JP2022130562A - light source module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source module with which optical losses are suppressed.

SOLUTION: A light source module comprises a plurality of visual light sources for outputting visual lights mutually differing in wavelength, and an optical waveguide circuit optically connected to each of the plurality of visible light sources. The optical waveguide circuit includes a plurality of waveguides optically connected to one of the visible light sources and respectively guiding the light outputted from one of the visible light sources, at least one multiplexer/splitter optically connected to one of the waveguides and multiplexing or splitting the light guided through one of the waveguides, a clad for enclosing the plurality of waveguides and the at least one multiplexer/splitter, and a polarization synthesizer/separator for polarization synthesizing or separating two visible lights the polarized waves of which are orthogonal to each other, the plurality of waveguides and the at least one multiplexer/splitter being composed of quartz glass that contains zirconia (ZrO₂).

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a light source module that outputs visible light.

In recent years, the development of portable projectors, head-up displays (HUDs), head-mounted displays (HMDs), etc. has been accelerating, and there is a strong demand for ultra-miniaturization of scanning laser projection devices. 2. Description of the Related Art As a main component of a scanning laser projection apparatus, there is a multiplexing module that multiplexes light output from each of a red light source, a green light source, and a blue light source, which are visible light sources. A light source module is configured including a visible light source and a multiplexing module.

As a multiplexing module, there is one manufactured using a spatial coupling technique such as a dichroic mirror. However, the spatial coupling type multiplexing module requires extremely precise mounting of multiple parts such as lenses, which causes an increase in module size, and an increase in optical system loss due to axis misalignment during assembly. There are some issues that may arise. Therefore, a planar lightwave circuit (PLC) type multiplexing module composed of a silica-based glass waveguide that can be manufactured using a semiconductor process is attracting attention as a means for solving the above problems. (See Patent Documents 1 to 3).

JP 2013-195603 A JP 2019-35876 A WO2017/065225

In an optical waveguide circuit such as a PLC, germania (GeO ₂ ) is generally added as a dopant for increasing the refractive index to the core that constitutes the waveguide. However, when a multiplexing module of an optical waveguide circuit composed of a germania-doped core is applied to visible light, the optical loss of the multiplexing module may increase.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light source module in which light loss is suppressed.

In order to solve the above-described problems and achieve an object, a light source module according to one aspect of the present invention includes a plurality of visible light sources that output visible light having different wavelengths, and and an optical waveguide circuit optically connected, wherein the optical waveguide circuit is optically connected to one of the visible light sources and guides the light output from one of the visible light sources, respectively. a plurality of waveguides, and at least one multiplexer/demultiplexer that is optically connected to any of the waveguides and multiplexes or demultiplexes each of the lights guided through any of the waveguides. , a cladding surrounding the plurality of waveguides and the at least one multiplexer/demultiplexer; and the plurality of waveguides and the at least one multiplexer/demultiplexer are made of silica-based glass containing zirconia (ZrO ₂ ).

The plurality of waveguides and the at least one multiplexer/demultiplexer may guide the visible light in a single mode.

The optical waveguide circuit has a first end face into which the visible light is input and a second end face from which the visible light is output, and the first end face and the second end face are substantially perpendicular to each other. good too.

The plurality of visible light sources may include a plurality of visible light sources that output visible light with overlapping spectra, and the at least one multiplexer/demultiplexer may multiplex or demultiplex the visible lights with overlapping spectra. .

The optical waveguide circuit may further include an optical switch for switching a waveguide from which the visible light is output.

The plurality of visible light sources may include a visible light source having a luminous body that outputs visible light having a wavelength different from that of the irradiated primary light, and may include a primary light source that outputs the primary light to irradiate the luminous body. .

The plurality of visible light sources may include a red light source that outputs red light, a green light source that outputs green light, and a blue light source that outputs blue light.

At least one of the plurality of waveguides may be bent.

The plurality of waveguides and the at least one multiplexer/demultiplexer may have a zirconia (ZrO ₂ ) concentration of 2 mol % or more.

The plurality of waveguides and the at least one multiplexer/demultiplexer may have a zirconia (ZrO ₂ ) concentration of 7.75 mol % or more.

The clad may be made of pure silica glass, and in the blue region, the plurality of waveguides and the at least one multiplexer/demultiplexer may have a relative refractive index difference of 0.8% or more with respect to the clad.

The plurality of waveguides and the at least one multiplexer/demultiplexer may have a relative refractive index difference of 3.5% or more.

ADVANTAGE OF THE INVENTION According to this invention, it is effective in the ability to implement|achieve the light source module by which the optical loss was suppressed.

FIG. 1 is a schematic configuration diagram of a light source module according to Embodiment 1. FIG. FIG. 2 is a diagram showing a part of the cross section taken along the line XX of FIG. FIG. 3 is a diagram showing an example of the relationship between the relative refractive index difference Δ and the core size. FIG. 4 is a diagram showing an example of the relationship between the relative refractive index difference Δ and the dopant concentration. FIG. 5 is a diagram showing an example of deformation of the waveguide. FIG. 6 is a diagram showing an example of the application range of the core size and the dopant material with respect to the relative refractive index difference Δ. FIG. 7 is a schematic configuration diagram of a light source module according to Embodiment 2. FIG. FIG. 8 is a schematic configuration diagram of a light source module according to Embodiment 3. FIG. FIG. 9 is a schematic configuration diagram of a light source module according to Embodiment 4. FIG. 10 is a schematic configuration diagram of a light source module according to Embodiment 5. FIG. 11A and 11B are diagrams showing a schematic configuration and operation of a light source module according to Embodiment 6. FIG. FIG. 12 is a schematic configuration diagram of a light source module according to Embodiment 7. FIG. 13 is a schematic configuration diagram of a light source module according to Embodiment 8. FIG.

Embodiments will be described below with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, in the description of the drawings, the same or corresponding elements are given the same reference numerals as appropriate. Also, it should be noted that the drawings are schematic, and the relationship of dimensions of each element, the ratio of each element, and the like may differ from reality. Even between the drawings, there are cases where portions with different dimensional relationships and ratios are included.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a light source module according to Embodiment 1. FIG. The light source module 100 includes a plurality of visible light sources, namely, a green light source 11, a blue light source 12, and a red light source 13, and an optical waveguide circuit 20, which is a PLC made of silica glass.

Green light source 11, blue light source 12, and red light source 13 are, for example, semiconductor laser elements. The green light source 11 outputs green visible light L1. The wavelength of visible light L1 is, for example, 495 nm to 570 nm. The blue light source 12 outputs blue visible light L2. The wavelength of visible light L2 is, for example, 450 nm to 495 nm. The red light source 13 outputs red visible light L3. The wavelength of visible light L3 is, for example, 620 nm to 750 nm. The visible lights L1, L2, and L3 have different wavelengths.

The optical waveguide circuit 20 is optically connected to each of the green light source 11, the blue light source 12, and the red light source 13. FIG. In this embodiment, the optical waveguide circuit 20 has a first end face 20a and a second end face 20b facing the first end face 20a. The green light source 11, the blue light source 12, and the red light source 13 are connected to the first end surface 20a through bad joints.

The optical waveguide circuit 20 has waveguides 21 , 22 , 23 , 25 and 27 , multiplexers/demultiplexers 24 and 26 and a clad 28 . The waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26 are a plurality of waveguides optically connected to the green light source 11, the blue light source 12, and the red light source 13, and at least one Corresponds to multiplexer/demultiplexer.

The cladding 28 surrounds the waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26. FIG. FIG. 2 shows a state in which the cladding 28 surrounds the waveguide 27 . The clad 28 includes a lower clad 28a positioned below each waveguide and multiplexer/demultiplexer, and an upper clad 28b positioned above and laterally of each waveguide and multiplexer/demultiplexer. The clad 28 is formed on, for example, a silicon substrate or a glass substrate (not shown).

The waveguide 21 is optically connected to the green light source 11 at the first end surface 20a, and guides the visible light L1. The waveguide 22 is optically connected to the blue light source 12 at the first end face 20a and guides the visible light L2. The waveguide 23 is optically connected to the red light source 13 at the first end surface 20a, and guides the visible light L3. That is, visible lights L1, L2, and L3 are input to the first end surface 20a.

The multiplexer/demultiplexer 24 is optically connected to the waveguides 21 , 22 and 25 . The multiplexer/demultiplexer 24 multiplexes the visible light L<b>1 and the visible light L<b>2 and outputs the combined light to the waveguide 25 . The waveguide 25 guides the visible light L1 and the visible light L2.

The multiplexer/demultiplexer 26 is optically connected to the waveguides 23 and 25 . The multiplexer/demultiplexer 26 multiplexes the visible light L1, the visible light L2, and the visible light L3, and outputs the combined light to the waveguide 27. FIG.

