JP2012078606A - Optical waveguide, manufacturing method of optical waveguide, optical waveguide module and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical waveguide with reduced optical coupling loss in optical coupling with a light-emitting device and enabling high quality optical communication, to provide a method of efficiently manufacturing the optical waveguide, and to provide an optical waveguide module and electronic equipment which include the optical waveguide and enable high quality optical communication.SOLUTION: An optical waveguide module 10 includes an optical waveguide 1 in which a mirror 16 is formed, a circuit board 2 provided above the optical waveguide 1, and a light-emitting device 3 mounted on the circuit board 2. The optical waveguide 1 has a clad layer 11, a core layer 13, and a clad layer 12, which are laminated in this order from the bottom. On a top surface of the clad layer 12, a rugged pattern 100 is formed by arranging a plurality of recesses locally-recessing the top surface at an area on an optical path connecting between the mirror 16 and the light-emitting device 3. The rugged pattern 100 provides an antireflection function of light to the surface of the optical waveguide 1.

Description

  The present invention relates to an optical waveguide, an optical waveguide manufacturing method, an optical waveguide module, and an electronic device.

  In recent years, with the wave of computerization, wideband lines (broadband) capable of communicating a large amount of information at high speed have been spreading. Also, as devices for transmitting information to these broadband lines, transmission devices such as router devices and WDM (Wavelength Division Multiplexing) devices are used. In these transmission apparatuses, a large number of signal processing boards in which arithmetic elements such as LSIs and storage elements such as memories are combined are installed, and each line is interconnected.

  Each signal processing board has a circuit in which arithmetic elements, storage elements, etc. are connected by electrical wiring. However, with the increase in the amount of information to be processed in recent years, each board has a very high throughput. It is required to transmit. However, with the speeding up of information transmission, problems such as generation of crosstalk and high frequency noise and deterioration of electric signals are becoming apparent. For this reason, electrical wiring becomes a bottleneck, making it difficult to improve the throughput of the signal processing board. Similar problems are also becoming apparent in supercomputers and large-scale servers.

  On the other hand, an optical communication technique for transferring data using an optical carrier wave has been developed, and in recent years, an optical waveguide is becoming popular as a means for guiding the optical carrier wave from one point to another point. This optical waveguide has a linear core part and a clad part provided so as to cover the periphery thereof. The core part is made of a material that is substantially transparent to the light of the optical carrier wave, and the cladding part is made of a material having a refractive index lower than that of the core part.

  In the optical waveguide, light introduced from one end of the core portion is conveyed to the other end while being reflected at the boundary with the cladding portion. A light emitting element such as a semiconductor laser is disposed on the incident side of the optical waveguide, and a light receiving element such as a photodiode is disposed on the emission side. Light incident from the light emitting element propagates through the optical waveguide, is received by the light receiving element, and performs communication based on the flickering pattern of the received light or its intensity pattern.

  If the electrical wiring in the signal processing board is replaced by such an optical waveguide, it is expected that the problem of the electrical wiring as described above will be solved and the signal processing board can be further increased in throughput.

  By the way, when replacing electric wiring with an optical waveguide, a light emitting element and a light receiving element are provided in order to perform mutual conversion between an electric signal and an optical signal, and an optical waveguide formed by optically connecting the light emitting element and the light receiving element therebetween. A waveguide module is used.

  For example, Patent Document 1 discloses an optical interface having a printed circuit board, a light emitting element mounted on the printed circuit board, and an optical waveguide provided on the lower surface side of the printed circuit board. The optical waveguide and the light emitting element are optically connected through a through hole, which is a through hole for transmitting an optical signal, formed on the printed board.

  However, the optical interface as described above has a problem that the optical coupling loss is large in the optical coupling between the light emitting element and the optical waveguide. Specifically, when the signal light emitted from the light emitting portion of the light emitting element passes through the through hole and enters the optical waveguide, a part of the signal light is reflected at the interface between the through hole and the optical waveguide. This reflection causes attenuation of the signal light incident on the optical waveguide, and the reflected light returns to the light emitting portion, thereby impairing the light emission stability of the light emitting element.

JP 2005-294407 A

  An object of the present invention is to provide an optical waveguide with small optical coupling loss when optically coupled to a light emitting element and capable of high-quality optical communication, an optical waveguide manufacturing method capable of efficiently manufacturing such an optical waveguide, and An object of the present invention is to provide an optical waveguide module and an electronic device that include an optical waveguide and are capable of high-quality optical communication.

Such an object is achieved by the present inventions (1) to (14) below.
(1) the core part;
A clad portion provided so as to cover a side surface of the core portion;
An optical path conversion unit that is provided in the middle of the core unit or on an extension line, and converts the optical path of the core unit to the outside of the cladding unit,
Of the surface of the clad portion, provided at least at a site optically connected to the core portion via the optical path changing portion, the convex portion projecting the surface locally or locally dented An optical waveguide comprising: a concave / convex pattern formed by arranging a plurality of concave portions.

  (2) The optical waveguide according to (1), wherein the convex portions and the concave portions are regularly arranged at regular intervals.

  (3) The optical waveguide according to (2), wherein an arrangement cycle between the convex portions and an arrangement cycle between the concave portions in the concavo-convex pattern are equal to or less than a wavelength of signal light incident on the optical waveguide.

  (4) The light according to any one of (1) to (3), wherein a height of the convex portion and a depth of the concave portion in the concave / convex pattern are equal to or less than a wavelength of signal light incident on the optical waveguide. Waveguide.

  (5) The optical waveguide according to any one of (1) to (4), wherein the convex portion and the concave portion have a columnar shape, a conical shape, a hemispherical shape, or a shape conforming thereto.

