WO2011083812A1 - 光結合構造および光送受信モジュール - Google Patents
光結合構造および光送受信モジュール Download PDFInfo
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- WO2011083812A1 WO2011083812A1 PCT/JP2011/050076 JP2011050076W WO2011083812A1 WO 2011083812 A1 WO2011083812 A1 WO 2011083812A1 JP 2011050076 W JP2011050076 W JP 2011050076W WO 2011083812 A1 WO2011083812 A1 WO 2011083812A1
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- optical
- semiconductor element
- optical coupling
- resin
- optical transmission
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/02—Structural details or components not essential to laser action
- H01S5/022—Mountings; Housings
- H01S5/0225—Out-coupling of light
- H01S5/02251—Out-coupling of light using optical fibres
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
- G02B6/4214—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
- G02B6/4236—Fixing or mounting methods of the aligned elements
- G02B6/4239—Adhesive bonding; Encapsulation with polymer material
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4219—Mechanical fixtures for holding or positioning the elements relative to each other in the couplings; Alignment methods for the elements, e.g. measuring or observing methods especially used therefor
- G02B6/422—Active alignment, i.e. moving the elements in response to the detected degree of coupling or position of the elements
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
- H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
- H01L2224/45001—Core members of the connector
- H01L2224/45099—Material
- H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
- H01L2224/45117—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
- H01L2224/45124—Aluminium (Al) as principal constituent
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
- H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
- H01L2224/45001—Core members of the connector
- H01L2224/45099—Material
- H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
- H01L2224/45138—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
- H01L2224/45144—Gold (Au) as principal constituent
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
- H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
- H01L2224/45001—Core members of the connector
- H01L2224/45099—Material
- H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
- H01L2224/45138—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 950°C and less than 1550°C
- H01L2224/45147—Copper (Cu) as principal constituent
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
- H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
- H01L2224/42—Wire connectors; Manufacturing methods related thereto
- H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
- H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
- H01L2224/4805—Shape
- H01L2224/4809—Loop shape
- H01L2224/48091—Arched
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/02—Structural details or components not essential to laser action
- H01S5/022—Mountings; Housings
- H01S5/0225—Out-coupling of light
- H01S5/02255—Out-coupling of light using beam deflecting elements
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/02—Structural details or components not essential to laser action
- H01S5/022—Mountings; Housings
- H01S5/0233—Mounting configuration of laser chips
- H01S5/02345—Wire-bonding
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/02—Structural details or components not essential to laser action
- H01S5/022—Mountings; Housings
- H01S5/0235—Method for mounting laser chips
- H01S5/02355—Fixing laser chips on mounts
- H01S5/0236—Fixing laser chips on mounts using an adhesive
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
- H01S5/4025—Array arrangements, e.g. constituted by discrete laser diodes or laser bar
Definitions
- the present invention relates to an optical module used in an optical communication technique, an optical transmission technique, and an optical information recording technique, and more particularly to an optical coupling structure that optically couples an optical semiconductor element and an optical transmission path in the optical module.
- the optical module includes an optical semiconductor element mounted on a substrate and an optical transmission path arranged so that the optical axis is parallel to the substrate.
- a structure as shown in FIG. 16 is generally used in order to optically couple the light receiving and emitting part of the optical semiconductor element and the end of the optical transmission line.
- the optical transmission path 104 (particularly the core 105) and the optical semiconductor element 101 are optically combined by combining the condenser lens 102 installed on the optical semiconductor element 101 and the optical path conversion mirror 103. Connected (optical coupling).
- the refractive index of the condensing lens 102, the reflectance of the optical path conversion mirror 103, and the like need to be adjusted to desired values.
- the number of parts required for optical coupling increases.
- Patent Document 1 discloses a guide groove on the surface of an optical mounting substrate and an optical fiber mounted in the guide groove.
- an optical device including a tapered surface located on an axis and having a mirror formed on the tapered surface.
- Patent Document 2 a substrate having a V-groove having a reflective surface formed obliquely at a position facing the end portion of the optical waveguide and a space between the end portion of the optical waveguide and the reflective surface are filled.
- a coupling structure of an optical waveguide and a light receiving element which includes a refractive index matching agent having substantially the same refractive index as that of the core of the waveguide and a light receiving element that receives outgoing light reflected by a reflecting surface.
- Patent Document 3 describes a method for joining optical components that can simplify and simplify the connection between optical components in an optical transceiver module.
- an optical fiber and a light receiving / emitting element arranged so that their optical axes are substantially coincided with each other are pressure-bonded via an uncured transparent resin composition, and the optical fiber is pulled back to uncured transparent resin composition.
- the stretched transparent resin composition is cured.
- a semiconductor laser element, a monitor photodiode, and an optical fiber are sealed in a transparent resin, and the rear output light of the semiconductor laser element is reflected at the interface between the transparent resin and air so as to enter the monitor photodiode.
- a semiconductor laser device has been proposed.
- Japanese Unexamined Patent Publication No. 2003-167175 Japanese Patent No. 2985791 Japanese Laid-Open Patent Publication No. 9-197196 Japanese Laid-Open Patent Publication No. 2000-269584
- the semiconductor laser device of Patent Document 4 is intended to monitor the rear output light of a semiconductor laser element having a large aperture angle, it can be used even if the optical coupling efficiency is low.
- the optical signal is incident on the light receiving element from the optical fiber having a small aperture angle, or when the optical signal is incident on the optical fiber from the light emitting element, the reliability of the transmission of the optical signal is ensured if the coupling efficiency is low. There is a problem that it is difficult. Further, it is considered that the position and shape of the resin interface serving as the reflective surface depend on the application amount of the transparent resin and the step shape of the substrate.
- a step is formed on the substrate, it is necessary to design and manufacture the position and shape of the resin interface in accordance with the shape and size of the step, resulting in an increase in manufacturing cost. Further, it is necessary that a reflection surface exists at an intersection where the optical axis perpendicular to the semiconductor laser element and the optical axis perpendicular to the monitor photodiode element intersect. However, it is not easy to form the resin so that the interface of the resin is located at the intersection.
- the present invention has been made in view of the above circumstances, and can be manufactured at low cost and higher efficiency in a positional relationship in which the optical axis of the optical transmission path and the optical axis of the light receiving and emitting element have a predetermined angle. It is an object of the present invention to provide an optical coupling structure of an optical semiconductor element and an optical transmission line in an optical module including an optical coupling unit capable of transmitting an optical signal.
- An optical coupling structure includes an optical semiconductor element having a light emitting / receiving portion on an upper surface and mounted on a substrate on a lower surface side, and a predetermined optical axis of the optical semiconductor element
- An optical transmission line having an optical axis that intersects at an angle of the substrate and spaced from the mounting surface of the substrate, and an optical path between the optical semiconductor element and the optical transmission path, and the light
- An optical coupling unit that optically couples between the semiconductor element and the optical transmission line;
- the optical coupling portion is made of a resin that is transparent to transmitted light.
- the resin is in close contact with at least a part of the light receiving / emitting part of the optical semiconductor element and at least a part of the end of the optical transmission path, and the optical semiconductor element and the optical transmission path serve as the optical coupling part. It is bonded by the resin itself that constitutes it.
- the resin constituting the optical coupling portion may be disposed in the upper surface of the optical semiconductor element.
- the resin may be disposed apart from a power supply wiring wire-bonded to the upper surface of the optical semiconductor element.
- the end face of the optical transmission line is more than the end face of the optical semiconductor element when the optical semiconductor element is viewed from the side and above. It may exist inside the optical semiconductor element.
- the outer surface of the resin constituting the optical coupling portion is on the side of the light emitting / receiving portion of the optical semiconductor element and the end of the optical transmission line The shape may be recessed.
- the outer surface of the resin constituting the optical coupling portion may have a convex shape.
- the resin forming the optical coupling portion is an intersection of an optical axis of the optical semiconductor element and an optical axis of the optical transmission line. The position where the outer surface of the resin does not exist at the position and faces the light emitting / receiving portion is between the intersection and the light emitting / receiving portion, and the outer surface of the resin faces the end of the optical transmission path The position to perform may be between the intersection and the end of the optical transmission line.
- the resin constituting the optical coupling unit may be disposed below the height of the upper end of the end face of the optical transmission line. .
- the optical coupling portion has a circular shape, an elliptical shape, or a fan shape when the optical coupling portion is viewed from above. Either may be sufficient.
- the periphery of the optical coupling unit may be covered with a gas.
- the periphery of the optical coupling portion may be covered with a clad resin layer having a refractive index lower than that of the resin constituting the optical coupling portion.
- the power supply wiring of the optical semiconductor element may be covered with the cladding resin layer.
- An optical transceiver module includes a light receiving element and a light emitting element mounted on a mounting surface of the same substrate, and a first optical transmission disposed apart from the mounting surface of the substrate.
- a first optical coupling portion that optically couples between the light receiving element and the first optical transmission path, and between the light emitting element and the second optical transmission path.
- a second optical coupling unit that optically couples the light receiving element, the first optical transmission line, and the first optical coupling unit to form a first optical coupling structure, and the light emitting element,
- the two optical transmission lines and the second optical coupling portion constitute a second optical coupling structure.
- One or both of the first optical coupling structure and the second optical coupling structure constitute the optical coupling structure according to any one of (1) to (12).
- a method for manufacturing an optical coupling structure according to an aspect of the present invention is the method for manufacturing an optical coupling structure according to any one of (1) to (12) above, and an optical semiconductor element provided on a substrate
- a step of curing the resin to form an optical coupling portion is the method for manufacturing an optical coupling structure according to any one of (1) to (12) above, and an optical semiconductor element provided on a substrate.
- the resin may be applied to the light emitting and receiving unit away from the power supply wiring wire-bonded to the upper surface of the optical semiconductor element. Good.
- the optical coupling part can be manufactured at a low cost without using many components, and an optical signal can be transmitted with higher efficiency. Since the optical semiconductor element can be mounted so that its optical axis is in a direction perpendicular to the substrate (vertical direction of the present invention), the light emitting / receiving portion of the optical semiconductor element is directed to the side opposite to the mounting surface. Can be implemented. This facilitates mounting by die bonding or wire bonding. Furthermore, it is possible to connect wirings important for transmission characteristics with the shortest line length, which makes it difficult for noise to ride and good transmission characteristics can be obtained. Further, it is easy to inspect the appearance of bonding, and it is easy to find a connection failure.
- FIG. 1A It is a principal part enlarged view of the optical module shown to FIG. 1A, and has shown the case where an optical semiconductor element is a light receiving element. It is a principal part enlarged view of the optical module shown to FIG. 1A, and has shown the case where an optical semiconductor element is a light emitting element. It is sectional drawing which shows an example of an optical module in case the outer surface of an optical coupling part is concave shape in the optical coupling structure which concerns on the 1st example of this invention. It is a principal part enlarged view of the optical module shown to FIG.
- FIG. 2A It is a principal part enlarged view of the optical module shown to FIG. 2A, and has shown the case where an optical semiconductor element is a light emitting element.
- the direction away from the light emitting / receiving unit with reference to the surface on which the light emitting / receiving unit of the optical semiconductor element is present is upward (for example, upward in FIGS. 1A to 2C), and the direction approaching the light receiving / emitting unit. Is the lower side (for example, the lower side of FIGS. 1A to 2C). Further, a direction perpendicular to the vertical direction defined above (for example, the horizontal direction in FIGS. 1A to 2C) is defined as a horizontal direction.
- FIG. 1A shows an example of an optical module including the optical coupling structure according to the first embodiment.
- the optical module 5 shown in FIG. 1A is disposed along the mounting surface 4a of the substrate 4 and the optical semiconductor element 1 mounted on the mounting surface 4a, which is the upper surface of the substrate 4, and away from the mounting surface 4a of the substrate 4.
- An optical transmission path 2, and an optical coupling portion 3 that converts an optical path between the optical semiconductor element 1 and the optical transmission path 2 and optically couples the optical semiconductor element 1 and the optical transmission path 2. I have.
- the optical axis 1b of the optical semiconductor element 1 and the optical axis 2b of the optical transmission path 2 intersect each other at a predetermined angle ⁇ .
- the predetermined angle ⁇ is 0 ° ⁇ ⁇ 180 °.