The multiplexers/demultiplexers 24 and 26 have a known configuration, such as a directional coupler type, a multimode interference type, or a Y-branch type, and have a structure including waveguides. Due to the reciprocity of light, the multiplexers/demultiplexers 24 and 26 also have a demultiplexing function. For example, when visible light L1 and visible light L2 are input from waveguide 25, multiplexer/demultiplexer 24 can demultiplex these and output them to waveguides 21 and 22, respectively.

The waveguide 27 is optically connected to the multiplexer/demultiplexer 26 . The waveguide 27 guides visible light L1, visible light L2, and visible light L3, and is RGB light including visible light L1, visible light L2, and visible light L3 from the second end surface 20b of the optical waveguide circuit 20. It outputs visible light L4.

The waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26 will be described more specifically. The waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26 are made of silica-based glass containing zirconia (ZrO ₂ ), which is a dopant that increases the refractive index. On the other hand, clad 28 is made of, for example, pure silica glass. Here, pure silica glass is defined as including silica glass containing no impurities and silica glass containing impurities but not containing impurities that change the refractive index of silica glass. The relative refractive index difference Δ of the waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26 with respect to the clad 28 is 3.5% in this embodiment. The mode field diameters of green light source 11, blue light source 12, and red light source 13 are elliptical, such as 1 μm×15 μm or 1 μm×30 μm. Therefore, by setting the relative refractive index difference Δ to 3.5%, the core size of the waveguides 21, 22, and 23 can be reduced to about 1 μm×1 μm. Thereby, the connection loss in the butt-joint connection between the green light source 11, the blue light source 12, and the red light source 13 can be reduced to about 0.1 dB. The waveguides 21, 22, 23, 25, 27 and the multiplexer/demultiplexers 24, 26 have a cross-sectional size and a relative refractive index difference Δ under the condition that at least the guided visible light is guided in a single mode. relationship is set. However, the waveguides 21, 22, 23, 25, 27 and the multiplexer/demultiplexers 24, 26 have cross-sectional sizes and relative refractive index differences Δ and relationship may be set.

All of the waveguides 21, 22, 23, 25 and 27 are bent. For example, the waveguide 25 is bent into a U-turn shape twice, and its maximum bending radius is 150 μm. The waveguide 27 is bent in an S shape and has a maximum bending radius of 250 μm. Since the relative refractive index difference Δ is as high as 3.5%, bending loss is extremely reduced even if the bending radius of the waveguide 25 is 150 μm. By bending the waveguide in this way, the length of the light source module 100, that is, the distance between the first end surface 20a and the second end surface 20b, is shortened, and the degree of freedom in layout of the waveguide is increased. The bending radii of the waveguides 21, 22, 23, 25 and 27 can be further reduced as the relative refractive index difference Δ is increased. When the relative refractive index difference Δ is 3.5%, the minimum bending radii are 100 μm, 150 μm and 250 μm for wavelengths of 460 nm, 530 nm and 640 nm, respectively. The minimum bending radius is the minimum radius at which the loss due to bending is 0.05 dB or less when the waveguide is bent by 90 degrees.

The optical waveguide circuit 20 can be manufactured, for example, as follows. First, by FHD (Flame Hydrolysis Deposition) method, fine particles of silica-based glass are deposited on a substrate and heated to turn the glass fine particles into transparent glass to form the lower clad 28a. Subsequently, a silica-based glass fine particle layer, which serves as a waveguide, is deposited on the lower clad 28a by sputtering. At this time, zirconia is added to SiO ₂ to make the refractive index of the silica-based glass fine particle layer higher than that of the lower clad 28a. Subsequently, an etching mask made of resist is formed by photolithography using a photomask having a circuit pattern of the waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26 of the optical waveguide circuit 20. FIG. Subsequently, using an etching gas such as a fluorine-based gas, the silica-based glass fine particle layer not covered with the etching mask is dry-etched. Next, fine particles of silica-based glass are deposited by the FHD method and heated to turn the fine particles of glass into transparent glass to form the upper clad 28b.

The effects of including zirconia in the waveguides 21, 22, 23, 25 and 27 for guiding or combining visible light and the multiplexers/demultiplexers 24 and 26 will be described in more detail.

FIG. 3 is a diagram showing an example of the relationship between the relative refractive index difference Δ and the core size. The core size is the length of one side of a square when the cross-sectional shape of the waveguide perpendicular to the longitudinal direction is a square. The core size indicates a value that can guide light of wavelength λ in a single mode. As the wavelength λ, as shown in FIG. It is necessary to significantly reduce the core size. For example, when the relative refractive index difference Δ is 0.45%, the core size is 7.5 μm on a side at a wavelength of 1550 nm, and 3 μm on a side at a wavelength of 460 nm. FIG. 3 shows the case of single-mode waveguide, but also in the case of multi-mode waveguide, the wavelength dependence of the core size shows a similar tendency.

Moreover, FIG. 4 is a diagram showing an example of the relationship between the relative refractive index difference Δ and the dopant concentration. Here, the dopant concentration is the concentration in quartz glass. As shown in FIG. 4, the dopant concentration required for zirconia to achieve the same relative refractive index difference Δ is about 1/4 or less of germania.

Ｉはレイリー散乱光の強度、Ｉ_０は入射光の強度、λはレイリー散乱光の波長、Ｒはドーパント粒子からの距離、Ｖはドーパント粒子の体積、θは散乱角、ｎはドーパント粒子の屈折率である。 Here, if a dopant exists in the waveguide, the dopant generates Rayleigh scattered light. The generation of Rayleigh scattered light causes light loss. The following formula holds for the intensity of Rayleigh scattered light generated by dopant particles in quartz glass.

I is the intensity of the Rayleigh scattered light, _I0 is the intensity of the incident light, λ is the wavelength of the Rayleigh scattered light, R is the distance from the dopant particle, V is the volume of the dopant particle, θ is the scattering angle, and n is the refraction of the dopant particle. rate.

As can be seen from the above equation, the Rayleigh scattered light intensity is inversely proportional to λ to the fourth power. Therefore, Rayleigh scattered light is stronger in the visible light region than when λ is 1550 nm. On the other hand, the Rayleigh scattered light intensity is inversely proportional to R squared. Therefore, when zirconia is used as a dopant, the dopant concentration for realizing the same relative refractive index difference Δ can be reduced to about 1/4 or less compared to germania, so that ^R2 can be increased to about 16 times or more. As a result, the use of zirconia as a dopant can reduce the intensity of Rayleigh scattered light, thereby suppressing light scattering.

Furthermore, glasses generally have a lower softening point at higher dopant concentrations. Therefore, when a dopant is added to a waveguide of an optical waveguide circuit, the waveguide may be deformed in a 1000° C.-class heating step such as vitrification in the manufacturing process. For example, in FIG. 5, the waveguide patterns 121 and 122 of the germania-doped silica-based glass fine particle layer are formed on the lower clad 128a, and then the silica-based glass fine particle layer 128b serving as the upper clad is formed by the FHD method. indicates the case. In this case, stress is applied to the waveguide patterns 121 and 122 of the directional coupler softened under high temperature in the FHD method from the silica-based glass fine particle layer 128b, and the waveguide patterns 121 and 122 are deformed so as to be inclined toward each other. Sometimes.

On the other hand, when zirconia is used as a dopant, the dopant concentration for realizing the same relative refractive index difference Δ can be reduced to about 1/4 or less compared to the case of germania, so deformation of the waveguide is suppressed. be able to. Furthermore, the melting point of zirconia is 2715° C., which is about 2.5 times higher than the melting point of germania, and the mechanical strength is also high, so deformation can be suppressed even at a higher concentration. In particular, as shown in FIG. 3, when using light in the visible light region, it is necessary to significantly reduce the core size. Therefore, suppressing the deformation of the waveguide is suitable for making the shape and size of the waveguide highly accurate.

FIG. 6 is a diagram showing an example of the application range of the core size and the dopant material with respect to the relative refractive index difference Δ. As a wavelength band, a communication band of about 1530 nm to 1560 nm and a visible light region are shown, and in particular, 1550 nm and 460 nm are shown. The relationship between the core size and the relative refractive index difference Δ is the same as shown in FIG. The relationship between the relative refractive index difference Δ and the dopant concentration is the same as shown in FIG.

Region A is an example of a region having a relative refractive index difference Δ and a core size in which deformation of the waveguide does not occur at a high temperature of 1000° C. class. Note that the clad is pure quartz glass. Region B is an example of a region of relative refractive index difference Δ and core size in which deformation of the waveguide may occur at a high temperature of 1000° C. class. Region C is an example of a region of core size and relative refractive index difference Δ in which melting of the waveguide can occur at a high temperature of 1000° C. class. As shown in FIG. 6, at a wavelength of 1550 nm, the range of region A is relatively wide even in the case of germania, but at a wavelength of 460 nm, it is significantly narrower. On the other hand, in the case of zirconia, it can be seen that the range of region A is extremely wide. In the case of FIG. 6, at a wavelength of 460 nm in the blue region, if the relative refractive index difference Δ is 0.8% or more or the core size is 2.2 μm or less, the effect of zirconia is high, and the relative refractive index difference Δ is 3.5. % or more or the core size is 1 μm or less, the effect of zirconia is even higher. When this relative refractive index difference Δ is converted into a dopant concentration using the relationship of FIG. If so, the effect of zirconia is even higher.

