WO2021166413A1

WO2021166413A1 - Optical waveguide multiplexer, light source module, two-dimensional light beam scanning device, and light beam scanning video projection device

Info

Publication number: WO2021166413A1
Application number: PCT/JP2020/047632
Authority: WO
Inventors: 勝山俊夫; 山田祥治; 中尾慧
Original assignee: 国立大学法人福井大学
Priority date: 2020-02-20
Filing date: 2020-12-21
Publication date: 2021-08-26
Also published as: JP7105498B2; JP2021131498A

Abstract

The present invention pertains to an optical waveguide multiplexer, a light source module, a two-dimensional light beam scanning device, and a light beam scanning video projection device, and provides an optical waveguide multiplexer that has a simple structure and is easily fabricated. The present invention has a plurality of optical waveguides (2)-(3), and a region (6) that forms a single optical waveguide while light beams propagated through the plurality of optical waveguides (2)-(3) are multiplexed on an emission-end-surface (7) side, the emission end surface (7) of the region (6) being configured so as to be in a longitudinal direction range of 10-90% of the overall light leakage, in which light beams propagating through the optical waveguides (2)-(3) leak to the outside from the optical waveguides.

Description

Optical waveguide type combiner, light source module, two-dimensional light beam scanning device and light beam scanning type image projection device

The present invention relates to an optical waveguide type combiner, a light source module, a two-dimensional light beam scanning device, and an optical beam scanning type image projection device. Provided are an optical waveguide type combiner and an optical beam scanning type image projection device, which can be miniaturized with less loss and have a simple structure.

Conventionally, various types of light beam combiners are known as devices that combine light beams such as a plurality of laser beams and radiate them as one beam. Among them, those using an optical fiber or an optical waveguide can be miniaturized (see, for example, Patent Documents 1 to 3), and as shown in Cited Documents 1 to 3, three of them are used. As a method of combining the optical beams of the above, there is known a method of bringing each optical fiber or optical waveguide close to each other in the vicinity of the light emitting end.

FIG. 11 is a schematic perspective view of an example of a two-dimensional optical beam scanning device proposed by the present inventor. An optical waveguide type optical wave guide 50 is provided on a substrate 60 on which a movable mirror portion 61 is formed, and the optical waveguide type optical wave guide is provided. The blue semiconductor laser chip 51, the green semiconductor laser chip 52, and the red semiconductor laser chip 53 may be coupled to the waveguide 50. Since the movable mirror portion 61 is miniaturized, the overall size after integration can be reduced even when it is integrated with a light source that generates a light beam. In particular, in the case of a light source in which an optical beam is emitted from a semiconductor laser chip or an optical waveguide type optical combiner, the semiconductor laser chip or the optical waveguide type optical combiner may be formed on a Si substrate or a metal plate substrate. By forming the light source and the two-dimensional optical scanning mirror device on these substrates, there is an effect that the overall size after integration can be reduced.

This two-dimensional light beam scanning device and a two-dimensional scanning control unit that applies a two-dimensional optical scanning signal to the electromagnetic coil 70 to scan the emitted light emitted from the light source in two dimensions are provided, and the scanned emitted light is collected. By combining with an image forming unit that projects onto a surface to be projected, for example, a spectacle-type retinal scanning display can be obtained.

Japanese Unexamined Patent Publication No. 2016-118750 Japanese Unexamined Patent Publication No. 2019-20618 Japanese Unexamined Patent Publication No. 2019-35876

However, in the inventions described in Patent Documents 1 to 3, since the optical fiber and the optical waveguide are bundled at the exit end, the combined emission beam does not come out from one point, but the optical fiber and the optical wave guide. It will be emitted separately from each emission end of the waveguide. This has a drawback that, for example, when the emitted beam is two-dimensionally scanned and the image is projected on a screen or the like, the projected image is blurred.

Therefore, Patent Document 3 provides a configuration in which the blurring of the image is reduced as much as possible by making the distance between the emission ends close to 15 μm or less, but there is a drawback that it cannot be applied to high-definition image generation.

On the other hand, in the case of an optical waveguide type combiner, for example, a method of merging two optical waveguides into one instead of simply adjoining them to form one optical waveguide and combining them (Y-type combiner). Is widely known (see, for example, Non-Patent Document 1). This method is simple, but when using an optical waveguide that can propagate only in the basic mode, in principle, when one light beam is used, light leaks at the confluence part, and the combined light beam It is known that the power is reduced by 3 dB (1/2) (see, for example, Non-Patent Document 1).

