JP2010152274A - Optical integrated device and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the optical coupling efficiency between an optical semiconductor element and an optical waveguide in an optical integrated device and to improve temperature characteristics. <P>SOLUTION: The optical integrated device having the optical semiconductor element and the optical waveguide integrated on a substrate 11 includes: a lower clad layer 12 provided on a part of a substrate 11; an optical semiconductor element 15 which is provided on the substrate 11 and is disposed so that a light emission end surface or a light incidence end surface may face one end surface of the lower clad layer 12; an optical waveguide 13 which is provided on the lower clad layer 12 and has a front end portion tapered toward one end part of the lower clad layer 12; and an upper clad layer 14 which is provided on the lower clad layer 12 and the front end portion of the optical waveguide 13 along a line connecting the light emission end surface or the light incidence end surface of the optical semiconductor element 15 and the front end portion of the optical waveguide 13, and has a refractive index higher than that of the lower clad layer 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical integrated device in which an optical semiconductor element and an optical waveguide are integrated on a substrate, and a manufacturing method thereof.

  In recent years, optical wiring technology has attracted attention as a technology for solving the problem of wiring delay associated with high integration of LSIs. The optical wiring technology is a method of transmitting an optical signal using an optical waveguide, and does not increase the wiring resistance and inter-wiring capacitance accompanying the miniaturization of the LSI, and can further increase the operation speed. An opto-electric hybrid LSI has been proposed as an LSI that performs signal transmission using such an optical wiring.

  In an opto-electric hybrid LSI, signal processing by each functional block is performed electrically, and an optical signal is transmitted between these functional blocks. For this reason, a light emitting element that converts an optical signal to be transmitted into an electric signal and a light receiving element that converts an electric signal subjected to signal processing into an optical signal are required. As a light emitting element that converts an electrical signal into an optical signal, a semiconductor laser such as an edge emitting laser or a surface emitting laser (VCSEL) is used, and there is a report example of operation in the GHz band.

  As an optical integrated device that is an integrated form of these semiconductor lasers and optical waveguides, a laser structure is formed by wafer bonding on the upper portion of the optical waveguide (Non-Patent Document 1), and the optical waveguide and the laser structure are interposed via an organic film. And an optical waveguide and a laser structure directly mounted on Si as a substrate (Patent Document 1).

However, since the structure described in Non-Patent Document 1 has an air layer below the laser structure, it is difficult to efficiently dissipate the heat generated in the laser part, and good temperature characteristics are not obtained. Moreover, since the structure described in Non-Patent Document 2 has a laser element formed on the organic film, heat dissipation is poor and good temperature characteristics cannot be obtained. Further, since an organic film layer exists between the laser element and the optical waveguide, it is difficult to efficiently couple the output light from the laser element to the optical waveguide. The structure described in Patent Document 1 requires highly accurate alignment when arranging a laser element with respect to an optical waveguide, and it is very difficult to obtain highly efficient optical coupling.
Japanese Patent Laid-Open No. 2004-85868 Optics Express, Vol. 14, Issue 20, pp. 9203-9210 2006 3rd IEEE International Conference on Group IV Photonics, pp. 188-191.

  An object of the present invention is to provide an optical integrated device capable of obtaining highly efficient optical coupling between an optical semiconductor element and an optical waveguide and having excellent temperature characteristics, and a method for manufacturing the same.

  An optical integrated device according to an aspect of the present invention includes a lower clad layer provided on a part of a substrate and a light emitting end face or a light incident end face opposed to one end face of the lower clad layer. And an optical waveguide provided on the lower cladding layer, the tip portion of which is tapered toward one end of the lower cladding layer, and a light emitting end face of the optical semiconductor device Alternatively, an upper cladding layer having a refractive index larger than that of the lower cladding layer provided on the lower cladding layer and on the distal end portion of the optical waveguide along a line connecting the light incident end surface and the distal end portion of the optical waveguide. It was characterized by comprising.