It should be noted that the ranges of the regions A, B, and C, which are regions of the relative refractive index difference Δ and the core size shown in FIG.

As described above, the light source module 100 according to the first embodiment suppresses light loss due to Rayleigh scattering, and is a light source module with higher output. Further, in the light source module 100, since the waveguides 21, 22, 23, 25, 27 and the multiplexers/demultiplexers 24, 26 are highly accurate in size, the optical characteristics are highly accurate, and the manufacturability is also good. In addition, the light source module 100 has a high degree of freedom in layout and can be downsized, for example.

Here, a light source module having the same configuration as that of the light source module according to the first embodiment was produced. The multiplexer/demultiplexer was of multimode interference (MMI) type. The fabricated optical waveguide circuit could be fabricated in a very small size of 3 mm×0.5 mm in plan view. Moreover, the connection loss of the butt joint connection between each visible light source and the optical waveguide circuit was 0.2 dB or less. The loss from each visible light source to the output end of the optical waveguide circuit was 0.5 dB or less, and an extremely low loss could be realized.

(Embodiment 2)
FIG. 7 is a schematic configuration diagram of a light source module according to Embodiment 2. FIG. The light source module 100A includes a green light source 11, a blue light source 12, a red light source 13, and an optical waveguide circuit 20A.

The green light source 11, blue light source 12, red light source 13, and visible light L1, L2, and L3 are the same as the corresponding elements in the first embodiment.

The optical waveguide circuit 20A is optically connected to each of the green light source 11, the blue light source 12, and the red light source 13. FIG. In this embodiment, the optical waveguide circuit 20 has a first end surface 20Aa and a second end surface 20Ab that is substantially orthogonal to the first end surface 20Aa without facing it. The green light source 11, the blue light source 12, and the red light source 13 are connected to the first end surface 20Aa through bad joints.

The optical waveguide circuit 20A has waveguides 21A, 22A, 23A, 25A and 27A, multiplexers/demultiplexers 24A and 26A, and a clad 28A. The waveguides 21A, 22A, 23A, 25A, 27A and the multiplexers/demultiplexers 24A, 26A are a plurality of waveguides optically connected to the green light source 11, the blue light source 12, and the red light source 13, and at least one Includes multiplexer/demultiplexer.

The clad 28A surrounds the waveguides 21A, 22A, 23A, 25A, 27A and the multiplexers/demultiplexers 24A, 26A. The clad 28A has the same configuration as the clad 28 of the first embodiment.

The waveguide 21A is optically connected to the green light source 11 at the first end face 20Aa, and guides the visible light L1. The waveguide 22A is optically connected to the blue light source 12 at the first end surface 20Aa and guides the visible light L2. The waveguide 23A is optically connected to the red light source 13 at the first end surface 20Aa and guides the visible light L3.

The multiplexer/demultiplexer 24A is optically connected to the waveguides 21A, 22A and 25A. The multiplexer/demultiplexer 24A multiplexes the visible light L1 and the visible light L2 and outputs the multiplexed light to the waveguide 25A. The waveguide 25A guides the visible light L1 and the visible light L2.

The multiplexer/demultiplexer 26A is optically connected to the waveguides 23A and 25A. The multiplexer/demultiplexer 26A multiplexes the visible light L1, the visible light L2, and the visible light L3, and outputs the multiplexed light to the waveguide 27A.

The multiplexers/demultiplexers 24A and 26A have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27A is optically connected to the multiplexer/demultiplexer 26A. The waveguide 27A guides visible light L1, visible light L2, and visible light L3, and is RGB light including visible light L1, visible light L2, and visible light L3 from the second end surface 20Ab of the optical waveguide circuit 20A. It outputs visible light L4.

The waveguides 21A, 22A, 23A, 25A, 27A and the multiplexers/demultiplexers 24A, 26A are made of silica-based glass containing zirconia, like the corresponding elements in the first embodiment. The relative refractive index difference Δ of the waveguides 21A, 22A, 23A, 25A, 27A and the multiplexers/demultiplexers 24A, 26A with respect to the clad 28A is 3.5% in this embodiment. The relationship between the cross-sectional size of the waveguides 21A, 22A, 23A, 25A, 27A and the multiplexer/demultiplexer 24A, 26A and the relative refractive index difference Δ under the condition that at least the guided visible light is guided in a single mode is set, it may be set to a condition for multimode waveguide.

All of the waveguides 21A, 22A, 23A, 25A and 27A are bent. For example, the waveguides 21A and 23A are bent in an L shape, and the maximum bend radius is 150 μm. The waveguide 22A is bent in an S shape and has a maximum bending radius of 150 μm. The waveguide 25A is bent in an S shape, and its maximum bending radius is 150 μm. The waveguide 27A is bent in a U shape and has a maximum bending radius of 250 μm. Since the relative refractive index difference Δ is as high as 3.5%, bending loss is extremely reduced even if the bending radius of the waveguide is 150 μm. Since the waveguide is bent in this way, the light source module 100A can output visible light L1, L2, and L3 input from the first end surface 20a as visible light L4 from the second end surface 20b, which is substantially perpendicular to the light source module 100A. can. Along with this, the light source module 100A has a higher degree of freedom in layout of the waveguides. Also, the light source module 100A has a shorter length, that is, the distance between the second end face 20b and the opposite end face. The bending radii of the waveguides 21, 22, 23, 25 and 27 can be further reduced as the relative refractive index difference Δ is increased.

The light source module 100A according to the second embodiment suppresses light loss due to Rayleigh scattering, and becomes a light source module with higher output. In addition, since the light source module 100A has high accuracy in the size of the waveguide and the multiplexer/demultiplexer, the accuracy in the optical characteristics is also high, and the manufacturability is also good. In addition, the light source module 100A has a high degree of freedom in layout and can be downsized, for example. Moreover, since the visible light L1, L2, and L3 input from the first end surface 20a can be output as the visible light L4 from the second end surface 20b, which is substantially perpendicular to the first end surface 20a, the visible light L1, L2, and L3 can be Uncoupled components that are not coupled to the waveguides 21A, 22A, and 23A at the time of input to the end surface 20a hardly reach the second end surface 20b as stray light. As a result, the quality deterioration of the visible light L4 due to non-bonded components is greatly suppressed.

In the second embodiment, the green light source 11, the blue light source 12, and the red light source 13 are all arranged on the first end surface 20Aa side. Alternatively, two may be arranged on the end face side facing the first end face 20Aa. Even in such an arrangement, the visible light L4 can be output from the second end surface 20b by appropriately designing the layout of the waveguides and optical couplers.

(Embodiment 3)
FIG. 8 is a schematic configuration diagram of a light source module according to Embodiment 3. FIG. The light source module 100B includes green light sources 11Ba, 11Bb, 11Bc and 11Bd, blue light sources 12Ba, 12Bb, 12Bc and 12Bd, red light sources 13Ba, 13Bb, 13Bc and 13Bd, and an optical waveguide circuit 20B.

The green light sources 11Ba, 11Bb, 11Bc, and 11Bd have the same configuration as the green light source 11 of Embodiment 1, but each output visible light in the green region and having different wavelengths. Note that the spectra of the green visible light overlap each other. A graph G11 shows the intensity spectrum of the light output from each of the green light sources 11Ba to 11Bd. The horizontal axis indicates the wavelength, and each light has a different wavelength.

The blue light sources 12Ba, 12Bb, 12Bc, and 12Bd have the same configuration as the blue light source 12 of Embodiment 1, but each output visible light in the blue region with different wavelengths. Note that the visible light in the blue region overlaps each other in spectrum. A graph G21 shows the intensity spectrum of the light output from each of the blue light sources 12Ba to 12Bd. Each light has a different wavelength.

The red light sources 13Ba, 13Bb, 13Bc, and 13Bd have the same configuration as the red light source 13 of Embodiment 1, but each output visible light in the red region with different wavelengths. The spectra of the red visible light overlap each other. A graph G31 shows the intensity spectrum of the light output from each of the red light sources 13Ba to 13Bd. Each light has a different wavelength.

The optical waveguide circuit 20B is optically connected to each of the green light sources 11Ba-11Bd, the blue light sources 12Ba-12Bd, and the red light sources 13Ba-13Bd. In this embodiment, the optical waveguide circuit 20B has a first end surface 20Ba and a second end surface 20Ab facing the first end surface 20Ba. The green light sources 11Ba to 11Bd, the blue light sources 12Ba to 12Bd, and the red light sources 13Ba to 13Bd are connected to the first end surface 20Aa through bad joints.

