wavelength light source module, and the method of manufacturing the optical waveguide device of the present invention will be described in detail with reference to the attached drawings.

Fig.1 (a) is a top view of the light guide device 10 of one Embodiment, FIG.1 (b) is arrow sectional drawing of AA 'of the light guide device 10 shown to Fig.1 (a). is there.
The light guide device 10 is a device that emits incident light. The light guide device 10 includes a glass substrate 12, three fibers 14a, 14b and 14c, and adhesive layers 16a, 16b and 16c. The light guiding device 10 shown in FIG. 1A is three fibers 14a, 14b and 14c, but in another embodiment, the number of fibers may be one, two, four or the like.

Each of the three fibers 14a, 14b, 14c is provided on the glass substrate 10, and has entrances 18a, 18b, 18c and exits 20a, 20b, 20c for light emitted from three laser light sources (laser diodes). . Here, the entrances 18a, 18b, and 18c are provided on one side of the glass substrate 12, precisely aligned with the position of the light emission point of the laser light source (laser diode), and disposed at a constant interval. There is. That is, the entrances 18a, 18b, and 18c are fixed at predetermined positions of the glass substrate 12 in precise alignment with the arrangement positions of the respective laser light sources (laser diodes). Laser light sources 22a, 22b and 22c for emitting light incident on the respective entrances 18a, 18b and 18c are provided near the respective entrances 18a, 18b and 18c. Each of the three fibers 14a, 14b, and 14c is a fiber without cladding, for example, a fiber with an outer diameter of 3 μm to 5 μm from the entrances 18a, 18b, and 18c to the exit 20a, 20b, and 20c. , 18b, 18c lead to the exit 20a, 20b, 20c. That is, each of the fibers 14a, 14b and 14c is made of a single material from 18a, 18b and 18c to the exit ports 20a, 20b and 20c, and the external atmosphere (air, water, gas, It has a function of being exposed to the liquid and guiding light from the entrances 18a, 18b, 18c to the exits 20a, 20b, 20c. Hereinafter, the fibers 14a, 14b and 14c are also referred to as cores 14a, 14b and 14c.

The adhesive layers 16a, 16b and 16c are between the glass substrate 12 and a part of the fibers 14a, 14b and 14c so that the entrances of the fibers 14a, 14b and 14c can be accurately positioned on the glass substrate 12 with high accuracy. It consists of an intervening adhesive. The adhesive layers 16a, 16b and 16c are used to fix the entrance and exit of the fibers 14a, 14b and 14c at the designated positions of the glass substrate 12, ie, the positions corresponding to the arrangement positions of the three laser light sources. Be

Such a light guiding device 10 has the refractive indices of the fibers 14a, 14b and 14c, the refractive index of the adhesive of the adhesive layers 16a, 16b and 16c, and the refractive index of the glass substrate 12 as n1, n2 and n3, respectively. When n1> n2 and n1> n3 are satisfied. Further, according to one embodiment, (n1 ^2- n2 ² ) ^(1/2) and (n1 ^2- n3 ² ) ^(1/2) satisfy the condition of more than 0.1 and less than 0.15. By setting n1> n2 and n1> n3, total reflection can be achieved at the interface between the fibers 14a, 14b and 14c and the adhesive in contact with the fibers 14a, 14b and 14c and the glass substrate 12.
According to one embodiment, the refractive index n1 of the fibers 14a, 14b, 14c is in the range of 1.5 to 1.9, the refractive index n2 of the adhesive is in the range of 1.3 to 1.5, It is preferable that a material capable of combining numerical values of n1, n2 and n3 be selected in this range, where the range of the refractive index n3 of is 1.4 to 1.9. In particular, by setting n1 to 1.6 or more, the values of n2 and n3 can be easily selected as appropriate.

According to one embodiment, the fibers 14a, 14b, 14c contact the adhesive layers 16a, 16b, 16c in the first cut of the fibers 14a, 14b, 14c, as shown in FIG. 1 (b). It is arranged to have a region 24 and a second region 26 in contact with the glass substrate 12 sandwiched by two first regions 24, and the portions other than the first region 24 and the second region 26 have an external atmosphere. For example, it is preferable to be in contact with air. In the second region 26, the fibers 14a, 14b, and 14c may not be in contact with the glass substrate 12. The fibers 14a, 14b, 14c come into contact with the glass substrate 12 between the two first regions 24 in contact with the adhesive layers 16a, 16b, 16c, thereby stabilizing the circular fibers 14a, 14b, 14c into a glass. It can be fixed to the substrate 12. Further, since the portions other than the first region 24 and the second region 26 of the fibers 14a, 14b, 14c are in contact with the external atmosphere, for example air, there is a path along the glass surface of the fibers 14a, 14b, 14c in particular. Even when bent at a large angle, the side surfaces of the fibers 14a, 14b, 14c (surfaces parallel to the glass surfaces of the fibers 14a, 14b, 14c and orthogonal to the extending direction of the fibers 14a, 14b, 14c) contact air. Therefore, much of the light propagating in the fibers 14a, 14b and 14c is completely reflected. Therefore, there is almost no light leakage. In the cross sections of the fibers 14a, 14b, 14c, the length of the arc contacting the fibers 14a, 14b, 14c with air is preferably 75% to 95% of the entire circumference. As a result, while the fibers 14a, 14b, 14c are stably fixed to the glass substrate 12, the light leakage is suppressed in the deflection parts even if the fibers 14a, 14b, 14c have the deflection part in which the direction changes. be able to.

As shown in FIG. 1 (a), the fibers 14a, 14b, 14c have a form without the clad layer of the optical fiber cable, so the diameter of the fibers 14a, 14b, 14c is compared with the diameter of the fiber optic cable with clad layer. Very small. The diameter of the fibers 14a, 14b, 14c can be, for example, 5 μm or less and 3 to 4 μm. For this reason, as shown in FIG. 1 (a), the fibers 14a, 14b and 14c can be arranged close to each other at the exit ports 20a, 20b and 20c because there is no cladding like conventional optical fibers, For example, the center-to-center distance between adjacent light emission ports 20a, 20b, and 20c can be 3.5 μm. For this reason, the light radiate | emitted from the exit 20a, 20b, 20c which approached is radiate | emitted as substantially one light. For example, in the case where collimating lenses or the like are disposed in front of the light emission ports 20a, 20, and 20c to make parallel light, one light is obtained.