- “converting the optical path between the optical semiconductor element and the optical transmission path” means that light emitted from the optical semiconductor element 1 enters the optical transmission path 2. Furthermore, it means changing the optical path of the light (that is, the traveling direction of the light).
- the optical semiconductor element 1 is a light receiving element
- “converting the optical path between the optical semiconductor element and the optical transmission path” means that light emitted from the optical transmission path 2 is incident on the optical semiconductor element 1.
- the optical path of the light (that is, the traveling direction of the light) is changed.
- the optical component joining method of Patent Document 3 described above is different from the present invention in that both optical axes are coaxial and no optical path conversion is required.
- the end 2a of the optical transmission line 2 is not located on the extension line of the optical axis 1b of the optical semiconductor element 1. That is, when the optical semiconductor element 1 is a light emitting element, when light emitted from the optical semiconductor element 1 is transmitted along the optical axis 1b, the light does not enter the end 2a of the optical transmission line 2.
- the positional relationship between the optical semiconductor element 1 and the optical transmission line 2 requires the presence of a predetermined optical coupling part 3 in order for the light emitted from the optical semiconductor element 1 to reach the end 2 a of the optical transmission line 2.
- the light emitting / receiving unit 1 a of the optical semiconductor element 1 is not located on the extension line of the optical axis 2 b of the optical transmission line 2. That is, when the optical semiconductor element 1 is a light receiving element, when the light emitted from the optical transmission path 2 is transmitted along the optical axis 2b, the light does not enter the light receiving / emitting part 1a of the optical semiconductor element 1.
- the positional relationship between the optical semiconductor element 1 and the optical transmission path 2 requires the presence of a predetermined optical coupling section 3 in order for the light emitted from the optical transmission path 2 to reach the light emitting / receiving section 1a of the optical semiconductor element 1. To do.
- the optical semiconductor element 1 has a light emitting / receiving unit 1a as a part for emitting or entering an optical signal.
- the light emitting / receiving unit 1a is a light receiving unit.
- the light emitting / receiving unit 1a is a light emitting unit. Examples of the light emitting element include a light emitting diode (LED), a laser diode (LD), and a surface emitting laser (VCSEL). A photodiode (PD) etc. are mentioned as a light receiving element.
- the light emitting / receiving unit 1 a is provided on the upper surface 1 c of the optical semiconductor element 1.
- the vertical direction in the present invention is based on the mounting surface 4a on which the optical semiconductor element 1 is mounted on the substrate 4, and the direction away from the substrate 4 is upward (above FIGS. 1A to 1C) and the direction approaching the substrate 4 is downward (FIG. 1A to 1C below).
- a direction perpendicular to the vertical direction according to the above definition (the horizontal direction in FIGS. 1A to 1C) is defined as a horizontal direction.
- the vertical direction and horizontal direction in the present invention do not depend on the direction of gravity except when the transparent resin 31 is uncured and has fluidity as shown in FIGS. 3 and 4.
- the optical semiconductor element 1 is electrically connected to the circuit wiring 6 formed on the mounting surface 4a of the substrate 4 by a bonding material.
- the optical semiconductor element 1 is electrically connected to the circuit wiring 6 by the power supply wiring composed of an electrode (not shown) formed on the upper portion (surface) of the optical semiconductor element 1 and the wire wiring 7.
- the lower surface (back surface) 1d of the optical semiconductor element 1 and the circuit wiring 6 are electrically connected by a conductive adhesive (not shown).
- various general insulating substrates such as a glass epoxy substrate and a ceramic substrate can be used.
- the wire wiring 7 include a gold (Au) wire, an aluminum (Al) wire, a copper (Cu) wire, and the like.
- optical transmission line 2 examples include optical fibers such as silica-based optical fibers and plastic optical fibers (POF), and substrate-type optical waveguides such as quartz optical waveguides and polymer optical waveguides.
- optical axis 2b is linear at least in the vicinity of the end 2a so that the direction of light entering and exiting the optical coupling unit 3 is constant.
- the optical semiconductor element 1 is disposed such that the optical axis 1b intersects the optical axis 2b of the optical transmission line 2 (particularly, the optical axis 2b near the end 2a) at a predetermined angle ⁇ .
- the optical axes 1b and 2b of the optical semiconductor element 1 and the optical transmission line 2 are preferably arranged perpendicularly (or substantially perpendicular) to each other.
- the optical coupling unit 3 is made of a resin that is transparent to transmitted light.
- the resin constituting the optical coupling unit 3 is in close contact with at least a part of the light emitting / receiving unit 1 a of the optical semiconductor element 1 and at least a part of the end 2 a of the optical transmission path 2.
- the transparent resin here refers to a resin capable of transmitting light transmitted between the optical semiconductor element 1 and the optical transmission line 2. Therefore, the color tone is not necessarily limited to a colorless and transparent tone under visible light. Further, since the optical path length in the resin through which light is transmitted is short, it is only necessary to have some transparency.
- the transparent resin for example, a UV curable resin or a thermosetting resin can be used. Specific examples of the transparent resin include acrylic resins, epoxy resins, and silicone resins.
- FIG. 1A shows a case where the optical coupling unit 3 covers the entire surface of the end 2 a of the optical transmission line 2 and the upper end of the optical coupling unit 3 is attached to the upper part of the optical transmission line 2. ing.
- a part of the end 2a of the optical transmission line 2 may be exposed outside the optical coupling unit 3A.
- the resin constituting the optical coupling portion 3A is in a plane including the optical axis 1b of the optical semiconductor element 1 and the optical axis 2b of the optical transmission path 2 (in the plane on the paper surface of FIG. 5) and Outside the surface (front side and back side of the paper surface of FIG.
- the distance from the light emitting / receiving unit 1a of the optical semiconductor element 1 to the outer surface 3a of the optical coupling unit 3 and the distance from the end surface 2a of the optical transmission path 2 to the outer surface 3a of the optical coupling unit 3 are larger than those in the case of FIGS. Is also shortened.
- the entire surface of the core (not shown) exposed at the end 2a of the optical transmission line 2 is covered with the optical coupling portion 3A.
- the height 2d of the upper end 2c is a height with respect to the mounting surface 4a of the substrate 4 (distance in a direction perpendicular to the mounting surface 4a).
- the optical coupling unit 3 is configured such that the light incident on the optical coupling unit 3 from the optical transmission path 2 is a transparent resin that constitutes the optical coupling unit 3 and an external gas (for example, the light is reflected by the difference in refractive index from the interface 3a (the outer surface 3a of the optical coupling portion 3) with air, dry nitrogen gas, etc., and enters the optical semiconductor element 1 (see FIG. 1B).
- the distance x from the end face 2a of the optical transmission line 2 to the optical axis 1b of the optical semiconductor element 1 satisfies _30 ⁇ x ⁇ 60 ⁇ m, and the distance y from the optical axis 2b of the optical transmission line 2 to the optical semiconductor element 1 is It is preferable to satisfy 0 ⁇ y ⁇ 20 ⁇ m.
- the distance x is 60 ⁇ m or more and the distance y is 20 ⁇ m or more, particularly in the case of light with a large divergence angle, there is a possibility that the proportion of light that is not received by the light receiving unit 1a increases due to light diffusion.
- the optical semiconductor element 1 is a light emitting element
- the light incident on the optical coupling unit 3 from the optical semiconductor element 1 is the refractive index of the interface 3a between the transparent resin constituting the optical coupling unit 3 and the external gas. It is reflected by the difference and enters the optical transmission line 2 (see FIG. 1C).
- the angle ⁇ 2 formed by the tangent line T 2 and the upper surface 1c of the optical semiconductor element 1 is 30 °. It is preferable that ⁇ 2 ⁇ 60 °.
- the optical path length in the optical coupling unit 3 is shortened when the distance x satisfies 30 ⁇ x ⁇ 60 ⁇ m and the distance y satisfies 0 ⁇ y ⁇ 20 ⁇ m, the connection loss due to light diffusion is reduced. Can be suppressed.
- the optical semiconductor element 1 and the optical coupling unit 3 and between the optical transmission line 2 and the optical coupling unit 3 there is no refractive index matching agent or air due to a gap.
- the path 2 is connected only with the resin constituting the optical coupling portion 3.
- the optical coupling unit 3 of the present embodiment has the following configuration in order to easily realize optical coupling between the optical semiconductor element 1 and the optical transmission line 2.
- the outer surface 3 a of the optical coupling part 3 forms an interface with an external gas, and the optical semiconductor element 1 and the optical transmission path 2 are bonded together by the resin itself that constitutes the optical coupling part 3.
- the optical semiconductor element 1 and the optical transmission path 2 are connected by the resin constituting the optical coupling unit 3, and parts and adhesives other than the optical semiconductor element 1, the optical transmission path 2, and the optical coupling unit 3 are used. Without adjusting the positional relationship between the optical semiconductor element 1 and the parts other than the optical transmission path 2, the positional relationship between the optical semiconductor element 1 and the optical transmission path 2 can be adjusted at low cost and easily.
- the optical path between the optical semiconductor element 1 and the optical transmission path 2 can be converted, and the optical semiconductor element 1 and the optical transmission path 2 can be optically coupled with high efficiency.
- “bonded by the resin itself” means that the optical semiconductor element and the resin constituting the optical coupling portion are directly connected to the optical transmission path and the resin constituting the optical coupling portion, It means that there is no other material such as a resin (refractive index matching agent or air by a gap) between the optical semiconductor element and the optical coupling portion and between the optical transmission line and the optical coupling portion. What is necessary is just to take the state by the said definition in the state (stationary state) where tensile force is not applied, and the adhesive force with respect to tension is not ask
- the end portion 2a of the optical transmission line 2 and the light receiving / emitting portion 1a of the optical semiconductor element 1 are optically coupled by the optical coupling portion 3 made of a single transparent resin, which is extremely low cost and simple. It can be produced by a process.
- the single transparent resin here means that the component (composition) is uniform (single), the transmittance for light of a specific wavelength is uniform, and is not physically two or more layers (no interface). Including meaning.
- the shape of the optical coupling portion 3 of this embodiment is such that the outer surface 3a is convex.
- the outer surface 3a having a convex shape due to the increased optical path length. Due to the lens effect, the light can be effectively focused on the optical semiconductor element 1. As a result, the optical connection loss can be suppressed below a certain level. Further, when the spread angle of the light emitted from the optical transmission line 2 (or the optical semiconductor element 1) is relatively small, the above effect becomes more remarkable.
- the lens effect of the outer surface 3a is more dominant than the optical path length in the optical coupling unit 3 with respect to the connection loss. become. Furthermore, in the configuration as described above, by increasing the light condensing property on the outer surface 3a, the alignment of the optical transmission line 2 with respect to the light emitting / receiving portion 1a of the optical semiconductor element 1 can be facilitated.
- the position A facing the light emitting / receiving unit 1a may be convex on the opposite side to the light emitting / receiving unit 1a, and (b) the end of the optical transmission line 2
- the position B facing 2a may be convex on the side opposite to the end 2a of the optical transmission path 2, and (c) the position A facing the light emitting / receiving section 1a and the end of the optical transmission path 2 It may be a convex shape between the position B facing 2a, or may be a convex shape from two or more viewpoints of (a) to (c). Further, in the embodiment shown in FIG.
- the resin constituting the optical coupling portion 3 exists at the position of the intersection P where the optical axis 1b of the optical semiconductor element 1 and the optical axis 2b of the optical transmission line 2 intersect. Even if the outer surface 3a of the optical coupling part 3 is convex, the resin does not exist at the position of the intersection P between the optical axes 1b and 2b, and the outer surface 3a of the resin faces the light emitting / receiving part 1a.
- the position at which the outer surface 3a of the resin faces the end 2a of the optical transmission path 2 is between the intersection P and the end 2a of the optical transmission path 2. It is also possible to have a shape in between. This is preferable because the optical path in the optical coupling unit 3 is further shortened.
- the resin constituting the optical coupling portion 3 is preferably disposed in the upper surface 1c when viewed from above the upper surface 1c of the optical semiconductor element 1.
- the spread of the resin can be easily controlled without using a mold, and the shape of the optical coupling portion 3 made of the resin is stably produced. be able to.