  An optical integrated device according to another aspect of the present invention includes an optical semiconductor element having a light incident end surface and a light emitting end surface provided at a central portion on a substrate, and the optical semiconductor provided on the substrate. A first lower clad layer disposed on one end face of the light incident end face of the device; and provided on the first lower clad layer, with a tip portion directed toward one end of the first lower clad layer. Along the line connecting the first optical waveguide narrowed in a tapered shape, the light incident end face of the optical semiconductor element, and the tip end portion of the first optical waveguide, and on the first lower cladding layer and the A first upper clad layer having a refractive index larger than that of the first lower clad layer provided on a tip portion of the first optical waveguide; and a light emitting end face of the optical semiconductor element provided on the substrate. 2nd lower part arrange | positioned with one end surface facing A lad layer, a second optical waveguide provided on the second lower cladding layer and having a tip portion tapered toward one end of the second lower cladding layer; and The second lower portion provided on the second lower cladding layer and on the distal end portion of the second optical waveguide along a line connecting a light emitting end surface and the distal end portion of the second optical waveguide. A second upper clad layer having a refractive index larger than that of the clad layer, and light incident on the first upper clad layer and the first lower clad layer from the tip of the first optical waveguide. The light that is coupled to the light incident end face of the optical semiconductor element and that is incident on the second lower cladding layer and the second upper cladding layer from the optical semiconductor element is incident on the cladding by the second upper cladding layer. The second light is attracted to the layer side Characterized in that for coupling the tip portion of the road.

  Also, in the method of manufacturing an optical integrated device according to another aspect of the present invention, a lower clad layer is formed on a part of a substrate, and a tip part is directed to one end of the clad layer on the clad layer. Forming a tapered optical waveguide; forming an optical semiconductor element on the substrate with a light emitting end face or a light incident end face facing one end face of the lower cladding layer; and the lower cladding. An upper cladding layer having a refractive index larger than that of the lower cladding layer on the layer and on the tip portion of the optical waveguide, a line connecting the light emitting end surface or the light incident end surface of the optical semiconductor element and the tip portion of the optical waveguide And a step of forming along the line.

  According to the present invention, the optical semiconductor element is excellent in heat dissipation by mounting the optical semiconductor element directly on the substrate. In addition, high-efficiency optical coupling can be obtained by optically coupling the optical semiconductor element and the optical waveguide using the refractive index difference between the lower cladding layer and the upper cladding layer. That is, the optical coupling efficiency between the optical semiconductor element and the optical waveguide can be improved and the temperature characteristics can be improved.

  The details of the present invention will be described below with reference to the illustrated embodiments.

(First embodiment)
FIG. 1 is a diagram for explaining an optical integrated device according to the first embodiment of the present invention. FIG. 1A is a plan view of the optical integrated device viewed from above, and FIG. It is arrow AA 'sectional drawing of Fig.1 (a).

A lower clad layer 12 made of a SiO ₂ film is formed on the Si substrate 11, and a part of the lower clad layer 12 is removed to form an exposed portion of the Si substrate and an end face of the lower clad layer 12.

  A thin optical fiber waveguide 13 made of Si is formed on a part of the lower cladding layer 12 such that the tip is separated from the end of the lower cladding layer 12 and the tip is directed to the end of the lower cladding layer. The thickness of the lower cladding layer 12 is 1 to 3 μm, and the Si fine wire optical waveguide 13 is 200 to 400 nm thick and 300 to 600 nm wide. The tip portion 13a of the Si fine wire optical waveguide 13 is processed into a taper shape, and the tip width is 80 nm.

  A semiconductor laser (optical semiconductor element) 15 as a light emitting element is mounted on the exposed portion of the substrate from which a part of the lower cladding layer 12 has been removed. An upper cladding layer 14 is formed so as to cover the semiconductor laser 15 and the fine line optical waveguide 13 in order to optically couple the semiconductor laser 15 and the fine line optical waveguide 13. The upper cladding layer 14 is made of a material having a higher refractive index than that of the lower cladding layer 12, such as polyimide, SiON, or SiN.

  Here, the upper clad layer 14 is not necessarily filled between the semiconductor laser 15 and the lower clad layer 12, and is formed on at least the lower clad layer 12 so as to cover the distal end portion 13 a of the thin optical waveguide 13. Just do it.