As shown in FIG. 1A, in the optical waveguide device 10, the separation distance between the centers of the light emission ports of the adjacent optical waveguides of the fibers 14a, 14b and 14c is defined by the light entrance ports of the two optical waveguides. The fibers 14a, 14b, 14c are bent in order to be very small compared to the distance between the centers of However, even if the fibers 14a, 14b, 14c are bent, the portions other than the first region 24 and the second region 26 of the fibers 14a, 14b, 14c are in contact with the external atmosphere, for example, air, so the fibers 14a, 14b , 14c leaks into the air in a small amount. By taking advantage of such advantages, according to one embodiment, the light entrances 18a, 18b and 18c and the light exits 20a, 20b and 20c of the fibers 14a, 14b and 14c are all directed in the same direction, (See FIG. 1 (a)) between the centers of the light emission ports of the adjacent fibers of the fibers 14a, 14b, and 14c, and the incidence of the light of the two adjacent optical waveguides. The fiber can be curved so as to be less than or equal to one-hundredth, preferably less than or equal to one-hundredth, of the separation La between the centers of the ports (see FIG. 1 (a)). In this case, the distance between the entrances 18a, 18b, 18c and the exit 20a, 20b, 20c along the traveling direction of light at the entrances 18a, 18b, 18c and the exit 20a, 20b, 20c (shortest When distance is Lb (see FIG. 1A), the ratio Lb / La is preferably 3.0 or less, and more preferably 1.0 or less. The lower limit of the ratio Lb / La is not particularly limited, but is preferably 0.1. That is, even if the separation distance Lb is shortened, the fibers 14a, 14b, and 14c are curved in a state in which light leakage is suppressed, and the separation distance Δ is equal to or smaller than one hundredth or less of the separation distance La. Preferably it can be made into 1/500 or less, more preferably 1/1000 or less. Therefore, the size of the optical waveguide device 10 can be made compact.
The separation distance Δ can be, for example, greater than 1 time and 1.5 times or less of the outer diameter φ of the fibers 14a, 14b, 14c (for example, the outer diameter is 10 μm or less, preferably φ 3 μm to φ 5 μm). The separation distance Δ of 1 means that adjacent fibers are in contact with each other. As described above, the fibers 14a, 14b, and 14c can cause the light emission ports to approach each other so that the lights emitted from the light emission ports are combined and emitted as substantially one light beam. For example, the emission ports are arranged closely spaced at intervals (for example, 1 μm or less) so as not to contact each other in a row at a designated location. In this case, in the vicinity of the emission ports of the fibers 14a, 14b and 14c, the fibers are fixed so as not to contact each other with an adhesive or the like interposed therebetween. The number of fibers used for the optical waveguide device 10 is not limited to three, and may be three or more, for example, four or five.

The optical waveguide device 10 is suitably used for a multi-wavelength light source module as one embodiment.
In the multi-wavelength light source module, first to nth fibers (n is a natural number of 2 or more) for guiding a plurality of light beams having different wavelengths from the entrance to the exit as the above-mentioned fibers are provided on the glass substrate 12. The first to n-th fibers are provided with a light guide device configured to be close to each other at the exit so that the combined light from the exit may exit. Furthermore, the multi-wavelength light source module emits a plurality of laser light sources fixed to the glass substrate 12 such that each of the plurality of light beams is incident on the entrance of each of the first to n-th fibers. (Not shown). The laser light source emits, for example, visible light such as RGB three primary colors or non-visible light such as near-infrared light as a plurality of light.

Fig.2 (a) is a figure which shows an example of the cross section of the optical waveguide apparatus 100 which is one Embodiment. The configuration of the optical waveguide device 100 shown in FIG. 2 (a) is different from the configuration shown in FIG. 1 (b), but the optical waveguide device 100 shown in FIG. 2 (a) is the fiber 14a shown in FIG. Similar to 14b and 14c, a plurality of optical waveguides are provided on the substrate.

The optical waveguide device 100 shown in FIG. 2A includes a silicon substrate 112, a core (optical waveguide) 114, a lower cladding layer 116D, and an upper cladding layer 116U.
The optical waveguide device 100 can be manufactured by sequentially laminating the lower cladding layer 116D, the core 114, and the upper cladding layer 116U on the silicon substrate 112 using a semiconductor manufacturing process.
The lower cladding layer 116D and the upper cladding layer 116U are SiO ₂ (refractive index is, for example, 1.46). The thickness of the lower cladding layer 116D and the upper cladding layer 116U is, for example, about 1 μm or less to several μm, which is determined by other factors.
The core 114 is also made of SiO ₂ and has a refractive index of, for example, 1.51. The core (optical waveguide) 114 extends continuously with the same material from the entrance to the exit, and is formed by connecting the members along the path, and is an interface such as a connection surface crossing the path. Do not have The core 114 is manufactured by adjusting the film forming conditions to have a high refractive index of 1.51. The thickness of the core 114 is, for example, 3.5 μm to 5 μm. The lower cladding layer 116D and the upper cladding layer 116U are oxide films of the same SiO ₂ as the core 114, and the refractive index is, for example, 1.46. In this case, the numerical aperture NA of the core (optical waveguide) 114, 0.4039 ⁽⁼ (1.51 2 -1.46 ^{2) (1/2)),} and the maximum receiving angle becomes 23.8 degrees.

Such an optical waveguide device 100 has the following features.
The core (optical waveguide) 114 extends continuously with the same material from the continuous medium, that is, from the entrance to the exit, and is formed by connecting the members along the path, and is a connection that crosses the path Since there is no interface such as a surface, there are no obstacles that cause light refraction or light leakage.
An upper clad layer 116U is provided on the core 114, and a lower clad layer 116 is provided on the lower side. The surfaces on both sides in the width direction are in contact with air. Regarding the propagation characteristics of light incident on the core 114 which is an optical waveguide having such a structure, that is, the propagation characteristics of light in the vertical direction inside the optical waveguide and in the horizontal direction on the side surfaces of both sides, the upper cladding layer 116U and the lower In the propagation characteristics in the vertical direction in which the cladding layer 116D is provided, the optical waveguide is not bent in the vertical direction, so for example, a core having a refractive index of 1.51 with respect to the refractive index 1.46 of the upper cladding layer 116U and the lower cladding layer 116D. The light propagated in 114 is totally reflected when it strikes the interface between the upper cladding layer 116U and the lower cladding layer 116D. Therefore, the light reaches the exit while being incident from the entrance and is completely confined in the core 114 in the vertical direction. On the other hand, in the propagation characteristics of light in the left and right direction inside the optical waveguide, the side surfaces of the core 114 on both sides (the left and right surfaces in FIG. 2A) have a difference in refractive index Is a large interface, the path of the core 114 along the surface of the silicon substrate 112 is largely curved as shown in FIG. 3 described later, that is, the optical waveguide for emitting the incident light is the direction of the optical waveguide Even in the case where the light source has a deflection part that greatly changes, it is possible to confine the light incident from the entrance of the core 114 which is an optical waveguide as it is within the core 114 to the exit. For example, the critical angle at which total reflection of light can be maintained in the optical waveguide is about 41.5 degrees because the refractive index of air is 1.0, for example, when the refractive index of the core 114 is 1.51. . The critical angle means that the total reflection can be maintained even if the deflection part is bent at a large angle. Even if the upper cladding layer 116U is not provided, the light in the optical waveguide that has been incident in the vertical direction can be similarly confined, but the upper cladding layer 116U is provided for the following reasons. That is, in an optical waveguide formed in a planar shape on a silicon substrate 112, that is, a PLC (planar lightwave circuit), in order to smooth the incidence and the emission of light at the entrance and the exit of the light, Polishing may be necessary. The upper cladding layer 116U is used to function as a protective film in this polishing.