  (6) The shape of the said convex part and the said recessed part is an optical waveguide in any one of said (1) thru | or (4) which is a protruding item | line or a concave item.

  (7) The optical waveguide according to any one of (1) to (6), wherein the optical path conversion unit includes a reflective surface provided so as to obliquely cross at least the core unit.

(8) the core part;
A clad portion provided so as to cover a side surface of the core portion;
An optical path conversion unit that is provided in the middle of the core unit or on an extension line, and converts the optical path of the core unit to the outside of the cladding unit,
Of the surface of the cladding part, provided at least at a site optically connected to the core part by the optical path changing part, a convex part that locally protrudes the surface or a concave part that is locally recessed A method of manufacturing an optical waveguide having a plurality of concave and convex patterns,
Preparing a base material having the core part, the clad part, and the optical path changing part;
A method of manufacturing an optical waveguide, comprising: pressing a molding die against the surface of the base material to locally protrude or dent a part of the surface to form the concavo-convex pattern. .

  (9) The method for manufacturing an optical waveguide according to (8), wherein the uneven pattern is formed by pressing the heated mold against the surface of the base material and then cooling the mold.

(10) A core layer comprising a core part, and a side clad part provided adjacent to a side surface of the core part;
A first cladding layer and a second cladding layer provided adjacent to both surfaces of the core layer;
An optical path conversion unit that is provided in the middle or on an extension line of the core unit and converts the optical path of the core unit to the outside of the second cladding layer,
Of the surface of the second clad layer, provided at least at a site optically connected to the core portion by the optical path changing portion, the convex portion protruding locally or the local depression of the surface A method of manufacturing an optical waveguide having a concavo-convex pattern formed by arranging a plurality of recesses,
Forming the first cladding layer;
Forming the core layer on the formed first cladding layer;
Applying a clad layer-forming composition on the core layer to form a liquid film;
Forming the concave / convex pattern and forming the second cladding layer by curing the liquid coating or the semi-cured product thereof while pressing a mold on the liquid coating or the semi-cured product thereof. An optical waveguide manufacturing method characterized by the above.

(11) A core layer comprising: a core portion; and a side clad portion provided adjacent to a side surface of the core portion;
A first cladding layer and a second cladding layer provided adjacent to both surfaces of the core layer;
An optical path conversion unit that is provided in the middle or on an extension line of the core unit and converts the optical path of the core unit to the outside of the second cladding layer,
Of the surface of the second clad layer, provided at least at a site optically connected to the core portion by the optical path changing portion, the convex portion protruding locally or the local depression of the surface A method of manufacturing an optical waveguide having a concavo-convex pattern formed by arranging a plurality of recesses,
Applying the composition for forming a cladding layer on a mold, forming a liquid film or a semi-cured product of the liquid film, and then curing to obtain the second cladding layer having the concavo-convex pattern formed thereon;
Forming the core layer on the formed second cladding layer;
And a step of forming the first cladding layer on the core layer.

(12) The optical waveguide according to any one of (1) to (7) above,
An optical waveguide module comprising: an optical element optically connected to the core portion through the optical path changing portion and the concave / convex pattern.

  (13) The optical waveguide module according to (12), further including a condenser lens provided between the uneven pattern and the optical element.

  (14) An electronic apparatus comprising the optical waveguide module according to (12) or (13).

  According to the present invention, since the concave / convex pattern is provided, the optical coupling loss when optically coupled to the light emitting element can be reduced, so that the optical carrier has a high S / N ratio and enables high-quality optical communication. An optical waveguide can be obtained.

Further, according to the present invention, such an optical waveguide can be efficiently manufactured.
Further, according to the present invention, by providing such an optical waveguide, an optical waveguide module and an electronic device capable of high-quality optical communication can be obtained.

It is a perspective view which shows 1st Embodiment of the optical waveguide module of this invention. It is the sectional view on the AA line of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is a longitudinal cross-sectional view which shows the other structural example of the optical waveguide module shown in FIG. It is the elements on larger scale which take out and show an optical waveguide among optical waveguide modules shown in FIG. It is a perspective view which shows an example of the shape of a recessed part or a convex part. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the optical waveguide module of this invention. It is a longitudinal cross-sectional view which shows 3rd Embodiment of the optical waveguide module of this invention. It is a figure which shows 4th Embodiment of the optical waveguide module of this invention, Comprising: It is the perspective view (it shows partially permeate | transmitting) which took out only the optical waveguide and reversed it upside down. It is a figure (longitudinal sectional view) for demonstrating the 1st method of manufacturing the optical waveguide module shown in FIG. It is a figure (longitudinal sectional view) for demonstrating the 2nd method of manufacturing the optical waveguide module shown in FIG. It is a figure (longitudinal sectional view) for demonstrating the 3rd method of manufacturing the optical waveguide module shown in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an optical waveguide, an optical waveguide manufacturing method, an optical waveguide module, and an electronic device according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

<Optical waveguide module>
<< First Embodiment >>
First, the optical waveguide of the present invention and the first embodiment of the optical waveguide module of the present invention including the optical waveguide will be described.

  1 is a perspective view showing a first embodiment of the optical waveguide module of the present invention, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. In the following description, the upper side of FIGS. 2 and 3 is referred to as “upper” and the lower side is referred to as “lower”. In each figure, the thickness direction is emphasized.

  An optical waveguide module 10 shown in FIG. 1 includes an optical waveguide 1, a circuit board 2 provided above the optical waveguide 1, and a light emitting element 3 (optical element) mounted on the circuit board 2.

  The optical waveguide 1 has a long band shape, and the circuit board 2 and the light emitting element 3 are provided at one end of the optical waveguide 1 (the left end in FIG. 2).