  As shown in FIG. 2, the semiconductor laser 15 includes a mesa-shaped double heterostructure 152 formed on a semiconductor substrate 151, an upper electrode 153 on the double heterostructure 152, and a lower electrode 154 on the substrate 151. Is formed.

The basic structure of the present embodiment can be realized by the SOI substrate 10 in which a Si layer is formed on a Si substrate via a buried insulating film. That is, the lower cladding layer 12 is a buried insulating film (SiO ₂ film) of the SOI substrate, and the optical waveguide 13 is obtained by processing the Si layer of the SOI substrate 10 into a thin line shape.

  In the present embodiment, the vertical position of the center of the light output portion of the semiconductor laser 15 is between the upper cladding layer 14 and the lower cladding layer 12, and propagates through the upper cladding layer 14 to the end of the lower cladding layer 12. To do. Then, after entering from the end of the lower cladding layer 12, it travels between the upper cladding layer 14 and the lower cladding layer 12, but is attracted to the upper cladding layer 14 having a high refractive index, so that the optical waveguide 13 has a tapered shape. It will couple | bond with the front-end | tip part 13a efficiently.

  FIG. 3 shows the positional relationship between the semiconductor laser 15 and the optical waveguide 13 and the state of light propagation when the optical integrated device of this embodiment is viewed from above. The semiconductor laser 15 and the optical waveguide 13 are installed such that the light emitting direction of the semiconductor laser 15 and the light propagation direction of the optical waveguide 13 have a predetermined angle, and the angle is in the range of 5 degrees to 20 degrees. . That is, the angle between the surface perpendicular to the light emitting direction of the semiconductor laser 15 and the end surface of the lower cladding layer 12 is set in the range of 5 degrees to 20 degrees. By arranging in this way, when the light emitted from the semiconductor laser 15 is reflected at the end of the lower cladding layer 12, it is possible to suppress the return light to the semiconductor laser 15. As a result, the semiconductor laser 15 can be stably operated.

  Here, when the angle between the surface perpendicular to the light emitting direction of the semiconductor laser 15 and the end surface of the lower cladding layer 12 is smaller than 5 degrees, the return light suppressing effect is hardly recognized. If the angle exceeds 20 degrees, sufficient coupling efficiency (70% or more) at the end face of the lower cladding layer 12 cannot be obtained.

  FIG. 4 is a diagram showing a state of light propagation in the optical integrated device of this embodiment. FIG. 4A is a diagram showing a light distribution in the width direction (X direction) when the optical integrated device is viewed from above, and FIG. 4B is a thickness direction when viewed from the side surface of the optical integrated device. (Y direction) It is a figure which shows light distribution, and the light intensity is high in the white part in a figure. FIG. 4C shows the optical coupling efficiency to the thin optical waveguide 13 in the light traveling direction (Z direction). From these figures, it can be seen that the light output from the semiconductor laser 15 is efficiently coupled to the optical waveguide 13.

  As a result of calculating the coupling efficiency using the light propagation simulation by the beam propagation method, the distance between the semiconductor laser 15 and the end of the lower cladding layer 12 is 5 μm, the refractive index of the upper cladding layer 14 is 1.6, and the width of the upper cladding layer 14 is. 4 μm, the thickness of the upper cladding layer 14 is 0.7 μm, the refractive index of the lower cladding layer is 1.45, the thickness of the lower cladding layer 12 is 3 μm, and the light incident position is the boundary between the upper cladding layer 14 and the lower cladding layer 12. A coupling efficiency of 80% or more was obtained.

  Next, an example of a method for manufacturing the optical integrated device of this embodiment will be described with reference to FIG. In this example, the SOI substrate 10 is used and wafer bonding is used. 5A to 5C are cross-sectional views, and in FIGS. 5D to 5F, the upper view is a plan view and the lower view is a cross-sectional view.

  First, as shown in FIG. 5A, the Si layer of the SOI substrate 10 is processed to form the optical waveguide 13 including the tapered portion 13a. Subsequently, as shown in FIG. 5B, the lower cladding layer 12 is partially etched away to form an end surface of the lower cladding layer 12 and a part of the Si substrate 11 is exposed. Then, as shown in FIG. 5C, after attaching the semiconductor wafer 16 having the laser layer structure 18 to the exposed portion of the Si substrate, the unnecessary support substrate 17 is removed.