Such a device configuration can be manufactured by a semiconductor process. FIG. 2B is a view showing an example of the laminated structure in the process of producing the optical waveguide device 100.
On the silicon substrate 112, an elementary clad layer 116D ^* to be a component of the lower clad layer 116D is formed. The elementary cladding layer 116D ^* is, for example, a SiO ₂ oxide film having a refractive index of 1.46.
After that, a waveguide film 114 ^* to be the element of the core 114 is formed on the upper surface of the element clad layer 116D ^* . The waveguide film 114 ^* is, for example, a SiO ₂ oxide film having a refractive index of 1.51.
Further, an elementary clad layer 116U ^* to be a component of the upper clad layer 116U is formed on the waveguide film 114 ^* . Containing clad layer 116U ^* of material is the same material as the element cladding layer 116D ^*.
Thereafter, a photoresist mask 130 of a predetermined pattern is formed at a position where the optical waveguide pattern of the core 114 is to be formed.
Thus, the laminated structure shown in FIG. 2 (b) is produced. The laminated structure is subjected to etching using a photoresist mask 130, for example, dry etching, to produce an optical waveguide device 100 provided with an optical waveguide shown in FIG. 2A.

That is, according to one embodiment, the optical waveguide device 100 can be manufactured by the following method.
In the method of manufacturing the optical waveguide device 100 having the lower cladding layer 116D, the core 114 (optical waveguide), and the upper cladding layer 116U,
(1) An elementary clad layer 116D ^* (lower clad film) which becomes element of at least lower clad layer 116D from the surface side of substrate 212, waveguide film 114 ^* which becomes element of core 114 (optical waveguide), and upper clad layer 116U An upper clad layer 116U ^* (upper clad film), which becomes the element of the upper layer, is sequentially stacked to form a stacked structure.
(2) Next, using the photoresist mask 130 in the outermost layer of the formed laminated structure, etching is performed so that the side surface of the waveguide film 114 ^* is exposed, whereby the core 114 whose side surfaces on both sides are exposed to the outside Optical waveguide).

FIG. 3 is a plan view showing another example of the optical waveguide path in the optical waveguide device 100. Since the optical waveguide device 100 shown in FIG. 2A can be manufactured using semiconductor process technology, as shown in FIG. 1A, a plurality of optical waveguides can be approached in the vicinity of the emission port. In addition, as shown in FIG. 3, the number of exit ports can be reduced to one by providing a junction 124 where a plurality of (three in FIG. 3) optical waveguides merge into one path. That is, the optical waveguide device 100 can be an optical multiplexing device. Thereby, the light emitted from the emission port can be completely emitted as one light. Thus, the path for merging the plurality of optical waveguides can be manufactured by adjusting the mask pattern of the photoresist pattern 130. In this case, the side surfaces on both sides of the core 114 (left and right surfaces in FIG. 2A) are interface surfaces where the difference in refractive index (difference in refractive index between the core 114 and air) is large. For example, when the refractive index of the core 114 is 1.51, the critical angle of incidence can be 41.5 degrees (= arcsin (1 / 1.51)). be able to. Therefore, even if the degree of bending of the deflection is made steeper than in the prior art, it is possible to suppress the leakage of light propagating through the core 114. Therefore, the distance L (see FIG. 3) from the entrance to the exit can be shortened without changing the separation distance D (see FIG. 3) between the centers of the entrances of the optical waveguides, making the optical waveguide device 100 compact. can do.
In this case, the inclination angle between the two cores 114 (the first optical waveguide and the second optical waveguide) in the junction 124 is preferably 2 degrees or less, and more preferably 1 degree or less. Thereby, it is possible to suppress the transmission loss of light in the merging section 124.

FIG. 4A is a view showing an example of the cross section of the optical waveguide device 200 in another embodiment. The configuration of the optical waveguide device 200 shown in FIG. 4 (a) is different from the configuration shown in FIG. 1 (b), but the optical waveguide device 200 shown in FIG. 4 (a) is also the optical waveguide 14a shown in FIG. , 14b and 14c, a plurality of optical waveguides are provided on the substrate.

The optical waveguide device 200 shown in FIG. 4A includes a silicon substrate 212, a core (optical waveguide) 214, a lower cladding layer 216D, and an upper cladding layer 216U. Silicon substrate 212, core 214, lower clad layer 216D, and upper clad layer 216U have the same configuration as silicon substrate 112, core 114, lower clad layer 116D, and upper clad layer 116U shown in FIG. 2A. , The description is omitted. The optical waveguide device 200 differs from the optical waveguide device 100 shown in FIG. 2A in that the upper cladding layer 116U covers the side surface on one side of the core 114 (the left surface in FIG. 4A). The side surface of the other side (the right side surface in FIG. 4A) is not covered but is in contact with air.

Even in such an optical waveguide device 200, as in the optical waveguide device 200 shown in FIG. 2A, the other side surface of the core 214 is a boundary surface where the difference in refractive index is large. Even if the portion where the path is curved to one side, that is, the optical waveguide for emitting the incident light has a deflecting portion in which the direction of the optical waveguide is bent and changed to one side, Total reflection can be maintained. Moreover, the core (optical waveguide) 214 continuously extends from the entrance to the exit with the same material, and is formed by connecting the members along the route, such as a connection surface crossing the route Since there is no interface, even if the light propagated in the light guide is refracted, there are no obstacles that cause light leakage.

