Optical integrated circuit

Abstract

This optical integrated circuit comprises an optical waveguide device, a light-emitting device, and a support unit. The optical waveguide device includes a substrate, and an optical waveguide layer that is disposed on the substrate and includes an input coupler and an optical waveguide. The light-emitting device is spaced apart from the optical waveguide device. The light-emitting device includes a light-emitting layer and a phase modulation layer. The phase modulation layer includes a base layer and a plurality of different refractive index regions. The support unit includes a first support portion in which one device is disposed, and a second support portion that supports the other device. The distance between the optical waveguide device and the light-emitting device is smaller than the width of the second support portion in the direction in which the one device and the second support portion are lined up.

Description

Optical Integrated Circuit

[0001] The present disclosure relates to integrated optical circuits.

[0002] A known optical integrated circuit (PIC) includes a substrate, an optical waveguide layer disposed on the substrate, and a light-emitting device disposed on the optical waveguide layer. In such an optical integrated circuit, the optical waveguide layer includes an input coupler and an optical waveguide optically coupled to the input coupler, and light emitted from the light-emitting device is coupled into the optical waveguide layer by the input coupler and propagates along the optical waveguide.

[0003] In order to suppress optical loss between the light-emitting device and the optical waveguide, in the optical integrated circuit described in Non-Patent Document 1, a vertical-cavity surface-emitting laser (VCSEL) element, which is a light-emitting device, is arranged on the optical waveguide layer in a state inclined with respect to the optical waveguide layer.

[0004] Erik Haglund and 8 others, “High-power single transverse and polarization mode VCSEL for silicon photonics integration”, Vol. 27, No. 13, 24 Jun 2019, OPTICS EXPRESS, p. 18892-18899

[0005] However, in the optical integrated circuit described in Non-Patent Document 1, the support of the vertical-cavity surface-emitting laser element, which is the light-emitting device, is unstable, and therefore the optical loss between the light-emitting device and the optical waveguide increases over time, which may result in deterioration of the light propagation characteristics in the optical waveguide.

[0006] An object of the present disclosure is to provide an optical integrated circuit that can suppress deterioration of the light propagation characteristics in an optical waveguide.

[0007] An optical integrated circuit according to one aspect of the present disclosure includes: [1] "an optical waveguide device; a light-emitting device; and a support unit supporting the optical waveguide device and the light-emitting device, wherein the optical waveguide device includes a substrate; and an optical waveguide layer disposed on the substrate on one side in a thickness direction of the substrate, the optical waveguide layer including an input coupler and an optical waveguide optically coupled to the input coupler, the light-emitting device being spaced apart from the optical waveguide device on the one side and having a first surface on the optical waveguide layer side and a second surface opposite to the optical waveguide layer, the light-emitting device including a light-emitting layer and a phase modulation layer optically coupled to the light-emitting layer, the phase modulation layer includes a base layer and a plurality of modified refractive index areas having a refractive index different from that of the base layer and two-dimensionally distributed in a plane intersecting a thickness direction of the base layer, the support unit includes a first support section on which one of the optical waveguide device and the light-emitting device is disposed, and a second support section attached to the first support section so as to be aligned with the one device and supporting the other of the optical waveguide device and the light-emitting device, wherein the distance between the optical waveguide device and the light-emitting device is smaller than the width of the second support section in a direction in which the one device and the second support section are aligned. The optical integrated circuit described in [1] uses a light-emitting device including a light-emitting layer and a phase modulation layer optically coupled to the light-emitting layer. Therefore, for example, even if the light-emitting device is not tilted with respect to the optical waveguide layer, light emitted from the light-emitting device can be made incident on an input coupler at a desired angle, and optical loss between the light-emitting device and the optical waveguide can be suppressed. Furthermore, since the distance between the optical waveguide device and the light-emitting device is smaller than the width of the second support member supporting the optical waveguide device or the light-emitting device, light emitted from the light-emitting device can be accurately incident on the input coupler. Since the width of the second support member supporting the optical waveguide device or the light-emitting device is larger than the distance between the optical waveguide device and the light-emitting device, the support of the optical waveguide device or the light-emitting device by the second support member can be maintained in a stable state. Therefore, the optical integrated circuit described in [1] can suppress deterioration of the light propagation characteristics in the optical waveguide.

[0008] An optical integrated circuit according to one aspect of the present disclosure may be [2] "the optical integrated circuit according to [1], in which the distance between the light emitting layer and the second surface is shorter than the distance between the light emitting layer and the first surface." According to the optical integrated circuit according to [2], the light emitting layer, which is a heat generation source, is located farther away from the optical waveguide layer, so that the optical waveguide layer can be prevented from being affected by heat.

[0009] An optical integrated circuit according to one aspect of the present disclosure may be [3] "the optical integrated circuit according to [1] or [2], wherein the phase modulation layer is configured to tilt the optical axis of light traveling along the optical path between the light emitting layer and the input coupler with respect to the thickness direction of the substrate." According to the optical integrated circuit according to [3], for example, optical loss between the light emitting device and the optical waveguide can be suppressed without employing a configuration in which the light emitting device is tilted with respect to the optical waveguide layer. Furthermore, since an optical member for tilting the optical axis of light traveling along the optical path between the light emitting layer and the input coupler is not required, the configuration can be simplified.

[0010] An optical integrated circuit according to one aspect of the present disclosure may be [4] "the optical integrated circuit according to any one of [1] to [3], in which the width of the second support portion is greater than the thickness of the first support portion in the thickness direction of the substrate." According to the optical integrated circuit according to [4], the support of the optical waveguide device or the light-emitting device by the second support portion can be maintained in a more stable state.

[0011] An optical integrated circuit according to one aspect of the present disclosure may be [5] "an optical integrated circuit according to any one of [1] to [4], in which the distance between the optical waveguide device and the light-emitting device is smaller than the thickness of one of the devices in the thickness direction of the substrate." According to the optical integrated circuit according to [5], the distance between the optical waveguide device and the light-emitting device can be made smaller, so that light emitted from the light-emitting device can be made incident on the input coupler with higher accuracy.

[0012] An optical integrated circuit according to one aspect of the present disclosure may be [6] "the optical integrated circuit according to any one of [1] to [5], in which, when the second support member supports the optical waveguide device, the thickness of the substrate is greater than the distance between the optical waveguide device and the light-emitting device." According to the optical integrated circuit according to [6], the substrate has a sufficient thickness, making the optical waveguide device less likely to deform, and therefore the support of the optical waveguide device by the second support member can be maintained in a more stable state.