The optical waveguide circuit 20B includes a green multiplexer/demultiplexer 21B, a blue multiplexer/demultiplexer 22B, a red multiplexer/demultiplexer 23B, waveguides 25B and 27B, multiplexers/demultiplexers 24B and 26B, and a clad 28B. have. The green multiplexer/demultiplexer 21B, the blue multiplexer/demultiplexer 22B, the red multiplexer/demultiplexer 23B, the waveguides 25B and 27B, and the multiplexer/demultiplexers 24B and 26B are composed of green light sources 11Ba to 11Bd and blue light source 12Ba. 12Bd, corresponding to a plurality of waveguides and at least one multiplexer/demultiplexer optically connected to red light sources 13Ba-13Bd.

The clad 28B surrounds the green multiplexing/demultiplexing section 21B, the blue multiplexing/demultiplexing section 22B, the red multiplexing/demultiplexing section 23B, the waveguides 25B and 27B, and the multiplexer/demultiplexers 24B and 26B. The clad 28B has the same configuration as the clad 28 of the first embodiment.

The green multiplexer/demultiplexer 21B includes six waveguides 21Ba and three multiplexers/demultiplexers 21Bb. The green combining/demultiplexing section 21B is configured as follows. Four of the waveguides 21Ba are optically connected to the respective green light sources 11Ba to 11Bd at the first end surface 20Ba, and guide the visible light output from each. Each of the two multiplexers/demultiplexers 21Bb multiplexes two visible lights and outputs them to the remaining two waveguides 21Ba, respectively. The remaining one multiplexer/demultiplexer 21Bb further multiplexes the visible light guided through each of the two waveguides 21Ba, and outputs it to the remaining one waveguide 21Ba.

The visible light output from the green multiplexing/demultiplexing section 21B has a wide spectral shape, as indicated by the graph G12, where the intensity spectra of the light output from the green light sources 11Ba to 11Bd overlap little by little.

The blue multiplexer/demultiplexer 22B includes six waveguides 22Ba and three multiplexers/demultiplexers 22Bb, like the green multiplexer/demultiplexer 21B. The blue multiplexing/demultiplexing unit 22B is configured in the same manner as the green multiplexing/demultiplexing unit 21B, multiplexes the visible lights output from each of the blue light sources 12Ba to 12Bd, and outputs them to one waveguide 22Ba. is configured to

The visible light output from the blue multiplexing/demultiplexing section 22B has a wide spectral shape, as the spectrums of the light output from the blue light sources 12Ba to 12Bd overlap little by little, as shown in the graph G22.

The red multiplexer/demultiplexer 23B includes six waveguides 23Ba and three multiplexers/demultiplexers 23Bb, like the green multiplexer/demultiplexer 21B. The red multiplexing/demultiplexing section 23B is configured in the same manner as the green multiplexing/demultiplexing section 21B. is configured to

The visible light output from the red multiplexing/demultiplexing section 23B has a wide spectral shape, as shown in graph G32, in which the intensity spectra of the light output from each of the blue light sources 12Ba to 12Bd overlap little by little.

The multiplexer/demultiplexer 24B is optically connected to the green multiplexer/demultiplexer 21B and the blue multiplexer/demultiplexer 22B. The multiplexer/demultiplexer 24B multiplexes the visible lights output from the green multiplexer/demultiplexer 21B and the blue multiplexer/demultiplexer 22B, and outputs the combined light to the waveguide 25B. The waveguide 25B guides the combined visible light.

The multiplexer/demultiplexer 26B is optically connected to the waveguide 25B and the red multiplexer/demultiplexer 23B. The multiplexer/demultiplexer 26B multiplexes the visible lights output from the waveguide 25B and the red multiplexer/demultiplexer 23B, and outputs the combined light to the waveguide 27B.

The multiplexers/demultiplexers 24A and 26A have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27B is optically connected to the multiplexer/demultiplexer 26B. The waveguide 27B guides the combined visible light, and outputs visible light L5, which is RGB light having a spectrum shown in graph G4, from the second end surface 20Bb of the optical waveguide circuit 20B.

The green multiplexer/demultiplexer 21B, the blue multiplexer/demultiplexer 22B, the red multiplexer/demultiplexer 23B, the waveguides 25B and 27B, and the multiplexer/demultiplexers 24B and 26B are made of silica-based glass containing zirconia, The relative refractive index difference Δ with respect to the clad 28B is 3.5% in this embodiment. The green multiplexer/demultiplexer 21B, the blue multiplexer/demultiplexer 22B, the red multiplexer/demultiplexer 23B, the waveguides 25B and 27B, and the multiplexer/demultiplexers 24B and 26B guide at least visible light in a single mode. Although the condition is set to the relationship between the cross-sectional size and the relative refractive index difference Δ, it may be set to the multimode waveguide condition.

Here, when the visible light source is a laser light source, speckle noise may occur because laser light, which is visible light, has high coherency. On the other hand, in the light source module 100B according to the third embodiment, the intensity spectrum of the light output from each of the green light sources 11Ba to 11Bd gradually overlaps in the green region, thereby generating light having a wide spectral shape. . Similarly, the intensity spectra of the light emitted from each of the blue light sources 12Ba to 12Bd are gradually overlapped in the blue region to generate light having a wide spectrum shape. Similarly, in the red region, the intensity spectra of the light output from the red light sources 13Ba to 13Bd are gradually overlapped to generate light having a wide spectrum shape. This suppresses the occurrence of speckle noise in the visible light L5 output from the light source module 100B.

Furthermore, the light source module 100B is suppressed in light loss due to Rayleigh scattering, and becomes a light source module with higher output. In addition, since the light source module 100B has high accuracy in the sizes of the waveguides and the multiplexer/demultiplexer, the accuracy in the optical characteristics is also high, and the manufacturability is also good. In addition, the light source module 100B has a high degree of freedom in layout and can be downsized, for example.

(Embodiment 4)
FIG. 9 is a schematic configuration diagram of a light source module according to Embodiment 4. FIG. The light source module 100C includes green light sources 11Ca and 11Cb, blue light sources 12Ca and 12Cb, red light sources 13Ca and 13Cb, and an optical waveguide circuit 20C.

The green light sources 11Ca and 11Cb have the same configuration as the green light source 11 of the first embodiment, but are arranged so as to output TE (Transverse Electric) polarized light to the optical waveguide circuit 20C. Here, the TE polarized wave is a polarized wave parallel to the substrate surface of the optical waveguide circuit 20C. The blue light sources 12Ca and 12Cb have the same configuration as the blue light source 12 of Embodiment 1, but are arranged so as to output TE polarized light to the optical waveguide circuit 20C. The red light sources 13Ca and 13Cb have the same configuration as the red light source 13 of Embodiment 1, but are arranged so as to output TE polarized light to the optical waveguide circuit 20C.

The optical waveguide circuit 20C is optically connected to each of the green light sources 11Ca and 11Cb, the blue light sources 12Ca and 12Cb, and the red light sources 13Ca and 13Cb. In this embodiment, the optical waveguide circuit 20C has a first end surface 20Ca and a second end surface 20Cb facing the first end surface 20Ca. The green light sources 11Ca and 11Cb, the blue light sources 12Ca and 12Cb, and the red light sources 13Ca and 13Cb are connected to the first end face 20Ca through bad joints.

The optical waveguide circuit 20C includes a green polarized wave combiner/separator 21C, a blue polarized wave combiner/separator 22C, a red polarized wave combiner/separator 23C, waveguides 25C and 27C, and multiplexers/demultiplexers 24C and 26C. and a clad 28C. The green polarization synthesis/separation unit 21C, the blue polarization synthesis/separation unit 22C, the red polarization synthesis/separation unit 23C, the waveguides 25C and 27C, and the multiplexers/demultiplexers 24C and 26C are connected to the green light source 11Ca. , 11Cb, blue light sources 12Ca, 12Cb, red light sources 13Ca, 13Cb, and a plurality of waveguides and at least one multiplexer/demultiplexer.

The clad 28C includes a green polarized wave combiner/separator 21C, a blue polarized wave combiner/separator 22C, a red polarized wave combiner/separator 23C, waveguides 25C and 27C, and multiplexers/demultiplexers 24C and 26C. Surrounding. The clad 28C has the same configuration as the clad 28 of the first embodiment.

The green polarization combiner/separator 21C includes four waveguides 21Ca, one polarization rotator 21Cb, and one polarization combiner/separator 21Cc. The green polarized wave combiner/separator 21C is configured as follows. Two of the waveguides 21Ca are optically connected to the green light sources 11Ca and 11Cb at the first end surface 20Ca, respectively, and guide the TE polarized visible light output from each of them. The polarization rotator 22Cb rotates the plane of polarization of the TE-polarized visible light by 90 degrees into a TM (Transverse Magnetic) polarized wave, and outputs it to the remaining one waveguide 21Ca. The polarization synthesizer/separator 21Cc polarization-synthesizes the TE-polarized visible light and the TM-polarized visible light, and further outputs the combined light to the remaining one waveguide 21Ca.