Such a device configuration can be manufactured by a semiconductor process. FIGS. 4B and 4C are diagrams showing an example of the laminated structure in the process of producing the optical waveguide device 200. FIG.

On the silicon substrate 212, an elementary clad layer 216D ^* to be a component of the lower clad layer 216D is formed. The elementary cladding layer 216D ^* is, for example, a SiO ₂ oxide film having a refractive index of 1.46.
After that, a waveguide film 214 ^** serving as the element of the core 214 is formed on the upper surface of the uncoated layer 216D ^* . The waveguide film 214 ^** is, for example, a SiO ₂ oxide film having a refractive index of 1.51.
Thereafter, a photoresist mask 230 of a predetermined pattern is formed at a position where the optical waveguide pattern of the core 214 is to be formed. FIG. 4B shows an example of the laminated structure in which the photoresist pattern 230 is formed.

Thereafter, the first etching using the photoresist mask 230 of a predetermined pattern, for example, dry etching is performed to expose the side surfaces on both sides of the waveguide film 214 ^** , and further until the underlying bare cladding layer 216D ^* is exposed. Do the etching.
After this, an elementary clad layer 216U ^* to be the element of the upper clad layer 216U is formed on the etched laminated structure. Thereafter, a photoresist mask 232 having a predetermined pattern is formed at a position where the core 214 shown in FIG. 4A is to be formed. At this time, the position on one side (left side in FIG. 4B) of the photoresist mask 232 is exposed in the previous etching on one side (left side in FIG. 4B) of the waveguide film 214 ^* . was located outside the Shirubehamaku 214 ^* than the position, the position of the other side of the photoresist mask 232 (the right side in FIG. 4 (b)), Shirubehamaku 214 ^* the other side of the in the previous etching A photoresist mask 232 is formed so as to be located closer to the remaining portion (waveguide core) of the waveguide film 214 ^* than the position where the side surface (left side in FIG. 4B) is exposed. FIG. 4C shows an example of the laminated structure in which the photoresist mask 232 is formed. A part of the waveguide film 214 ^** remaining by the first etching is referred to as a waveguide core 214 ^* .

Thereafter, the laminated structure shown in FIG. 4 (c), a photoresist pattern 232 a second etching with a mask, for example, dry etching is performed, Shirubehamaku 214 ^** shown in FIG. 4 (c) Under the other side of the waveguide core 214 ^* (right side in FIG. 4 (b)) and the other side of the waveguide core 214 ^* (right in FIG. 4 (b)) Etching is performed until the cladding layer 216D is exposed. The uncoated layer 216U ^* on one side of the waveguide core 214 ^* (left side in FIG. 4B) may or may not be etched. As a result, a part of the waveguide core 214 ^* is etched away, and an optical waveguide having a layer configuration as shown in FIG. 4A can be formed. Thus, the optical waveguide device 200 provided with the optical waveguide shown in FIG. 4A can be manufactured.

That is, according to one embodiment, the optical waveguide device 200 can be manufactured by the following method.
(1) From the surface side of the substrate 212, an element clad layer 216D ^* (lower clad film) to be a element of at least the lower clad layer 216D and a waveguide film 214 ^** to be a element of the core 214 (optical waveguide) were sequentially stacked Form a laminated structure.
(2) By etching the waveguide film 214 ^** using the photoresist mask 230 (second resist mask) as shown in FIG. 4B on the outermost layer of the laminated structure, the elementary cladding layer 216 D ^* A waveguide core 214 ^{* in} which a part of the waveguide film 214 ^** is left is formed on the upper layer of the (lower cladding film).
(3) An elementary clad layer 216U ^* (upper clad film) to be the element of the upper clad layer 216U is formed on the outermost layer of the etched laminated structure.
(4) Next, on the substrate 212 of the remaining waveguide core 214 ^* , as shown in FIG. 4C, on the outermost layer of the laminated structure in which the element clad layer 216U ^* (upper clad film) is formed. When using the photoresist mask 232 pattern portions do not overlap (third resist mask), by etching the portion of the element cladding layer 216U ^* (upper cladding layer) and the waveguide core 214 ^*, core 214 ( The core 214 (optical waveguide) is formed such that one side surface of the optical waveguide is exposed to the outside and the other side is in contact with the upper cladding layer 216U.

Since the optical waveguide device 200 shown in FIG. 4A can be manufactured using semiconductor process technology, as shown in FIG. 1A, bringing a plurality of optical waveguides close to each other in the vicinity of the emission port In addition, as shown in FIG. 3, a plurality of optical waveguides can be merged into one path, and the exit can be one. Thus, the path for merging the plurality of optical waveguides can be manufactured by adjusting the patterns of the photoresist masks 230 and 232.

FIG. 5 is a plan view of an optical waveguide device 300 of one embodiment using the optical waveguide of the laminated structure shown in FIG. 4A. FIG. 5 omits illustration of the upper clad layer laminated on the core, and shows it intelligibly. FIG. 5 is also a conceptual view showing the shape of the core. Hereinafter, the cores such as the cores 314a to 314c will be described in other words as an optical waveguide.

Each of the optical waveguides 314a and 314c in the optical waveguide device 300 shown in FIG. 5 has a configuration of an optical waveguide in which the side surface on one side of the core shown in FIG. 4A is exposed and in contact with air. The optical waveguide 314 b has a configuration of an optical waveguide in which the side surfaces on both sides of the core shown in FIG. 2A are exposed and in contact with air.

The optical waveguides 314a and 314c include deflection portions (corner portions) 322a1, 322a2, 322c1, and 322c2 which are bent substantially at right angles. The deflecting portions 322a1, 322a2, 322c1, and 322c2 are provided so as to be sandwiched between the linearly extending straight portions. The side surfaces of the optical waveguides outside the corners of the deflecting portions 322a1, 322a2, 322c1, and 322c2 are boundary surfaces in contact with air. This side is an inclined surface.
The optical waveguides 314a, 314b, and 314c merge at the merging portion 324, and the lights having passed through the optical waveguides 314a, 314b, and 314c are combined.
Here, the inclination angle with respect to the linear portion of the inclined surface in the deflection portions 322a1, 322a2, 322c1, and 322c2 can be, for example, in the range of 45 degrees ± 3. As a result, the deflecting portions 322a1, 322a2, 322c1, and 322c2 (corner portions) can be sharply bent, and the inclination angle of the optical waveguides 314a and 314c with respect to the merging portion 324 can be reduced. Transmission loss can be suppressed.