  The light emitting element 3 is an element that converts an electrical signal into an optical signal, emits the optical signal from the light emitting unit 31, and enters the optical waveguide 1. The light emitting element 3 shown in FIG. 2 has a light emitting part 31 provided on the lower surface thereof, and an electrode 32 for energizing the light emitting part 31. The light emitting unit 31 emits an optical signal downward in FIG. Note that the arrows shown in FIG. 2 are examples of the optical path of the signal light emitted from the light emitting element 3.

  On the other hand, a mirror (optical path conversion unit) 16 is provided corresponding to the position of the light emitting element 3 in the optical waveguide 1. The mirror 16 converts the optical path of the optical waveguide 1 extending in the left-right direction in FIG. 2 to the outside of the optical waveguide 1. In FIG. 2, the mirror 16 is optically connected to the light emitting portion 31 of the light emitting element 3. The optical path is converted by 90 °. By passing through such a mirror 16, the signal light emitted from the light emitting element 3 can be made incident on the optical waveguide 1. Although not shown, a light receiving element is provided at the other end of the optical waveguide 1. This light receiving element is also optically connected to the optical waveguide 1, and the signal light incident on the optical waveguide 1 reaches the light receiving element. As a result, optical communication is possible in the optical waveguide module 10.

  Here, a portion of the surface of the optical waveguide 1 through which the optical path that connects the mirror 16 and the light emitting unit 31 passes is provided with a convex portion that locally protrudes the surface or a concave portion that is locally recessed. A concavo-convex pattern 100 formed by arranging a plurality at intervals is formed (see FIG. 3). The concavo-convex pattern 100 can suppress reflection of signal light incident on the optical waveguide 1 from the light emitting unit 31 and can relatively increase the incident efficiency. As a result, the optical coupling efficiency between the light emitting element 3 and the optical waveguide 1 is improved.

Hereinafter, each part of the optical waveguide module 10 will be described in detail.
(Optical waveguide)
An optical waveguide 1 shown in FIG. 1 is configured by a belt-like laminate in which a clad layer (first clad layer) 11, a core layer 13, and a clad layer (second clad layer) 12 are laminated in this order from below. The Among these, as shown in FIG. 1, the core layer 13 is formed with a single core portion 14 that is linear in a plan view, and a side cladding portion 15 that is adjacent to the side surface of the core portion 14. The core part 14 is extended | stretched along the longitudinal direction of a strip | belt-shaped laminated body, and is located in the approximate center of the width | variety of a laminated body. In FIG. 1, the core portion 14 is provided with dots.

  In the optical waveguide 1 shown in FIG. 2, the light incident through the mirror 16 is totally reflected at the interface between the core portion 14 and the clad portion (each clad layer 11, 12 and each side clad portion 15). It can be propagated to the end. Thereby, optical communication can be performed based on at least one of the blinking pattern of light received at the emitting end and the intensity pattern of light.

  In order to cause total reflection at the interface between the core part 14 and the clad part, a difference in refractive index needs to exist at the interface. Although the refractive index of the core part 14 should just be larger than the refractive index of a clad part, and the difference is not specifically limited, It is preferable that it is 0.5% or more of the refractive index of a clad part, and it is 0.8% or more. Is more preferable. On the other hand, the upper limit value may not be set, but is preferably about 5.5%. If the difference in refractive index is less than the lower limit, the effect of transmitting light may be reduced, and even if the upper limit is exceeded, no further increase in light transmission efficiency can be expected.

The difference in refractive index is expressed by the following equation, where A is the refractive index of the core portion 14 and B is the refractive index of the cladding portion.
Refractive index difference (%) = | A / B-1 | × 100

  Moreover, in the structure shown in FIG. 1, although the core part 14 is formed in linear form by planar view, you may be curving, branching, etc. in the middle, The shape is arbitrary.

  The cross-sectional shape of the core portion 14 is generally a square such as a square or a rectangle (rectangle), but is not particularly limited, and is not limited to a circle, such as a perfect circle or an ellipse, a rhombus, a triangle, or a pentagon. A polygon such as

  The width and height of the core portion 14 are not particularly limited, but are preferably about 1 to 200 μm, more preferably about 5 to 100 μm, and still more preferably about 20 to 70 μm.

  The constituent material of the core layer 13 is not particularly limited as long as the above-described refractive index difference is generated. Specifically, the core layer 13 is an acrylic resin, a methacrylic resin, a polycarbonate, a polystyrene, an epoxy resin, or an oxetane resin. Other cyclic ether resins, polyamides, polyimides, polybenzoxazoles, polysilanes, polysilazanes, and various resin materials such as cyclic olefin resins such as benzocyclobutene resins and norbornene resins, quartz glass, borosilicate glass Such as a glass material.

  Of these, norbornene resins are particularly preferable. These norbornene-based polymers include, for example, ring-opening metathesis polymerization (ROMP), combination of ROMP and hydrogenation reaction, polymerization by radical or cation, polymerization using a cationic palladium polymerization initiator, and other polymerization initiators ( For example, it can be obtained by any known polymerization method such as polymerization using a polymerization initiator of nickel or another transition metal).

  On the other hand, the clad layers 11 and 12 are located below and above the core layer 13, respectively. The clad layers 11 and 12 together with the side clad parts 15 constitute a clad part surrounding the outer periphery of the core part 14, thereby allowing the optical waveguide 1 to propagate the signal light without leaking. Functions as an optical path.