Similar to the green polarization synthesis/separation unit 21C, the blue polarization synthesis/separation unit 22C includes four waveguides 22Ca, one polarization rotator 22Cb, and one polarization synthesis/separation device 22Cc. I have. The blue polarization synthesis/separation unit 22C is configured in the same manner as the green polarization synthesis/separation unit 21C, and converts the TE polarized visible light output from each of the blue light sources 12Ca and 12Cb into TE polarized visible light. It is configured to output to one waveguide 22Ca as polarization combined light of light and TM polarized visible light.

Similar to the green polarization synthesis/separation unit 21C, the red polarization synthesis/separation unit 23C includes four waveguides 22Ca, one polarization rotator 22Cb, and one polarization synthesis/separation unit 22Cc. I have. The red polarization synthesis/separation unit 23C is configured in the same manner as the green polarization synthesis/separation unit 21C, and converts the TE polarized visible light output from each of the red light sources 13Ca and 13Cb into TE polarized visible light. It is configured to output to one waveguide 23Ca as polarization combined light of light and TM polarized visible light.

Due to the reciprocity of light, the polarization combiners/separators 21Cc, 22Cc, and 23Cc also have a polarization separation function. For example, when unpolarized visible light is input, the polarization synthesizer/separator 21Cc can separate it into TE polarized light and TM polarized light.

The multiplexer/demultiplexer 24C is optically connected to the green polarized wave combiner/separator 21C and the blue polarized wave combiner/separator 22C. The multiplexer/demultiplexer 24C multiplexes the polarization combined light output from the green polarized wave combiner/separator 21C and the blue polarized wave combiner/separator 22C, and outputs the combined light to the waveguide 25C. The waveguide 25C guides the combined polarized light.

The multiplexer/demultiplexer 26C is optically connected to the waveguide 25C and the red polarized wave combiner/separator 23C. The multiplexer/demultiplexer 26C multiplexes the polarization multiplexed light output from the waveguide 25C and the red polarization multiplexer/separator 23C, and outputs the multiplexed light to the waveguide 27C.

The multiplexers/demultiplexers 24C and 26C have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27C is optically connected to the multiplexer/demultiplexer 26C. The waveguide 27C guides the combined polarized light and outputs visible light L6, which is RGB light, from the second end surface 20Cb of the optical waveguide circuit 20C.

The green polarized wave combiner/separator 21C, the blue polarized wave combiner/separator 22C, the red polarized wave combiner/separator 23C, the waveguides 25C and 27C, and the multiplexers/demultiplexers 24C and 26C contain zirconia. It is made of silica-based glass, and has a relative refractive index difference Δ with respect to the clad 28B of 3.5% in this embodiment. The green polarization synthesis/separation unit 21C, the blue polarization synthesis/separation unit 22C, the red polarization synthesis/separation unit 23C, the waveguides 25C and 27C, and the multiplexers/demultiplexers 24C and 26C at least guide visible light. Although the relationship between the cross-sectional size and the relative refractive index difference Δ is set as the condition for single-mode waveguide, it may be set as the condition for multi-mode waveguide.

In the light source module 100C according to the fourth embodiment, polarization-combined light including TE-polarized visible light and TM-polarized visible light is generated from the light output from each of the green light sources 11Ca and 11Cb in the green region. . Similarly, in the blue region, polarization combined light is generated from the light output from each of the blue light sources 12Ca and 12Cb. Similarly, in the red region, polarization combined light is generated from the light output from each of the red light sources 13Ca and 13Cb. This suppresses the occurrence of speckle noise in the visible light L5 output from the light source module 100C.

Furthermore, the light source module 100C has suppressed light loss due to Rayleigh scattering, and is a light source module with higher output. In addition, since the light source module 100C has high accuracy in the size of the waveguide and the multiplexer/demultiplexer, the accuracy in the optical characteristics is also high, and the manufacturability is also good. In addition, the light source module 100C has a high degree of freedom in layout and can be downsized, for example.

(Embodiment 5)
10 is a schematic configuration diagram of a light source module according to Embodiment 5. FIG. The light source module 100D includes four green light sources 11, four blue light sources 12, four red light sources 13, and an optical waveguide circuit 20D.

Since the green light source 11, the blue light source 12, and the red light source 13 are the same as the corresponding elements of the first embodiment, description thereof will be omitted. Graph G71 shows the intensity spectrum of the light output from each green light source 11 . The horizontal axis indicates the wavelength, and each light has substantially the same wavelength. A graph G61 shows the intensity spectrum of the light output from each blue light source 12 . Each light has approximately the same wavelength. A graph G81 shows the intensity spectrum of the light output from each red light source 13 . Each light has approximately the same wavelength.

The optical waveguide circuit 20</b>D is optically connected to each green light source 11 , each blue light source 12 , and each red light source 13 . In this embodiment, the optical waveguide circuit 20D has a first end surface 20Da and a second end surface 20Db facing the first end surface 20Da. Each green light source 11, each blue light source 12, and each red light source 13 are bad joint-connected to the first end surface 20Da.

The optical waveguide circuit 20D includes a green multiplexing/demultiplexing section 21D, a blue multiplexing/demultiplexing section 22D, a red multiplexing/demultiplexing section 23D, waveguides 25D and 27D, multiplexers/demultiplexers 24D and 26D, and a clad 28D. have. The green multiplexing/demultiplexing unit 21D, the blue multiplexing/demultiplexing unit 22D, the red multiplexing/demultiplexing unit 23D, the waveguides 25D and 27D, and the multiplexer/demultiplexers 24D and 26D are connected to each green light source 11 and each blue light source 12. , corresponding to a plurality of waveguides and at least one multiplexer/demultiplexer optically connected to each red light source 13 .

The clad 28D surrounds the green multiplexing/demultiplexing section 21D, the blue multiplexing/demultiplexing section 22D, the red multiplexing/demultiplexing section 23D, the waveguides 25D and 27D, and the multiplexer/demultiplexers 24D and 26D. The clad 28D has the same configuration as the clad 28 of the first embodiment.

The green multiplexer/demultiplexer 21D includes six waveguides 21Da and three multiplexer/demultiplexers 21Db. The green multiplexing/demultiplexing section 21D is configured similarly to the green multiplexing/demultiplexing section 21B according to the third embodiment. That is, the green multiplexing/demultiplexing section 21D multiplexes the visible light output from each green light source 11, and outputs it from one waveguide 21Da.

The visible light output from the green multiplexing/demultiplexing section 21D has a high-output spectral shape as the intensity spectrum of the light output from each green light source 11 overlaps, as shown in graph G72.

The blue multiplexing/demultiplexing section 22D includes six waveguides 22Da and three multiplexing/demultiplexing devices 22Db, similarly to the blue multiplexing/demultiplexing section 22B. The blue multiplexing/demultiplexing section 22D is configured in the same manner as the blue multiplexing/demultiplexing section 22B, multiplexes the visible light output from each blue light source 12, and outputs from one waveguide 22Da.

The visible light output from the blue multiplexing/demultiplexing section 22D has a high-output spectral shape as the intensity spectrum of the light output from each blue light source 12 overlaps, as shown in the graph G62.

The red multiplexing/demultiplexing section 23D, like the red multiplexing/demultiplexing section 23B, includes six waveguides 23Da and three multiplexing/demultiplexing devices 23Db. The red multiplexing/demultiplexing section 23D is configured in the same manner as the red multiplexing/demultiplexing section 23B, multiplexes the visible light output from each blue light source 12, and outputs from one waveguide 23Da.

The visible light output from the red multiplexing/demultiplexing section 23D has a high-output spectral shape due to overlapping of the intensity spectra of the light output from each red light source 13, as shown in graph G82.

The multiplexer/demultiplexer 24D is optically connected to the green multiplexer/demultiplexer 21D and the blue multiplexer/demultiplexer 22D. The multiplexer/demultiplexer 24D multiplexes the visible lights output from the green multiplexer/demultiplexer 21D and the blue multiplexer/demultiplexer 22D, and outputs the combined light to the waveguide 25D. A waveguide 25D guides the combined visible light.

The multiplexer/demultiplexer 26D is optically connected to the waveguide 25D and the red multiplexer/demultiplexer 23D. The multiplexer/demultiplexer 26D multiplexes the visible lights output from the waveguide 25D and the red multiplexer/demultiplexer 23D, and outputs the combined light to the waveguide 27D.

The multiplexers/demultiplexers 24D and 26D have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27D is optically connected to the multiplexer/demultiplexer 26D. The waveguide 27D guides the combined visible light, and outputs visible light L7, which is RGB light having a spectrum shown in graph G9, from the second end surface 20Db of the optical waveguide circuit 20D.