- a part not involved in light transmission for example, the part 3b overlying the optical transmission line 2 in FIG. 1A, the lower side of the optical transmission line 2, and the optical semiconductor element 1 It does not matter that the portion 3c sandwiched between the upper surface 1c has a convex shape. However, it is not desirable that the resin constituting the optical coupling unit 3 hangs down from the lower portion 3 c of the optical transmission line 2 to the end surface 1 s of the optical semiconductor element 1 when the optical coupling unit 3 is manufactured.
- the resin constituting the optical coupling portion 3 is disposed apart from the power supply wiring (wire wiring) 7 wire-bonded to the upper surface of the optical semiconductor element 1 and does not contact the wire wiring 7.
- the resin comes into contact with the wire wiring 7, the shape of the resin collapses, and good coupling efficiency cannot be obtained.
- the resin shape changes due to a slight difference in the contact method between the resin and the wire wiring 7, the resin shape tends to vary. Since it is very difficult to control the manner of contact between the resin and the wire wiring 7, it is very effective in terms of manufacturing stability to prevent the wire wiring 7 from contacting. In this case, the wire wiring 7 that should avoid contact with the resin protrudes upward from the upper surface 1 c of the optical semiconductor element 1.
- the external wiring of the optical semiconductor element 1 is planarly formed along the upper surface 1c and the side surface of the optical semiconductor element 1, it is not always necessary to avoid contact. Further, not only the wire wiring 7 but also a structure that largely protrudes from the upper surface 1c of the optical semiconductor element 1, it is preferable to avoid the resin constituting the optical coupling portion from coming into contact with these structures.
- the end surface 2a of the optical transmission line 2 is obtained when the optical semiconductor element 1 is viewed from the side surface direction (FIGS. 1A to 1C) and from above (FIGS. 12A to 12C). It is preferable that the optical semiconductor element 1 exists inside the optical semiconductor element 1 from the end face 1s of the optical semiconductor element 1 (a side surface surrounding the upper surface 1c). Since the end face 2a of the optical transmission line 2 exists inside the optical semiconductor element 1, the optical path length in the optical coupling unit 3 can be shortened. Moreover, as shown to FIG. 12A, when the shape of the optical coupling part 3 is seen from the upper direction, it is preferable that it is circular shape or elliptical shape.
- the shape of the optical coupling part 3 when the shape of the optical coupling part 3 is seen from the upper direction, it is more preferable that it is a fan shape.
- a mirror having a square shape when viewed from above as in the prior art the shape when the optical path conversion mirror 103 shown in FIG. 16 is viewed from above
- a certain distance from the optical transmission path 2 is used. Light emitted with a divergence angle cannot be collected in the light emitting / receiving section 1a of the optical semiconductor element 1, resulting in an increase in connection loss.
- the optical coupling part 3 since the optical coupling part 3 has a circular shape or an elliptical shape when viewed from above, from the light emitting part (end surface 2a of the optical transmission line 2) to the outer surface 3a of the optical coupling part 3 And the distance from the outer surface 3a to the light emitting / receiving unit 1a (that is, the optical path length in the optical coupling unit 3) becomes shorter, and the emitted light is reflected by the outer surface 3a so as to gather at the light receiving / emitting unit 1a. . Therefore, the connection loss between the optical semiconductor element 1 and the optical transmission line 2 can be further suppressed. Furthermore, when the shape of the optical coupling unit 3 is a fan shape when viewed from above, the optical path length can be made shorter than in the case of a circular shape or an elliptical shape. I can plan.
- FIG. 2A shows another example of an optical module provided with the optical coupling structure according to the first embodiment.
- the optical module 15 shown in FIG. 2A has a shape in which the outer surface of the resin constituting the optical coupling unit 14 is recessed toward the light emitting / receiving unit 1 a of the optical semiconductor element 1 and the end 2 a of the optical transmission line 2. In this way, the outer surface of the resin constituting the optical coupling unit 14 is recessed into the light emitting / receiving unit 1a of the optical semiconductor element 1 and the end 2a side of the optical transmission line 2, so that the inside of the optical coupling unit 14 Can be shortened.
- the transparent resin constituting the optical coupling portion 14 does not exist at the position of the intersection P where the optical axis 2b of the optical transmission path 2 and the optical axis 1b of the optical semiconductor element 1 intersect, and the optical coupling portion 14 It is preferable that the outer surface 14a (interface between the optical coupling unit 14 and the external gas) is recessed toward the light emitting / receiving unit 1a of the optical semiconductor element 1 and the end 2a of the optical transmission line 2.
- the outer surface 14a of the optical coupling portion 14 in order for the outer surface 14a of the optical coupling portion 14 to have a recessed shape, at least, (1) A concave surface portion 11 having a shape in which a position A facing the light emitting / receiving portion 1a is recessed toward the light emitting / receiving portion 1a, (2) A concave surface portion 12 having a shape in which the position B facing the end 2a of the optical transmission path 2 is recessed toward the end 2a of the optical transmission path 2, (3) A concave surface portion 13 having a concave shape between a position A facing the light emitting / receiving section 1a and a position B facing the end 2a of the optical transmission line 2; You need to have Further, when the optical semiconductor element 1 is a light receiving element, the outer surface 14a at a position B where the optical axis 2b and the outer surface 14a of the optical transmission path 2 intersect relates tangent T 3, the tangent line T 3 and the optical semiconductor element 1 preferably, the angle phi 3 and the upper surface
- the distance x from the end face 2a of the optical transmission line 2 to the optical axis 1b of the optical semiconductor element 1 satisfies 30 ⁇ x ⁇ 60 ⁇ m, and the distance y from the optical axis 2b of the optical transmission line 2 to the optical semiconductor element 1 is It is preferable to satisfy 0 ⁇ y ⁇ 20 ⁇ m.
- the distance x is 60 ⁇ m or more and the distance y is 20 ⁇ m or more, particularly in the case of light with a large divergence angle, there is a possibility that the proportion of light that is not received by the light receiving unit 1a increases due to light diffusion.
- the distance x satisfies 30 ⁇ x ⁇ 60 ⁇ m and the distance y satisfies 0 ⁇ y ⁇ 20 ⁇ m, an increase in connection loss due to light diffusion can be suppressed.
- the optical semiconductor element 1 is a light emitting element
- the tangent line T 4 of the outer surface 14a at the position A where the optical axis 1b of the light emitting element intersects the outer surface 14a is related to the tangent line T 4 and the upper surface 1c of the optical semiconductor element 1.
- angle phi 4 and is preferably a 30 ° ⁇ 4 ⁇ 60 ° ( see Fig. 2C).
- the emitted light from the optical semiconductor element 1 can be effectively condensed on the optical transmission line 2 (for example, the core when the optical transmission line 2 is an optical fiber), and an increase in connection loss is suppressed. it can.
- the distance x from the end face 2a of the optical transmission line 2 to the optical axis 1b of the optical semiconductor element 1 satisfies 30 ⁇ x ⁇ 60 ⁇ m, and the optical semiconductor element 1 from the optical axis 2b of the optical transmission line 2 It is preferable that the distance y satisfies the following condition: 0 ⁇ y ⁇ 20 ⁇ m. The same effect as described above can be obtained.
- a portion that does not participate in light transmission for example, a portion 14b that is on the upper side of the optical transmission line 2 in FIG. 2A, or a portion that is sandwiched between the lower side of the optical transmission line 2 and the upper surface 1c of the optical semiconductor element 1 It is acceptable that 14c has a convex shape. Further, unlike the optical module 15A shown in FIG. 6, there is no portion 14b over the optical transmission line 2, and a part of the end 2a of the optical transmission line 2 is exposed outside the optical coupling part 14A. Also good.
- the concave surface portion 11 on the light emitting / receiving portion 1a side in (1) is, for example, near the position A where the optical axis 1b of the optical semiconductor element 1 intersects the outer surface 14a of the resin, and the outer surface 14a of the resin is on the resin side. What is necessary is just to form the concave surface used as a concave.
- the concave surface portion 12 on the optical transmission path 2 side in (2) is, for example, in the vicinity of the position B where the optical axis 2b of the optical transmission path 2 intersects the outer surface 14a of the resin, and the outer surface 14a of the resin is concave on the resin side. It is only necessary to form a concave surface.
- the concave surface portion 13 in (3) includes, for example, a position A where the optical axis 1b of the optical semiconductor element 1 intersects the outer surface 14a of the resin, and an optical axis 2b of the optical transmission path 2 is the outer surface 14a of the resin. It suffices that the line segment AB connecting the intersecting position B passes through the outside of the resin (external gas side) between AB and forms a concave surface in which the outer surface 14a of the resin is concave.
- the optical coupling unit 14 of this embodiment is configured such that the optical semiconductor element 1 and the optical transmission path 2 are connected (integrated) by the resin itself constituting the optical coupling unit 14.
- the optical path between the optical semiconductor element 1 and the optical transmission path 2 can be easily converted at low cost, and the optical semiconductor element 1 and the optical transmission path 2 can be optically coupled with high efficiency.
- the resin constituting the optical coupling portion 14 is disposed in the upper surface 1c when viewed from above the upper surface 1c of the optical semiconductor element 1, the resin spreads without using a mold or the like. And the like, and the shape of the optical coupling portion 14 made of the resin can be stably produced.
- the resin constituting the optical coupling portion 14 does not come into contact with the power supply wiring 7 wire-bonded to the upper surface of the optical semiconductor element 1, the resin shape of the optical coupling portion 14 is unlikely to vary.
- the optical connection structure can be manufactured. Further, when the end surface 2a of the optical transmission line 2 is present inside the optical semiconductor element 1 from the end surface 1s of the optical semiconductor element 1 when the optical semiconductor element 1 is viewed from the side surface direction and the upward direction, the optical coupling portion The optical path length in 14 can be shortened. Furthermore, when the optical coupling portion 14 is viewed from above, it is preferable that the optical coupling portion 14 has a circular shape, an elliptical shape, or a fan shape. The same effect as described for the convex shape can be obtained.
- the outer surface 14a of the optical coupling portion 14 has a concave shape, the light 10 emitted from the optical transmission path 2 and reflected by the outer surface 14a of the optical coupling portion 14 is reflected as shown in FIG.
- the reflection position on the outer surface 14a of the optical coupling part 14 can be brought close to the optical semiconductor element 1 and the optical transmission path 2, and the optical path length in the optical coupling part 14 can be shortened. .
- a stable optical connection can be established without increasing connection loss.
- the optical semiconductor element 1 is a light emitting element
- the light 10 emitted from the light emitting / receiving section 1a of the optical semiconductor element 1 is reflected by the outer surface 14a of the optical coupling section 14 and is incident on the optical transmission line 2.
- the optical connection loss tends to increase. This is because, as shown in FIG. 7, when light is emitted from the optical transmission line 2 (or light receiving and emitting unit 1 a), it has a certain spread angle and travels while spreading in the optical coupling unit 14. . As shown in FIG. 8, when the outer surface 3a of the optical coupling unit 3 has a convex shape, the position where the light 10 is reflected by the outer surface 3a of the optical coupling unit 3 becomes far, and the optical path length in the optical coupling unit 3 becomes longer. By increasing the length, particularly when light having a large divergence angle is emitted, the light may diffuse and connection loss may increase. As shown in FIG.
- the optical coupling portion 14 has no resin at the intersection P where the optical axis 1b of the optical semiconductor element 1 and the optical axis 2b of the optical transmission line 2 intersect, and the outer surface 14a of the resin receives and emits light.
- a position A facing the portion 1a is between the intersection P and the light emitting / receiving portion 1a, and a position B where the outer surface 14a of the resin faces the end 2a of the optical transmission path 2 is between the intersection P and the optical transmission path 2. It is preferably between the end 2a.
- the shape of the optical coupling portion 16 collapses around a portion (attachment portion) 17 where the resin adheres to the power supply wiring 7.
- the position where the light is reflected by the outer surface 16a of the optical coupling unit 16 is far from the optical transmission path 2 and the optical semiconductor element 1, and the optical path length in the optical coupling unit 16 is increased.
- the light diffuses and the connection loss increases, and it is difficult to produce a shape that achieves high coupling efficiency. That is, good coupling efficiency cannot be obtained.
- the shape is not very stable, resulting in large manufacturing variations.