In the case of image generation using this combined wave light, in order to prevent unnecessary optical interference and speckle noise, an optical waveguide that propagates in the basic mode is usually used, and the optical wave guide is reduced by 3 dB. Waveguides are a fatal drawback in terms of light efficiency. The present invention solves the problems of the above-mentioned Patent Documents 1 to 3 and the problems of the Y-type combiner, can be miniaturized, and has a simple structure, and is a high-efficiency optical waveguide type combiner. Provide a vessel.

In one embodiment, the optical waveguide type combiner has a plurality of optical waveguides and a region in which light beams propagating through the plurality of optical waveguides are combined to form one optical waveguide on the emission end face side. The light beam whose exit end surface of the region propagates through the optical waveguide exists within a longitudinal range of 10% to 90% of the total leakage light leaking to the outside from the optical waveguide.

In another aspect, the light source module has the above-mentioned optical waveguide type combiner and a plurality of light sources that incident the light beam into the optical waveguide type combiner.

Further, in another aspect, the two-dimensional light beam scanning device includes the above-mentioned light source module and a two-dimensional light scanning mirror device that scans the combined light from the light source module in two dimensions.

Further, in another aspect, the light beam scanning image projection device includes the above-mentioned two-dimensional light beam scanning device and an image forming unit that projects the combined wave light scanned by the two-dimensional light scanning mirror device onto the projected surface. Has.

As one aspect, an optical waveguide type combiner that is easy to configure and manufacture can be obtained in an optical waveguide type combiner, a light source module, a two-dimensional optical beam scanning device, and an optical beam scanning type image projection device. In addition, the optical waveguide type combiner and the optical beam, which can be miniaturized by reducing the loss of the optical beam intensity in the branch type optical waveguide that constitutes the combiner of the optical waveguide type combiner, and have a simple configuration. A scanning image projection apparatus is provided.

It is explanatory drawing of the optical waveguide type combiner of embodiment of this invention. It is explanatory drawing of the leakage light in a Y type optical combiner. It is explanatory drawing of the wave combination principle in embodiment of this invention. It is explanatory drawing of the range of the beam spread in embodiment of this invention. It is explanatory drawing of the optical waveguide type combiner of Example 1 of this invention. It is explanatory drawing of the optical waveguide type combiner of Example 2 of this invention. It is explanatory drawing of the optical waveguide type combiner of Example 3 of this invention. It is explanatory drawing of the optical waveguide type combiner of Example 4 of this invention. It is explanatory drawing of the optical waveguide type combiner of Example 5 of this invention. It is explanatory drawing of the optical waveguide type combiner of Example 6 of this invention. It is a schematic perspective view of an example of a conventional two-dimensional light beam scanning apparatus.

Here, the optical waveguide type combiner according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is an explanatory view of an optical waveguide type combiner according to an embodiment of the present invention, FIG. 1 (a) is a plan view, and FIG. 1 (b) is a cross-sectional view on the incident end face side. Here, the light sources 21 to 23 are added to describe the light source module. The optical waveguide type combiner according to the embodiment of the present invention has a plurality of optical waveguides 13 to 15 and an optical waveguide region 17 in which light beams propagating through the plurality of optical waveguides 13 to 15 are combined on the emission end face side. Have. Here, when there is no emission end face, the light beams propagating in the plurality of optical waveguides 13 to 15 have the light beams confined in the optical waveguides 13 to 15 due to the gradual narrowing of the distance between the optical waveguides 13 to 15. , Gradually leaks from the optical waveguide to the outside, and finally, the three optical waveguides are completely integrated into one, and in a state of being confined in the optical waveguide, the optical waveguide is stably provided without leaking to the outside. It will propagate. However, the light beam propagating through the three optical waveguides is within the range of 10% to 90% of the total leaked light leaking to the outside from the optical waveguides 13 to 15 before stably propagating through one optical waveguide. Is provided with an emission end surface, and the range between the position in the longitudinal direction where leakage has begun and the emission end is defined as the optical waveguide region 17.