The green multiplexer/demultiplexer 21D, the blue multiplexer/demultiplexer 22D, the red multiplexer/demultiplexer 23D, the waveguides 25D and 27D, and the multiplexer/demultiplexers 24D and 26D are made of quartz glass containing zirconia. On the other hand, clad 28D is made of, for example, pure silica glass. The relative refractive index difference Δ of the green multiplexing/demultiplexing section 21D, the blue multiplexing/demultiplexing section 22D, the red multiplexing/demultiplexing section 23D, the waveguides 25D and 27D, and the multiplexer/demultiplexers 24D and 26D with respect to the clad 28D is 3 in this embodiment. 0.5%. The green multiplexer/demultiplexer 21D, the blue multiplexer/demultiplexer 22D, the red multiplexer/demultiplexer 23D, the waveguides 25D and 27D, and the multiplexer/demultiplexers 24D and 26D guide at least visible light in a single mode. Although the condition is set to the relationship between the cross-sectional size and the relative refractive index difference Δ, it may be set to the multimode waveguide condition.

Since the light source module 100D according to the fifth embodiment can output the visible light L7, which is high-power RGB light, a high-luminance light source module can be realized.

Furthermore, the light source module 100D is suppressed in light loss due to Rayleigh scattering, and becomes a light source module with higher output. In addition, since the light source module 100D has high accuracy in the size of the waveguide and the multiplexer/demultiplexer, the accuracy of the optical characteristics is also high, and the manufacturability is also good. In addition, the light source module 100D has a high degree of freedom in layout and can be downsized, for example.

Here, when the optical waveguide circuits of the light source modules of Embodiments 3 to 5 were produced, all of them could be made as small as 3.5 mm×2.5 mm in plan view.

(Embodiment 6)
11A and 11B are diagrams showing a schematic configuration and operation of a light source module according to Embodiment 6. FIG. As shown in FIG. 11(a), the light source module 100E includes a green light source 11, a blue light source 12, a red light source 13, and an optical waveguide circuit 20E.

Since the green light source 11, the blue light source 12, and the red light source 13 are the same as the corresponding elements of the first embodiment, description thereof will be omitted.

The optical waveguide circuit 20E is optically connected to each of the green light source 11, the blue light source 12, and the red light source 13. FIG. In this embodiment, the optical waveguide circuit 20E has a first end surface 20Ea and a second end surface 20Eb facing the first end surface 20Ea. The green light source 11, the blue light source 12, and the red light source 13 are arranged on the first end surface 20Ea side, but may be connected to the first end surface 20Da through a bad joint.

The optical waveguide circuit 20E has waveguides 21E, 22E, 23E, 25E, 27E, multiplexers/demultiplexers 24E, 26E, an optical switch 29E, and a clad 28E. Waveguides 21E, 22E, 23E, 25E, 27E, multiplexers/demultiplexers 24E, 26E, and optical switch 29E are a plurality of waveguides optically connected to green light source 11, blue light source 12, and red light source 13. Corresponding to the wave path and at least one multiplexer/demultiplexer.

The clad 28E surrounds the waveguides 21E, 22E, 23E, 25E, 27E, the multiplexers/demultiplexers 24E, 26E, and the waveguides of the optical switch 29E. The clad 28E has the same configuration as the clad 28 of the first embodiment.

The waveguide 21E is optically connected to the green light source 11 and guides the visible light L1. The waveguide 22E is optically connected to the blue light source 12 and guides the visible light L2. The waveguide 23E is optically connected to the red light source 13 and guides the visible light L3.

The multiplexer/demultiplexer 24E is optically connected to the waveguides 21E, 22E, and 25E. The multiplexer/demultiplexer 24E multiplexes the visible light L1 and the visible light L2 and outputs them to the waveguide 25E. The waveguide 25E guides the visible light L1 and the visible light L2.

The multiplexer/demultiplexer 26E is optically connected to the waveguides 23E and 25E. The multiplexer/demultiplexer 26E multiplexes the visible light L1, the visible light L2, and the visible light L3, and outputs the multiplexed light to the waveguide 27E.

The multiplexers/demultiplexers 24E and 26E have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27E is optically connected to the multiplexer/demultiplexer 26E and the optical switch 29E. The waveguide 27E guides the visible light L1, the visible light L2, and the visible light L3, and outputs the visible light L1, the visible light L2, and the visible light L3 to the optical switch 29E.

The optical switch 29E includes waveguide type multiplexers/demultiplexers 29Ea and 29Eb and a heater 29Ec. The multiplexers/demultiplexers 29Ea and 29Eb have a 2-input×2-output configuration. One of the two input waveguides of the multiplexer/demultiplexer 29Ea is optically connected to the waveguide 27E. Each of the two output waveguides of the multiplexer/demultiplexer 29Ea is optically connected to each of the two input waveguides of the multiplexer/demultiplexer 29Eb. The multiplexers/demultiplexers 29Ea and 29Eb constitute a Mach-Zehnder interferometer. The two output waveguides 28Eb1 and 28Eb2 of the multiplexer/demultiplexer 29Eb both extend to the second end surface 20Eb in this embodiment. Hereinafter, the output waveguides 28Eb1 and 28Eb2 may be referred to as main port and idle port, respectively.

The heater 29Ec is provided in the clad 28E above the arm formed by one output waveguide of the multiplexer/demultiplexer 29Ea and one input waveguide of the multiplexer/demultiplexer 29Eb. When a drive current is supplied to the heater 29Ec from a controller (not shown), the heater 29Ec generates heat to heat the arm. Thus, the optical switch 29E functions as an optical switch that selectively outputs the light input from the waveguide 27E from either one of the output waveguides 28Eb1 and 28Eb2 by controlling the drive current.

The waveguides 21E, 22E, 23E, 25E, 27E, the multiplexer/demultiplexers 24E, 26E, and the waveguides of the optical switch 29E are made of quartz-based glass containing zirconia, and the relative refractive index difference Δ with respect to the clad 28D is In the embodiment it is 3.5%. The waveguides of the waveguides 21E, 22E, 23E, 25E, 27E, the multiplexers/demultiplexers 24E, 26E, and the optical switch 29E have their cross-sectional sizes and relative refractions under the condition that at least the guided visible light is guided in a single mode. Although the relationship with the index difference Δ is set, it may be set to the condition of multimode waveguide.

Here, in FIG. 11A, the outputs of the green light source 11, the blue light source 12, and the red light source 13 are in an ON state, and output visible light L1, L2, and L3, respectively. On the other hand, the optical switch 29E is in the OFF state. At this time, visible light L4, which is RGB light including visible light L1, visible light L2, and visible light L3, is output from output waveguide 28Eb1, which is a main port.

On the other hand, in FIG. 11B, the outputs of the green light source 11, the blue light source 12, and the red light source 13 are in an OFF state. On the other hand, the optical switch 29E is in ON state. At this time, visible light L4a, which is RGB light including visible light L1a, visible light L2a, and visible light L3a, is output from output waveguide 28Eb1, which is an idle port.

As a result, when the outputs of the green light source 11, the blue light source 12, and the red light source 13 are in the OFF state, even if the visible light L1a, the visible light L2a, and the visible light L3a are output, these are the output leads that are the main ports. There is no output from the wave path 28Eb1. As a result, the light source module 100E has a high extinction ratio between when the visible light L4 is output from the main port and when it is not output, and the light source module 100E has a high dynamic range and high contrast.

Alternatively, the green light source 11, the blue light source 12, and the red light source 13 may be turned on all the time, and the optical switch 29E may switch between outputting the visible light L4 from the main port and outputting it from the idle port. In this case as well, the extinction ratio between when the visible light L4 is output from the main port and when it is not output is high, resulting in a light source module with a high dynamic range and high contrast.

(Embodiment 7)
FIG. 12 is a schematic configuration diagram of a light source module according to Embodiment 7. FIG. The light source module 100F includes a green light source 11, a blue light source 12, a red light source 13, and an optical waveguide circuit 20F.

Green light source 11, blue light source 12, and red light source 13 are the same as the corresponding elements in the first embodiment.

The optical waveguide circuit 20F is optically connected to each of the green light source 11, the blue light source 12, and the red light source 13. FIG. In this embodiment, the optical waveguide circuit 20F has a first end face 20Fa and a second end face 20Fb facing the first end face 20Fa. The green light source 11, the blue light source 12, and the red light source 13 are arranged on the first end face 20Fa side, but may be connected to the first end face 20Fa through a bad joint.

The optical waveguide circuit 20F has variable optical attenuators 21F, 22F, 23F, waveguides 25F, 27F, multiplexers/demultiplexers 24F, 26F, and a clad 28F. Variable optical attenuators 21F, 22F, 23F, waveguides 25F, 27F, and multiplexers/demultiplexers 24F, 26F are a plurality of waveguides optically connected to green light source 11, blue light source 12, and red light source 13. Corresponding to the wave path and at least one multiplexer/demultiplexer.

The clad 28E surrounds the waveguides of the variable optical attenuators 21F, 22F, 23F, the waveguides 25F, 27F, and the multiplexers/demultiplexers 24F, 26F. The clad 28E has the same configuration as the clad 28 of the first embodiment.