- the optical coupling portion is not disposed in the upper surface 1c of the optical semiconductor element 1 when viewed from above, the resin forming the optical coupling portion is easily spread when the optical coupling portion is manufactured, and the light is optically coupled.
- the reflection position on the outer surface of the part tends to be far.
- the optical path length in the optical coupling portion becomes long, the light diffuses and the connection loss tends to increase.
- the spread of the resin is difficult to stabilize, a large manufacturing variation occurs.
- surroundings of transparent resin are covered with gas. Since the refractive index difference between the transparent resin and the gas is large, the reflectance of light at the interface can be increased. Thereby, the light coupling efficiency can be further improved.
- the optical coupling units 3 and 14 of the present embodiment are configured such that the optical semiconductor element 1 and the optical transmission line 2 are connected (integrated) by the resin itself constituting the optical coupling units 3 and 14, 3 and 14 are disposed in the upper surface 1c of the optical semiconductor element 1, the optical coupling portions 3 and 14 are not in contact with the power supply wiring 7 wire-bonded to the upper surface of the optical semiconductor element 1, and the optical coupling Since the periphery of the portions 3 and 14 is covered with gas, and more preferably, the outer surface 14a of the optical coupling portion 14 has a recessed shape, the position and angle as the reflecting surface of the shape of the interface of the transparent resin Even if it is not precisely controlled, highly efficient optical coupling can be stably realized with lower fabrication accuracy.
- the optical semiconductor element 1 is mounted on the mounting surface 4a of the substrate 4 such that the light emitting / receiving portion 1a is on the opposite side of the mounting surface 4a of the substrate 4 (upper side in FIGS. 1A to 1C). Therefore, mounting by die bonding or wire bonding becomes possible. As a result, it is possible to connect wires important for transmission characteristics with the shortest line length, and it is difficult for noise to ride, and good transmission characteristics can be obtained. Further, it is easy to inspect the appearance of bonding, and it is easy to find a connection failure.
- a method for manufacturing the optical modules 5 and 15 having the configuration shown in FIGS. 1A to 2C will be exemplified.
- a substrate 4 on which circuit wiring 6 is previously formed on the mounting surface 4 a and the optical semiconductor element 1 is mounted is prepared.
- an uncured transparent resin 31 is applied to the light emitting / receiving portion 1a of the optical semiconductor element 1 using a resin dipping device 29 such as a precision dispenser. It is desirable to apply the transparent resin 31 within a range that fits on the upper surface 1 c of the optical semiconductor element 1. At this time, the transparent resin 31 is applied away from the power supply wiring so that the transparent resin 31 does not come into contact with the power supply wiring 7.
- the end 2 a of the optical transmission line 2 is inserted into the optical semiconductor element 1 toward the transparent resin 31 placed on the optical semiconductor element 1 (in the direction of arrow L). Then, the optical transmission path 2 inserted into the transparent resin 31 is moved away from the optical semiconductor element 1. At this time, the optical transmission line 2 is slowly pulled up from the optical semiconductor element 1 obliquely upward (in the direction of arrow R).
- the transparent resin 31 for example, UV (ultraviolet) irradiation or heating is performed as necessary to cure the transparent resin 31.
- UV (ultraviolet) irradiation or heating is performed as necessary to cure the transparent resin 31.
- the optical coupling parts 3 and 14 that optically connect (optically couple) the optical semiconductor element 1 and the optical transmission line 2 are formed, and the optical modules 5 and 15 are completed.
- the shape of the transparent resin 31 after the optical transmission line 2 is pulled up in the oblique direction is (1) the interfacial tension between the transparent resin 31 and the optical semiconductor element 1, and (2) the transparent resin 31 and the optical transmission line. 2 and (3) the surface tension between the transparent resin 31 and the external gas. That is, (A) a member of the optical semiconductor element 1, the optical transmission path 2, and the transparent resin 31, and (B) a state of the member such as the surface state of the optical semiconductor element 1 and the optical transmission path 2 and the viscosity of the transparent resin 31, (C) Depends on the mounting conditions such as the application amount of the transparent resin 31 in FIG. 3 and the insertion amount and pull-up amount of the optical transmission path 2 in FIG.
- the shape of the transparent resin 31 is naturally the same. Whether the outer surfaces 3a and 14a of the optical coupling parts 3 and 14 are concave or convex, or when the optical coupling parts 3 and 14 are viewed from above, they are circular, elliptical, or fan-shaped. It can be controlled by these conditions.
- the amount of pulling up of the optical transmission line 2 in the R direction has an optimum value according to the structure of the optical transmission line 2 and the optical semiconductor element 1 to be used, the coating amount of the transparent resin 31, and the like. If such optimum values are examined in advance, it is possible to automate all the manufacturing processes described above, thereby realizing further labor saving of the manufacturing process. Further, when the optical coupling portions 3 and 14 are manufactured, it is not necessary to transmit light between the optical semiconductor element 1 and the optical transmission path 2, and passive alignment is possible. Even if the position of the passive alignment is slightly deviated from the optimal position due to a change in the amount of resin applied, the transparent semiconductor 31 is connected to the surface of the transparent resin 31 because the optical semiconductor element 1 and the optical transmission path 2 are connected.
- the transparent resin 31 is placed on the optical semiconductor element 1, the optical transmission line 2 is inserted into the transparent resin 31 and pulled up in an oblique direction, and then the transparent resin
- the optical coupling portions 3 and 14 that optically connect (optically couple) the optical semiconductor element 1 and the optical transmission line 2 simply by curing 31. Therefore, when the optical coupling portions 3 and 14 are formed, an optical module can be manufactured at a very low cost with a small number of steps and a small number of components without the need for a metal mold or the like.
- the formation method of the optical coupling parts 3 and 14 is not limited to the said method.
- the tip of the optical transmission line 2 is disposed above the optical semiconductor element 1, and a transparent resin 31 is provided so as to cover the tip of the optical transmission line 2 and the light emitting / receiving portion 1 a of the optical semiconductor element 1.
- the transparent resin 31 may be cured after the tip of the optical transmission line 2 is pulled up in an oblique direction. That is, in order to form the optical coupling portions 3 and 14 by pulling up the tip of the optical transmission line 2 in the transparent resin 31 in an oblique direction, the step of arranging the tip of the optical transmission line 2 on the optical semiconductor element 1 and The order of the steps for disposing the transparent resin 31 may be reversed from the method described above.
- condition (C ′) “mounting conditions such as the coating amount of the transparent resin 31 and the position and the lifting amount of the optical transmission line 2 before lifting” are adopted. If the conditions (A), (B), and (C ′) are the same, the shape of the transparent resin 31 is naturally the same. In addition, if the procedure is different, the optimum value of the amount of pulling up of the optical transmission line 2 in the R direction may change. Therefore, it is desirable to examine the optimum value by performing an experiment in the same procedure as in practice.
- Patent Document 4 describes a semiconductor laser device in which a transparent resin is coated along a step of a substrate so that backward output light of the semiconductor laser element is incident on a monitor photodiode. Since the optical module manufacturing method of this embodiment does not require the transparent resin to adhere to the substrate, it is necessary to add processing steps (V-groove, step, etc.) of the substrate 4 when forming the optical coupling portions 3, 14. Absent. For this reason, the substrate can be manufactured at low cost even if the substrate is not limited to a substrate that can use plane anisotropic etching, such as a silicon substrate, but a substrate with low workability such as a glass epoxy substrate.
- FIGS. 13 and 14 show an example of an optical module provided with the optical coupling structure according to the second embodiment.
- the optical modules 9 and 19 shown in FIG. 13 and FIG. 14 are separated from the optical semiconductor element 1 mounted on the mounting surface 4a of the substrate 4 and the mounting surface 4a of the substrate 4 along the mounting surface 4a of the substrate 4.
- the optical transmission path 2 disposed, the optical coupling portions 3 and 14 for optically coupling the optical transmission path 2 and the optical semiconductor element 1, and the clad resin layer 8 covering the periphery of the optical coupling portions 3 and 14; It has.
- the optical modules 9 and 19 of this embodiment are clad made of a second resin whose refractive index is lower than the transparent resin (first resin) constituting the optical coupling portions 3 and 14 around the optical coupling portions 3 and 14.
- the point covered with the resin layer 8 is different from the optical modules 5 and 15 according to the first embodiment.
- the optical semiconductor element 1, the optical transmission line 2, the substrate 4, the circuit wiring 6, the wire wiring 7, and the like can be configured similarly to the optical modules 5 and 15 according to the first embodiment.
- the clad resin layer 8 is formed of a resin having a refractive index lower than that of the transparent resin constituting the optical coupling portions 3 and 14, light transmitted through the optical coupling portions 3 and 14 is directed toward the clad resin layer 8. It can suppress that it injects into and scatters.
- the periphery of the clad resin layer 8 can be sealed with a resin (not shown) having a higher refractive index than that of the optical coupling portions 3 and 14.
- the refractive index here refers to the refractive index at the wavelength of light transmitted between the optical semiconductor element 1 and the optical transmission line 2.
- a UV curable resin or a thermosetting resin can be used as the second resin.
- Specific examples of the second resin include acrylic resins, epoxy resins, and silicone resins.
- the clad resin layer 8 is formed by applying and curing a second resin after forming the optical coupling portions 3 and 14 as shown in FIGS.
- the optical coupling portions 3 and 14 of this embodiment are the same as those of the first embodiment except that the optical coupling portions 3 and 14 are covered with the clad resin layer 8.
- FIG. 13 shows a case where the outer surface 3a of the optical coupling portion 3 has a convex shape
- FIG. 14 shows a case where the outer surface 14a of the optical coupling portion 14 has a concave shape.
- the first resin constituting the optical coupling portions 3 and 14 is formed by the optical semiconductor element 1 and the optical transmission line 2 being connected (integrated) by the first resin itself constituting the optical coupling portions 3 and 14.
- the optical path between the optical semiconductor element 1 and the optical transmission path 2 can be easily converted at low cost, and the optical semiconductor element 1 and the optical transmission path 2 can be optically coupled with high efficiency.
- the first resin constituting the optical coupling portions 3 and 14 is disposed in the upper surface 1c of the optical semiconductor element 1 when viewed from above, the first resin is used without using a mold or the like. It is easy to control the spread of the light, and the shapes of the optical coupling portions 3 and 14 made of the first resin can be stably produced. Further, since the resin constituting the optical coupling portions 3 and 14 does not come into contact with the power supply wiring 7 wire-bonded to the upper surface of the optical semiconductor element 1, the resin shape of the optical coupling portions 3 and 14 is less likely to vary. Can be manufactured. Further, since the end face 2 a of the optical transmission line 2 is disposed inside the optical semiconductor element 1, the optical path length in the optical coupling portions 3 and 14 can be shortened.
- the interface 14a between the optical coupling portion 14 and the clad resin layer 8 has a concave shape like the optical coupling portion 14 of the first embodiment described above.
- the light of the first embodiment described above is used. Similar to the coupling part 3, if the interface between the optical coupling part and the clad resin layer 8 has a convex shape, the same effect as that obtained with the optical coupling part 3 of the first embodiment can be obtained.
- the clad resin layer 8 in the optical module 9 of this embodiment functions as a clad resin for the optical coupling portions 3 and 14.
- the optical semiconductor element 1 is a light receiving element
- the light incident on the optical coupling portions 3 and 14 from the optical transmission path 2 is the refractive index of the interfaces 3a and 14a between the optical coupling portions 3 and 14 and the clad resin layer 8.
- the light is reflected by the difference and enters the optical semiconductor element 1.
- the optical semiconductor element 1 is a light emitting element
- the light incident on the optical coupling parts 3 and 14 from the optical semiconductor element 1 passes through the interfaces 3 a and 14 a between the optical coupling parts 3 and 14 and the clad resin layer 8.
- the light is reflected by the difference in refractive index and enters the optical transmission line 2.
- the optical transmission line 2 is fixed to the mounting surface 4 a of the substrate 4 by the clad resin layer 8.
- the direction of the optical axis 2b in the vicinity of the end 2a of the optical transmission path 2 is difficult to move, and even when an external force is applied to the optical transmission path 2, deterioration of optical coupling can be suppressed.
- the wire wiring 7 is covered and protected by the clad resin layer 8, it is possible to prevent disconnection of the wire wiring 7 (feeding wiring) that is easily damaged by external stress. Since the end 2a of the optical transmission line 2, the optical coupling parts 3 and 14, and the optical semiconductor element 1 are covered with the clad resin layer 8, they can be protected from external stress.