As shown in FIG. 1 (b), each optical waveguide 13 to 15 is composed of a core (13 to 15), a lower clad row 12 surrounding the core (13 to 15), and an upper clad layer 16. Due to the total reflection caused by the refractive index of the core being higher than the refractive index of the cladding, the light is confined in the cores of the optical waveguides 13 to 15 and the light propagates. The cross section of the cores of the optical waveguides 13 to 15 is preferably square or circular, but of course, the cross section may be rectangular or elliptical. In these cases, the height of the core is different from the width of the core.

FIG. 2 is an explanatory diagram of leaked light in the Y-type optical combiner. Light that combines waves is incident on the

optical waveguides

2 and 3 provided on the substrate 1 from the light incident ends 4 and 5. Light may be incident by arranging light sources such as semiconductor lasers and LEDs directly facing each other at the light incident ends 4 and 5, and light may be incident through a lens, or from a front-sphere optical fiber or the like. It may be incident.

The incident light is guided by the

optical waveguides

2 and 3, respectively, and reaches the optical wave wave region 6, where the light is combined, and if there is a light emission end 7, the light emission end 7 is directed toward the external space. Be radiated. When the propagating light is the basic mode light, leakage light to other than the optical waveguide peculiar to the Y-type optical waveguide occurs in the photosynthetic wave region 6, and the power of the light propagating in the optical waveguide is significantly reduced.

That is, the light beams propagating in the

optical waveguides

2 and 3 gradually narrow the distance between the

optical waveguides

2 and 3, so that the light beams confined in the

optical waveguides

2 and 3 gradually move from the

optical waveguides

2 and 3. It leaks to the outside, and finally, the two

optical waveguides

2 and 3 are completely integrated into one, and in a state of being confined in the

optical waveguides

2 and 3, the optical waveguide is stably provided without leaking to the outside. It will propagate. However, the light beam propagating through the two

optical waveguides

2 and 3 leaks to the outside from the

optical waveguides

2 and 3 before it stably propagates through one optical waveguide as the light beam 9 that propagates stably. Reference numeral 10 in the figure is the entire leaked light. In FIG. 2, the region surrounded by the alternate long and short dash line is the region of 0% to 100% of the leaked light, and the region surrounded by the dotted line is the region of 10% to 90%.

However, as shown in FIG. 3, by bringing the light emitting end 7 closer to the region where the

optical waveguides

2 and 3 intersect, both the leaked light and the light propagating in the waveguide are equally directed toward the outside as synchrotron radiation 8. Be radiated. Therefore, since the synchrotron radiation 8 is radiated from a narrow region to the outside, the light loss peculiar to the Y-type optical combiner is substantially eliminated. Specifically, the emission end face 7 is provided within a range of 10% to 90% of the total leakage light, and the range between the longitudinal position where the leakage starts and the emission end surface 7 is defined as the photosynthetic wave region 6. Twice

What is important here is that the phase of the leaked light and the phase of the light originally propagating in the

optical waveguides

2 and 3 are almost the same, so that unnecessary interference and specifications between the leaked light and the light propagating in the

optical waveguides

2 and 3 are required. No interference is generated, and light emission with excellent light quality can be obtained. In addition, although the case where the propagating light is the basic mode light is described here, even in the mode higher than the basic mode, when the mode number is small, the leakage light and the inside of the

optical waveguide

2 and 3 are similarly described. No unnecessary interference or speckle noise with the propagated light occurs. Therefore, if the propagation of the basic mode is the maximum component, the same configuration can be applied to modes higher than the basic mode and when light with a smaller mode number propagates.

The optical wave-guided region 6 is a region in which the

optical waveguides

2 and 3 are combined, and when the light incident from the light incident ends 4 and 5 gradually begins to transfer to the adjacent

optical waveguides

2 and 3, at the same time, the core of the optical waveguide It is a region between the position in the longitudinal direction of the waveguide and the light emitting end 8 where radiation starts as leaked light to the outside and the leaked light becomes 10% of the total leaked light. The light emitting end 8 is formed at a position in the longitudinal direction before the leaked light becomes 90% of the total leaked light. Specifically, the length h of the optical wave region 6 is the position in the longitudinal direction of the combiner where radiation starts as leaked light outside the core of the optical waveguide and the leaked light becomes 10% of the total leaked light. It is defined by the distance from the light emitting end. The smaller h is, the better, but it is sufficient as long as the phase difference between the leaked light and the light that should originally propagate does not become large. Specifically, it has been confirmed that when h is 300 μm or less, more preferably 200 μm or less, the influence of the phase difference is small.