  Next, the semiconductor laser layer structure 18 bonded to the exposed portion of the Si substrate is processed to form an element structure of the semiconductor laser 15. Specifically, the laser stripe 19 is formed as shown in FIG. 5D, and the electrode 20 is formed as shown in FIG. 5E. Subsequently, as shown in FIG. 5F, the upper clad layer 14 is formed so as to optically connect the laser stripe 19 and the optical waveguide 13. At this time, the laser stripe 19, the upper clad layer 14, and the optical waveguide 13 do not necessarily need to be on the same straight line. By arranging the upper clad layer 14 so as to connect the laser stripe 19 and the optical waveguide 13, It is possible to compensate for misalignment.

  As described above, according to the present embodiment, the semiconductor laser 15 is directly bonded to the exposed portion of the Si substrate so that the light emission direction of the semiconductor laser 15 is oblique to the light propagation direction of the optical waveguide 13. Since the semiconductor laser 15 is connected by the upper clad layer 14, stable operation is possible without being affected by the return light, and high optical coupling efficiency can be obtained. In addition, the semiconductor laser 15 is directly mounted on the substrate 10 to provide excellent heat dissipation. Therefore, an optical integrated device having a light-emitting device that is stable, highly efficient, and excellent in temperature characteristics can be obtained.

(Second Embodiment)
FIG. 6 is a diagram showing a manufacturing process of the optical integrated device according to the second embodiment of the present invention. 6A to 6C are cross-sectional views, and in FIGS. 6D to 6F, the upper view is a plan view and the lower view is a cross-sectional view. The same parts as those in FIG. 5 are denoted by the same reference numerals.

  Similar to the first embodiment described above, as shown in FIG. 6A, the Si layer of the SOI substrate 10 is processed to form the optical waveguide 13. Thereafter, as shown in FIG. 6B, the lower clad layer 12 is partially removed by etching to expose the Si substrate 11. Then, as shown in FIG. 6C, a metal pattern 21 for flip-chip mounting the semiconductor laser chip 22 having the laser layer structure 18 is formed on the exposed portion of the Si substrate, and the semiconductor laser chip 22 is flip-chip mounted. To do.

  Next, as shown in FIGS. 6D and 6E, after the support substrate 17 of the laser chip 22 is removed, the laser stripe 19 and the electrode 20 are formed. Thereafter, as shown in FIG. 6F, the upper clad layer 14 is formed so as to optically connect the laser stripe 19 and the optical waveguide 13.

  As described above, according to the present embodiment, the return light is mounted by mounting the semiconductor laser 15 on the exposed portion of the Si substrate so that the light emission direction of the semiconductor laser 15 is oblique to the light propagation direction of the optical waveguide 13. Therefore, stable operation is possible without being affected by the above, and high optical coupling efficiency can be obtained. Therefore, the same effect as the first embodiment can be obtained.

(Third embodiment)
7A and 7B are diagrams for explaining an optical integrated device according to the third embodiment of the present invention. FIG. 7A is a plan view, and FIG. 7B is a view of FIG. It is AA 'sectional drawing. In addition, the same code | symbol is attached | subjected to FIG. 1 and an identical part, and the detailed description is abbreviate | omitted.

  In the first embodiment, the return light to the semiconductor laser 15 is suppressed by providing an angle of 5 to 20 degrees between the light emission direction of the semiconductor laser 15 and the light propagation direction of the optical waveguide 13. Then, the return light is suppressed by another method. That is, in this embodiment, the positional relationship between the semiconductor laser 15 and the optical waveguide 13 is linear, but the end surface of the lower cladding layer 12 is inclined from the perpendicular to the light propagation direction. Specifically, the end surface of the lower cladding layer 12 is inclined 5 to 20 degrees from the perpendicular to the light propagation direction.

  With such a configuration, even when the positional relationship between the laser stripe 19 and the optical waveguide 13 is linear, the end surface of the lower cladding layer 12 has an angle that is not perpendicular to the light propagation direction as shown in FIG. If it is formed, there is an effect of suppressing the return light similarly to the first embodiment. Therefore, as in the first embodiment, the semiconductor laser 15 can be stably operated.