[0013] An optical integrated circuit according to one aspect of the present disclosure may be [7] "the optical integrated circuit according to any one of [1] to [6], in which the thickness of the first support member is greater than the distance between the optical waveguide device and the light-emitting device." According to the optical integrated circuit according to [7], the first support member has a sufficient thickness, making it less likely to deform, and therefore the support of the optical waveguide device or the light-emitting device by the second support member can be maintained in a more stable state.

[0014] An optical integrated circuit according to one aspect of the present disclosure may be [8] "the optical integrated circuit according to any one of [1] to [7], wherein the phase modulation layer is configured to focus light traveling along an optical path between the light emitting layer and the input coupler onto the input coupler." According to the optical integrated circuit according to [8], light emitted from the light emitting layer can be efficiently incident on the input coupler. Furthermore, since an optical member for focusing light traveling along an optical path between the light emitting layer and the input coupler is not required, the configuration can be simplified.

[0015] According to the present disclosure, it is possible to provide an optical integrated circuit that can suppress deterioration of the light propagation characteristics in an optical waveguide.

[0016] FIG. 1 is a cross-sectional view of an optical integrated circuit according to a first embodiment. FIG. 2 is a cross-sectional view of the optical integrated circuit taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view of the light-emitting device shown in FIG. 1. FIG. 4 is a plan view of the phase modulation layer shown in FIG. 3. FIG. 5 is a cross-sectional view of an optical integrated circuit according to a second embodiment. FIG. 6 is a graph showing the relationship between the focal length and the focused width in the light-emitting device shown in FIG. 1. FIG. 7 is a cross-sectional view of an optical integrated circuit according to a modified example. FIG. 8 is a cross-sectional view of an optical integrated circuit according to a modified example. FIG. 9 is a cross-sectional view of an optical integrated circuit according to a modified example. FIG. 10 is a cross-sectional view of an optical integrated circuit according to a modified example. FIG. 11 is a cross-sectional view of an optical integrated circuit according to a modified example.

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and duplicated explanations will be omitted. [First Embodiment]

[0018] 1 and 2, the optical integrated circuit 1A includes a support unit 2, an optical waveguide device 3, and a light-emitting device 4. Hereinafter, the thickness direction of a substrate 31 constituting the optical waveguide device 3 will be referred to as the Z-axis direction, a direction perpendicular to the Z-axis direction will be referred to as the X-axis direction, and a direction perpendicular to both the Z-axis direction and the X-axis direction will be referred to as the Y-axis direction.

[0019] The support unit 2 supports the optical waveguide device 3 and the light-emitting device 4. The support unit 2 includes a first support portion 21 and a pair of second support portions 22. The first support portion 21 is a submount formed in a plate shape (e.g., a rectangular plate shape) with its thickness direction in the Z-axis direction. As an example, the first support portion 21 is configured by forming wiring on the surface of a base material made of ceramics (e.g., aluminum nitride or silicon carbide) with excellent heat dissipation properties. As an example, the thickness of the first support portion 21, its width in the X-axis direction, and its width in the Y-axis direction are each approximately several hundred μm. The pair of second support portions 22 are disposed on the surface 21 a of the first support portion 21 and face each other in the Y-axis direction. Each second support portion 22 is a sidewall extending in the X-axis direction with its height direction in the Z-axis direction. The material of each second support portion 22 is, for example, ceramics.

[0020] The optical waveguide device 3 is disposed on a pair of second supports 22. Specifically, the optical waveguide device 3 is disposed on an end surface 22a of each second support 22 opposite the first support 21, and faces the surface 21a of the first support 21 in the Z-axis direction. In other words, the optical waveguide device 3 is supported directly (i.e., without any other support) by the pair of second supports 22. The optical waveguide device 3 includes a substrate 31 and an optical waveguide layer 32. The substrate 31 is formed in a plate shape (e.g., a rectangular plate shape) with its thickness direction in the Z-axis direction. The material of the substrate 31 is, for example, silicon. As an example, the thickness of the substrate 31, the width of the substrate 31 in the X-axis direction, and the width of the substrate 31 in the Y-axis direction are each approximately several hundred μm.

[0021] The optical waveguide layer 32 is disposed on one side in the Z-axis direction (the lower side in FIGS. 1 and 2 ) of the substrate 31. The optical waveguide layer 32 is composed of an intermediate layer 34 and a pair of clad layers 35 and 36 formed integrally on the substrate 31. The clad layer 35 is located on the substrate 31 side with respect to the intermediate layer 34, and the clad layer 36 is located on the opposite side of the intermediate layer 34 from the substrate 31. In the optical integrated circuit 1A, when viewed from the Z-axis direction, the outer edge of the optical waveguide layer 32 coincides with the outer edge of the substrate 31. As an example, the thickness of the optical waveguide layer 32 is approximately several μm to several tens of μm, and the width of the optical waveguide layer 32 in the X-axis direction and the width of the optical waveguide layer 32 in the Y-axis direction are each approximately several hundred μm.

[0022] An input coupler 37 and an optical waveguide 38 are formed in the intermediate layer 34. That is, the optical waveguide layer 32 includes the input coupler 37 and the optical waveguide 38. The input coupler 37 is a grating coupler. The input coupler 37 has a plurality of grating grooves aligned in the X-axis direction, each of which opens to one side in the Z-axis direction. As an example, the width of the input coupler 37 in the X-axis direction and the width of the input coupler 37 in the Y-axis direction are each several μm to several tens of μm. The optical waveguide 38 is optically coupled to the input coupler 37 and extends from the input coupler 37 to one side in the X-axis direction (the right side in FIG. 2 ). The width of the optical waveguide 38 in the Y-axis direction gradually decreases toward one side in the X-axis direction. As an example, the width of the optical waveguide 38 in the Y-axis direction is several μm to several tens of μm at the end on the input coupler 37 side and is approximately 0.5 μm at the end opposite the input coupler 37. The input coupler 37 and the optical waveguide 38 are made of, for example, silicon. The portions of the intermediate layer 34 other than the "input coupler 37 and the optical waveguide 38" and the pair of clad layers 35, 36 are made of, for example, silicon oxide. The input coupler 37 is not limited to a grating coupler, and may be an edge coupler or the like.

[0023] The light-emitting device 4 is disposed on the first support 21 on the other side in the Z-axis direction (upper side in FIGS. 1 and 2 ). Specifically, the light-emitting device 4 is disposed on the surface 21 a of the first support 21 between a pair of second support parts 22, and faces the surface 32 a of the optical waveguide layer 32 on the light-emitting device 4 side in the Z-axis direction. In other words, each second support part 22 is attached to the first support part 21 so as to be aligned with the light-emitting device 4 in the Y-axis direction. The light-emitting device 4 is spaced apart from the optical waveguide device 3 on one side in the Z-axis direction. In other words, a gap is formed between the optical waveguide device 3 and the light-emitting device 4.