Further, it is most desirable that the spread d of the synchrotron radiation emitted from the photosynthetic region 6 at the light emitting end can be regarded as a point light source, and it is better that it is small, but the desirable value is 15 μm or less. As shown in FIG. 4, the spread d at the light emission end of the synchrotron radiation is defined by the full width at half maximum of the light power distribution.

The core diameters of the optical waveguides 13 to 15 may be the same, but as shown in FIG. 1, when light having different wavelengths is incident on the three optical waveguides 13 to 15, each optical waveguide 13 to 15 depends on the wavelength. It is advisable to make the diameters different from each other so as to propagate the basic mode. However, even if the diameter is such that the next higher-order mode after the basic mode can propagate, the higher-order mode attenuates in a short distance, so unless a large number of modes are propagated, the basic mode is practically the same. It can be a propagating optical waveguide. In this case, the light that leaks to the outside at the earliest spreads the most at the exit end face, so the length of the optical wave region 17 is defined by the optical waveguide that leaks the light to the outside at the earliest.

Alternatively, the core diameter of the optical waveguides 13 to 15 may be gradually reduced from the incident side, and the diameter of the light emitting end may be smaller than the light incident end. In this case, a homogeneous emitted light beam can be obtained as compared with the case where the core diameters of the optical waveguides 13 to 15 do not change over the entire length of the optical waveguide.

The number of optical waveguides 13 to 15 is arbitrary, but when three optical waveguides 13 to 15 are used, red, green, and blue light beams are incident on each of the three optical waveguides 13 to 15, respectively. An optical waveguide type combiner of the three primary colors of light can be obtained.

Further, the number of optical waveguides may be four or more, and in that case, for example, in addition to the three primary colors of light, red, green, and blue, infrared light, ultraviolet light, or yellow is propagated. An optical waveguide may be added, and the optical waveguide may be aligned near the light emitting end.

Note that the light incident ends do not have to be all formed on the same end face, and the optical waveguide may be provided with a bent waveguide that bends the light at a right angle. In this case, bending loss occurs and the combined wave efficiency is slightly deteriorated, but the influence of stray light due to incident light can be reduced.

In order to form the light source module, as shown in FIG. 1A, a plurality of light sources 21 to 23 that inject a light beam into the optical waveguide type combiner may be combined. A semiconductor laser is typical as the light sources 21 to 23 in this case, but a light emitting diode (LED) may also be used. Further, a lens may be provided between the plurality of light sources 21 to 23 and the incident ends of the plurality of optical waveguides 13 to 15 of the optical combiner. Further, instead of the light sources 21 to 23, the optical fiber emission end may be installed at the position of the light source to guide the light emitted from the optical fiber to the optical waveguides 13 to 15.

In order to form the two-dimensional optical beam scanning apparatus, the optical combiner in the two-dimensional optical scanning apparatus shown in FIG. 11 may be combined with the above-mentioned optical waveguide type combiner. Further, in order to form the image projection device, the above-mentioned two-dimensional scanning device and the two-dimensional scanning in which a two-dimensional optical scanning signal is applied to the electromagnetic coil 70 to scan the emitted light emitted from the light source in two dimensions. The control unit and the image forming unit that projects the scanned emitted light onto the projected surface may be combined. As the image projection device, a spectacle-type retinal scanning display is typical.

Next, the optical waveguide type combiner according to the first embodiment of the present invention will be described with reference to FIG. 5A and 5B are explanatory views of the optical waveguide type combiner according to the first embodiment of the present invention, FIG. 5A is a plan view, and FIG. 5B is a cross-sectional view on the incident end face side. Here, the light sources 41 to 43 will be added to describe the light source module. As shown in FIG. 5A, the optical waveguide type optical waveguide of the first embodiment of the present invention is an optical waveguide 33 having a plurality of core widths of 2 μm that injects light from a plurality of light sources 41 to 43 having different wavelengths. The light combined by the optical combiner unit 37, which has to 35 and combines the light propagating through the optical waveguides 33 to 35, is emitted from the exit end face.

As shown in FIG. 5A, the light beam from the red semiconductor laser chip (41) is input to the optical waveguide 33, the light beam from the green semiconductor laser chip (42) is input to the optical waveguide 34, and the blue semiconductor The light beam from the laser chip (43) is input to the optical waveguide 35.