As shown in FIG. 5A, the side surfaces outside the corners of the optical waveguides 314a to 314c in the deflecting portions 322a1, 322a2, 322c1, and 322c2 (corner portions) are inclined at 45 degrees with respect to the straight portion. It is flat and sloped. Moreover, as shown in FIG. 7A described later, the side surface outside the corner is exposed and in contact with the air. Therefore, the side surfaces outside the corners in the deflecting portions 322a1, 322a2, 322c1, and 322c2 are boundary surfaces where the difference in refractive index is large. Therefore, the critical angle decreases, and incident light from the entrance satisfies the total reflection condition at this interface and is confined to the exit. In addition, the optical waveguides 314a to 314c continuously extend from the entrance to the exit with the same material, and are formed by connecting the members in the middle of the path, such as a connection surface crossing the path. Because it does not have a surface, there are no obstructions that cause light refraction or light leakage.

According to one embodiment, the optical waveguides 314a, 314b, 314c are formed of SiO ₂ oxide film (refractive index = 1.51), and the upper cladding layer and the lower cladding layer are SiO ₂ oxide films (refractive index = 1). .46).
According to another embodiment, the optical waveguides 314a, 314b, and 314c are made of a SiO ₂ oxide film having a refractive index of 1.46 and a substance (eg, GeO ₂ ) that increases the refractive index. The upper clad layer and the lower clad layer are formed by adding a substance (for example, fluorine F) whose refractive index decreases to a SiO ₂ oxide film having a refractive index of 1.46.
In another embodiment, the optical waveguides 314a, 314b and 314c are formed of SiO ₂ oxide film (refractive index = 1.46), and the upper cladding layer and the lower cladding layer are SiO ₂ oxide films (refractive index Is less than 1.46).

As described above, the entrances of the optical waveguides 314a, 314b, 314c (the first optical waveguide, the second optical waveguide, and the third optical waveguide) of the optical waveguide device 300 are respectively the first side (the lower side in FIG. 5) of the substrate. And the outlet 320 of the optical waveguides 314a, 314b, 314c (the first optical waveguide, the second optical waveguide, and the third optical It is provided along the second side (upper side in FIG. 5) opposite to the first side.
Of the optical waveguides 314a, 314b, 314c (first optical waveguide, second optical waveguide, and third optical waveguide), the optical waveguides 314a, 314c (second optical waveguide, third optical waveguide) respectively The side wall in the width direction of two places provided with two parts (corner parts) and deflection parts (corner parts) is the upper cladding layer 316 (FIG. 6C) inside the corners in the deflection parts (corner parts) In contact with the reference, and in contact with the air clad layer with air as the clad element outside the corner. The side wall on the outer side (corner outer side) of the deflection portion (corner portion) is formed of a plane. The merging portion 324 of the optical waveguides 314a, 314b, 314c (the first optical waveguide, the second optical waveguide, and the third optical waveguide) includes two of the optical waveguides 314a, 314c (the second optical waveguide and the third optical waveguide). It is located on the side of the exit 320 with respect to the location of one deflection part (corner part).
As described above, since two deflection portions are provided for each of the optical waveguides 314a and 314c, the distance L can be shortened while maintaining the distance D constant. Thereby, a compact optical waveguide device 300 can be configured. According to one embodiment, the ratio L / D can be less than or equal to 3.0, preferably less than or equal to 1.0. The lower limit of the ratio L / D is not particularly limited, but is 0.1.

Further, as shown in FIG. 5, the optical waveguide 314 b (first optical waveguide) linearly extends from the entrance of the optical waveguide 314 b (first optical waveguide) to the exit 320. At this time, according to one embodiment, the optical waveguide 314a (second optical waveguide) and the optical waveguide 314c (third optical waveguide) extend from the respective entrances of the optical waveguides 314a and 314c as paths, to form the optical waveguide 314b ( A first linear portion extending in parallel to the first optical waveguide), and deflection portions 322a1 and 322c1 for deflecting light passing through the first linear portion toward the optical waveguide 314b (first optical waveguide) First corner portion), a second straight portion for guiding light passing through the deflecting portions 322a1 and 322c1 (first corner portion) to approach the optical waveguide 314b (first optical waveguide), and the second straight portion Light which has passed through the light source is deflected to be directed to the merging portion 324, and light which has passed through the deflecting portions 322a2 and 322c2 (second corner portion). And a third straight portion for guiding so as to reach the merging unit 324. By providing the path of such a configuration, the deflecting portions 322a1 and 322c1 (first corner portion) and the deflecting portions 322a2 and 322c2 (second corner portion) are about 90 degrees (within the range of 90 degrees ± 3 degrees). Since the reflection corner is formed, when the incident light is in the single transverse mode, the light in the single transverse mode is propagated from the first straight part to the second straight part and from the second straight part to the third straight part without breaking down. It can be done. Further, in this case, since two reflection corners of about 90 degrees are provided, in the deflecting portions 322a1 and 322c1 (first corner portion), a direction in which the light is made to approach the optical waveguide 314b (first optical waveguide) , And the light is deflected so as to approach the optical waveguide 314b (first optical waveguide) in the deflecting portions 322a2 and 322c2 (second corner portion), so that the optical waveguide 314b (first optical waveguide) The inclination angle of the optical waveguide 314a (second optical waveguide) or the optical waveguide 314c (third optical waveguide) can be reduced, and can be 2 degrees or less, 1 degree or less, or 0.5 degree or less. .
When a large light source device is used instead of a laser light source as a light source device for emitting light incident on the entrances of the optical waveguides 314a to 314c, the number of light source devices is very large (for example, 5 to 10 or 64) Even when the distance between the entrances is increased, the optical waveguides 314a and 314c are made to the optical waveguide 314b by the deflectors 322a1 and 322c1 (first corner) and the deflectors 322a2 and 322c2 (second corner). For example, the light waveguides can be merged at an inclination angle as small as, for example, 2 degrees or less.
In the embodiment shown in FIG. 5, the paths of the optical waveguide 314a (second optical waveguide) and the optical waveguide 314c (third optical waveguide) are formed in line symmetry, but the paths may not necessarily be formed in line symmetry. When the path length of light is the same between the optical waveguide 314 a (second optical waveguide) and the optical waveguide 314 c (third optical waveguide), the light incident on these two is emitted at the same emission intensity at the emission port 320 can do.