[0024] The light-emitting device 4 emits light L, which is laser light, toward the optical waveguide layer 32. The light-emitting device 4 is a laser element that forms a standing wave in an in-plane direction perpendicular to the Z-axis direction and emits a phase-controlled plane wave as light L toward the optical waveguide layer 32. The light-emitting device 4 is a static-integrable phase modulating (S-iPM) laser element that can output an optical image of any shape in the Z-axis direction, a direction tilted with respect to the Z-axis direction, or a plurality of directions including these directions.

[0025] The light-emitting device 4 includes a semiconductor layer 40 and a pair of electrodes 41 and 42. The semiconductor layer 40 is formed in a plate shape (e.g., a rectangular plate shape) with its thickness direction aligned in the Z-axis direction. The semiconductor layer 40 includes a light-emitting layer 43 and a phase modulation layer 44. The phase modulation layer 44 is located on the opposite side of the light-emitting layer 43, which is the active layer, from the optical waveguide layer 32 and is optically coupled to the light-emitting layer 43. The phase modulation layer 44 includes a base layer 44a and multiple modified refractive index regions 44b. The multiple modified refractive index regions 44b have a refractive index different from that of the base layer 44a and are distributed two-dimensionally in a plane perpendicular to the Z-axis direction (a plane intersecting the thickness direction of the base layer 44a). As an example, the thickness of the semiconductor layer 40, the width of the semiconductor layer 40 in the X-axis direction, and the width of the semiconductor layer 40 in the Y-axis direction are each approximately several hundred microns.

[0026] The distance between the light-emitting layer 43 and the second surface 4b of the light-emitting device 4 is smaller than the distance between the light-emitting layer 43 and the first surface 4a of the light-emitting device 4. The first surface 4a is the surface of the light-emitting device 4 facing the optical waveguide layer 32, and the second surface 4b is the surface of the light-emitting device 4 opposite the optical waveguide layer 32. As an example, the distance between the light-emitting layer 43 and the second surface 4b is several μm to several tens of μm. When viewed from the Z-axis direction, the light-emitting layer 43 overlaps with the input coupler 37. That is, when viewed from the Z-axis direction, at least a portion of the light-emitting layer 43 overlaps with at least a portion of the input coupler 37. In the optical integrated circuit 1A, when viewed from the Z-axis direction, a portion of the light-emitting layer 43 overlaps with the entire input coupler 37. That is, when viewed from the Z-axis direction, the light-emitting layer 43 includes the input coupler 37. When viewed from the Z-axis direction, the center 43a of the light-emitting layer 43 overlaps with the input coupler 37. When viewed from the Z-axis direction, the center 43a of the light-emitting layer 43 is shifted to the other side in the X-axis direction (to the left in FIG. 2 ) with respect to the center 37a of the input coupler 37. Note that the center of a shape when viewed from the Z-axis direction means the center of gravity of the shape when viewed from the Z-axis direction if the shape is not point-symmetric.

[0027] The phase modulation layer 44 is configured to tilt the optical axis A of the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 with respect to the Z-axis direction and to focus the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 onto the input coupler 37. In the optical integrated circuit 1A, the optical axis A is tilted so as to connect the center 43a of the light emitting layer 43 when viewed from the Z-axis direction and the center 37a of the input coupler 37 when viewed from the Z-axis direction. In other words, the optical axis A is tilted so as to move closer to the optical waveguide 38 in the X-axis direction as it approaches the input coupler 37 in the Z-axis direction.

[0028] A portion of the electrode 41 and the electrode 42 are disposed on the surface of the semiconductor layer 40 opposite the optical waveguide layer 32. That is, the portion of the electrode 41 and the electrode 42 are disposed on the second surface 4b side of the light-emitting device 4. The portion of the electrode 41 is electrically and physically connected to the electrode pad 211 via a bonding member such as solder. The electrode 42 is electrically and physically connected to the electrode pad 212 via a bonding member such as solder. The electrode pads 211 and 212 are part of the wiring included in the first support 21 and are disposed on the surface 21a of the first support 21. In the optical integrated circuit 1A, an external wiring is connected to the wiring of the first support 21, so that a current is supplied to the light-emitting layer 43 of the light-emitting device 4.

[0029] The optical integrated circuit 1A configured as described above has the following dimensional relationships. As shown in FIG. 1 , the distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the width W of each second support portion 22 in the Y-axis direction (the direction in which one device and the second support portion 22 are lined up; in this embodiment, the direction along the surface 21 a of the first support portion 21). The width W of each second support portion 22 is larger than the thickness T1 of the first support portion 21. The distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the thickness T2 of the light-emitting device 4. The thickness T3 of the substrate 31 of the optical waveguide device 3 supported by the pair of second support portions 22 is larger than the distance D between the optical waveguide device 3 and the light-emitting device 4. The thickness T1 of the first support portion 21 is larger than the distance D between the optical waveguide device 3 and the light-emitting device 4. As an example, the distance D is about several μm to 20 μm, the thicknesses T1 and T3 are about 200 to 700 μm, the thickness T2 is about 200 to 500 μm, and the width W is about 500 μm to several mm.

[0030] The configuration of the light-emitting device 4 described above will be described in more detail. As shown in FIG. 3 , the semiconductor layer 40 includes a semiconductor substrate 45, a pair of cladding layers 46 a and 46 b, and a contact layer 47 in addition to the light-emitting layer 43 and the phase modulation layer 44. The phase modulation layer 44 is located on the second surface 4 b side of the light-emitting layer 43. In the light-emitting device 4, the cladding layer 46 a, the light-emitting layer 43, the phase modulation layer 44, the cladding layer 46 b, and the contact layer 47 are stacked on the semiconductor substrate 45 in this order from the first surface 4 a side. The semiconductor substrate 45, the pair of cladding layers 46 a and 46 b, and the contact layer 47 are made of compound semiconductors (e.g., GaAs-based semiconductors, InP-based semiconductors, and nitride-based semiconductors). The energy band gaps of the cladding layers 46 a and 46 b are larger than the energy band gap of the light-emitting layer 43.

[0031] The phase modulation layer 44 may be located on the first surface 4a side with respect to the light emitting layer 43. That is, the phase modulation layer 44 may be located on the optical waveguide layer 32 side with respect to the light emitting layer 43. In this case, the phase modulation layer 44 may be disposed between the light emitting layer 43 and the cladding layer 46a. The semiconductor layer 40 may further include at least one of an optical guide layer disposed between the light emitting layer 43 and the cladding layer 46a and an optical guide layer disposed between the light emitting layer 43 and the cladding layer 46b. The optical guide layer may include a carrier barrier layer for efficiently confining carriers in the light emitting layer 43.