  The average thickness of the clad layers 11 and 12 is preferably about 0.1 to 1.5 times the average thickness of the core layer 13 (average height of each core portion 14). More preferably, the average thickness of the clad layers 11 and 12 is not particularly limited, but is usually preferably about 1 to 200 μm and about 3 to 100 μm, respectively. More preferably, it is about 5 to 60 μm. Thereby, the function as a clad layer is suitably exhibited while preventing the optical waveguide 1 from becoming unnecessarily large (thickened).

  Further, as the constituent material of each of the cladding layers 11 and 12, for example, the same material as the constituent material of the core layer 13 described above can be used, but a norbornene polymer is particularly preferable.

  Further, when selecting the constituent material of the core layer 13 and the constituent materials of the clad layers 11 and 12, the material may be selected in consideration of the refractive index difference between them. Specifically, the refractive index of the constituent material of the core layer 13 is sufficiently larger than the refractive index of the cladding layers 11 and 12 in order to surely totally reflect light at the boundary between the core layer 13 and the cladding layers 11 and 12. What is necessary is just to select a material so that it may become. Thereby, a sufficient refractive index difference is obtained in the thickness direction of the optical waveguide 1, and light can be prevented from leaking from the core portion 14 to the cladding layers 11 and 12.

  From the viewpoint of suppressing light attenuation, it is also important that the adhesiveness (affinity) between the constituent material of the core layer 13 and the constituent materials of the cladding layers 11 and 12 is high.

  As described above, the mirror 16 is provided in the middle of the optical waveguide 1 (see FIG. 2). The mirror 16 is formed of an inner wall surface of a space (cavity) obtained by digging in the middle of the optical waveguide 1. A part of this inner wall surface is a plane that crosses the core portion 14 at an angle of 45 °, and this plane becomes the mirror 16. The optical waveguide 1 and the light emitting unit 31 are optically connected via the mirror 16.

  A reflective film may be formed on the mirror 16 as necessary. As the reflective film, a metal film such as Au, Ag, or Al is preferably used.

  Further, an uneven pattern 100 is formed on the upper surface of the cladding layer 12. The uneven pattern 100 will be described in detail later.

  The optical waveguide 1 may further include a support film provided on the lower surface of the cladding layer 11 and a cover film provided on the upper surface of the cladding layer 12. Among these, when a cover film is provided, it is provided outside the region where the uneven pattern 100 is formed.

  Examples of the constituent material of the support film and the cover film include various resin materials such as polyethylene terephthalate (PET), polyolefin such as polyethylene and polypropylene, polyimide, and polyamide.

  Moreover, each average thickness of a support film and a cover film is although it does not specifically limit, It is preferable that it is about 5-200 micrometers, and it is more preferable that it is about 10-100 micrometers.

  The support film and the clad layer 11 and the cover film and the clad layer 12 are bonded or bonded. Examples of the method include thermocompression bonding, bonding with an adhesive or an adhesive, and the like. Can be mentioned.

  Among these, as an adhesive layer, various hot-melt-adhesives (polyester type | system | group, modified olefin type | system | group) etc. are mentioned other than an acrylic adhesive, a urethane type adhesive agent, a silicone type adhesive agent, for example. Moreover, as a thing with especially high heat resistance, thermoplastic polyimide adhesive agents, such as a polyimide, a polyimide amide, a polyimide amide ether, a polyester imide, a polyimide ether, are used preferably.

  Moreover, although the average thickness of an contact bonding layer is not specifically limited, It is preferable that it is about 1-100 micrometers, and it is more preferable that it is about 5-60 micrometers.

(Light emitting element)
As described above, the light-emitting element 3 has the light-emitting portion 31 and the electrode 32 on the lower surface, and specifically, a semiconductor laser such as a surface-emitting laser (VCSEL), a light-emitting diode (LED), or the like. It is a light emitting element.

  On the other hand, the semiconductor element 4 is mounted on the circuit board 2 of the optical waveguide module 10 shown in FIGS. The semiconductor element 4 is an element that controls the operation of the light emitting element 3, and has an electrode 42 on the lower surface. Examples of the semiconductor element 4 include a combination IC including a driver IC, a transimpedance amplifier (TIA), a limiting amplifier (LA), and various LSIs and RAMs.

  The light emitting element 3 and the semiconductor element 4 are electrically connected by a circuit board 2 to be described later, and the semiconductor element 4 is configured so that the light emission pattern of the light emitting element 3 and the intensity pattern of light emission can be controlled.

(Circuit board)
A circuit board 2 is provided above the optical waveguide 1, and the lower surface of the circuit board 2 and the upper surface of the optical waveguide 1 are bonded via an adhesive layer 5.

  As shown in FIG. 2, the circuit board 2 includes an insulating substrate 21, a conductor layer 22 provided on the lower surface thereof, and a conductor layer 23 provided on the upper surface. The light emitting element 3 and the semiconductor element 4 mounted on the circuit board 2 are electrically connected via the conductor layer 23.

  Here, since the light emitting portion 31 of the light emitting element 3 and the mirror 16 of the optical waveguide 1 are optically connected, the optical path of the signal light penetrates the insulating substrate 21 in the thickness direction. . Therefore, the insulating substrate 21 is preferably made of a light-transmitting material. Thereby, the transmission efficiency of an optical path can be improved. The insulating substrate 21 may be formed with a through hole that opens in a region corresponding to the optical path.

  The insulating substrate 21 is preferably flexible. The flexible insulating substrate 21 contributes to improving the adhesion between the circuit board 2 and the optical waveguide 1 and has an excellent followability to a shape change. As a result, when the optical waveguide 1 is flexible, the entire optical waveguide module 10 is also flexible and has excellent mountability. Further, when the optical waveguide module 10 is bent, it is possible to reliably prevent the insulating substrate 21 and the conductor layers 22 and 23 from peeling and the circuit board 2 and the optical waveguide 1 from peeling. This prevents a decrease in insulation and a decrease in transmission efficiency.