Further, as shown in FIG. 5, the optical waveguide 314a (second optical waveguide) and the optical waveguide 314c (third optical waveguide) at the junction are merged from the direction inclined with respect to the optical waveguide 314b (first optical waveguide) However, the inclination angle of the optical waveguide 314a (second optical waveguide) and the optical waveguide 314c (third optical waveguide) with respect to the optical waveguide 314b (first optical waveguide) at the merging portion 324 at this time is 5 degrees, It may be as follows, may be 2 degrees or less, may be 1 degree or less, and may be 0.5 degree or less. Thereby, it is possible to suppress the transmission loss of light at the merging portion.

The optical waveguide device 300 having such a configuration is manufactured as follows.
That is, of the laminated structure shown in FIG. 4C, the laminated structure 300 ^* at the stage before the photoresist mask 232 is formed is manufactured. FIG. 6 is a view showing an example of the laminated structure 300 ^* . In this laminated structure 300 ^* , an element clad layer (upper clad film) to be an element of the upper clad layer is formed on the upper layer of the shape (the shape in which the part outside the deflection section is an angle) of the optical waveguides 314a to 314c. ) Is formed. FIG. 7A is an enlarged view of a region X to be the deflection portion (corner portion) shown in FIG. 7 (a) to 7 (e) are diagrams for explaining an example of the configuration of a laminated structure 300 ^* obtained by the process described below. 7 (b) is a cross-sectional view taken along the line AA 'shown in FIG. 7 (a), and FIG. 7 (c) is a cross-sectional view taken along the line BB' shown in FIG. 7 (a) is there.

As shown in FIGS. 7B and 7C, the stacked structure 300 ^* is formed on the silicon substrate 350 and the element clad layer (lower clad film) 352 which is the element of the lower clad layer. A waveguide core 354 ^* is formed, and an element clad layer (upper clad film) 356 to be a component of the upper clad layer is formed thereon (see FIG. 7B).
As shown in FIG. 7 (b), the waveguide core 354 ^* areas in the laminated structure 300 ^* includes a horizontal line is attached portion, indicated by the portions assigned with the horizontal dashed line, the area of the unit cladding layer 356 Are indicated by the upper right hatched part and the upper right hatched and dashed part, but the part attached with a horizontal broken line and the upper right hatched part with a dashed line will be described later. It shows the part to be removed in the process.

As shown in FIG. 7D, a photomask 358 is stacked on the top of the uncoated layer 356 which is the uppermost layer of the stacked structure 300 ^* . The photomask 358 is formed such that the region Ea shown in FIG. 7A is etched. The photomask 358 (fourth resist mask) has a pattern in which a part of the location on the outer side (corner outer side) of the deflection part (corner part) does not overlap.
Therefore, as shown in FIG. 7 (e), etching is performed using a photomask 358 to form an inclined surface which is inclined with respect to the straight portion on the outer side (corner outer side) of the deflection portion (corner portion). can do. The reference numeral 354 in FIG. 7 (e) corresponds to the optical waveguides 314a to 314c.

That is, the optical waveguide device 300 is manufactured by the following manufacturing method.
(1) From the surface side of the silicon substrate 350, a laminated structure is formed by sequentially laminating an element clad layer (lower clad film) 352 which becomes element of the lower clad layer and a waveguide film which becomes element of the optical waveguide.
(2) A waveguide core is formed in the upper layer of the lower cladding film 352 by etching the waveguide film on the outermost layer of the laminated structure using the second resist mask, thereby forming a waveguide core 354 ^* . When the shape of the waveguide core 354 ^* is viewed from above the silicon substrate 350, the shape is two straight lines like the optical waveguide 314a (second optical waveguide) and the optical waveguide 314c (third optical waveguide). The shape of the waveguide film is formed to include a portion and a deflection portion (corner portion) sandwiched by the straight portions.
(3) An elementary clad layer (upper clad film) 356 to be a component of the upper clad layer is formed on the outermost layer of the etched laminated structure. Thereby, a laminated structure 300 ^* as shown in FIG. 6 is obtained. However, at this stage, as shown in FIG. 6, the corner outside of the deflection portion (corner portion) is a corner.
(4) Using the photomask 358 (fourth resist mask) of a pattern in which a part of the place outside the corner of the deflection part (corner part) does not overlap on the outermost surface of the laminated structure 300 ^* on which the elementary clad layer 356 is formed. Then, by etching the portion outside the corner of the waveguide core 354 ^* , an inclined surface inclined with respect to the straight portion is formed on the side outside the corner. Thereby, as shown in FIG. 5, the deflection | deviation part 322a1, 322a2, 322c1, 322c2 provided with an inclined surface is produced.

FIG. 8 is a plan view of an optical waveguide device 400 of another embodiment different from that of FIG. 5 using the optical waveguide of the laminated structure shown in FIG. 4 (a). FIG. 8 illustrates the upper cladding layer stacked on the core in a simplified manner, with the illustration thereof omitted. FIG. 8 is also a conceptual view showing the shape of the core.
The optical waveguide device 400 includes optical waveguides 414a to 414d which are four cores, and guides the light incident from the entrances 418a to 418d to one exit 420. Each of the four optical waveguides 414a to 414d has the configuration of the optical waveguide shown in FIG. 4 (a). Each of the optical waveguides 414a to 414d includes deflecting portions 422a to 422d (corner portions) bent substantially at right angles along the path. The deflecting portions 422a to 422d (corner portions) are sandwiched between two linear portions extending linearly. In the vicinity of the exit 420, a junction 424 where the optical waveguides 414a to 414d merge is provided. The portions of the optical waveguides 414a to 414d from the entrances 418a to 418d to the deflecting portions 422a to 422d and the portions from the deflecting portions 422a to 422d to the merging portion 424 extend linearly. Therefore, the deflection angle in the deflecting portion 422a closest to the merging portion 424 exceeds 90 degrees, and the deflection angle decreases with distance from the merging portion 424, and the deflection angle in the deflection portion 422d farthest from the merging portion 424 is It is 90 degrees.
The upper cladding layer corresponding to the upper cladding layer 216U shown in FIG. 4A, which constitutes the four optical waveguides 414a to 414d, has a predetermined width with respect to the optical waveguides 414a to 414d in the width direction of the optical waveguides 414a to 414d. It has been extended to the end of the range.

Inclined surfaces are formed outside the corners of the deflecting portions 422a to 422d of the optical waveguide device 400 having such a configuration. The formation of this inclined surface is formed by the method shown in FIGS. 7 (a) to 7 (e). That is, the optical waveguide device 400 is also manufactured by the method of manufacturing the optical waveguide device 300 described above.
The inclination angle of the side surfaces 426a to 426d (inclined surface) with respect to the straight portion can be, for example, in the range of 45 degrees ± 3. As a result, the deflecting portions 422a to 422d (corner portions) can be sharply bent, the inclination angle between the optical waveguides at the merging portion can be reduced, and the transmission loss of light at the merging portion can be suppressed.