_{As shown in FIG. 4B, each optical waveguide has a SiO 2} layer 32 having a thickness of 1 mm and a thickness of 20 μm provided on the (100) plane Si substrate 31 as a lower clad layer, and the SiO ₂ layer. A core layer having a width × height of 2 μm × 2 μm is formed by etching _{the Ge-doped SiO 2} glass provided on the 32, and an upper clad layer composed _{of a SiO 2 layer having a thickness of 9 μm on the core layer is formed on the core layer.} 36 ( _{thickness on the SiO 2} layer 22 is 11 μm) is provided. In this case, the difference in refractive index between the core layer and the clad layer is 0.5%.

The total length of the optical combiner is 2000 μm, and the width is 300 μm. Further, the distance between the incident ends of the optical waveguides 33 to 35 is 100 μm. The atmosphere outside the optical waveguide type combiner is air, and the length of the optical waveguide region 37 is 140 μm.

Here, the wavelength of the light incident on the optical waveguide 33 is 638 nm (red), the wavelength of the light incident on the optical waveguide 34 is 520 nm (green), and the wavelength of the light incident on the optical waveguide 35 is 450 nm (blue). do. As a light incident method, light is incident through light sources 41 to 43 arranged at intervals of 10 μm. At this time, the synchrotron radiation from the emission end of the combined light and the horizontal radiation full angle are 8 deg (three color average), the vertical radiation full angle is 5 deg (three color average), and the combined wave efficiency is 90% (three colors). Average). In Example 1, red light was incident on the optical waveguide 33, green light was incident on the optical waveguide 34, and blue light was incident on the optical waveguide 35. Naturally, blue light was incident on the optical waveguide 33, red light on the optical waveguide 34, and optical waveguide 34. Green light may be incident on the 35, and it goes without saying that the same effect can be obtained with other combinations. Such other combinations are the same in the examples described below.

Next, the optical waveguide type combiner according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a plan view of the optical waveguide type combiner according to the second embodiment of the present invention, and FIG. 6B is a cross-sectional view of the incident end face side. Here, too, the light sources 41 to 43 will be added to describe the light source module. As shown in FIGS. 6 (a) and 6 (b), the optical waveguide type optical waveguide of the second embodiment of the present invention has a plurality of optical waveguides 33 to 35 having different widths in the first embodiment. The other configurations are the same as those in the first embodiment.

The core width of the optical waveguide 33 that guides 638 nm (red) light is 2.2 μm, and the core width of the optical waveguide 34 that guides 520 nm (green) light is 1.9 μm, guiding 450 nm (blue) light. The core width of the wave-guided optical waveguide 35 is 1.7 μm. The height of the cores of all the optical waveguides 33 to 35 is 2 μm and does not change in the longitudinal direction, and the width and height of the cores at the emission ends of the combined light are 2 μm × 2 μm. The length of the entire optical waveguide type combiner is 2000 μm, the width is 300 μm, the distance between the incident ends of the optical waveguides 33 to 35 is 100 μm, and the length of the optical waveguide region 37 is 120 μm. Synchrotron radiation from the emission end of the combined light and full-width lateral radiation are 8 deg (average of 3 colors), respectively.
The vertical radiation full-width is 5 deg (three-color average), and the combined wave efficiency is 90% (three-color average).

In the second embodiment, the widths of the cores of the three optical waveguides 33 to 35 are optimized so that the light propagating in each of them propagates as the basic mode, and the structure is such that the higher-order mode is less likely to be excited. There is. Therefore, unnecessary inter-mode interference does not occur in the emitted light.

Next, the optical waveguide type combiner according to the third embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 is a plan view of the optical waveguide type combiner according to the third embodiment of the present invention, and FIG. 7B is a cross-sectional view of the incident end face side. Here, too, the light sources 41 to 43 will be added to describe the light source module. As shown in FIG. 7A, the optical waveguide is changed to a tapered shape with a width of 33 to 35. The core width and height at the light incident ends of the three optical waveguides 33 to 35 were all the same 2 μm × 2 μm, and the core width and height at the emitted end of the combined light were set to 0.3 μm × 2 μm. It is a thing. The length of the optical combiner portion 37 is 180 μm, and other configurations are the same as those in the first embodiment.