(Fourth embodiment)
8A and 8B are diagrams for explaining an optical integrated device according to the fourth embodiment of the present invention. FIG. 8A is a plan view, and FIG. 8B is a view of FIG. 8A. It is AA 'sectional drawing. In addition, the same code | symbol is attached | subjected to FIG. 1 and an identical part, and the detailed description is abbreviate | omitted.

  This embodiment differs from the first embodiment described above in that the refractive index between the semiconductor laser 15 and the end surface of the lower cladding layer 12 is higher than that of the upper cladding layer 14 between the Si substrate 11 and the region. One or more kinds of low materials 23 are provided. That is, not the upper clad layer 14 but the low refractive index material 23 is provided in the region between the semiconductor laser 15 and the lower clad layer 12, and the upper clad 14 is disposed on the material 23.

  With such a configuration, it is possible to more effectively suppress the spread of the propagation light in the vertical direction by inserting the low refractive index material 23. Therefore, not only the same effect as the first embodiment can be obtained, but also there is an advantage that a more efficient coupling can be obtained.

  In the structure of the present embodiment, the portion where the low refractive index material 23 is filled in the region between the semiconductor laser 15 and the end face of the lower cladding layer 12 may be a cavity. Further, the structure of the present embodiment is applicable to any of the first to third embodiments.

(Fifth embodiment)
FIG. 9 is a view for explaining an optical integrated device according to the fifth embodiment of the present invention. FIG. 9 (a) is a plan view, and FIG. 9 (b) is an arrow view of FIG. 9 (a). It is AA 'sectional drawing. In addition, the same code | symbol is attached | subjected to FIG. 1 and an identical part, and the detailed description is abbreviate | omitted.

  In the first embodiment, a light emitting element is used as an optical semiconductor element, and light from the light emitting element is coupled to the optical waveguide. However, a light receiving element is used as the optical semiconductor element, and light from the optical waveguide is coupled to the light receiving element. You may make it let it.

  In this case, in the structure shown in FIG. 1, a light receiving element 35 such as a photodiode may be used instead of the light emitting element 15 such as a semiconductor laser.

  Light input to the optical waveguide 13 enters the upper cladding layer 14 and the lower cladding layer 12 from the tapered portion 13a, passes through the upper cladding layer 14 and the lower cladding layer 12, and is coupled to the light receiving element 35. At this time, by making the refractive index of the upper clad layer 14 higher than that of the lower clad layer 12, it is possible to prevent the light incident on the lower clad layer 12 from spreading to the substrate 11, so that the light receiving element 35 can be efficiently used. Can be combined.

(Sixth embodiment)
FIG. 10 is a view for explaining an optical integrated device according to the fifth embodiment of the present invention. FIG. 10 (a) is a plan view, and FIG. 10 (b) is an arrow view of FIG. 10 (a). It is AA 'sectional drawing. In addition, the same code | symbol is attached | subjected to FIG. 1 and an identical part, and the detailed description is abbreviate | omitted.

  In the present embodiment, the structure of FIG. 1 is opposed to each other, and light input to the optical semiconductor element 45, light output from the optical semiconductor element 45, and optical signal processing in the optical semiconductor element 45 are possible. . As the optical semiconductor element 45 shown here, for example, a semiconductor laser, a light receiving element, an optical power monitor, an optical modulator, an optical switch, an optical amplifier, a wavelength conversion element, an optical attenuator, an optical isolator, or the like can be used. Further, the present embodiment can be applied to any of the first to fourth embodiments.

An optical semiconductor element 45 is mounted at the center on the Si substrate 11. On the left side of the optical semiconductor element 45 on the Si substrate 11, a first lower clad layer 112 made of a SiO ₂ film is formed so that the end face faces the light incident end face of the optical semiconductor element 45. A first thin-line optical waveguide 113 made of Si is formed on a part of the lower clad layer 112 so that the tip is separated from the end of the lower clad layer 112 and the tip is directed to the end of the lower clad layer 112. Has been. Conditions such as the thickness and width of the lower cladding layer 112 and the optical waveguide 113 are the same as those in the first embodiment.