According to one embodiment, as shown in FIG. 8, the orientations of the entrances 418a-418d and the exit 420 are 90 degrees apart, and the silicon substrate has a rectangular shape, and the entrances 418a-418d and The exit 420 is provided on two mutually orthogonal sides SE1 and SE2 each having four rectangular vertices X. At this time, since the direction of the path can be rapidly changed by the deflecting portions 422a to 422d, the distance L1 between the center of the exit 420 and the apex X is the entrance 418d farthest from the apex X among the entrances. Or less than 10% of the distance L2 between the center of the and the vertex X. Since the distance L1 can be considerably shortened, a compact optical waveguide device 400 can be configured.

The optical waveguide devices 100 to 400 are suitably used in a multi-wavelength light source module as one embodiment. In the multi-wavelength light source module, each of a plurality of light beams having different wavelengths is incident on the entrance of each of the optical waveguides in any one of the optical waveguide devices 100 to 400 and any one of the optical waveguide devices 100 to 400 And a plurality of laser light sources (not shown) for emitting a plurality of lights fixed to the substrate. The laser light source emits, for example, visible light such as RGB three primary colors or non-visible light such as near-infrared light as a plurality of light.

The light guide device, the optical waveguide device, the multi-wavelength light source module, and the method for manufacturing the optical waveguide device according to the present invention have been described in detail above, but the present invention is not limited to the above embodiments and does not deviate from the subject matter of the present invention Of course, various improvements and modifications may be made within the scope.
For example, in the optical waveguide devices 100 to 400, although a silicon substrate is used, it is not limited to a silicon substrate, and a glass substrate, a metal substrate or the like can also be used.

DESCRIPTION OF SYMBOLS 10 Light guide apparatus 12 Glass substrates 14a, 14b, 14c Fibers 16a, 16b, 16c Bonding layers 18a, 18b, 18c, 418a, 418b, 418d Entrance ports 20a, 20b, 20c, 320, 420 Exit ports 22a, 22b, 22c laser light source 24 first region 26 second region 100, 200, 300, 400 light waveguide device 112, 212, 350 silicon substrate 114, 214, 314a, 314b, 314c, 414, 414a, 414b, 414c, 414d core Waveguide)
114 ^* , 214 ^** Waveguide film 214 ^* Waveguide core 116D, 216D Lower cladding layer 116U, 216U Upper cladding layer 116D ^* , 116U ^* , 216D ^* , 352, 356 Elementary cladding layer 124, 324 Merged portions 130, 230, 232, 358 Photoresist patterns 322a, 322b, 322c, 322d, 422a1, 422a2, 422c1, 422c2 Deflectors 300 ^* Laminated structures 326a, 326b, 326c, 326d Side surface 354 Waveguide film

Claims (21)