[0032] In the phase modulation layer 44, the multiple modified refractive index areas 44b include a periodic lattice structure. When the equivalent refractive index of the mode is n and the lattice spacing is a, the wavelength λ selected by the phase modulation layer 44 is ０ is "λ ０ = (√2) a × n". This wavelength λ ０ is a wavelength included in the emission wavelength range of the light emitting layer 43, and forms a standing wave at the M-point photonic band edge of the square lattice. ０It is possible to select a nearby band edge wavelength and output it to the outside. Light incident on the phase modulation layer 44 forms a predetermined mode in accordance with the arrangement of the multiple modified refractive index regions 44b within the phase modulation layer 44, and is emitted as light L from the light-emitting device 4 to the other side in the Z-axis direction (the upper side in FIG. 3). Note that, since vertical diffraction does not usually occur at the M-point photonic band edge, it is not possible to extract a beam pattern outside the plane. Therefore, the phase distribution formed by the phase modulation layer 44 is designed so that the phase distribution corresponding to the diffraction vector V is further superimposed on the phase distribution φ0 of the beam pattern, so that the in-plane component of the wave vector of at least one of the four fundamental waves constituting the M-point photonic band edge is smaller than 2π / λ corresponding to the light line. Furthermore, in a triangular lattice, the J-point photonic band edge can be utilized. In this case, the wavelength λ ０ is "λ ０ = (3 / 2) a × n". The phase distribution formed by the phase modulation layer 44 is designed so that the in-plane component of the wave vector of at least one of the six fundamental waves constituting the J-point photonic band edge is smaller than 2π / λ corresponding to the light line by further superimposing the phase distribution corresponding to the diffraction vector V on the phase distribution φ0 of the beam pattern. The phase modulation layer 44 may be designed to form not only the M-point photonic band edge and the J-point photonic band edge but also other photonic band edges.

[0033] The light-emitting layer 43, the phase modulation layer 44, the pair of cladding layers 46a, 46b, and the contact layer 47 are separated into a first portion 40A and a second portion 40B by a groove 40C that opens on the side opposite to the semiconductor substrate 45. The bottom surface of the groove 40C reaches the semiconductor substrate 45. Light L is generated in the first portion 40A and emitted from the first portion 40A. In the light-emitting device 4, the phase modulation layer 44 in the first portion 40A includes multiple modified refractive index regions 44b, but the phase modulation layer 44 in the second portion 40B does not include multiple modified refractive index regions 44b.

[0034] An insulating film 48 is formed on each surface of the first portion 40A and the second portion 40B. The insulating film 48 is not formed on the central region of the surface of the contact layer 47 of the first portion 40A or on the bottom surface of the groove 40C. An anti-reflection film 49 is formed on the surface of the semiconductor substrate 45 opposite to the first portion 40A.

[0035] The electrode 41 extends from the insulating film 48 formed on the surface of the contact layer 47 of the second portion 40B onto the bottom surface of the groove 40C and makes ohmic contact with the semiconductor substrate 45 on the bottom surface of the groove 40C. The electrode 42 makes ohmic contact with the contact layer 47 of the first portion 40A on a central region of the surface of the contact layer 47 of the first portion 40A (i.e., a region where the insulating film 48 is not formed). The surface of the part of the electrode 41 opposite the second portion 40B and the surface of the electrode 42 opposite the first portion 40A are located on the same plane. The current injection region 40a of the light-emitting device 4 is a region where the electrode 42 and the contact layer 47 are in contact with each other.

[0036] In the light-emitting device 4, when a driving current is supplied between the pair of electrodes 41 and 42, electrons and holes recombine in the light-emitting layer 43 of the first portion 40A, causing the light-emitting layer 43 of the first portion 40A to emit light. The electrons and holes contributing to this light emission, as well as the light generated in the light-emitting layer 43 of the first portion 40A, are efficiently confined between the cladding layers 46a and 46b in the first portion 40A. The light generated in the light-emitting layer 43 of the first portion 40A then enters the phase modulation layer 44 in the first portion 40A and forms a predetermined mode corresponding to the lattice structure in the phase modulation layer 44. The light L emitted from the phase modulation layer 44 of the first portion 40A is emitted outside the light-emitting device 4 via the anti-reflection film 49. The light L may be emitted from the light-emitting device 4 not only as +1st-order light (plus first-order diffracted light) but also as -1st-order light (minus first-order diffracted light).

[0037] An example of the configuration of the phase modulation layer 44 (the configuration of the phase modulation layer 44 in the first portion 40A) will be described in more detail. As shown in FIGS. 4A and 4B , a virtual elementary lattice is set in the phase modulation layer 44 in a plane perpendicular to the Z-axis direction. The elementary lattice is a square lattice having sides parallel to the X-axis direction and sides parallel to the Y-axis direction. In the plane perpendicular to the Z-axis direction, a plurality of unit constituent regions R are two-dimensionally arranged with the X-axis direction as the row direction and the Y-axis direction as the column direction. Each unit constituent region R is a square region centered on a lattice point O of the square lattice. The center of gravity of each unit constituent region R coincides with the lattice point O of the corresponding square lattice. One modified refractive index region 44b is disposed in each unit constituent region R. The shape of each modified refractive index region 44b when viewed from the Z-axis direction is, for example, circular. Each lattice point O may be located outside or within the corresponding modified refractive index region 44b.

[0038] Each modified refractive index area 44b has a center of gravity G. The center of gravity G of each modified refractive index area 44b is located at a position relative to the corresponding lattice point O that corresponds to the phase modulation amount of a predetermined phase distribution. Here, the angle between the vector from the lattice point O toward the center of gravity G and the X-axis is defined as α(x, y). x indicates the position of the xth lattice point on the X-axis, and y indicates the position of the yth lattice point on the Y-axis. When the rotation angle α is 0°, the direction of the vector connecting the lattice point O and the center of gravity G coincides with the positive direction of the X-axis. Furthermore, the length of the vector connecting the lattice point O and the center of gravity G is defined as r(x, y). As an example, r(x, y) is constant throughout the phase modulation layer 44, regardless of the values ​​of x and y.