The variable optical attenuator 21F includes waveguide type multiplexers/demultiplexers 21Fa and 21Fb, and a heater 21Fc. The multiplexers/demultiplexers 21Fa and 21Fb have a 2-input×2-output configuration. One of the two input waveguides of the multiplexer/demultiplexer 21Fa is optically connected to the green light source 11. FIG. Each of the two output waveguides of the multiplexer/demultiplexer 21Fa is optically connected to each of the two input waveguides of the multiplexer/demultiplexer 21Fb. The multiplexers/demultiplexers 21Fa and 21Fb constitute a Mach-Zehnder interferometer. Of the two output waveguides 21Fb1 and 21Fb2 of the multiplexer/demultiplexer 21Fb, the output waveguide 21Fb1 is optically connected to the multiplexer/demultiplexer 24F. The output waveguide 21Fb2 extends to the second end surface 20Eb.

The heater 21Fc is provided in the clad 28F above the arm formed by one output waveguide of the multiplexer/demultiplexer 21Fa and one input waveguide of the multiplexer/demultiplexer 21Fb. When a drive current is supplied to the heater 21Fc from a controller (not shown), the heater 21Fc generates heat to heat the arm. Thus, the variable optical attenuator 21F functions as a variable optical attenuator that changes the intensity of the visible light L1 input from the green light source 11 and outputs it from the output waveguide 21Fb1 by controlling the driving current.

The variable optical attenuator 22F includes waveguide type multiplexers/demultiplexers 22Fa and 22Fb and a heater 22Fc. The multiplexers/demultiplexers 22Fa and 22Fb have a 2-input×2-output configuration. One of the two input waveguides of multiplexer/demultiplexer 22Fa is optically connected to blue light source 12 . Each of the two output waveguides of the multiplexer/demultiplexer 22Fa is optically connected to each of the two input waveguides of the multiplexer/demultiplexer 22Fb, forming a Mach-Zehnder interferometer. Of the two output waveguides 22Fb1 and 22Fb2 of the multiplexer/demultiplexer 22Fb, the output waveguide 22Fb1 is optically connected to the multiplexer/demultiplexer 24F. The output waveguide 22Fb2 extends to the second end surface 20Eb.

The heater 22Fc is provided in the clad 28F above the arm formed by one output waveguide of the multiplexer/demultiplexer 22Fa and one input waveguide of the multiplexer/demultiplexer 22Fb. When a drive current is supplied to the heater 22Fc from a controller (not shown), the heater 22Fc generates heat to heat the arm. Accordingly, the variable optical attenuator 22F functions as a variable optical attenuator that changes the intensity of the visible light L2 input from the blue light source 12 and outputs it from the output waveguide 22Fb1 by controlling the drive current.

The variable optical attenuator 23F includes waveguide type multiplexers/demultiplexers 23Fa and 22Fb and a heater 23Fc. The multiplexers/demultiplexers 23Fa and 23Fb have a 2-input×2-output configuration. One of the two input waveguides of multiplexer/demultiplexer 23Fa is optically connected to red light source 13 . Each of the two output waveguides of the multiplexer/demultiplexer 23Fa is optically connected to each of the two input waveguides of the multiplexer/demultiplexer 23Fb, forming a Mach-Zehnder interferometer. Of the two output waveguides 23Fb1 and 23Fb2 of the multiplexer/demultiplexer 23Fb, the output waveguide 23Fb1 is optically connected to the multiplexer/demultiplexer 24F. The output waveguide 23Fb2 extends to the second end surface 20Eb.

The heater 23Fc is provided in the clad 28F above the arm formed by one output waveguide of the multiplexer/demultiplexer 23Fa and one input waveguide of the multiplexer/demultiplexer 23Fb. When a drive current is supplied to the heater 23Fc from a controller (not shown), the heater 23Fc generates heat to heat the arm. Accordingly, the variable optical attenuator 23F functions as a variable optical attenuator that changes the intensity of the visible light L3 input from the red light source 13 and outputs it from the output waveguide 23Fb1 by controlling the drive current.

The multiplexer/demultiplexer 24F is optically connected to the output waveguide 21Fb1 of the variable optical attenuator 21F, the output waveguide 22Fb1 of the variable optical attenuator 22F, and the waveguide 25F. The multiplexer/demultiplexer 24F multiplexes the visible light L1 whose intensity is changed by the variable optical attenuator 21F and the visible light L2 whose intensity is changed by the variable optical attenuator 22F, and outputs the combined light to the waveguide 25F. The waveguide 25F guides the visible light L1 and the visible light L2.

The multiplexer/demultiplexer 26F is optically connected to the output waveguide 23Fb1 and the waveguide 25F of the variable optical attenuator 23F. The multiplexer/demultiplexer 26F multiplexes the visible light L1, the visible light L2, and the visible light L3 whose intensity is changed by the variable optical attenuator 22F, and outputs the combined light to the waveguide 27F.

The multiplexers/demultiplexers 24F and 26F have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27F is optically connected to the multiplexer/demultiplexer 26F. The waveguide 27F guides the combined visible light, and outputs visible light L8, which is RGB light, from the second end surface 20Fb of the optical waveguide circuit 20F.

The waveguides of the variable optical attenuators 21F, 22F, 23F, the waveguides 25F, 27F, and the multiplexer/demultiplexers 24F, 26F are made of silica-based glass containing zirconia, and the relative refractive index difference Δ with respect to the clad 28F is In the embodiment it is 3.5%. The waveguides of the variable optical attenuators 21F, 22F, 23F, the waveguides 25F, 27F, and the multiplexer/demultiplexers 24F, 26F have a cross-sectional size and a relative refraction under the condition that at least guided visible light is guided in a single mode. Although the relationship with the index difference Δ is set, it may be set to the condition of multimode waveguide.

The light source module 100F according to the seventh embodiment integrates the variable optical attenuators 21F, 22F, and 23F, and can output the visible light L8 in which the intensity of the RGB components is individually changed. module can be implemented.

Furthermore, the light source module 100F has suppressed light loss due to Rayleigh scattering, and is a light source module with higher output. In addition, since the light source module 100F has high accuracy in the sizes of the waveguides and the multiplexer/demultiplexer, the accuracy in the optical characteristics is also high, and the manufacturability is also good. In addition, the light source module 100F has a high degree of freedom in layout, and can be downsized, for example.

In Embodiments 6 and 7, the optical switch 29E and the variable optical attenuators 21F, 22F, and 23F have a Mach-Zehnder configuration including heaters, but they may be replaced with variable optical attenuators having other configurations, or semiconductor A material other than silica-based glass may be used as the material.

(Embodiment 8)
13 is a schematic configuration diagram of a light source module according to Embodiment 8. FIG. The light source module 100G includes a blue light source 14, a green light source 15, a red light source 16, and an optical waveguide circuit 20G.

Blue light source 14 is, for example, an array-type semiconductor laser element. The blue light source 14 includes waveguide-type active layers 14a, 14b, and 14c arranged in an array. The active layers 14a, 14b, and 14c each output blue visible light L2G.

Optical waveguide circuit 20G is optically connected to blue light source 14, green light source 15, and red light source 16, respectively. In this embodiment, the optical waveguide circuit 20G has a first end face 20Ga and a second end face 20Gb substantially orthogonal to the first end face 20Ga. The blue light source 14 is connected to the first end surface 20Ga through a bad joint. Optical connection between the optical waveguide circuit 20G and the green light source 15 and the red light source 16 will be described later.

The optical waveguide circuit 20G has waveguides 21G, 22G, 23G, 25G and 27G, multiplexers/demultiplexers 24G and 26G, and a clad 28G. The waveguides 21G, 22G, 23G, 25G, 27G and the multiplexers/demultiplexers 24G, 26G are a plurality of waveguides optically connected to the blue light source 14, the green light source 15, and the red light source 16, and at least It corresponds to one multiplexer/demultiplexer.

The clad 28G surrounds the waveguides 21G, 22G, 23G, 25G, 27G and the multiplexers/demultiplexers 24G, 26G. The clad 28G has the same configuration as the clad 28 of the first embodiment.

The waveguide 21G is optically connected to the active layer 14a of the blue light source 14 at the first end surface 20Ga, and guides the visible light L2G. A green light source 15 is provided so as to traverse the waveguide 21G. The green light source 15 is a glass plate inserted into a groove formed in the optical waveguide circuit 20G in this embodiment. Green light source 15 contains a green phosphor made of a known material. The green light source 15 emits green visible light L1G when irradiated with the visible light L2G guided through the waveguide 21G. The visible light L1G is guided through the waveguide 21G. In addition, the waveguide 21G has a tapered structure 21Ga in the width direction in order to reduce the loss of the visible lights L1G and L2G. The green light source 15 is not particularly limited, and may be made of a resin containing a phosphor.

The waveguide 22G is optically connected to the active layer 14b of the blue light source 14 at the first end face 20Ga, and guides the visible light L2G.