  The optical semiconductor element 45 and the optical waveguide 113 are installed such that the light incident direction of the optical semiconductor element 45 and the light propagation direction of the optical waveguide 113 have a predetermined angle, and the angle ranges from 5 degrees to 20 degrees. It is. That is, the angle between the surface perpendicular to the light incident direction of the optical semiconductor element 45 and the end surface of the lower cladding layer 112 is set in the range of 5 degrees to 20 degrees.

  In order to optically couple the optical semiconductor element 45 and the fine-line optical waveguide 113, a first upper cladding layer 114 is formed so as to cover the optical semiconductor element 45 and the fine-line optical waveguide 113. The upper cladding layer 114 is made of a material having a higher refractive index than that of the lower cladding layer 112, for example, polyimide, SiON, or SiN.

On the right side of the optical semiconductor element 45 on the Si substrate 11, a second lower clad layer 212 made of a SiO ₂ film is formed so that the end face faces the light emitting end face of the optical semiconductor element 45. A second thin-wire optical waveguide 213 made of Si is formed on a part of the lower cladding layer 212 such that the tip is separated from the end of the lower cladding layer 212 and the tip is directed to the end of the lower cladding layer 212. Has been. Conditions such as thickness and width of the lower clad layer 212 and the optical waveguide 213 are the same as those in the first embodiment.

  The optical semiconductor element 45 and the optical waveguide 213 are installed such that the light emitting direction of the optical semiconductor element 45 and the light propagation direction of the optical waveguide 213 have a predetermined angle, and the angle is in the range of 5 degrees to 20 degrees. It is. That is, the angle between the surface perpendicular to the light emitting direction of the optical semiconductor element 45 and the end surface of the lower cladding layer 212 is set in the range of 5 degrees to 20 degrees.

  In order to optically couple the optical semiconductor element 45 and the thin line optical waveguide 213, a second upper cladding layer 214 is formed so as to cover the optical semiconductor element 45 and the thin line optical waveguide 213. The upper cladding layer 214 is made of a material having a higher refractive index than that of the lower cladding layer 212, such as polyimide, SiON, or SiN.

  Here, the upper clad layers 114 and 214 are not necessarily filled between the optical semiconductor element 45 and the lower clad layers 112 and 212, and at least the tips of the thin optical waveguides 113 and 213 are formed on the lower clad layers 112 and 212. What is necessary is just to be formed so that the parts 113a and 213a may be covered.

  In the structure of the present embodiment, light incident on the first optical waveguide 113 is incident on the first upper cladding layer 114 and the first lower cladding layer 112 from the distal end portion 113a of the first optical waveguide 113. . Then, it passes through the upper cladding layer 114 and the lower cladding layer 112 and is coupled to the optical semiconductor element 45. At this time, by making the refractive index of the upper clad layer 114 higher than that of the lower clad layer 112, it is possible to prevent light incident on the lower clad layer 112 from spreading to the substrate 11 and to improve the efficiency of the optical semiconductor element 45. Can be combined well.

  On the other hand, the light emitted from the optical semiconductor element 45 passes through the second upper cladding layer 214 between the optical semiconductor element 45 and the lower cladding layer 122 and enters the lower cladding layer 122. Then, it passes through the lower cladding layer 212 and is coupled to the tip portion of the second optical waveguide 213. At this time, by making the refractive index of the upper clad layer 214 higher than that of the lower clad layer 212, light traveling through the lower clad layer 212 is attracted to the upper clad layer 14 having a high refractive index. Thus, it can be efficiently coupled to the 13 tapered tip portions 13a.

  As described above, according to the present embodiment, by directly mounting the optical semiconductor element 45 on the Si substrate 11, it is possible to improve the heat dissipation of the optical semiconductor element 45. In addition, the optical semiconductor element 45 and the optical waveguides 113 and 213 are optically coupled using the difference in refractive index between the lower cladding layers 112 and 212 and the upper cladding layers 114 and 214 to obtain highly efficient optical coupling. Can do. That is, the optical coupling efficiency between the optical semiconductor element 45 and the optical waveguides 113 and 213 can be improved and the temperature characteristics can be improved.