[0039] The direction of the vector connecting the lattice point O and the center of gravity G, i.e., the rotation angle α of the center of gravity G of the modified refractive index area 44b around the lattice point O, is individually set for each lattice point O according to the phase distribution φ(x, y) corresponding to the desired shape of the light L, which is the output light. The phase distribution φ(x, y) has a specific value for each position determined by the values ​​of x and y, but is not necessarily expressed by a specific function. The rotation angle distribution α(x, y) is determined by extracting the phase distribution φ(x, y) from the complex amplitude distribution obtained by Fourier transforming the desired shape of the light L. When calculating the complex amplitude distribution from the desired shape of the light L, it is preferable to apply an iterative algorithm such as the Gerchberg-Saxton (GS) method, which is commonly used in calculations for hologram generation. In this case, it is possible to improve the reproducibility of the beam pattern. The final phase distribution Φ is obtained by further adding a "phase distribution for diffracting the standing wave at the M-point photonic band edge in the plane-perpendicular direction" and a "phase distribution for focusing." Specifically, if the phase distribution of the two-dimensional pattern is Φ(2D), the phase distribution of M-point emission is Φ(M), and the phase distribution of collected light is Φ(Focus), the actual phase distribution Φ is "Φ=Φ(2D)+Φ(M)+Φ(Focus)". An example of obliquely collecting light with a single focal length is as follows. If the lattice spacing is a and the two-dimensional hole positions are (x, y)=a(Nx, Ny), the respective phase distributions are expressed by the following equations. Φ(Tilt)=((√2)π / a)(sin θt)(x(cos θr)+y(sin θr)) Φ(M)=(π / a)(x+y) Φ(Focus)=(π / (λf))(x ２ +y ２ ) θt: Tilt angle from the surface normal Z axis θr: Azimuth angle in the surface relative to the X axis f: Focal length

[0040] When designing a multi-point beam with multiple focal lengths, the phase distribution of the pattern for each focal length can be calculated as described above, and then superimposed. In this case, instead of adding the phases, methods such as taking the sum of complex amplitudes or randomly combining them can be used. In this way, the phase distribution can be designed.

[0041] As described above, the center of gravity G of each modified refractive index area 44b is located at a position relative to the corresponding lattice point O that corresponds to the phase modulation amount of a predetermined phase distribution. In the light-emitting device 4, the phase distribution of the phase modulation layer 44 includes an element for focusing the light L emitted outside the light-emitting device 4. Note that, for the center of gravity G of each modified refractive index area 44b, the rotation angle α around the lattice point O is set individually for each lattice point O, but the setting of the center of gravity G of each modified refractive index area 44b is not limited thereto. For example, the center of gravity G of each modified refractive index area 44b may be set so that the distance between each center of gravity G and each lattice point O is an individual distance on a straight line passing through each lattice point O (a straight line extending from each lattice point O at a common angle). Furthermore, instead of the position of the center of gravity G of each modified refractive index area 44b, the size of each modified refractive index area 44b may be modulated, or the position of the center of gravity G of each modified refractive index area 44b and the size of each modified refractive index area 44b may be modulated simultaneously.

[0042] As shown in (b) of FIG. 4, when the center of gravity G of each modified refractive index region 44b in the phase modulation layer 44 is shifted onto the axis D, linearly polarized light L is emitted. As shown in (a) of FIG. 4, when the center of gravity G of each modified refractive index region 44b in the phase modulation layer 44 is shifted circumferentially, circularly polarized light L is emitted. Since linearly polarized light L is more likely to have improved coupling efficiency to the input coupler 37 than circularly polarized light L, from this perspective, a configuration in which the center of gravity G of each modified refractive index region 44b in the phase modulation layer 44 is shifted onto the axis D is preferred. Each modified refractive index region 44b may have a pattern (e.g., a double hole) formed by multiple holes. In this case, a pair of modified refractive index regions 44b is arranged within each unit constituent region R.

[0043] As described above, the optical integrated circuit 1A uses the light-emitting device 4 including the light-emitting layer 43 and the phase modulation layer 44 optically coupled to the light-emitting layer 43. Therefore, for example, even if the light-emitting device 4 is not tilted relative to the optical waveguide layer 32, the light L emitted from the light-emitting device 4 can be incident on the input coupler 37 at a desired angle, thereby suppressing optical loss between the light-emitting device 4 and the optical waveguide 38. Furthermore, since the distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the width W of each second support portion 22 supporting the optical waveguide device 3, the light L emitted from the light-emitting device 4 can be accurately incident on the input coupler 37. Since the width W of each second support portion 22 supporting the optical waveguide device 3 is larger than the distance D between the optical waveguide device 3 and the light-emitting device 4, the support of the optical waveguide device 3 by the pair of second support portions 22 can be maintained in a stable state. Therefore, the optical integrated circuit 1A can suppress deterioration of the light propagation characteristics in the optical waveguide 38.

[0044] In the optical integrated circuit 1A, the distance between the light emitting layer 43 and the second surface 4b is shorter than the distance between the light emitting layer 43 and the first surface 4a. This places the light emitting layer 43, which is a heat generation source, farther away from the optical waveguide layer 32, thereby preventing the optical waveguide layer 32 from being affected by heat. Furthermore, because the light emitting layer 43, which is a heat generation source, is closer to the first support section 21, heat generated in the light emitting layer 43 can be efficiently dissipated to the first support section 21.

[0045] In the optical integrated circuit 1A, the phase modulation layer 44 is configured to tilt the optical axis A of the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 with respect to the Z-axis direction. This makes it possible to suppress optical loss between the light emitting device 4 and the optical waveguide 38, for example, without employing a configuration in which the light emitting device 4 is tilted with respect to the optical waveguide layer 32. Furthermore, since an optical member for tilting the optical axis of the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 is not required, the configuration can be simplified.

[0046] In the optical integrated circuit 1A, the width W of each second support portion 22 is greater than the thickness T1 of the first support portion 21. This allows the pair of second support portions 22 to maintain support of the optical waveguide device 3 in a more stable state.

[0047] In the optical integrated circuit 1A, the distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the thickness T2 of the light-emitting device. This allows the distance D between the optical waveguide device 3 and the light-emitting device 4 to be made smaller, so that the light L emitted from the light-emitting device 4 can be made incident on the input coupler 37 with greater accuracy.

[0048] In the optical integrated circuit 1A, the thickness T3 of the substrate 31 of the optical waveguide device 3 supported by the pair of second support parts 22 is greater than the distance D between the optical waveguide device 3 and the light-emitting device 4. This provides the substrate 31 with a sufficient thickness, making the optical waveguide device 3 less likely to deform, and therefore the support of the optical waveguide device 3 by the pair of second support parts 22 can be maintained in a more stable state.

[0049] In the optical integrated circuit 1A, the thickness T1 of the first support portion 21 is larger than the distance D between the optical waveguide device 3 and the light-emitting device 4. This provides the first support portion 21 with a sufficient thickness, making the first support portion 21 less likely to deform, and therefore the support of the optical waveguide device 3 by the pair of second support portions 22 can be maintained in a more stable state.