- the mechanical strength of the entire optical coupling structure between the optical semiconductor element 1 and the optical transmission line 2 can be increased.
- the clad resin layer 8 is provided so as to function as a protective layer of the wire wiring 7 or a protective layer of the optical coupling structure, the clad resin layer 8 as these protective layers can be easily formed. .
- FIG. 15 is a perspective view showing an optical transceiver module according to an embodiment of the present invention.
- the optical transceiver module 50 according to the present embodiment includes a first optical semiconductor element 51 a that is a light receiving element and a second optical semiconductor element 51 b that are light emitting elements mounted on a mounting surface 54 a of the same substrate 54, and Optical coupling between the first optical transmission line 52a and the second optical transmission line 52b, which are spaced apart from the mounting surface 54a, and the first optical semiconductor element 51a and the first optical transmission line 52a. And a second optical coupling portion 53b that optically couples between the second optical semiconductor element 51b and the second optical transmission line 52b.
- the first optical semiconductor element 51a, the first optical transmission path 52a, and the first optical coupling portion 53a constitute a first optical coupling structure
- the second optical semiconductor element 51b, the second optical transmission path 52b, and The second optical coupling portion 53b constitutes a second optical coupling structure
- the first optical coupling structure and the second optical coupling structure both constitute an optical coupling structure similar to the optical modules 9 and 19 illustrated in FIGS. 13 and 14. ing.
- the optical coupling portions 53a and 53b are made of a resin that is transparent to the transmitted light, and the first resin is at least part of the light receiving and emitting portions of the optical semiconductor elements 51a and 51b and the optical transmission path.
- 52a and 52b are in close contact with at least a part of each end, and the optical semiconductor element 51a and the optical transmission path 52a, and the optical semiconductor element 51b and the optical transmission path 52b constitute the optical coupling sections 53a and 53b. It is directly connected by the resin itself.
- the first resin constituting the optical coupling portions 53a and 53b is disposed in the upper surface of the optical semiconductor elements 51a and 51b when viewed from above, and the resin constituting the optical coupling portions 53a and 53b.
- the power supply wirings 57a and 57b wire-bonded to the upper surfaces of the optical semiconductor elements 51a and 51b are not in contact with each other, and the end faces of the optical transmission lines 52a and 52b exist on the optical semiconductor elements 51a and 51b.
- the outer surface (or interface with the clad resin layer 59) of the optical coupling portions 53a and 53b may be a convex shape or a concave shape.
- the outer surfaces of the optical coupling portions 53a and 53b are recessed.
- the clad resin layer 59 may be omitted and the periphery of the optical coupling portions 53a and 53b may be covered with gas.
- optical semiconductor elements 51a and 51b are mounted side by side on a common substrate 54. These optical semiconductor elements 51 a and 51 b are electrically connected to circuit wiring 56 formed on the substrate 54 by a bonding material.
- the optical semiconductor elements 51a and 51b are provided by power supply wiring composed of electrodes (not shown) formed on the upper portions (surfaces) of the optical semiconductor elements 51a and 51b and the wire wirings 57a and 57b. Are electrically connected to the circuit wiring 56.
- the back surfaces of the optical semiconductor elements 51a and 51b and the circuit wiring 56 are electrically connected by a conductive adhesive (not shown).
- the circuit wiring 56 and the wire wirings 57a and 57b are independently provided with a wiring connected to the light emitting element and a wiring connected to the light receiving element.
- the first optical transmission path 52a and the second optical transmission path 52b are integrally covered with a common covering material 58.
- a common covering material 58 For this reason, when the optical coupling portions 53a and 53b are manufactured, when the optical transmission lines 52a and 52b are inserted into the transparent resin (in the L direction) in the same manner as in FIG. 4, light is then transmitted in the oblique direction (R direction).
- the operation can be simplified by operating both the optical transmission paths 52a and 52b at a time.
- an optical fiber tape core or a substrate type optical waveguide can be used as the plurality of optical transmission lines 52a and 52b integrated with the common covering material 58.
- the covering material 58 may be opaque to the light transmitted through the optical transmission paths 52a and 52b.
- the optical semiconductor elements 51a and 51b, the optical transmission lines 52a and 52b, and the optical coupling portions 53a and 53b may be covered with a single clad resin layer 59.
- the clad resin layer 59 is formed of a resin having a refractive index lower than that of the transparent resin constituting the optical coupling portions 53a and 53b, light transmitted through the optical coupling portions 53a and 53b is directed toward the clad resin layer 59. It can suppress that it injects into and scatters.
- the periphery of the clad resin layer 59 can be sealed with a resin (not shown) having a higher refractive index than that of the optical coupling portions 53a and 53b.
- the optical transmission paths 52 a and 52 b integrated by the common covering material 58 are fixed to the mounting surface 54 a of the substrate 54 by the clad resin layer 59.
- the direction of the optical axis near the ends of the optical transmission paths 52a and 52b is difficult to move, and deterioration of optical coupling can be suppressed even if an external force acts on the optical transmission paths 52a and 52b.
- the wire wirings 57a and 57b are covered and protected by the clad resin layer 59, it is possible to prevent the wire wirings 57a and 57b (feeding wiring) that are easily damaged by external stress from being disconnected.
- the end portions of the optical transmission lines 52a and 52b, the optical coupling portions 53a and 53b, and the optical semiconductor elements 51a and 51b are covered with the clad resin layer 59, they can be protected from external stress. Therefore, the mechanical strength of the entire optical coupling structure can be increased.
- the optical transmission / reception module 50 of FIG. 15 comprises the optical transmission module in which the optical semiconductor elements 51a and 51b are both light emitting elements, or the optical semiconductor elements 51a and 51b are both light receiving elements. It is also possible to configure a receiving module.
- the clad resin layer 59 can cover only the periphery of some of the optical coupling portions 53a and 53b.
- the number of optical semiconductor elements mounted on the optical module is not limited to one or two, and may be three or more.
- the required number of optical coupling structures between the optical semiconductor element and the optical transmission line can be provided according to the number of optical semiconductor elements.
- Example 1 As shown in FIGS. 1A to 4, a silica-based multimode optical fiber having a cladding diameter of 125 ⁇ m and a core diameter of 50 ⁇ m was prepared as the optical transmission line 2.
- the optical semiconductor element 1 has a PD as a light receiving element (opening diameter of the light receiving part is 80 ⁇ m), a VCSEL as a light emitting element (opening diameter of the light emitting part is 12 ⁇ m), and the transparent resin 31 is a UV curable resin (acrylic resin).
- the substrate 4 was a glass epoxy substrate, and the wire wiring 7 was a gold wire.
- the tip of the optical fiber is inserted into the transparent resin, and the diagonal 30
- the optical fiber was pulled up so that the pulling distance was 40 ⁇ m upward.
- the transparent resin 31 was cured by irradiating UV onto the transparent resin, thereby producing the optical coupling structures 5 and 15 shown in FIGS. 1A to 2C.
- the refractive index of the cured resin constituting the optical coupling portions 3 and 14 is 1.58.
- optical modules in which the positional relationship between the optical transmission line and the optical semiconductor element was optimized were prepared using the resins of samples D, H, and K, and the connection loss in each was measured. The results are shown in Table 2.
- the shape of the optical coupling portion of each module as viewed from above is a fan shape as shown in FIG. 12C when the sample D is used, and a fan as shown in FIG. 12C when the sample H is used.
- the shape and the sample K were elliptical.
- Example 2 The optical coupling part was produced by unifying the time from when the optical fiber was pulled up until UV irradiation was performed, and the shape of the obtained optical coupling part was observed.
- Table 3 shows the case in which the time from when the optical fiber is pulled up to UV irradiation is unified to 3 seconds
- Table 4 shows the case in which the time from the optical fiber to UV irradiation is unified to 2 minutes. .
- an optical module in which the positional relationship between the optical transmission line and the optical semiconductor element was optimized was prepared using the resins of samples D, H, and K, and the connection loss in each was measured.
- the above-described 30 ° ⁇ ⁇ 60 °, 30 ⁇ x ⁇ 60 ⁇ m, and 0 ⁇ y ⁇ 20 ⁇ m were satisfied.
- the shape of the optical coupling portion of each module as viewed from above is a fan shape as shown in FIG. 12C when the sample D is used, and a fan as shown in FIG. 12C when the sample H is used.
- the shape and the sample K were elliptical.
- Table 5 shows the case where the time from when the optical fiber is pulled up to UV irradiation is unified to 3 seconds
- Table 6 shows the case where the time from when the optical fiber is pulled up to UV irradiation is unified to 2 minutes. .
- the optical semiconductor element and the optical transmission line are bonded by the resin itself constituting the optical coupling portion, so that the optical coupling portion can be manufactured at low cost and is high.
- the optical signal could be transmitted with efficiency.
- the connection loss is very small.
- the connection loss is very small compared to the convex shape.
- the optical coupling portion can be manufactured at a low cost without using a large number of components, and an optical signal can be transmitted with higher efficiency.