The waveguide 23G is optically connected to the active layer 14c of the blue light source 14 at the first end surface 20Ga, and guides the visible light L2G. A red light source 16 is provided so as to traverse the waveguide 21G. The red light source 16 is a glass plate inserted into a groove formed in the optical waveguide circuit 20G in this embodiment. Red light source 16 contains a red phosphor made of a known material. The red light source 16 emits red visible light L3G when irradiated with the visible light L2G guided through the waveguide 23G. The visible light L3G is guided through the waveguide 23G. The waveguide 23G has a tapered structure 23Ga in the width direction in order to reduce the loss of visible light L2G and L3G. Note that the red light source 16 is not particularly limited, and may be made of a resin containing a phosphor.

As described above, the light source module 100G includes the green light source 15 having a light emitter that outputs the visible light L1G having a different wavelength from the visible light L2G when irradiated with the visible light L2G as the primary light, and and a red light source 16 having a luminous body that outputs visible light L3G having a different wavelength from the visible light L2G when irradiated with the visible light L2G. The active layers 14a and 14c of the blue light source 14 function as a primary light source that outputs visible light L2G as primary light.

The multiplexer/demultiplexer 24G is optically connected to the waveguides 21G, 22G, and 25G. The multiplexer/demultiplexer 24G multiplexes the visible light L2G and the visible light L1G and outputs the multiplexed light to the waveguide 25G. The waveguide 25G guides the visible light L2G and the visible light L1G.

The multiplexer/demultiplexer 26G is optically connected to the waveguides 23G and 25G. The multiplexer/demultiplexer 26G multiplexes the visible light L1G, the visible light L2G, and the visible light L3G, and outputs the multiplexed light to the waveguide 27G.

The multiplexers/demultiplexers 24G and 26G have the same configuration as the multiplexers/demultiplexers 24 and 26 of the first embodiment.

The waveguide 27G is optically connected to the multiplexer/demultiplexer 26G. The waveguide 27G guides visible light L1G, visible light L2G, and visible light L3G, and is RGB light including visible light L1G, visible light L2G, and visible light L3G from the second end surface 20Gb of the optical waveguide circuit 20G. It outputs visible light L9.

The waveguides 21G, 22G, 23G, 25G, 27G and the multiplexers/demultiplexers 24G, 26G are made of silica-based glass containing zirconia, and the relative refractive index difference Δ with respect to the clad 28G is 3.5% in this embodiment. be. The waveguides 21G, 22G, 23G, 25G, and 27G and the multiplexer/demultiplexers 24G and 26G have a cross-sectional size and a relative refractive index difference Δ under the condition that at least the guided visible light is guided in a single mode. Although the relationship is set, it may be set to the condition of multimode waveguide.

Waveguides 21G, 22G, 23G, 25G and 27G are bent like waveguides 21A, 22A, 23A, 25A and 27A shown in FIG. Thereby, the light source module 100G can output the visible lights L1G, L2G, and L3G from the second end face 20Gb as the visible light L9. As a result, the quality deterioration of the visible light L10 due to non-bonded components is greatly suppressed.

The light source module 100G can be configured using, as visible light sources, a blue light source 14 as a primary light source, and a green light source 15 and a red light source 16 having light emitters. As a result, for example, RGB light can be generated using only a blue laser light source as a light source for supplying drive current. Moreover, in this embodiment, since the blue light source 14 is an array type light source, it can be easily optically connected to the optical waveguide circuit 20G.

In this embodiment, there is one primary light source and two visible light sources having light emitters, but the number is not particularly limited.

Also, in the above embodiment, there are three visible light sources, but the number is not particularly limited, and may be two or four or more. If the number of visible light sources is two, the number of multiplexers may be one.

Moreover, the present invention is not limited by the above embodiments. The present invention also includes those configured by appropriately combining the respective constituent elements described above. Further effects and modifications can be easily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the above-described embodiments, and various modifications are possible.

11, 11Ba, 11Bb, 11Bc, 11Bd, 11Ca, 11Cb, 15 green light source 12, 12Ba, 12Bb, 12Bc, 12Bd, 12Ca, 12Cb, 14 blue light source 13, 13Ba, 13Bb, 13Bc, 13Bd, 13Ca, 13Cb, 16 red Light sources 14a, 14b, 14c Active layers 20, 20A, 20B, 20C, 20D, 20E, 20F, 20G Optical waveguide circuits 20a, 20Aa, 20Ba, 20Ca, 20Da, 20Ea, 20Fa, 20Ga First end faces 20b, 20Ab, 20Bb, 20Cb, 20Db, 20Eb, 20Fb, 20Gb Second end faces 21, 21A, 21Ba, 21Ca, 21Da, 21E, 21G, 22, 22A, 22Ba, 22Ca, 22Da, 22E, 22G, 23, 23A, 23Ba, 23Ca, 23Da, 23E, 23G, 25, 25A, 25B, 25C, 25D, 25E, 25F, 25G, 27, 27A, 27B, 27C, 27D, 27E, 27F, 27G Waveguides 21B, 21D Green multiplexing/demultiplexing sections 21Bb, 21Db, 21Fa , 21Fb, 22Bb, 22Db, 22Fb, 23Bb, 23Db, 23Fa, 23Fb, 24, 24A, 24B, 24C, 24D, 24E, 24F, 24G, 26, 26A, 26B, 26C, 26D, 26E, 26F, 26G, 29Ea , 29Eb multiplexer/demultiplexer 21C green polarized wave combiner/separator 22C blue polarized wave combiner/separator 23C red polarized wave combiner/separator 21Cb, 22Cb polarization rotator 21Cc, 22Cc, 23Cc polarization combiner/separator 21F, 22F, 23F variable optical attenuators 21Fb1, 21Fb2, 22Fb1, 22Fb2, 23Fb1, 23Fb2, 28Eb1, 28Eb2 output waveguides 21Fc, 22Fc, 23Fc, 29Ec heaters 21Ga, 23Ga tapered structures 22B, 22D blue multiplexing/demultiplexing sections 23B, 23D red Multiplexer/demultiplexer 28, 28A, 28B, 28C, 28D, 28E, 28F, 28G Claddings 28a, 128a Lower clad 28b Upper clad 29E Optical switches 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G Light source module 121, 122 Waveguide pattern 128b Silica-based glass fine particle layers A, B, C Regions G11, G12, G21, G22, G31, G32, G4, G61, G62, G63, G72, G82, G9 Graphs L1, L1a, L1G, L2, L2a, L 2G, L3, L3a, L3G, L4, L4a, L5, L6, L7, L8, L9 visible light

Claims (12)

a plurality of visible light sources each outputting visible light having different wavelengths;
an optical waveguide circuit optically connected to each of the plurality of visible light sources;
with
The optical waveguide circuit is
a plurality of waveguides that are optically connected to any of the visible light sources and guide light output from any of the visible light sources;
at least one multiplexer/demultiplexer that is optically connected to any of the waveguides and multiplexes or demultiplexes each of the lights guided through any of the waveguides;
a clad surrounding the plurality of waveguides and the at least one multiplexer/demultiplexer;
a polarization synthesizer/separator for polarization synthesis or polarization separation of the two visible lights having orthogonal polarizations;
and
The light source module, wherein the plurality of waveguides and the at least one multiplexer/demultiplexer are made of silica-based glass containing zirconia (ZrO ₂ ). 2. The light source module according to claim 1, wherein said plurality of waveguides and said at least one multiplexer/demultiplexer guide said visible light in a single mode. The optical waveguide circuit has a first end face into which the visible light is input and a second end face from which the visible light is output, and the first end face and the second end face are substantially perpendicular to each other. 3. The light source module according to claim 1 or 2, characterized in that: The plurality of visible light sources include a plurality of visible light sources that output visible light whose spectra overlap each other, and the at least one multiplexer/demultiplexer multiplexes or demultiplexes the visible lights whose spectra overlap each other. The light source module according to any one of claims 1 to 3. 5. The light source module according to claim 1, wherein said optical waveguide circuit further comprises an optical switch for switching a waveguide from which said visible light is output. The plurality of visible light sources includes a visible light source having a light emitter that outputs visible light having a wavelength different from that of the irradiated primary light,
6. The light source module according to any one of claims 1 to 5, further comprising a primary light source that outputs the primary light that irradiates the light emitter. 7. The plurality of visible light sources include a red light source that outputs red light, a green light source that outputs green light, and a blue light source that outputs blue light. A light source module as described in . 8. The light source module according to claim 1, wherein at least one of said plurality of waveguides is bent. 9. The light source module according to claim 1, wherein the plurality of waveguides and the at least one multiplexer/demultiplexer have a zirconia (ZrO ₂ ) concentration of 2 mol % or more. The light source according to any one of claims 1 to 9, wherein the plurality of waveguides and the at least one multiplexer/demultiplexer have a zirconia (ZrO ₂ ) concentration of 7.75 mol% or more. module. The clad is made of pure silica glass, and in a blue region, the plurality of waveguides and the at least one multiplexer/demultiplexer have a relative refractive index difference of 0.8% or more with respect to the clad. Item 11. The light source module according to any one of items 1 to 10. 12. The light source module according to claim 11, wherein said plurality of waveguides and said at least one multiplexer/demultiplexer have said relative refractive index difference of 3.5% or more.

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