(Modification)
The present invention is not limited to the above-described embodiments. In the embodiment, SiO ₂ is used as the lower clad layer, polyimide, SiON, SiN is used as the upper clad layer, and Si is used as the optical waveguide. However, these materials can be appropriately changed according to specifications. The refractive index of the upper clad layer may be higher than that of the lower clad layer. Further, the substrate is not necessarily limited to Si, and may be a glass substrate.

  Further, the structure of the optical device is not limited to the embodiment, and can be appropriately changed according to the specification. A light emitting element such as a semiconductor laser may be any element that can emit light in the lateral direction, and a light receiving element such as a photodiode may be any element that can enter light from the lateral direction.

  In addition, various modifications can be made without departing from the scope of the present invention.

1A and 1B are a plan view and a cross-sectional view illustrating a schematic configuration of an optical integrated device according to a first embodiment. FIG. 3 is a cross-sectional view illustrating an example of a light emitting element used in the optical integrated device according to the first embodiment. The figure which shows the intensity distribution in each part of the propagation direction of the propagation light of the optical integrated device concerning 1st Embodiment, and propagation light. It is a figure which shows the mode of the distribution of the propagation light inside the optical integrated device concerning 1st Embodiment, and coupling efficiency. FIG. 6 is a plan view and a cross-sectional view showing a manufacturing process of the optical integrated device according to the first embodiment. FIG. 6 is a plan view and a cross-sectional view showing a manufacturing process of an optical integrated device according to a second embodiment. The top view and sectional drawing which show schematic structure of the optical integrated device concerning 3rd Embodiment. The top view and sectional drawing which show schematic structure of the optical integrated device concerning 4th Embodiment. The top view and sectional drawing which show schematic structure of the optical integrated device concerning 5th Embodiment. The top view and sectional drawing which show schematic structure of the optical integrated device concerning 6th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... SOI substrate 11 ... Si substrate 12 ... Lower clad layer 13 ... Optical waveguide 13a ... Optical waveguide taper part 14 ... Upper clad layer 15 ... Semiconductor laser (optical semiconductor element)
DESCRIPTION OF SYMBOLS 16 ... Semiconductor wafer which has a laser structure 17 ... Support substrate 18 ... Layer structure for semiconductor lasers 19 ... Laser stripe 20 ... Electrode 21 ... Metal pattern 22 ... Semiconductor laser chip 23 ... Low refractive index material 35 ... Light receiving element (optical semiconductor element)
45 ... Optical semiconductor element 112 ... First lower clad layer 113 ... First thin-line optical waveguide 113a, 213a ... Front end portion 114 ... First upper clad layer 151 ... Semiconductor substrate 152 ... Double heterostructure portion 153 ... Upper electrode 154 ... Lower electrode 212 ... Second lower clad layer 213 ... Second thin-line optical waveguide 214 ... Second upper clad layer

Claims (17)