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Abstract
Description
本願は、2010年01月06日に、日本国に出願された特願2010-001100号に基づき優先権を主張し、その内容をここに援用する。
従来、この種の光モジュールにおいて、光半導体素子の受発光部と光伝送路の端部とを光学的に結合させるために、図16に示すような構造が一般に用いられている。この構造では、光半導体素子101の上に設置された集光レンズ102と、光路変換用ミラー103とを組み合わせることで、光伝送路104(特にそのコア105)と光半導体素子101とを光学的に接続(光結合)させる。
特許文献2には、光導波路の端部に対向する位置に斜めに形成された反射面を有するV溝が形成された基板と、光導波路の端部と反射面との間に充填され、光導波路のコアとほぼ同じ屈折率を有する屈折率整合剤と、反射面で反射した出射光を受光する受光素子とを備えた、光導波路と受光素子との結合構造が提案されている。
特許文献4には、半導体レーザ素子、モニタフォトダイオード、及び光ファイバが透明樹脂に封入され、半導体レーザ素子の後方出力光が透明樹脂と空気との界面において反射してモニタフォトダイオードに入射するようにした半導体レーザ装置が提案されている。
(1)本発明の一態様に係る光結合構造は、上面に受発光部を有し、かつ下面の側で基板に実装された光半導体素子と、前記光半導体素子の光軸に対して所定の角度で交差する光軸を有し、かつ前記基板の実装面から離間して配置された光伝送路と、前記光半導体素子と前記光伝送路との間の光路を変換し、かつ前記光半導体素子と前記光伝送路との間を光学的に結合する光結合部とを備える。前記光結合部は、伝送される光に対して透明な樹脂からなる。前記樹脂は、前記光半導体素子の受発光部の少なくとも一部および前記光伝送路の端部の少なくとも一部にそれぞれ密着し、前記光半導体素子と前記光伝送路とが、前記光結合部を構成する前記樹脂自身によって、接着されている。
(4)上記(1)から(3)に記載の光結合構造において、前記光伝送路の端面は、前記光半導体素子を側面方向および上方向から見たときに、前記光半導体素子の端面より前記光半導体素子の内側に存在してもよい。
(5)上記(1)から(4)に記載の光結合構造において、前記光結合部を構成する前記樹脂の外面が、前記光半導体素子の受発光部および前記光伝送路の端部の側に凹んだ形状となっていてもよい。
(6)上記(1)から(4)に記載の光結合構造において、前記光結合部を構成する前記樹脂の外面が凸形状となっていてもよい。
(7)上記(1)から(6)に記載の光結合構造において、前記光結合部をなす前記樹脂は、前記光半導体素子の光軸と前記光伝送路の光軸とが交差する交点の位置に存在せず、前記樹脂の外面が前記受発光部に対向する位置が、前記交点と前記受発光部との間にあり、かつ、前記樹脂の外面が前記光伝送路の端部に対向する位置が、前記交点と前記光伝送路の端部との間にあってもよい。
(8)上記(1)から(7)に記載の光結合構造において、前記光結合部を構成する前記樹脂は、前記光伝送路の端面の上端の高さより下側に配置されていてもよい。
(9)上記(1)から(8)に記載の光結合構造において、前記光結合部の形状が、前記光結合部を上方向から見たときに、円形状、楕円形状、または扇形状のいずれかであってもよい。
(10)上記(1)から(8)に記載の光結合構造において、前記光結合部の周囲が気体で覆われていてもよい。
(11)上記(1)から(8)に記載の光結合構造において、前記光結合部の周囲が光結合部を構成する樹脂より屈折率が低いクラッド樹脂層で覆われていてもよい。
(12)上記(11)に記載の光結合構造は、前記光半導体素子の給電用配線が前記クラッド樹脂層によって覆われていてもよい。
(14)本発明の一態様に係る光結構造の製造方法は、上記(1)から(12)のいずれかに記載の光結合構造の製造方法であって、基板に設けられた光半導体素子の受発光部に樹脂を塗布する工程と、前記基板に対して平行に、光伝送路を前記樹脂に差し込む工程と、前記光伝送路を前記半導体素子から遠ざける方向で、かつ斜め上方に移動させる工程と、前記樹脂を硬化させて光結合部とする工程と、を備える。予め求めておいた前記樹脂の塗布量、前記樹脂の粘度、前記光伝送路の差し込み量、前記光伝送路の斜め上方への移動量、及び前記樹脂を硬化させるまでの時間の相関関係に基づいて、前記光結合部の形状を凸形状にするのか又は凹み形状にするのかを制御する。
(15)上記(14)に記載の光結構造の製造方法において、前記樹脂は、前記光半導体素子の上面にワイヤボンディングしている給電用配線から離間して前記受発光部に塗布してもよい。
光半導体素子をその光軸が基板に対して垂直な方向(本発明の上下方向)になるように実装することができるので、光半導体素子の受発光部を実装面とは反対側に向けて実装することができる。これにより、ダイボンディングやワイヤボンディングによる実装が容易になる。さらに、伝送特性に重要な配線を最短の線路長でつなぐことができ、ノイズが乗りにくく、良好な伝送特性が得られる。また、ボンディングの外観検査が容易であり、接続不良を発見するのが容易になる。
なお、以下の説明において、上下方向に関し、光半導体素子の受発光部が存在する面を基準として、受発光部から遠ざかる方向を上方(例えば図1A~2Cの上方)、受発光部に近づく方向を下方(例えば図1A~2Cの下方)とする。また、前記の定義による上下方向に垂直な方向(例えば図1A~2Cの左右方向)を水平方向とする。本発明における上下方向および水平方向は、図3および図4に示すように透明樹脂31が未硬化で流動性を有する場合を除き、重力の方向に依存しない。
図1Aに、第1形態例に係る光結合構造を備えた光モジュールの一例を示す。
図1Aに示す光モジュール5は、基板4の上面である実装面4aに実装された光半導体素子1と、基板4の実装面4aに沿い、かつ基板4の実装面4aから離間して配置された光伝送路2と、光半導体素子1と光伝送路2との間の光路を変換し、かつ光半導体素子1と光伝送路2との間を光学的に結合する光結合部3とを備えている。光半導体素子1の光軸1bと光伝送路2の光軸2bとは、所定の角度θで互いに交差している。ここで、所定の角度θとは、0°<θ<180°である。
光半導体素子1が発光素子である場合には、「光半導体素子と光伝送路との間の光路を変換する」とは、光半導体素子1から出射した光が光伝送路2に入射するように、該光の光路(すなわち光の進行方向)を変えることを意味する。一方、光半導体素子1が受光素子である場合には、「光半導体素子と光伝送路との間の光路を変換する」とは、光伝送路2から出射した光が光半導体素子1に入射するように、該光の光路(すなわち光の進行方向)を変えることを意味する。なお、上述した特許文献3の光部品接合方法では、両者の光軸が同軸であり、光路の変換を要しない点で、本発明とは前提から相違している。
本形態例では、光半導体素子1の光軸1bの延長線上に光伝送路2の端部2aは位置しない。すなわち、光半導体素子1が発光素子である場合において、光半導体素子1から出射した光が光軸1bに沿って伝送されたときには、当該光が光伝送路2の端部2aに入射しない。光半導体素子1と光伝送路2との位置関係は、光半導体素子1から出射した光が光伝送路2の端部2aに到達するために、所定の光結合部3の存在を必要とする。
かつ、光伝送路2の光軸2bの延長線上に光半導体素子1の受発光部1aは位置しない。すなわち、光半導体素子1が受光素子である場合において、光伝送路2から出射した光が光軸2bに沿って伝送されたときには、当該光が光半導体素子1の受発光部1aに入射しない。光半導体素子1と光伝送路2との位置関係は、光伝送路2から出射した光が光半導体素子1の受発光部1aに到達するために、所定の光結合部3の存在を必要とする。
光半導体素子1が受光素子である場合は、受発光部1aは受光部である。光半導体素子1が発光素子である場合は、受発光部1aは発光部である。
発光素子としては、発光ダイオード(LED)、レーザダイオード(LD)、面発光レーザ(VCSEL)等が挙げられる。
受光素子としては、フォトダイオード(PD)等が挙げられる。
受発光部1aは、光半導体素子1の上面1cに設けられている。本発明における上下方向は、光半導体素子1が基板4に実装される実装面4aを基準とし、基板4から遠ざかる方向を上方(図1A~1Cの上方)、基板4に近づく方向を下方(図1A~1Cの下方)とする。また、前記の定義による上下方向に垂直な方向(図1A~1Cの左右方向)を水平方向とする。本発明における上下方向および水平方向は、図3および図4に示すように透明樹脂31が未硬化で流動性を有する場合を除き、重力の方向に依存しない。
基板4には、例えは、ガラスエポキシ基板、セラミック基板など、一般的な各種絶縁基板を使用することができる。ワイヤ配線7としては、例えば、金(Au)ワイヤ、アルミ(Al)ワイヤ、銅(Cu)ワイヤなどが挙げられる。
光伝送路2は、光結合部3に対する光の出入射の方向が一定となるように、少なくとも端部2a付近では、光軸2bが直線状であることが好ましい。
ここでいう透明樹脂とは、光半導体素子1と光伝送路2との間を伝送する光を透過させることが可能なものを指している。従って、必ずしも可視光下で無色透明な色調のものに限定されるものではない。また、光が伝送する樹脂内の光路長が短いため、ある程度透明性があればよい。
透明樹脂としては、例えば、UV硬化性樹脂や熱硬化性樹脂などを用いることができる。透明樹脂の具体例としては、アクリル系樹脂、エポキシ系樹脂、シリコーン系樹脂等が挙げられる。
なお、上端2cの高さ2dは、基板4の実装面4aを基準とした高さ(実装面4aに垂直な方向の距離)である。
また、光伝送路2の端面2aから光半導体素子1の光軸1bまでの距離xが_30<x<60μmを満たし、かつ光伝送路2の光軸2bから光半導体素子1までの距離yが0<y<20μmを満たすのが好ましい。距離xが60μm以上、距離yが20μm以上となると、特に広がり角の大きい光の場合、光の拡散によって受光部1aで受光されない光の割合が増大する虞がある。距離xが30<x<60μmを満たし、かつ距離yが0<y<20μmを満たすことによって、光の拡散による接続損失の増大を抑制することができる。
一方、光半導体素子1が発光素子の場合には、光半導体素子1から光結合部3に入射した光は、光結合部3を構成する透明樹脂と外部の気体との界面3aとの屈折率差により反射されて光伝送路2に入射する(図1C参照)。この際、光半導体素子1の光軸1bと外面3aとが交差する位置Aにおける外面3aの接線T2に関し、この接線T2と光半導体素子1の上面1cとのなす角φ2が30°<φ2<60°であるのが好ましい。これにより、光半導体素子1から出射する光が一定の広がり角を有する場合であっても、効果的に光を光伝送路2に入射させることができる。その結果、接続損失が増大するのを抑制できる。
また、上記と同様に、距離xが30<x<60μmを満たし、かつ距離yが0<y<20μmを満たすことによって光結合部3内の光路長が短くなるので、光の拡散による接続損失の増大を抑制できる。
光半導体素子1と光結合部3との間、および光伝送路2と光結合部3との間には、屈折率整合剤や間隙による空気などが存在せず、光半導体素子1と光伝送路2との間は、光結合部3を構成する樹脂のみで接続されている。
光結合部3の外面3aが外部の気体との界面を形成しており、光半導体素子1と光伝送路2とが、光結合部3を構成する樹脂自身によって、接着されている。光半導体素子1と光伝送路2とが、光結合部3を構成する樹脂自身によって、繋がることにより、光半導体素子1、光伝送路2、光結合部3以外の部品や接着剤を使用することなく、光半導体素子1、光伝送路2以外の部品との位置関係を調整することなく、光半導体素子1と光伝送路2との位置関係を調整するだけで、低コストで、簡単に、光半導体素子1と光伝送路2との間の光路を変換し、かつ光半導体素子1と光伝送路2とを高効率で光学的に結合することができる。
なお、本明細書において「樹脂自身によって接着されている」とは、光半導体素子と光結合部を構成する樹脂とが、および、光伝送路と光結合部を構成する樹脂とが直接繋がり、光半導体素子と光結合部との間、および光伝送路と光結合部との間に、樹脂等の別の材料(屈折率整合剤や間隙による空気など)が存在しないことを指している。引っ張り力が加わっていない状態(静止状態)で前記の定義による状態をとっていればよく、引っ張りに対する接着力は問わない。
さらに、本発明では、光伝送路2に対し、その先端を曲げるなどの特別な加工を施す必要がなく、低コストで光結合構造を作製することができる。
ここでいう単一の透明樹脂とは、成分(組成)が均一(単一)、特定の波長の光に対する透過率が均一、物理的に2層以上ではない(界面がない)など、いずれの意味も包含する。
この凸形状の外面3aにおいて、(a)受発光部1aに対向する位置Aが受発光部1aとは反対側に凸の形状となっていてもよく、(b)光伝送路2の端部2aに対向する位置Bが光伝送路2の端部2aとは反対側に凸の形状となっていてもよく、(c)受発光部1aに対向する位置Aと光伝送路2の端部2aに対向する位置Bとの間が凸の形状となっていてもよく、あるいは(a)~(c)のうち2つ以上の観点で凸の形状となっていてもよい。