  The Young's modulus (tensile modulus) of the insulating substrate 21 is preferably about 1 to 20 GPa and more preferably about 2 to 12 GPa in a general room temperature environment (around 20 to 25 ° C.). If the range of the Young's modulus is this level, the insulating substrate 21 has sufficient flexibility to obtain the above-described effects.

  Examples of the material constituting the insulating substrate 21 include various resin materials such as polyimide resins, polyamide resins, epoxy resins, various vinyl resins, and polyester resins such as polyethylene terephthalate resins. Of these, those mainly composed of a polyimide resin are preferably used. The polyimide resin is particularly suitable as a constituent material of the insulating substrate 21 because it has high heat resistance and excellent translucency and flexibility.

  Specific examples of the insulating substrate 21 include film substrates used for polyester copper-clad film substrates, polyimide copper-clad film substrates, aramid copper-clad film substrates, and the like.

  In addition, the average thickness of the insulating substrate 21 is preferably about 5 to 50 μm, and more preferably about 10 to 40 μm. The insulating substrate 21 having such a thickness has sufficient flexibility regardless of the constituent material. If the thickness of the insulating substrate 21 is within the above range, the optical waveguide module 10 can be thinned and the transmission loss of the insulating substrate 21 can be suppressed.

  Furthermore, if the thickness of the insulating substrate 21 is within the above range, it is possible to prevent the transmission efficiency from being lowered due to the divergence of the signal light. For example, the signal light emitted from the light emitting unit 31 of the light emitting element 3 is incident on the mirror 16 through the circuit board 2 while diverging at a constant emission angle, but the separation distance between the light emitting unit 31 and the mirror 16 is large. If it is too large, the signal light will diverge too much and the amount of light reaching the mirror 16 may be reduced. On the other hand, by setting the average thickness of the insulating substrate 21 within the above range, the separation distance between the light emitting unit 31 and the mirror 16 can be surely reduced, so that the signal light is diffused widely. The mirror 16 is reached. As a result, a decrease in the amount of light reaching the mirror 16 can be prevented, and a loss (optical coupling loss) associated with optical coupling between the light emitting element 3 and the optical waveguide 1 can be sufficiently reduced. Further, if the average thickness of the insulating substrate 21 is within the above range, sufficient optical coupling efficiency can be obtained without using a lens for condensing signal light, so that the structure of the optical waveguide module 10 is simplified. Therefore, the manufacturing yield of the optical waveguide module 10 can be increased.

  The insulating substrate 21 may be a single substrate, or may be a multilayer substrate (build-up substrate) formed by stacking a plurality of substrates. In this case, a patterned conductor layer is included between the layers of the multilayer substrate, and an arbitrary electric circuit may be formed in the conductor layer. Thereby, a high-density electric circuit can be constructed in the insulating substrate 21.

  Further, the insulating substrate 21 may be provided with one or a plurality of through holes penetrating in the thickness direction, and these through holes are filled with a conductive material, or the through holes A conductive material film may be formed along the inner wall surface. This conductive material becomes a through via that electrically connects both surfaces of the insulating substrate 21.

  The conductor layer 22 and the conductor layer 23 provided on the insulating substrate 21 are each made of a conductive material. A predetermined pattern is formed on each of the conductor layers 22 and 23, and this pattern functions as a wiring. When the through via is formed in the insulating substrate 21, the through via and each of the conductor layers 22 and 23 are connected, whereby the conductor layer 22 and the conductor layer 23 are partially connected.

  Examples of the conductive material used for each of the conductor layers 22 and 23 include aluminum (Al), copper (Cu), gold (Au), silver (Ag), platinum (Pt), nickel (Ni), and tungsten (W ) And various metal materials such as molybdenum (Mo).

  Moreover, although the average thickness of each conductor layer 22 and 23 is suitably set according to the electrical conductivity etc. which are requested | required of wiring, it shall be about 1-30 micrometers, for example.

  Also, the width of the wiring pattern formed on each conductor layer 22 and 23 is appropriately set according to the electrical conductivity required for the wiring, the thickness of each conductor layer 22 and 23, etc., for example, about 2 to 1000 μm It is preferable that the thickness is about 5 to 500 μm.

  In addition, such a wiring pattern is patterned in advance on a separately prepared substrate, for example, a method of patterning a conductor layer once formed on the entire surface (for example, partially etching a copper foil of a copper-clad substrate). It is formed by a method of transferring a conductor layer.

  Also, each of the conductor layers 22 and 23 shown in FIG. 3 has openings 221 and 231 provided so as not to interfere with the optical path between the light emitting portion 31 of the light emitting element 3 and the mirror 16. As a result, a gap 222 having a height corresponding to the thickness of the conductor layer 22 is generated in the opening 221, and a gap 232 having a height corresponding to the thickness of the conductor layer 23 is generated in the opening 231.

  Further, the light emitting element 3 or the semiconductor element 4 and the conductor layer 23 are electrically and mechanically connected by various solders, various brazing materials and the like.

  Examples of the solder and brazing material include Sn—Pb lead solder, Sn—Ag—Cu, Sn—Zn—Bi, Sn—Cu, Sn—Ag—In—Bi, Sn—Zn. -Various Al-based lead-free solders, various low-temperature brazing materials defined by JIS, etc.

  In addition, as the light emitting element 3 and the semiconductor element 4, a package specification element such as a BGA (Ball Grid Array) type or an LGA (Land Grid Array) type is used, for example.