[0050] In the optical integrated circuit 1A, the phase modulation layer 44 is configured to focus the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 onto the input coupler 37. This allows the light emitted from the light emitting layer 43 to be efficiently incident on the input coupler 37. Furthermore, since an optical member for focusing the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 is not required, the configuration can be simplified.

[0051] In particular, when focusing light L emitted from the light-emitting device 4 onto the input coupler 37, the shorter the distance D between the optical waveguide device 3 and the light-emitting device 4, the smaller the focused width of light L entering the input coupler 37. Therefore, the configuration of the optical integrated circuit 1A that can stably support the optical waveguide device 3 and the light-emitting device 4 at a small distance D is extremely effective. Furthermore, the configuration of the light-emitting device 4 that can be surface-mounted on the first support portion 21 having wiring is extremely effective because it does not require the use of wires that would hinder reducing the distance D between the optical waveguide device 3 and the light-emitting device 4. Note that even when the light L emitted from the light-emitting device 4 is parallel light, a small distance D between the optical waveguide device 3 and the light-emitting device 4 is preferable because a large distance D between the optical waveguide device 3 and the light-emitting device 4 makes it difficult to direct the light L to the target position due to the influence of diffraction broadening. [Second Embodiment]

[0052] 5, the optical integrated circuit 1B differs from the above-described optical integrated circuit 1A mainly in that the optical waveguide device 3 is disposed on a first support portion 21, and the light-emitting device 4 is supported by a pair of second support portions 22. Hereinafter, a description of the configuration of the optical integrated circuit 1B that is the same as that of the optical integrated circuit 1A will be omitted, and only the configuration of the optical integrated circuit 1B that differs from that of the optical integrated circuit 1A will be described in detail.

[0053] In the optical integrated circuit 1B, the support unit 2 includes a first support 21, a pair of second support members 22, and a third support member 23. The third support member 23 is a submount formed in a plate shape (e.g., a rectangular plate shape) with its thickness in the Z-axis direction. As an example, the third support member 23 is configured by forming wiring on the surface of a base material made of ceramics (e.g., aluminum nitride or silicon carbide) with excellent heat dissipation properties. As an example, the thickness of the third support member 23, its width in the X-axis direction, and its width in the Y-axis direction are each approximately several hundred μm. The third support member 23 is disposed on the pair of second support members 22. Specifically, the third support member 23 is disposed on the end surface 22a of each second support member 22 and faces the surface 21a of the first support member 21 in the Z-axis direction. Note that in the optical integrated circuit 1B, no wiring is provided on the first support member 21.

[0054] The optical waveguide device 3 is disposed on one side in the Z-axis direction (upper side in FIG. 5 ) on the first support 21. Specifically, the optical waveguide device 3 is disposed on the surface 21a of the first support 21 between a pair of second supports 22, with the optical waveguide layer 32 positioned on one side in the Z-axis direction relative to the substrate 31. In other words, each second support 22 is attached to the first support 21 so as to be aligned with the optical waveguide device 3 in the Y-axis direction.

[0055] The light-emitting device 4 is disposed on the third support 23 on the other side in the Z-axis direction (the lower side in FIG. 5 ). Specifically, the light-emitting device 4 is disposed on the surface 23a of the third support 23 on the first support 21 side between the pair of second support parts 22, with a portion of the electrode 41 and the electrode 42 positioned on one side of the semiconductor layer 40 in the Z-axis direction. In other words, the light-emitting device 4 is indirectly supported by the pair of second support parts 22 (i.e., via the third support parts 23). The light-emitting device 4 is spaced from the optical waveguide device 3 on one side in the Z-axis direction. In other words, a gap is formed between the optical waveguide device 3 and the light-emitting device 4. A portion of the electrode 41 is electrically and physically connected to the electrode pad 231 via a bonding member such as solder. The electrode 42 is electrically and physically connected to the electrode pad 232 via a bonding member such as solder. The electrode pads 231 and 232 are part of the wiring included in the third support portion 23, and are arranged on the surface 23a of the third support portion 23. In the optical integrated circuit 1B, an external wiring is connected to the wiring of the third support portion 23, so that a current is supplied to the light-emitting layer 43 of the light-emitting device 4.

[0056] The optical integrated circuit 1B configured as described above has the following dimensional relationships. That is, the distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the width W of each second support portion 22 in the Y-axis direction. The distance D between the optical waveguide device 3 and the light-emitting device 4 is, for example, several μm to several tens of μm. The width W of each second support portion 22 is larger than the thickness T1 of the first support portion 21. The distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the thickness T4 of the optical waveguide device 3. The thickness T1 of the first support portion 21 is larger than the distance D between the optical waveguide device 3 and the light-emitting device 4. As an example, the distance D is approximately several μm to 20 μm, the thickness T1 is approximately 300 to 700 μm, the thickness T4 is approximately 200 to 500 μm, and the width W is approximately 500 μm to several mm.

[0057] As described above, the optical integrated circuit 1B uses the light-emitting device 4 including the light-emitting layer 43 and the phase modulation layer 44 optically coupled to the light-emitting layer 43. Therefore, for example, even if the light-emitting device 4 is not tilted relative to the optical waveguide layer 32, the light L emitted from the light-emitting device 4 can be incident on the input coupler 37 at a desired angle, thereby suppressing optical loss between the light-emitting device 4 and the optical waveguide 38. Furthermore, since the distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the width W of each second support portion 22 supporting the light-emitting device 4, the light L emitted from the light-emitting device 4 can be accurately incident on the input coupler 37. Since the width W of each second support portion 22 supporting the light-emitting device 4 is larger than the distance D between the optical waveguide device 3 and the light-emitting device 4, the support of the light-emitting device 4 by the pair of second support portions 22 can be maintained in a stable state. Therefore, the optical integrated circuit 1B can suppress deterioration of the light propagation characteristics in the optical waveguide 38.

[0058] In the optical integrated circuit 1B, the distance between the light emitting layer 43 and the second surface 4b is shorter than the distance between the light emitting layer 43 and the first surface 4a. This places the light emitting layer 43, which is a heat generation source, farther away from the optical waveguide layer 32, thereby preventing the optical waveguide layer 32 from being affected by heat. Furthermore, because the light emitting layer 43, which is a heat generation source, is closer to the third support section 23, heat generated in the light emitting layer 43 can be efficiently released to the third support section 23.

[0059] In the optical integrated circuit 1B, the phase modulation layer 44 is configured to tilt the optical axis A of the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 with respect to the Z-axis direction. This makes it possible to suppress optical loss between the light emitting device 4 and the optical waveguide 38, for example, without employing a configuration in which the light emitting device 4 is tilted with respect to the optical waveguide layer 32. Furthermore, since an optical member for tilting the optical axis of the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 is not required, the configuration can be simplified.