また、図1Aに示す形態例では、光半導体素子1の光軸1bと光伝送路2の光軸2bとが交差する交点Pの位置に光結合部3を構成する樹脂が存在している。なお、光結合部3の外面3aは凸形状である場合であっても、光軸1b,2bの交点Pの位置には前記樹脂が存在せず、樹脂の外面3aが受発光部1aに対向する位置が、交点Pと受発光部1aとの間にあり、かつ、樹脂の外面3aが光伝送路2の端部2aに対向する位置が、交点Pと光伝送路2の端部2aとの間にある形状とすることも可能である。この場合、光結合部3内の光路がより短縮するので好ましい。
本形態例の光結合部3において、光の伝送に関与しない部分、例えば、図1Aにおける光伝送路2の上側にかかっている部分3bや、光伝送路2の下側と光半導体素子1の上面1cとの間に挟まれた部分3cが凸形状になっているのは差し支えない。しかしながら、光結合部3の作製時に、光結合部3を構成する樹脂が、光伝送路2の下側の部分3cから光半導体素子1の端面1sに垂れ落ちることは望ましくない。
なお、この場合において樹脂の接触を避けるべきワイヤ配線7とは、光半導体素子1の上面1cより上方に突出したものである。光半導体素子1の外部配線が光半導体素子1の上面1cおよび側面に沿って平面的に形成されている場合は、必ずしも接触を避ける必要はない。また、ワイヤ配線7に限らず、光半導体素子1の上面1cから大きく突出した構造物が存在する場合は、光結合部を構成する樹脂がこれら構造物と接触するのを避けることが好ましい。
また、図12Aに示すように、光結合部3の形状は、その上方向から見たときに、円形状あるいは楕円形状となっているのが好ましい。さらに、図12B及び12Cに示すように、光結合部3の形状が、その上方向から見たときに、扇形状であるのがより好ましい。
従来のように上方向から見たときに方形状であるミラー(図16に示されている光路変換用ミラー103を上方向から見たときの形状)を用いる場合、光伝送路2から一定の広がり角をもって出射した光を光半導体素子1の受発光部1aに集めることができず、その結果、接続損失が増加してしまう。一方、本形態例では、光結合部3が上方向から見たときに円形状あるいは楕円形状を有するため、光の出射部(光伝送路2の端面2a)から光結合部3の外面3aまでの距離及び外面3aから受発光部1aまでの距離(すなわち、光結合部3内の光路長)がより短くなり、かつ出射した光が受発光部1aに集まるように外面3aにて反射される。したがって光半導体素子1と光伝送路2との間の接続損失をより抑えることができる。
さらに、上方向から見たとき光結合部3の形状を扇形状とした場合では、円形状や楕円形状の場合に比べて、光路長をより短くすることができるため、さらなる接続損失の低下が図れる。
さらに、光結合部14を構成する透明樹脂は、光伝送路2の光軸2bと光半導体素子1の光軸1bとが交差する交点Pの位置には存在せず、かつ光結合部14の外面14a(光結合部14と外部の気体との界面)が、光半導体素子1の受発光部1aおよび光伝送路2の端部2aの側に凹んだ形状となっていることが好ましい。
(1)受発光部1aに対向する位置Aが受発光部1a側に凹んだ形状の凹面部11、
(2)光伝送路2の端部2aに対向する位置Bが光伝送路2の端部2a側に凹んだ形状の凹面部12、
(3)受発光部1aに対向する位置Aと光伝送路2の端部2aに対向する位置Bとの間が凹んだ形状の凹面部13、
を有することを必要とする。
さらに、光半導体素子1が受光素子の場合には、光伝送路2の光軸2bと外面14aとが交差する位置Bにおける外面14aの接線T3に関し、この接線T3と光半導体素子1の上面1cとのなす角φ3が30°<φ3<60°であるのが好ましい(図2B参照)。これにより、効果的に光を受光素子に集光でき、接続損失が増大するのを抑制できる。
また、光伝送路2の端面2aから光半導体素子1の光軸1bまでの距離xが30<x<60μmを満たし、かつ光伝送路2の光軸2bから光半導体素子1までの距離yが0<y<20μmを満たすのが好ましい。距離xが60μm以上、距離yが20μm以上となると、特に広がり角の大きい光の場合、光の拡散によって受光部1aで受光されない光の割合が増大する虞がある。距離xが30<x<60μmを満たし、かつ距離yが0<y<20μmを満たすことによって、光の拡散による接続損失の増大を抑制することができる。
一方、光半導体素子1が発光素子の場合には、発光素子の光軸1bと外面14aとが交差する位置Aにおける外面14aの接線T4に関し、この接線T4と光半導体素子1の上面1cとのなす角φ4が30°<φ4<60°であるのが好ましい(図2C参照)。これにより、光半導体素子1からの出射光を効果的に光伝送路2(光伝送路2が光ファイバである場合には、例えばそのコア)に集光でき、接続損失が増大するのを抑制できる。また、上記と同様に、光伝送路2の端面2aから光半導体素子1の光軸1bまでの距離xが30<x<60μmを満たし、かつ光伝送路2の光軸2bから光半導体素子1までの距離yが0<y<20μmを満たすのが好ましい。上記と同様な効果が得られる。
光の伝送に関与しない部分、例えば、図2Aにおける光伝送路2の上側にかかっている部分14bや、光伝送路2の下側と光半導体素子1の上面1cとの間に挟まれた部分14cが凸形状になっているのは差し支えない。また、図6に示す光モジュール15Aのように、光伝送路2の上側にかかっている部分14bがなく、光伝送路2の端部2aの一部が光結合部14Aの外側に露出されてもよい。
また、(2)の光伝送路2側の凹面部12は、例えば、光伝送路2の光軸2bが樹脂の外面14aと交差する位置Bの近傍において、樹脂の外面14aが樹脂側に凹となる凹面を形成していればよい。
また、(3)の中間部の凹面部13は、例えば、光半導体素子1の光軸1bが樹脂の外面14aと交差する位置Aと、光伝送路2の光軸2bが樹脂の外面14aと交差する位置Bとの間を結ぶ線分ABがA-B間で樹脂の外側(外部の気体側)を通り、樹脂の外面14aが凹となる凹面を形成していればよい。
また、光結合部14を構成する樹脂が、光半導体素子1の上面1cの上方向から見たときに、上面1c内に配置されていることにより、型などを使用することなく、樹脂の広がりなどを制御しやすく、該樹脂からなる光結合部14の形状を安定して作製することができる。
また、光結合部14を構成する樹脂が、光半導体素子1の上面にワイヤボンディングしている給電用配線7と接触しないことにより、光結合部14の樹脂形状にばらつきが生じにくく、本形態例の光接続構造を製造することができる。
また、光伝送路2の端面2aが、光半導体素子1を側面方向および上方向から見たときに、光半導体素子1の端面1sより光半導体素子1の内側に存在することにより、光結合部14内の光路長を短くすることができる。さらに、光結合部14をその上方向から見たときに、この光結合部14が円形状、楕円形状、あるいは扇形状のいずれかであるのが好ましい。凸形状について述べたのと同様の効果が得られる。
また、光結合部14の外面14aが凹んだ形状となっていることにより、図7に示すように、光伝送路2から出射し、光結合部14の外面14aで反射した光10を、光半導体素子1の受発光部1aに受光させる際、光結合部14の外面14aにおける反射位置を光半導体素子1および光伝送路2に近づけ、光結合部14内の光路長を短くすることができる。その結果、接続損失が増大することなく、安定した光接続を構築できる。
光半導体素子1が発光素子であって、光半導体素子1の受発光部1aから出射した光10を光結合部14の外面14aで反射させ、光伝送路2に入射させる場合も同様である。
図8に示すように、光結合部3の外面3aが凸形状となっていると、光10が光結合部3の外面3aで反射する位置が遠くなり、光結合部3内の光路長が長くなることによって、特に広がり角の大きい光が出射される場合では、光が拡散し、接続損失が増大することがある。
図9に示すように、45°ミラーとして機能するように樹脂300を形成した場合、その反射面301の位置が遠く、光路が長いため、光10が広がってしまい、接続損失が大きくなってしまう。
図10に示すように、45°ミラーとなる樹脂310が大きく、光伝送路2の端面2aの上端2cの高さ2dを超える程度となると、端面2aから反射面311までの距離および光10の光路がさらに長くなる。
これら図2Aに示す凹面部11~13のうち、それぞれ光半導体素子1の受発光部1aおよび光伝送路2の端部2aの位置に近い部位が、透明樹脂の界面14aにおける反射によって光半導体素子1と光伝送路2との間を光結合するので、光が拡散する範囲が狭くなり、損失を低減することができる。このため、光結合部14は、光半導体素子1の光軸1bと光伝送路2の光軸2bとが交差する交点Pの位置には前記樹脂が存在せず、樹脂の外面14aが受発光部1aに対向する位置Aが交点Pと受発光部1aとの間にあり、かつ、樹脂の外面14aが光伝送路2の端部2aに対向する位置Bが交点Pと光伝送路2の端部2aとの間にあることが好ましい。
同様に、光結合部が、上方向から見て光半導体素子1の上面1c内に配置されていないと、光結合部を作製する際に光結合部をなす樹脂が拡がりやすく、光が光結合部の外面で反射する位置が遠くなりやすい。この結果、光結合部内の光路長が長くなることによって、光が拡散し、接続損失が増大しやすい。さらに樹脂の拡がり方が安定しづらいため、製造上大きなばらつきが生じる。
すなわち、本形態例の光結合部3,14は、光半導体素子1と光伝送路2とが光結合部3,14を構成する樹脂自身によって繋がる(一体となる)ことに加え、光結合部3,14が光半導体素子1の上面1c内に配置されていること、光結合部3,14が光半導体素子1の上面にワイヤボンディングしている給電用配線7と接触しないこと、および光結合部3,14の周囲が気体で覆われること、およびさらに好ましくは光結合部14の外面14aが凹んだ形状になっていることにより、透明樹脂の界面の形状について、反射面としての位置および角度を精密に制御しなくても、より低い作製精度で高効率な光結合を安定して実現することができる。
図3に示すように、予め実装面4aに回路配線6が形成され、光半導体素子1が実装された基板4を用意する。そして、光半導体素子1の受発光部1aに対して、精密ディスペンサ等の樹脂ディップ装置29を用いて、未硬化の透明樹脂31を塗布する。
透明樹脂31は、光半導体素子1の上面1cに収まる範囲内で塗布することが望ましい。この時、透明樹脂31が給電配線7と接触しないように、給電配線から離間して透明樹脂31を塗布する。
そして、透明樹脂31に差し込んだ光伝送路2を光半導体素子1から遠ざけるように移動する。このとき、光伝送路2は、光半導体素子1からゆっくりと斜め上方向(矢印Rの方向)に引き上げる。
なお、光結合部3,14の形成方法は、上記方法に限定されるものではない。例えば、光半導体素子1の上方に光伝送路2の先端を配置し、さらに光伝送路2の先端および光半導体素子1の受発光部1aを覆うように透明樹脂31を盛り付け、透明樹脂31中の光伝送路2の先端を斜め方向に引き上げた後、透明樹脂31を硬化させるという手順でもよい。つまり、透明樹脂31中の光伝送路2の先端を斜め方向に引き上げて光結合部3,14を形成するためには、光半導体素子1の上に光伝送路2の先端を配置する工程と、透明樹脂31を配置する工程の順序が上述の方法と逆でも構わない。
この場合、上記(C)の条件の代わりに、(C′)の条件:「透明樹脂31の塗布量や、引き上げ前の光伝送路2の位置および引き上げ量などの実装条件」が採用され、(A)、(B)、(C′)の条件が同じであれば、自ずと透明樹脂31の形状は同じになる。また、手順が相違すると、光伝送路2のR方向への引き上げ量の最適値も変わる可能性があるため、当該最適値は、実際と同じ手順で実験をして調べることが望ましい。
本形態例の光モジュールの製造方法は、透明樹脂を基板に付着させる必要がないので、光結合部3,14の形成に際して、基板4の加工工程(V溝や段差など)を追加する必要がない。このため、シリコン基板のように面異方性エッチングが利用可能な基板に限らず、ガラスエポキシ基板等のように加工性の低い基板であっても、低コストに基板作製が可能である。
クラッド樹脂層8は、光結合部3,14を構成する透明樹脂よりも屈折率の低い樹脂で形成されているので、光結合部3,14の中を伝送する光がクラッド樹脂層8の方に入射し散乱してしまうことを抑制することができる。さらに、クラッド樹脂層8の周囲を、光結合部3,14よりも高い屈折率を有する樹脂(図示せず)で封止することも可能になる。
クラッド樹脂層8は、図3および図4に示すようにして光結合部3,14を形成した後に、第2の樹脂を塗布して硬化することにより形成する。
光結合部3,14を構成する第1の樹脂は、光半導体素子1と光伝送路2とが、光結合部3,14を構成する第1の樹脂自身によって繋がる(一体となる)ことにより、低コストで、簡単に、光半導体素子1と光伝送路2との間の光路を変換し、かつ光半導体素子1と光伝送路2とを高効率で光学的に結合することができる。
また、光結合部3,14を構成する第1の樹脂が、上方向から見て光半導体素子1の上面1c内に配置されていることにより、型などを使用することなく、第1の樹脂の広がりなどを制御しやすく、第1の樹脂からなる光結合部3,14の形状を安定して作製することができる。
また、光結合部3,14を構成する樹脂が、光半導体素子1の上面にワイヤボンディングしている給電用配線7と接触しないことにより、光結合部3,14の樹脂形状にばらつきが生じにくく、製造することができる。
また、光伝送路2の端面2aが光半導体素子1の内側に配置されることにより、光結合部3,14内の光路長を短くすることができる。