  Further, when the conductor layer 23 and the solder (or brazing material) are in contact with each other, there is a possibility that a part of the metal component constituting the conductor layer 23 is dissolved on the solder side. This phenomenon is called “copper erosion” because it often occurs particularly with respect to the copper conductor layer 23. If copper erosion occurs, the conductor layer 23 may be thinned or damaged, and the function of the conductor layer 23 may be impaired.

  Therefore, it is preferable to previously form a copper erosion prevention film (underlayer) as a solder underlayer on the surface of the conductor layer 23 in contact with the solder. By forming the copper erosion preventing film, copper erosion is prevented and the function of the conductor layer 23 can be maintained over a long period of time.

  Examples of the constituent material of the copper corrosion prevention film include nickel (Ni), gold (Au), platinum (Pt), tin (Sn), palladium (Pd), and the like. A single layer composed of one kind of metal composition may be used, or a composite layer containing two or more kinds (for example, a Ni—Au composite layer, a Ni—Sn composite layer, etc.) may be used.

  The average thickness of the copper erosion preventing film is not particularly limited, but is preferably about 0.05 to 5 μm, and more preferably about 0.1 to 3 μm. Thereby, it is possible to exhibit a sufficient copper erosion preventing action while suppressing the electrical resistance of the copper erosion preventing film itself.

  In addition, the electrical connection between the light emitting element 3 or the semiconductor element 4 and the conductor layer 23 is performed by wire bonding, anisotropic conductive film (ADF), anisotropic conductive paste (ACP), etc. in addition to the connection method described above. It may be carried out by a manufacturing method using

  Among them, according to wire bonding, even if a difference in thermal expansion occurs between the light emitting element 3 or the semiconductor element 4 and the circuit board 2, the difference in thermal expansion can be absorbed by a highly flexible bonding wire. , Stress concentration on the connecting portion is prevented.

  Further, a sealing material 61 is disposed so as to surround the light emitting element 3 in the gap between the light emitting element 3 and the conductor layer 23 and in the side of the light emitting element 3. As a result, the sealing material 61 is also filled in the gap 232 resulting from the formation of the opening 231 in the conductor layer 23.

  On the other hand, a sealing material 62 is filled in the gap between the semiconductor element 4 and the conductor layer 23 and the side of the semiconductor element 4.

  Such sealing materials 61 and 62 improve the weather resistance (heat resistance, moisture resistance, atmospheric pressure change, etc.) of the light emitting element 3 and the semiconductor element 4 and also the light emitting element 3 and the semiconductor element from vibration, external force, foreign matter adhesion, and the like. 4 can be reliably protected.

  Examples of the sealing materials 61 and 62 include an epoxy resin, a polyester resin, a polyurethane resin, and a silicone resin.

  The circuit board 2 and the optical waveguide 1 are bonded to each other with an adhesive layer 5. Examples of the adhesive constituting the adhesive layer 5 include an epoxy adhesive, an acrylic adhesive, and a urethane adhesive. In addition to silicone adhesives, various hot melt adhesives (polyester-based, modified olefin-based) and the like can be mentioned. Moreover, as a thing with especially high heat resistance, thermoplastic polyimide adhesive agents, such as a polyimide, a polyimide amide, a polyimide amide ether, a polyester imide, a polyimide ether, are mentioned.

  Note that the adhesive layer 5 shown in FIG. 3 is provided so as to avoid an optical path connecting the light emitting portion 31 of the light emitting element 3 and the mirror 16. That is, the adhesive layer 5 has an opening 51 provided at a position corresponding to the optical path. The opening 51 prevents interference between the optical path and the adhesive layer 5.

  In the optical waveguide module 10 as described above, the signal light emitted from the light emitting portion 31 of the light emitting element 3 passes through the sealing material 61 filled in the gap 232, the insulating substrate 21, the gap 222, and the opening 51. Is incident on the optical waveguide 1.

  Note that the optical waveguide module 10 may have the circuit board 2 at the other end of the optical waveguide 1 or may have a connector or the like responsible for connection with other optical components.

FIG. 4 is a longitudinal sectional view showing another configuration example of the optical waveguide module shown in FIG.
In the optical waveguide module 10 shown in FIG. 4A, the circuit board 2 is also provided on the upper surface of the other end of the optical waveguide 1 (the right end in FIGS. 2 and 4). A light receiving element 7 and a semiconductor element 4 are mounted on the circuit board 2. A mirror 16 is formed in the optical waveguide 1 corresponding to the position of the light receiving portion 71 of the light receiving element 7.

  In such an optical waveguide module 10, when the signal light emitted from the optical waveguide 1 through the mirror 16 reaches the light receiving portion 71 of the light receiving element 7, the optical signal is converted into an electrical signal. In this way, optical communication between both ends of the optical waveguide 1 is performed.

  On the other hand, in the optical waveguide module 10 shown in FIG. 4B, a connector 20 that is connected to other optical components is provided at the other end of the optical waveguide 1. Examples of the connector 20 include a PMT connector used for connection with an optical fiber. By connecting the optical waveguide module 10 to the optical fiber via the connector 20, optical communication over a longer distance becomes possible.

  In FIG. 4, the case where one-to-one optical communication is performed between one end and the other end of the optical waveguide 1 has been described. However, a plurality of optical paths are provided at the other end of the optical waveguide 1. An optical splitter that can be branched may be connected.

(Uneven pattern)
Here, in the surface of the optical waveguide 1 (upper surface of the clad layer 12), the portion through which the optical path connecting the mirror 16 and the light emitting unit 31 passes is, as described above, a convex portion that locally protrudes the surface. Alternatively, a concavo-convex pattern 100 is formed by arranging a plurality of concave portions that are locally recessed. That is, the optical waveguide of the present invention has a concavo-convex pattern formed on the surface thereof.