[0060] In the optical integrated circuit 1B, the width W of each second support portion 22 is greater than the thickness T1 of the first support portion 21. This allows the pair of second support portions 22 to maintain support of the light-emitting device 4 in a more stable state.

[0061] In the optical integrated circuit 1B, the distance D between the optical waveguide device 3 and the light-emitting device 4 is smaller than the thickness T4 of the optical waveguide device 3. This allows the distance D between the optical waveguide device 3 and the light-emitting device 4 to be made smaller, so that the light L emitted from the light-emitting device 4 can be made incident on the input coupler 37 with higher accuracy.

[0062] In the optical integrated circuit 1B, the thickness T1 of the first support portion 21 is greater than the distance D between the optical waveguide device 3 and the light-emitting device 4. This provides the first support portion 21 with a sufficient thickness, making the first support portion 21 less likely to deform, and therefore the support of the light-emitting device 4 by the pair of second support portions 22 can be maintained in a more stable state.

[0063] In the optical integrated circuit 1B, the phase modulation layer 44 is configured to focus the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 onto the input coupler 37. This allows the light emitted from the light emitting layer 43 to be efficiently incident on the input coupler 37. Furthermore, since an optical member for focusing the light L traveling along the optical path P between the light emitting layer 43 and the input coupler 37 is not required, the configuration can be simplified.

[0064] In particular, when light L emitted from the light-emitting device 4 is focused onto the input coupler 37, the shorter the distance D between the optical waveguide device 3 and the light-emitting device 4, the smaller the focused width of the light L incident on the input coupler 37 can be, so the configuration of the optical integrated circuit 1B that can stably support the optical waveguide device 3 and the light-emitting device 4 at a small distance D is extremely effective. Furthermore, the configuration of the light-emitting device 4 that can be surface-mounted on the third support part 23 having wiring is extremely effective because it does not require the use of wires that would hinder the reduction of the distance D between the optical waveguide device 3 and the light-emitting device 4. [Relationship between focal length and focused width in a light-emitting device]

[0065] The relationship between the focal length and the light-collecting width in the light-emitting device 4 will be described with reference to Figures 6(a) and 6(b). Figures 6(a) and 6(b) show the beam quality M ２ 6 shows the light-collection width calculated for each focal length when assuming that π = 2. FIG. 6A shows the results when the refractive index of the portion of the light-emitting layer 43 located on the light-emitting side of the light L is set to 1, and FIG. 6B shows the results when the refractive index of the portion of the light-emitting layer 43 located on the light-emitting side of the light L is set to 3.17. As shown in FIGS. 6A and 6B, the light-emitting device 4 can collect light L into the input coupler 37, which has a width (width in each of the X-axis and Y-axis directions) of several tens of micrometers or less. Considering the size of the input coupler 37, the light-collection width is preferably 15 micrometers or less. FIG. 8B shows that when the focal length is set to 350 micrometers or less, the light-collection width can be 15 micrometers or less regardless of the width of the light-emitting layer 43, which is between 50 micrometers and 200 micrometers. [Modification]

[0066] The present disclosure is not limited to the first and second embodiments described above. For example, in the optical integrated circuit 1A, the first support 21 is not limited to having the structure (including shape) described above, as long as the light-emitting device 4 can be disposed on the first support 21. In the optical integrated circuit 1A, the pair of second support 22 is not limited to having the structure (including shape) described above, as long as they can directly or indirectly support the optical waveguide device 3. As an example, the optical waveguide device 3 may be directly or indirectly supported by a plurality of columnar second support 22, or may be directly or indirectly supported by a single second support 22. As an example in which the optical waveguide device 3 is directly supported by a single second support 22, as shown in FIG. 7, the optical waveguide device 3 may be fixed in a cantilevered state on the end surface 22a of a single second support 22. In either case, the material of each of the first support 21 and the second support 22 may be silicon (high resistance). In either case, the first support portion 21 and the second support portion 22 are not limited to being formed separately and then combined, but may be formed integrally.

[0067] In the optical integrated circuit 1B, the first support 21 is not limited to having the structure (including shape) described above, as long as the optical waveguide device 3 can be disposed on the first support 21. In the optical integrated circuit 1B, the pair of second support 22 is not limited to having the structure (including shape) described above, as long as they can directly or indirectly support the light-emitting device 4. As an example, the light-emitting device 4 may be directly or indirectly supported by a plurality of columnar second support 22, or may be directly or indirectly supported by a single second support 22. In either case, the materials of the first support 21, the second support 22, and the third support 23 may be silicon (high resistance). Furthermore, in either case, the first support 21 and the second support 22 are not limited to being formed separately and then combined, but may be formed integrally. Similarly, the second support 22 and the third support 23 are not limited to being formed separately and then combined, but may be formed integrally. Similarly, the first support portion 21, the second support portion 22, and the third support portion 23 are not limited to being formed separately and then combined, but may be formed integrally.

[0068] As shown in FIG. 8 , the light-emitting device 4 may have a light-shielding layer 50 having an opening 50a provided along the first surface 4a. The optical path P between the light-emitting layer 43 and the input coupler 37 passes through the opening 50a. This makes it possible to prevent unwanted light, such as −1st-order light emitted from the light-emitting layer 43, from entering the input coupler 37. The light-shielding layer 50 is formed into a film shape using, for example, a metal. The light-shielding layer 50 as described above is not limited to the optical integrated circuit 1A shown in FIG. 8 , and may be applied to all embodiments and modified examples including the optical integrated circuit 1B.

[0069] As shown in FIG. 9 , at least one spacer 25 may be disposed between the light-emitting device 4 and the optical waveguide device 3 so as not to block the optical path P between the light-emitting layer 43 and the input coupler 37. This allows the distance D between the optical waveguide device 3 and the light-emitting device 4 to be more reliably and stably maintained constant. As an example, one frame-shaped spacer 25 may be disposed between the light-emitting device 4 and the optical waveguide device 3, or multiple wall- or column-shaped spacers 25 may be disposed between the light-emitting device 4 and the optical waveguide device 3. The light-emitting device 4 is spaced on one side from the optical waveguide device 3 via the spacer 25. A space is formed between the light-emitting device 4 and the optical waveguide device 3 in a region through which light L emitted from the light-emitting device 4 passes, thereby spaced from the optical waveguide device 3 on one side. The spacer 25 described above is not limited to the optical integrated circuit 1A shown in FIG. 9 , but may be applied to all embodiments and modifications including the optical integrated circuit 1B.