Here, the wavelength of the light incident on the optical waveguide 23 is 638 nm (red), the wavelength of the light incident on the optical waveguide 24 is 520 nm (green), and the wavelength of the light incident on the optical waveguide 25 is 450 nm (blue). do. As a light incident method, light is incident through light sources 31 to 33 arranged at intervals of 100 μm. At this time, the synchrotron radiation from the emission end of the combined light and the horizontal radiation full angle are 7 deg (three color average), the vertical radiation full angle is 4 deg (three color average), and the combined wave efficiency is 90% (three colors). Average).

Next, the optical waveguide type combiner according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a plan view of the optical waveguide type combiner according to the fourth embodiment of the present invention, and FIG. 8B is a cross-sectional view of the incident end face side. In addition, here, the leading ball fibers 44 to 47 serving as a light source are added and described as a light source module. As shown in FIGS. 8A and 8B, the optical waveguide 38 for infrared waveguide is added to the plurality of optical waveguides 33 to 35 in the optical waveguide type optical waveguide of the first embodiment of the present invention. Yes, other configurations are the same as in Example 1 above.

As shown in FIG. 8A, the optical waveguide type optical waveguide of the fourth embodiment of the present invention is an optical waveguide 33 having a core width of 2 μm that injects light from a plurality of front bulb fibers 44 to 47 having different wavelengths. An optical waveguide 38 having an acore width of 4 μm is provided, and the light combined by the optical waveguide unit 37 that combines the light propagating through the optical waveguides 33 to 35, 38 is emitted from the exit end face.

As shown in FIG. 8A, a light beam having a wavelength of 638 nm from the tip ball fiber 44 is input to the optical waveguide 33, and a light beam having a wavelength of 520 nm from the tip ball fiber 45 is input to the optical waveguide 34. A light beam having a wavelength of 450 nm from the fiber 46 is input to the optical waveguide 35, and a light beam having a wavelength of 1550 nm from the tip ball fiber 47 is input to the optical waveguide 38.

The total length of the optical combiner is 5000 μm, and the width is 700 μm. The distance between the incident ends of the optical waveguides 33 to 35, 38 is 130 μm. The atmosphere outside the optical waveguide type combiner is air, the length of the optical wave-guide region 37 is 300 μ, and the light incident method is as follows. Light is incident through. The total horizontal radiation angle of the synchrotron radiation from the emitted end of the combined light is 9 deg (4 color average), the vertical radiation full angle is 6 deg. (4 color average), and the combined wave efficiency is 80% (4). Color average).

Next, the optical waveguide type combiner of the fifth embodiment of the present invention will be described with reference to FIG. 9, but the arrangement of the light source in the first embodiment is changed. FIG. 9 is an explanatory diagram of the optical waveguide type combiner according to the fifth embodiment of the present invention, and here, light sources 41 to 43 are added to describe the light source module. As shown in FIG. 9, the light source 41 is arranged on one long side of the 21 substrate, and the light source 43 is arranged on the other long side of the substrate 21. Therefore, the structure is such that the optical wave guides 33 and 35 are bent at a right angle in the middle. A deep trench with a depth of 30 μm is formed by etching using a focused ion beam method using Ga at the bent portion, so that the waveguide light is totally reflected by the trench side wall. As described above, although the waveguide type reflector is used, a curved waveguide having a small radius of curvature may be used.

Synchrotron radiation from the emission end of the combined light in Example 5: The horizontal radiation full angle is 8 deg. (3 color average), the vertical radiation full angle is 5 deg. (3 color average), and the combined wave efficiency is 70%. ((3 color average), and the combined wave efficiency is a little worse. This is because bending loss occurs, but the influence of stray light due to incident light can be reduced. Thus, according to the present invention. In the fifth embodiment, since the

light sources

41 and 43 are arranged on the long side of the substrate 21, the length of the light source module can be shortened when the light source module is configured.

Next, the optical waveguide type optical coupler according to the sixth embodiment of the present invention will be described with reference to FIG. FIG. 10 is an explanatory diagram of the optical waveguide type optical waveguide of the sixth embodiment of the present invention, and again, a light source is added and shown as a light source module so that the invention can be easily understood. As shown in FIG. 10, all the light sources 41 to 43 are arranged on one long side of the substrate 31. Here, too, a waveguide type reflector is used in order to bend at a right angle in the middle of the optical waveguides 33 to 35, but a curved waveguide having a small radius of curvature may be used.