  Without such a concavo-convex pattern 100, signal light is reflected at the interface between the gap 222 and the upper surface of the cladding layer 12, and the reflected light is a loss in optical coupling. As a result, the signal light is attenuated and the S / N ratio of optical communication is lowered.

  On the other hand, by providing the concave / convex pattern 100, a light reflection preventing function is imparted to the surface of the optical waveguide 1. As a result, the attenuation of the signal light is suppressed, and the S / N ratio of optical communication can be increased. And the optical waveguide 1 and the optical waveguide module 10 which can provide highly reliable and high quality optical communication are obtained.

  FIG. 5 is a partially enlarged view showing the optical waveguide extracted from the optical waveguide module shown in FIG. In the following description, the upper side in FIG. 5 is referred to as “upper” and the lower side is referred to as “lower”.

  In the concavo-convex pattern 100 shown in FIG. 5, the smooth surface of the optical waveguide 1 is locally recessed, and a plurality of concave portions 101 distributed at regular intervals are formed.

  The distribution pattern of the recesses 101 may be irregular, but is preferably a pattern that is regularly distributed at regular intervals. Thereby, the antireflection function by the concavo-convex pattern 100 becomes more reliable, and the antireflection function becomes uniform throughout the concavo-convex pattern 100. Specific examples of the distribution pattern include a tetragonal lattice pattern, a hexagonal lattice pattern, an octagonal lattice pattern, a radial pattern, a concentric circular pattern, and a spiral pattern.

  Further, the arrangement period (distance between the centers of the recesses 101) P between the adjacent recesses 101 is preferably equal to or less than the wavelength of the signal light emitted from the light emitting element 3. Thereby, in the uneven | corrugated pattern 100, the diffraction phenomenon of signal light hardly arises, and generation | occurrence | production of the loss accompanying a diffraction can be prevented. Optically, the refractive index of the space near the concavo-convex pattern 100 can be regarded as an intermediate value between the refractive index of the gap 222 and the refractive index of the cladding layer 12, and enters the concavo-convex pattern 100. The signal light behaves according to this deemed refractive index. In other words, the difference in refractive index at the interface between the gap 222 and the cladding layer 12 is relaxed by the space in the vicinity of the concavo-convex pattern 100, and the incident efficiency is remarkably improved. As a result, an increase in optical coupling loss due to reflection can be suppressed.

  Even when the interval between adjacent recesses 101 (the distance between the centers of the recesses 101) is not constant, for the same reason, the interval is preferably equal to or less than the wavelength of the signal light.

  Since the wavelength of the signal light emitted from the light emitting element 3 is generally about 150 to 1600 nm, the upper limit of the interval between the recesses 101 is set accordingly.

  On the other hand, the lower limit of the interval between the recesses 101 is not particularly limited, but is about 20 nm from the viewpoint of the ease of forming the recesses 101 and long-term reliability.

  Moreover, it is preferable that the ratio (occupancy) of the distance which the recessed part 101 occupies among the space | intervals of the recessed parts 101 is about 10 to 90%, It is more preferable that it is about 20 to 80%, 30 to 70%. More preferably, it is about. Thereby, the antireflection function by the concavo-convex pattern 100 becomes more reliable.

  On the other hand, the depth D of the recess 101 is preferably equal to or less than the wavelength of the signal light emitted from the light emitting element 3. Thereby, in the uneven | corrugated pattern 100, the diffraction phenomenon of signal light hardly arises, and generation | occurrence | production of the loss accompanying a diffraction can be prevented. Optically, the refractive index of the space near the concavo-convex pattern 100 can be regarded as an intermediate value between the refractive index of the gap 222 and the refractive index of the cladding layer 12, and enters the concavo-convex pattern 100. The signal light behaves according to this deemed refractive index. In other words, the difference in refractive index at the interface between the gap 222 and the cladding layer 12 is relaxed by the space in the vicinity of the concavo-convex pattern 100, and the incident efficiency is remarkably improved. As a result, an increase in optical coupling loss due to reflection can be suppressed.

  Since the wavelength of the signal light emitted from the light emitting element 3 is generally about 150 to 1600 nm, the upper limit of the depth of the recess 101 is set accordingly.

  On the other hand, the lower limit of the depth D of the concave portion 101 is not particularly limited, but is about 20 nm from the viewpoint of the ease of forming the concave portion 101 and long-term reliability.

  Further, even when the arrangement period P between the recesses 101 and the depth D of the recesses 101 are not less than or equal to the wavelength of the signal light emitted from the light emitting element 3, the above-described antireflection function is provided. In this case, although the improvement in incident efficiency cannot be expected so much, since the signal light is scattered by the concave / convex pattern 100, reflection to the light emitting element 3 side is suppressed. As a result, it is possible to prevent the light emission stability of the light emitting element 3 from being impaired as the reflected light is irradiated.

The shape of each recess 101 shown in FIG. 5 is such that the shape of the opening in plan view is a quadrangle, and the quadrangle is maintained in the depth direction. That is, each recess 101 has a quadrangular prism shape.
Here, FIG. 6 is a perspective view showing an example of the shape of the concave portion or the convex portion.

  The shape of each recess 101 is not limited to the shape shown in FIG. 5, and for example, a prismatic shape, a pyramid shape (see FIG. 6A), a truncated pyramid shape (see FIG. 6B), or a cylindrical shape (FIG. 6). (See (c)), conical (see FIG. 6 (d)), truncated cone (see FIG. 6 (e)), hemispherical, elliptical hemispherical, oval hemispherical, concave (convex), secondary The shape may be a curved rotator, a quartic curve rotator, a sixth-order curve rotator, a normal distribution curve rotator, a trigonometric curve rotator, or any other curved rotator. Further, two or more of these may be mixed.