[0070] As shown in FIGS. 10 and 11 , in an optical integrated circuit 1B, the light-emitting device 4 may be supported by a second support 22. First, the configuration of the optical integrated circuit 1B shown in FIG. 10 will be described, focusing on differences from the optical integrated circuit 1B shown in FIG. 5 . In the optical integrated circuit 1B shown in FIG. 10 , the light-emitting device 4 is disposed on the end surface 22a of the second support 22, with the first surface 4a facing the surface 32a of the optical waveguide layer 32. In the light-emitting device 4, an electrode 41 is disposed on the first surface 4a side. The electrode 41 has an opening 41a through which an optical path P passes between the light-emitting layer 43 and the input coupler 37. An electrode pad 231 is disposed on the end surface 22a of the second support 22, and the electrode 41 is electrically and physically connected to the electrode pad 231 via a bonding member such as solder. An electrode pad 232 is disposed on the end surface 22a of the second support 22, and the electrode 42 is electrically and physically connected to the electrode pad 232 via a wire 7. The wire 7 is connected to each of the electrode 42 and the electrode pad 232 .

[0071] Next, the configuration of the optical integrated circuit 1B shown in FIG. 11 will be described, focusing on the differences from the optical integrated circuit 1B shown in FIG. 10 . In the optical integrated circuit 1B shown in FIG. 11 , a submount 5 is disposed on a light-emitting device 4. The submount 5 is formed in a block shape (e.g., a rectangular parallelepiped) having a third surface 5a and a fourth surface 5b. The third surface 5a is the surface of the submount 5 facing the light-emitting device 4, and the fourth surface 5b is the surface of the submount 5 opposite the light-emitting device 4. The second surface 4b of the light-emitting device 4 is in surface contact with the third surface 5a of the submount 5. When viewed from the Z-axis direction, the submount 5 includes the light-emitting device 4. The thickness of the submount 5 in the Z-axis direction is greater than the thickness of the light-emitting device 4 in the Z-axis direction. As an example, the submount 5 is configured by forming wiring on the surface of a base material made of ceramics (e.g., aluminum nitride or silicon carbide) with excellent heat dissipation properties. As an example, the thickness of the submount 5, the width of the submount 5 in the X-axis direction, and the width of the submount 5 in the Y-axis direction are each approximately several hundred μm. The portion of the wiring of the submount 5 located on the third surface 5 a side is electrically and physically connected to the electrode 42 of the light-emitting device 4 via a bonding material such as solder. The electrode 41 is electrically and physically connected to the electrode pad 231 via a bonding material such as solder. The electrode 42 is electrically and physically connected to the electrode pad 232 via the wiring of the submount 5 and the wire 7. The wire 7 is connected to both the wiring of the submount 5 and the electrode pad 232. According to the optical integrated circuit 1B shown in FIG. 11 , heat generated in the light-emitting device 4 can be dissipated to the submount 5, thereby suppressing deterioration of the light output characteristics of the light-emitting device 4 itself.

[0072] In the light-emitting device 4, the groove 40C that separates a portion of the semiconductor layer 40 (specifically, the light-emitting layer 43, the phase modulation layer 44, the pair of cladding layers 46a, 46b, and the contact layer 47) into the first portion 40A and the second portion 40B is not limited to extending in a straight line when viewed from the Z-axis direction, but may also extend in an L-shape when viewed from the Z-axis direction.

[0073] In the light-emitting device 4, the phase modulation layer 44 may be configured so that the optical axis A of the light L traveling along the optical path P between the light-emitting layer 43 and the input coupler 37 forms a desired angle (including 0 degrees) with respect to the Z-axis direction. In the light-emitting device 4, the phase modulation layer 44 may be configured so that the light L traveling along the optical path P between the light-emitting layer 43 and the input coupler 37 becomes parallel light. In this case, an optical member for collimating the light L traveling along the optical path P between the light-emitting layer 43 and the input coupler 37 is not required, thereby simplifying the configuration.

[0074] 1A, 1B...optical integrated circuit, 2...support unit, 3...optical waveguide device, 4...light-emitting device, 4a...first surface, 4b...second surface, 21...first support portion, 22...second support portion, 31...substrate, 32...optical waveguide layer, 37...input coupler, 38...optical waveguide, 43...light-emitting layer, 44...phase modulation layer, 44a...base layer, 44b...modified refractive index area, A...optical axis, L...light, P...optical path.

Claims

1. An optical waveguide device comprising: an optical waveguide device; a light-emitting device; and a support unit supporting the optical waveguide device and the light-emitting device, wherein the optical waveguide device comprises a substrate and an optical waveguide layer disposed on the substrate on one side in a thickness direction of the substrate, the optical waveguide layer including an input coupler and an optical waveguide optically coupled to the input coupler, the light-emitting device being spaced apart on the one side from the optical waveguide device and having a first surface on the optical waveguide layer side and a second surface opposite to the optical waveguide layer, the light-emitting device comprising: a light-emitting layer and a phase modulation layer optically coupled to the light-emitting layer, the phase modulation layer comprising a base layer and a plurality of modified refractive index areas having a refractive index different from that of the base layer and distributed two-dimensionally in a plane intersecting the thickness direction of the base layer, the support unit comprising: a first support section on which one of the optical waveguide device and the light-emitting device is disposed; a second support attached to the first support so as to be aligned with the one device and supporting the other of the optical waveguide device and the light-emitting device, wherein the distance between the optical waveguide device and the light-emitting device is smaller than the width of the second support in a direction in which the one device and the second support are aligned.

2. The optical integrated circuit of claim 1, wherein the distance between said light emitting layer and said second surface is less than the distance between said light emitting layer and said first surface.

3. An optical integrated circuit according to claim 1 or 2, wherein the phase modulation layer is configured to tilt the optical axis of light traveling along an optical path between the light emitting layer and the input coupler with respect to the thickness direction of the substrate.

4. An optical integrated circuit according to any one of claims 1 to 3, wherein the width of the second support portion is greater than the thickness of the first support portion in the thickness direction of the substrate.

5. An optical integrated circuit according to any one of claims 1 to 4, wherein the distance between the optical waveguide device and the light-emitting device is smaller than the thickness of the one device in the thickness direction of the substrate.

6. An optical integrated circuit according to any one of claims 1 to 5, wherein when the second support section supports the optical waveguide device, the thickness of the substrate is greater than the distance between the optical waveguide device and the light-emitting device.

7. An optical integrated circuit according to any one of claims 1 to 6, wherein the thickness of the first support is greater than the distance between the optical waveguide device and the light-emitting device.

8. An optical integrated circuit according to any one of claims 1 to 7, wherein the phase modulation layer is configured to focus light traveling along an optical path between the light emitting layer and the input coupler onto the input coupler.

Images