1. It is a light guiding device for emitting incident light, and
   With a glass substrate,
   It is provided on the glass substrate, has an entrance and an exit for the light, is composed of a single material from the entrance to the exit, and is exposed to an external atmosphere surrounding the light guide, A fiber for guiding light from an entrance to the exit;
   An adhesive layer made of an adhesive interposed between a part of the fiber and the glass substrate is provided to fix the entrance and the exit of the fiber at a designated position of the glass substrate. ,
   When the refractive index of the fiber, the refractive index of the adhesive, and the refractive index of the glass substrate are n1, n2 and n3, respectively, n1> n2 and n1> n3 are satisfied. apparatus.
2. The fiber has, in a cut surface of the fiber, two first regions in contact with the adhesive layer, and a second region in contact with the glass substrate and not in contact with the glass substrate. ,
   The light guide device according to claim 1, wherein a portion other than the first area and the second area is in contact with the external atmosphere.
3. As the fibers, first and second fibers for guiding two lights are provided on the glass substrate,
   The separation distance Δ between the center of the light outlet of the first fiber and the center of the light outlet of the second fiber is the center of the light entrance of the first fiber and the light of the second fiber At least one of the first fiber and the second fiber is curved so as to approach each other as it goes to the exit so that the distance La between the center of the entrance and the center of the entrance is not more than 1/100
   When the separation distance between the entrance and exit of the first fiber or the separation between the entrance and exit of the second fiber is Lb, the distance between the separation La and the separation Lb is The light guide device according to claim 1, wherein the ratio Lb / La is 1.0 or less.
4. An optical waveguide device that emits incident light, wherein
   A substrate,
   An optical waveguide provided on the substrate, having an entrance and an exit for the light, and guiding the light from the entrance to the exit;
   A first cladding layer stacked between the optical waveguide and the substrate and in contact with the optical waveguide, the first cladding layer having a smaller refractive index than the refractive index of the optical waveguide;
   And a second cladding layer in contact with the optical waveguide and having a smaller refractive index than the refractive index of the optical waveguide on the side opposite to the first cladding layer with respect to the optical waveguide;
   The optical waveguide extends continuously with the same material from the entrance to the exit,
   In at least a part of the optical waveguide, the surface of the optical waveguide on at least one side in the width direction of the optical waveguide parallel to the surface of the substrate and orthogonal to the extension direction of the optical waveguide uses air as a cladding element An optical waveguide device in contact with an air clad layer.
5. And a third cladding layer in contact with the optical waveguide on one side in the width direction and having a smaller refractive index than the refractive index of the optical waveguide,
   The optical waveguide device according to claim 4, wherein the optical waveguide has a portion that is in continuous contact with the first cladding layer, the second cladding layer, and the third cladding layer.
6. The optical waveguide device according to claim 5, wherein the portion is provided in a linear portion extending in a straight line of the optical waveguide.
7. The optical waveguide includes a corner portion that bends the traveling direction of light on the substrate,
   The optical waveguide device according to claim 5, wherein the optical waveguide contacts the third cladding layer inside a corner at the corner portion and contacts the air cladding layer outside the corner.
8. The optical waveguide device according to claim 7, wherein the side surface outside the corner of the optical waveguide is a plane.
9. The optical waveguide device includes, as the optical waveguide, a first optical waveguide and a second optical waveguide for guiding two lights,
   The first optical waveguide and the second optical waveguide have different entrances, respectively.
   The optical waveguide device includes a junction where the first optical waveguide and the second optical waveguide merge with each other on the substrate, and a common exit of the first optical waveguide and the second optical waveguide. An optical waveguide device according to any one of claims 4 to 8.
10. The optical waveguide device according to claim 9, wherein an inclination angle between the first optical waveguide and the second optical waveguide at the junction is 2 degrees or less.
11. The optical waveguide device includes, as the optical waveguide, at least a first optical waveguide that guides at least three lights, a second optical waveguide, and a third optical waveguide.
    The first optical waveguide, the second optical waveguide, and the third optical waveguide have different entrances, respectively.
    The optical waveguide device includes a joining portion where the first optical waveguide, the second optical waveguide, and the third optical waveguide join together on the substrate, the first optical waveguide, the second optical waveguide, and the optical waveguide device. The optical waveguide device according to any one of claims 5 to 8, further comprising: a common exit of the third optical waveguide.
12. The entrances of the first optical waveguide, the second optical waveguide, and the third optical waveguide are respectively provided along the first side of the substrate,
    The emission ports of the first optical waveguide, the second optical waveguide, and the third optical waveguide are provided along the second side facing the same direction as the incident port and facing the first side.
    At least each of the second optical waveguide and the third optical waveguide among the first optical waveguide, the second optical waveguide, and the third optical waveguide has a corner portion that bends the traveling direction of the light on the substrate. Two widthwise side walls provided at two places and provided with the corner part are in contact with the third cladding layer inside the corner in the corner part and in contact with the air clad layer outside the corner,
    The side wall outside the corner is composed of a plane,
    The optical waveguide device according to claim 11, wherein the junction portion is located on the side of the exit with respect to the location of the corner portion of each of the second optical waveguide and the third optical waveguide.
13. A separation distance between the entrance of the first optical waveguide, the second optical waveguide, and the entrance of the third optical waveguide and the exit along the direction of the entrance is L, and the first optical waveguide is The ratio L / D is 3.0 or less when a center-to-center distance D between adjacent entrances of the entrances of the second optical waveguide and the third optical waveguide is set as D. An optical waveguide device according to claim 1.
14. The first optical waveguide linearly extends from the entrance of the first optical waveguide to the exit.
    Each of the second optical waveguide and the third optical waveguide, as a path, extends from the entrance of each of the second optical waveguide and the third optical waveguide and extends parallel to the first optical waveguide. A straight portion; a first corner portion for deflecting light passing through the first straight portion toward the first optical waveguide; and light passing through the first corner portion approaching the first optical waveguide A second straight portion guiding light to be guided, a second corner portion deflecting light passing through the second straight portion toward the merging portion, and the merging portion light passing through the second corner portion The optical waveguide device according to claim 12 or 13, further comprising: a third straight portion that guides light to reach the light source.
15. In the merging portion, the second optical waveguide and the third optical waveguide merge from a direction inclined with respect to the first optical waveguide,
    The light guide according to any one of claims 11 to 14, wherein an inclination angle of the second optical waveguide and the third optical waveguide with respect to the first optical waveguide in the confluence part is not more than 2 degrees. Wave equipment.
16. A method of manufacturing an optical waveguide device having a lower cladding layer, an optical waveguide, and an upper cladding layer,
    A laminated structure in which a lower cladding film serving as the element of the lower cladding layer, a waveguide film serving as the element of the optical waveguide, and an upper cladding film serving as the element of the upper cladding layer are sequentially stacked from the surface side of the substrate. Forming steps,
    Forming the optical waveguide with the side surfaces on both sides exposed to the outside by etching so that the side surface of the waveguide film is exposed using the first resist mask in the outermost layer of the laminated structure A method of manufacturing an optical waveguide device characterized in that.
17. A method of manufacturing an optical waveguide device having a lower cladding layer, an optical waveguide, and an upper cladding layer,
    Forming a laminated structure in which a lower cladding film serving as the element of at least the lower cladding layer from the surface side of the substrate and a waveguide film serving as the element of the optical waveguide are sequentially laminated;
    Forming the waveguide film in which a portion of the waveguide film is left over the lower cladding film by etching the waveguide film on the outermost layer of the laminated structure using a second resist mask; ,
    Forming an upper cladding film serving as the element of the upper cladding layer on the outermost surface of the etched layered structure;
    Using the third resist mask having a pattern in which a portion of the remaining waveguide film does not overlap with a portion of the remaining waveguide film on the outermost layer of the stacked structure in which the upper cladding film is formed, the upper cladding film and the above Forming the optical waveguide having a configuration in which one side surface of the optical waveguide is exposed to the outside and the other side is in contact with the upper cladding layer by etching a part of the remaining waveguide film. A method of manufacturing an optical waveguide device characterized in that.
18. A method of manufacturing an optical waveguide device having a lower cladding layer, an optical waveguide, and an upper cladding layer,
    Forming a laminated structure in which a lower cladding film serving as the element of at least the lower cladding layer from the surface side of the substrate and a waveguide film serving as the element of the optical waveguide are sequentially laminated;
    A part of the waveguide film is left on the upper layer of the lower cladding film by etching the waveguide film using the second resist mask in the outermost layer of the laminated structure, and the remaining waveguide film Forming a shape of a waveguide film such that the shape comprises two straight portions and a corner portion sandwiched between the straight portions when the shape is viewed from above the substrate;
    Forming an upper cladding film serving as the element of the upper cladding layer on the outermost surface of the etched layered structure;
    Using the fourth resist mask having a pattern in which a part of the place outside the corner of the corner portion does not overlap with the outermost surface of the laminated structure on which the upper cladding film is formed, the above-mentioned film being a part of the waveguide film Forming an inclined surface inclined with respect to the straight line portion on the side surface outside the corner by etching the portion outside the corner; and manufacturing the optical waveguide device.
19. The method for manufacturing an optical waveguide device according to claim 18, wherein an inclination angle of the inclined surface with respect to the linear portion is in a range of 45 degrees ± 3 degrees.
20. As the fibers, first to n-th fibers (where n is a natural number of 2 or more) for guiding a plurality of light beams having different wavelengths from the entrance to the exit are provided on the glass substrate. The light guide device according to any one of claims 1 to 3, wherein the n fibers have a configuration in which the light emitting ports approach each other so that the light combined in the light emitting ports is emitted.
    A plurality of laser light sources for emitting the plurality of lights fixed to the glass substrate such that each of the plurality of lights is incident on the entrance of each of the first fiber to the n-th fiber; Multi-wavelength light source module provided.
21. An optical waveguide device according to any one of claims 9 to 15,
    A plurality of laser light sources for emitting the plurality of light beams fixed to the substrate such that each of the plurality of light beams having different wavelengths is incident on the entrance of each of the optical waveguides; .

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