Synchrotron radiation from the emission end of the combined light in the examples: The horizontal radiation full angle is 8 deg. (3 color average), the vertical radiation full angle is 5 deg. (3 color average), and the combined wave efficiency is 70% (3 color average). (3 color average), and the combined wave efficiency is a little worse. This is because bending loss occurs, but the influence of stray light due to incident light can be reduced. Thus, the implementation of the present invention. In Example 6, since the light sources 41 to 43 are arranged on one long side of the substrate 31, the width of the light source module can be shortened when the light source module is configured.

Next, the two-dimensional optical beam scanning apparatus according to the eighth embodiment of the present invention will be described. However, the basic configuration is the conventional two-dimensional optical beam scanning shown in FIG. 11, only the configuration of the optical waveguide type combiner is different. Since it is the same as the device, FIG. 11 will be borrowed and described. The two-dimensional optical beam scanning apparatus of Example 7 of the present invention replaces the optical waveguide type combiner 50 in the two-dimensional optical beam optical scanning apparatus of FIG. 11 with the optical waveguide type combiner shown in Example 1 above. It is a thing. The optical waveguide type combiner may be replaced with the optical waveguide type combiner shown in Examples 2 to 6.

1

Substrates

2, 3

Optical waveguides

4, 5 Light incident end faces 6 Light confluence region 7 Light emission end faces 8 Emitted light 9 Stable propagating light beam 10 Overall leaked

light

11, 31

Substrate

12, 32 Lower clad layers 13 to 15, 33-35,38

Optical waveguide

16,36 Upper clad

layer

17,37 Optical wave region 21-23, 41-43 Light source 44-47 Tip bulb fiber 50 Optical waveguide type combiner 51 Blue semiconductor laser chip 52 Green semiconductor laser chip 53 Red semiconductor laser chip 60 Substrate 61 Movable mirror part 70 Electromagnetic coil

Claims

With multiple optical waveguides
On the exit end face side, the light beams propagating through the plurality of optical waveguides have a region that becomes one optical waveguide while being combined.
An optical waveguide type combined wave in which the emission end surface of the region is such that the light beam propagating through the optical waveguide exists in the longitudinal range of 10% to 90% of the total leaked light leaking from the optical waveguide to the outside. vessel.
The optical waveguide type combiner according to claim 1, wherein the plurality of optical waveguides are optical waveguides in which propagation in the basic mode is the maximum component.
The optical waveguide type according to claim 1 or 2, wherein at least one of the widths and heights of the cores of the plurality of optical waveguides gradually decreases from the light incident end face side of the plurality of optical waveguides toward the exit end face. Waveguide.
The optical waveguide type combiner according to any one of claims 1 to 3, wherein at least one of the core widths and heights of the plurality of optical waveguides is different from each other.
The optical waveguide type combiner according to any one of claims 1 to 4, wherein the number of the plurality of optical waveguides is three.
The optical waveguide type combiner according to claim 5, wherein the three optical waveguides are an optical waveguide that guides red light, an optical waveguide that guides green light, and an optical waveguide that guides blue light.
The optical waveguide type combiner according to any one of claims 1 to 4, wherein the number of the plurality of optical waveguides is 4 or more.
The optical waveguide type combiner according to any one of claims 1 to 7, wherein the length of the region is 200 μm or less.
The optical waveguide type combiner according to any one of claims 1 to 8, wherein the full width at half maximum of the optical power distribution at the emission end surface of the combined wave light emitted from the optical combined wave region is 15 μm or less.
The optical waveguide type combiner according to any one of claims 1 to 9.
A light source module having a plurality of light sources that incident the light beam on the optical waveguide type combiner.
The light source module according to claim 10, wherein a lens is provided between the plurality of light sources and a plurality of input optical waveguides of the optical waveguide type combiner.
The light source module according to claim 10 or 11, wherein the plurality of light sources are light sources emitted from a plurality of optical fibers.
The light source module according to any one of claims 10 to 12.
A two-dimensional light beam scanning device including a two-dimensional light scanning mirror device that two-dimensionally scans combined light from the light source module.
The two-dimensional optical scanning apparatus according to claim 13,
An optical beam scanning type image projection device including an image forming unit that projects the combined wave light scanned by the two-dimensional optical scanning mirror device onto a projected surface.