A lower clad layer provided on a part of the substrate;
An optical semiconductor element provided on the substrate and disposed with a light emitting end face or a light incident end face opposed to one end face of the lower cladding layer;
An optical waveguide provided on the lower clad layer, the tip portion being disposed toward one end of the lower clad layer, and the tip portion being tapered;
From the lower cladding layer provided on the lower cladding layer and on the distal end portion of the optical waveguide along a line connecting the light emitting end surface or the light incident end surface of the optical semiconductor element and the distal end portion of the optical waveguide. An upper cladding layer with a large refractive index,
An optical integrated device comprising:   The optical semiconductor element is a light emitting element, and light incident on the lower cladding layer and the upper cladding layer from the light emitting element is attracted to the cladding layer side by the upper cladding layer and coupled to the tip portion of the optical waveguide. The optical integrated device according to claim 1, wherein:   2. The optical integrated device according to claim 1, wherein the optical semiconductor element is a light receiving element, and the light incident on each of the cladding layers from the tip portion of the optical waveguide is coupled to the light incident end face of the light receiving element. .   3. The optical integrated device according to claim 2, wherein the light emitting direction of the light emitting element has a certain angle with respect to the light propagation direction of the optical waveguide.   5. The optical integrated device according to claim 4, wherein an angle formed by the light emitting direction of the light emitting element and the light propagation direction of the optical waveguide is in the range of 5 degrees to 20 degrees.   The light emitting direction of the light emitting element and the light propagation direction of the optical waveguide are in a straight line, and one end surface of the lower clad layer is inclined from perpendicular to the light emitting direction of the light emitting element. Item 3. The optical integrated device according to Item 2.   The optical integrated device according to claim 2, wherein the light emitting element is a semiconductor laser.   The said upper clad layer is continuously formed from the said optical semiconductor element to the front-end | tip part of the said optical waveguide through the edge part of the said lower clad layer. Optical integrated devices.   The optical integrated device according to claim 1, wherein the optical waveguide is a thin optical waveguide. The optical integrated device according to claim 9, wherein the thin-line optical waveguide is made of Si, and the lower clad layer is made of SiO ₂ .   The lower cladding layer is a buried insulating film of an SOI substrate in which a Si layer is formed on the Si substrate via a buried insulating film, and the optical waveguide is obtained by processing the Si layer of the SOI substrate into a linear shape. The optical integrated device according to any one of claims 1 to 3. An optical semiconductor element having a light incident end face and a light exit end face provided at a central portion on the substrate;
A first lower clad layer provided on the substrate and disposed with its one end face facing the light incident end face of the optical semiconductor element;
A first optical waveguide provided on the first lower cladding layer, having a tip portion disposed toward one end portion of the first lower cladding layer, and the tip portion being tapered.
Provided on the first lower cladding layer and on the tip portion of the first optical waveguide along a line connecting the light incident end face of the optical semiconductor element and the tip portion of the first optical waveguide; A first upper cladding layer having a refractive index greater than that of the first lower cladding layer;
A second lower clad layer provided on the substrate and disposed with its one end face facing the light emitting end face of the optical semiconductor element;
A second optical waveguide provided on the second lower cladding layer, the tip portion being disposed toward one end portion of the second lower cladding layer, and the tip portion being tapered.
Provided on the second lower cladding layer and on the tip portion of the second optical waveguide along a line connecting the light emitting end face of the optical semiconductor element and the tip portion of the second optical waveguide; A second upper cladding layer having a higher refractive index than the second lower cladding layer;
Comprising
Coupling light incident on the first upper cladding layer and the first lower cladding layer from the tip portion of the first optical waveguide to the light incident end surface of the optical semiconductor element;
Light incident on the second lower clad layer and the second upper clad layer from the optical semiconductor element is attracted to the clad layer side by the second upper clad layer, and the tip of the second optical waveguide An optical integrated device characterized by being coupled to a part. Forming a lower clad layer on a part of the substrate, and forming an optical waveguide on the clad layer so that a tapered tip portion is directed to one end of the clad layer;
A step of providing an optical semiconductor element on the substrate with a light emitting end face or a light incident end face opposed to one end face of the lower cladding layer;
An upper clad layer having a refractive index larger than that of the lower clad layer is formed on the lower clad layer and on the tip portion of the optical waveguide, and a light emitting end face or a light incident end face of the optical semiconductor element and a tip portion of the optical waveguide. Forming along the line connecting
A method of manufacturing an optical integrated device, comprising:   An SOI substrate having a Si layer formed on a Si substrate through a buried insulating film is prepared, used as a buried cladding lower clad layer of the SOI substrate, and the Si layer of the SOI substrate is used as the optical waveguide. The method of manufacturing an optical integrated device according to claim 13.   15. The method of manufacturing an optical integrated device according to claim 14, wherein the optical semiconductor element is mounted on a portion of the Si substrate exposed by selectively removing a part of the lower cladding layer.   14. The method of manufacturing an optical integrated device according to claim 13, wherein, as the step of providing the optical semiconductor element, the optical semiconductor element is mounted on the substrate by flip chip mounting.   As the step of providing the optical semiconductor element, a light emitting device substrate having a layer structure for a light emitting device is bonded onto the support substrate, and then the support substrate is removed, and then the light emitting device substrate is converted into a light emitting device structure. 14. The method of manufacturing an optical integrated device according to claim 13, wherein an electrode is formed on the light emitting device structure after processing.

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