また、上述した第1形態例の光結合部14と同様に、光結合部14とクラッド樹脂層8との界面14aが凹んだ形状となっていることが好ましい。なお、光伝送路2と光半導体素子1とを一定距離以上離して配置する必要がある場合や、出射光の広がり角が比較的小さいような場合等には、上述した第1形態例の光結合部3と同様に、光結合部とクラッド樹脂層8との界面を凸形状とすれば、第1形態例の光結合部3で得られるのと同様の効果が得られる。
ワイヤ配線7はクラッド樹脂層8に覆われ、保護されているので、外部の応力によって破損しやすいワイヤ配線7(給電用配線)の断線を防止することができる。
光伝送路2の端部2a、光結合部3,14、および光半導体素子1がクラッド樹脂層8により覆われているので、外部の応力からこれらを保護することができる。すなわち、光半導体素子1と光伝送路2との光結合構造全体の機械的強度を高くすることができる。
このように、クラッド樹脂層8がワイヤ配線7の保護層、あるいは光結合構造の保護層として機能するように設けられた場合、簡便にこれら保護層としてのクラッド樹脂層8を形成することができる。
第1の光半導体素子51a、第1の光伝送路52aおよび第1の光結合部53aが第1の光結合構造を構成し、第2の光半導体素子51b、第2の光伝送路52bおよび第2の光結合部53bが第2の光結合構造を構成している。
具体的には、光結合部53a,53bは、伝送される光に対して透明な樹脂からなり、第1の樹脂は、光半導体素子51a,51bの受発光部の少なくとも一部および光伝送路52a,52bの端部の少なくとも一部にそれぞれ密着し、光半導体素子51aと光伝送路52a、および光半導体素子51bと光伝送路52bとが、光結合部53a,53bを構成する第1の樹脂自身によって直接繋がっている。
さらに、光結合部53a,53bを構成する第1の樹脂が、上方向から見たときに光半導体素子51a,51bの上面内に配置されていること、光結合部53a,53bを構成する樹脂が、光半導体素子51a,51bの上面にワイヤボンディングしている給電用配線57a,57bと接触しないこと、および光伝送路52a,52bの端面が光半導体素子51a,51b上に存在することが好ましい。また、光結合部53a,53bの外面(またはクラッド樹脂層59との界面)が凸形状でもよいし、凹んだ形状であってもよい。なお、図示例では光結合部53a,53bの外面が凹んだ形状である。または、クラッド樹脂層59を省略して、光結合部53a,53bの周囲が気体で覆われる構成としてもよい。
これにより、第1の光伝送路52aから受光素子である第1の光半導体素子51aへの光結合においても、発光素子である第2の光半導体素子51bから第2の光伝送路52bへの光結合においても、低コストに、かつ簡易な工程で光結合構造を作製することが可能である。
共通する被覆材58で一体化された複数の光伝送路52a,52bとしては、光ファイバテープ心線や基板型光導波路などを用いることができる。被覆材58は、光伝送路52a,52bを伝送される光に対して不透明であってもよい。
クラッド樹脂層59は、光結合部53a,53bを構成する透明樹脂よりも屈折率の低い樹脂で形成されているので、光結合部53a,53bの中を伝送する光がクラッド樹脂層59の方に入射し散乱してしまうことを抑制することができる。さらに、クラッド樹脂層59の周囲を、光結合部53a,53bよりも高い屈折率を有する樹脂(図示せず)で封止することも可能になる。
また、ワイヤ配線57a,57bはクラッド樹脂層59に覆われ、保護されているので、外部の応力によって破損しやすいワイヤ配線57a,57b(給電用配線)の断線を防止することができる。
また、光伝送路52a,52bの端部、光結合部53a,53b、および光半導体素子51a,51bがクラッド樹脂層59により覆われているので、外部の応力から保護することができる。したがって、光結合構造全体の機械的強度を高くすることができる。
クラッド樹脂層59は、複数ある光結合部53a,53bのうち、一部の光結合部の周囲のみを覆うようにすることも可能である。
図1A~4に示すように、光伝送路2としてクラッド径が125μm、コア径が50μmの石英系マルチモード光ファイバを用意した。光半導体素子1には、受光素子としてPD(受光部の開口径は80μm)を、発光素子としてVCSEL(発光部の開口径は12μm)を、透明樹脂31にはUV硬化樹脂(アクリル系樹脂)を、基板4にはガラスエポキシ基板を、ワイヤ配線7には金ワイヤを用いた。光半導体素子1の受発光部1a(PDの受光部またはVCSELの発光部)の上に透明樹脂31を2nl(ナノリットル)塗布した後、この透明樹脂に光ファイバの先端を差し込んで、斜め30°上方に引上げ距離が40μmになるように光ファイバを引き上げた。この後、UVを透明樹脂に照射してこの透明樹脂31を硬化させることにより、図1A~2Cに示す光結合構造5,15を作製した。光結合部3,14を構成する硬化後の樹脂の屈折率は1.58である。
光ファイバを引き上げてからUVを照射するまでの時間は、各透明樹脂を使用した場合に接続損失が良好となる時間とした。従って、その時間は、使用した透明樹脂により異なる。その結果を表1に示す。
また、各モジュールの光結合部を上方向からみた場合の形状は、サンプルDを用いたものでは図12Cに示したような扇形状、サンプルHを用いたものでは図12Cに示したような扇形状、サンプルKを用いたものでは楕円形状であった。
光ファイバを引き上げてからUVを照射するまでの時間を統一して光結合部を作製し、得られた光結合部の形状を観測した。光ファイバを引き上げてからUVを照射するまでの時間を3秒に統一した場合を表3に、光ファイバを引き上げてからUVを照射するまでの時間を2分に統一した場合を表4に示す。
また、各モジュールの光結合部を上方向からみた場合の形状は、サンプルDを用いたものでは図12Cに示したような扇形状、サンプルHを用いたものでは図12Cに示したような扇形状、サンプルKを用いたものでは楕円形状であった。
光ファイバを引き上げてからUVを照射するまでの時間を3秒に統一した場合を表5に、光ファイバを引き上げてからUVを照射するまでの時間を2分に統一した場合を表6に示す。
また、光結合部がワイヤに接触しない場合、接続損失が非常に小さいものとなった。
また、光結合部の形状が凹形状の場合、凸形状の場合に比べて接続損失が非常に小さいものとなった。
φ1~4 接線T1~4と光半導体素子の上面とが成す角度
x 光伝送路の端面から光半導体素子の光軸までの距離
y 光伝送路の光軸から光半導体素子までの距離
θ 光軸同士の成す角度
P 光軸同士の交点
1,51a,51b 光半導体素子
1a 受発光部
1b 光半導体素子の光軸
1c 上面(表面)
1d 下面(裏面)
1s 光半導体素子の端面
2,52a,52b 光伝送路
2a 光伝送路の端部(端面)
2b 光伝送路の光軸
3,3A,14,14A,16,53a,53b 光結合部
3a,14a,16a 光結合部の外面(界面)
4,54 基板
4a,54a 基板の実装面
5,5A,15,15A 光モジュール
7,57a,57b ワイヤ配線(給電用配線)
8,59 クラッド樹脂層
9,19 光モジュール
50 光送受信モジュール
Claims (15)
- 上面に受発光部を有し、かつ下面の側で基板に実装された光半導体素子と、
前記光半導体素子の光軸に対して所定の角度で交差する光軸を有し、かつ前記基板の実装面から離間して配置された光伝送路と、
前記光半導体素子と前記光伝送路との間の光路を変換し、かつ前記光半導体素子と前記光伝送路との間を光学的に結合する光結合部とを備え、
前記光結合部は、伝送される光に対して透明な樹脂からなり、前記樹脂は、前記光半導体素子の受発光部の少なくとも一部および前記光伝送路の端部の少なくとも一部にそれぞれ密着し、
前記光半導体素子と前記光伝送路とが、前記光結合部を構成する前記樹脂自身によって、接着されていることを特徴とする光結合構造。 - 前記光結合部を構成する前記樹脂は、前記光半導体素子の前記上面内に配置されていることを特徴とする請求項1に記載の光結合構造。
- 前記樹脂は、前記光半導体素子の前記上面にワイヤボンディングしている給電用配線から離間して配置されていることを特徴とする請求項1に記載の光結合構造。
- 前記光伝送路の端面は、前記光半導体素子を側面方向および上方向から見たときに、前記光半導体素子の端面より前記光半導体素子の内側に存在することを特徴とする請求項1に記載の光結合構造。
- 前記光結合部を構成する前記樹脂の外面が、前記光半導体素子の受発光部および前記光伝送路の端部の側に凹んだ形状となっていることを特徴とする請求項1に記載の光結合構造。
- 前記光結合部を構成する前記樹脂の外面が凸形状となっていることを特徴とする請求項1に記載の光結合構造。
- 前記光結合部をなす前記樹脂は、前記光半導体素子の光軸と前記光伝送路の光軸とが交差する交点の位置に存在せず、
前記樹脂の外面が前記受発光部に対向する位置が、前記交点と前記受発光部との間にあり、かつ、前記樹脂の外面が前記光伝送路の端部に対向する位置が、前記交点と前記光伝送路の端部との間にあることを特徴とする請求項1~6のいずれかに記載の光結合構造。 - 前記光結合部を構成する前記樹脂は、前記光伝送路の端面の上端の高さより下側に配置されていることを特徴とする請求項1~7のいずれかに記載の光結合構造。
- 前記光結合部の形状が、前記光結合部を上方向から見たときに、円形状、楕円形状、または扇形状のいずれかであることを特徴とする請求項1~8のいずれかに記載の光結合構造。
- 前記光結合部の周囲が気体で覆われていることを特徴とする請求項1~8のいずれかに記載の光結合構造。
- 前記光結合部の周囲が、光結合部を構成する樹脂より屈折率が低いクラッド樹脂層で覆われていることを特徴とする請求項1~8のいずれかに記載の光結合構造。
- 前記光半導体素子の給電用配線が前記クラッド樹脂層によって覆われていることを特徴とする請求項11に記載の光結合構造。
- 同一の基板の実装面に実装された受光素子および発光素子と、前記基板の前記実装面から離間して配置された第1の光伝送路および第2の光伝送路と、前記受光素子と第1の光伝送路との間を光学的に結合する第1の光結合部と、前記発光素子と第2の光伝送路との間を光学的に結合する第2の光結合部とを備え、前記受光素子、第1の光伝送路および第1の光結合部が第1の光結合構造を構成するとともに、前記発光素子、第2の光伝送路および第2の光結合部が第2の光結合構造を構成した光送受信モジュールであって、
第1の光結合構造および第2の光結合構造の一方または両方が、請求項1~12のいずれかに記載の光結合構造を構成していることを特徴とする光送受信モジュール。 - 請求項1~12のいずれかに記載の光結合構造の製造方法であって、
基板に設けられた光半導体素子の受発光部に樹脂を塗布する工程と、
前記基板に対して平行に、光伝送路を前記樹脂に差し込む工程と、
前記光伝送路を前記半導体素子から遠ざける方向で、かつ斜め上方に移動させる工程と、
前記樹脂を硬化させて光結合部とする工程と、
を備え、
予め求めておいた前記樹脂の塗布量、前記樹脂の粘度、前記光伝送路の差し込み量、前記光伝送路の斜め上方への移動量、及び前記樹脂を硬化させるまでの時間の相関関係に基づいて、前記光結合部の形状を凸形状にするのか又は凹み形状にするのかを制御することを特徴とする光結合構造の製造方法。 - 前記光半導体素子の上面にワイヤボンディングしている給電用配線から離間して、前記樹脂を前記受発光部に塗布することを特徴とする請求項14に記載の光結合構造の製造方法。
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JP2019159114A (ja) * | 2018-03-13 | 2019-09-19 | 株式会社フジクラ | 光モジュールの製造方法、及び、光モジュール |
JP2019159112A (ja) * | 2018-03-13 | 2019-09-19 | 株式会社フジクラ | 光モジュールの製造方法、及び、光モジュール |
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Also Published As
Publication number | Publication date |
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EP3190439A1 (en) | 2017-07-12 |
EP2523029B1 (en) | 2017-02-15 |
EP2523029A1 (en) | 2012-11-14 |
JPWO2011083812A1 (ja) | 2013-05-13 |
CN102687050A (zh) | 2012-09-19 |
EP3428702A1 (en) | 2019-01-16 |
JP5265025B2 (ja) | 2013-08-14 |
CN102687050B (zh) | 2015-09-02 |
EP2523029A4 (en) | 2015-12-23 |
EP3428702B1 (en) | 2020-02-19 |
US8909010B2 (en) | 2014-12-09 |
EP3190439B1 (en) | 2018-08-29 |
US20120275747A1 (en) | 2012-11-01 |
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