  In addition, the shape according to the shape is also included in the shape as described above. Examples of the conforming shape include a shape in which corners of each shape are chamfered, a shape in which the shapes are connected, a shape in which the shapes are combined, and the like.

  Moreover, it is preferable that the shape of each recessed part 101 among each shape mentioned above is either a column shape, a cone shape, and a hemispherical shape, or a shape according to these. The concave / convex pattern 100 having the concave portion 101 having such a shape can impart an excellent antireflection function to the optical waveguide 1. In addition, since the isotropic antireflection function is exhibited even with respect to the signal light incident obliquely with respect to the upper surface of the optical waveguide 1, the incident angle dependency is small.

  Any of the various shapes exemplified above as the shape of the concave portion 101 can be a concave portion or a convex portion. Further, the shape shown in FIG. 6 may be an inverted shape.

  On the other hand, it is preferable that the shape of each recessed part 101 is a groove (linear groove | channel) (refer FIG.6 (f)). The concave / convex pattern 100 having the concave portion 101 having such a shape can impart a particularly excellent antireflection function to the optical waveguide 1. Moreover, in the case of a convex part, a protruding item | line (linear convex part) may be sufficient.

  Further, the uneven pattern 100 may be formed not only on a part of the optical waveguide 1 but also on the entire optical waveguide 1.

<< Second Embodiment >>
Next, a second embodiment of the optical waveguide module of the present invention will be described.

FIG. 7 is a longitudinal sectional view showing a second embodiment of the optical waveguide module of the present invention.
Hereinafter, although the second embodiment will be described, the description will focus on differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 7, the same components as those in the first embodiment are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  The optical waveguide module 10 shown in FIG. 7 is the same as that of the first embodiment except that the configurations of the circuit board 2 and the sealing material 61 are different.

  In the circuit board 2 shown in FIG. 7, corresponding to the openings 221 and 231 provided in the conductor layers 22 and 23, the insulating substrate 21 is also provided with an opening 211 that penetrates the insulating substrate 21. . Thereby, it can prevent that the optical path which connects the light emission part 31 of the light emitting element 3, and the mirror 16 interferes with the insulating substrate 21, and can improve optical coupling efficiency more.

  The inner diameter of the opening 211 is appropriately set according to the emission angle of the signal light emitted from the light emitting element 3 and the effective area of the mirror 16. The same applies to the openings 221 and 231 provided in the conductor layers 22 and 23 and the opening 51 provided in the adhesive layer 5.

  In the optical waveguide module 10 shown in FIG. 7, the sealing material 61 is also provided so as to surround directly under the light emitting unit 31 so as to avoid an optical path connecting the light emitting unit 31 and the mirror 16. Thereby, it can prevent that an optical path and the sealing material 61 interfere, and can further improve optical coupling efficiency.

  Therefore, in the optical waveguide module 10 shown in FIG. 7, the opening 10 </ b> L that penetrates the conductor layer 23, the insulating substrate 21, the conductor layer 22, and the adhesive layer 5 from the lower surface of the light emitting element 3 to the upper surface of the optical waveguide 1. Is formed. By providing such an opening 10L, there is no interference with the optical path connecting the light emitting unit 31 and the optical waveguide 1, so that the optical coupling efficiency is particularly high.

  The insulating substrate 21 according to the present embodiment may be a rigid substrate having a relatively high rigidity other than the flexible substrate described in the first embodiment.

  Such an insulating substrate 21 has high bending resistance, and prevents damage to the light emitting element 3 due to bending.

  The Young's modulus (tensile modulus) of the insulating substrate 21 is preferably about 5 to 50 GPa and more preferably about 12 to 30 GPa in a general room temperature environment (around 20 to 25 ° C.). If the range of the Young's modulus is about this level, the insulating substrate 21 can more reliably exhibit the effects as described above.

  As a material constituting such an insulating substrate 21, for example, paper, glass cloth, resin film or the like is used as a base material, and a phenol resin, a polyester resin, an epoxy resin, a cyanate resin, a polyimide is used as the base material. And those impregnated with a resin material such as a fluororesin and a fluororesin.

  Specifically, in addition to insulating substrates used for composite copper-clad laminates such as glass cloth / epoxy copper-clad laminates, glass nonwoven fabrics / epoxy copper-clad laminates, polyetherimide resin substrates, polyetherketone resin substrates Examples thereof include heat-resistant and thermoplastic organic rigid substrates such as polysulfone resin substrates, and ceramic rigid substrates such as alumina substrates, aluminum nitride substrates, and silicon carbide substrates.

  Further, when the insulating substrate 21 is made of the above-described material, the average thickness is preferably about 300 μm to 3 mm, more preferably about 500 μm to 2.5 mm.

«Third embodiment»
Next, a third embodiment of the optical waveguide module of the present invention will be described.

FIG. 8 is a longitudinal sectional view showing a third embodiment of the optical waveguide module of the present invention.
Hereinafter, the third embodiment will be described, but the description will focus on the differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 8, the same components as those of the first embodiment are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  The optical waveguide module 10 shown in FIG. 8A is the same as that of the first embodiment except that it has a condensing lens 8 provided on the lower surface of the insulating substrate 21 so as to protrude into the gap 222. . The condensing lens 8 condenses the signal light emitted from the light emitting element 3, and can increase the optical coupling efficiency.

  Note that the focal length of the condenser lens 8 is set so that the convergent light is irradiated within the effective area of the mirror 16. Thereby, there is almost no signal light irradiated outside the effective region, and the optical coupling efficiency can be reliably increased.

  In addition to setting the focal length of the condenser lens 8, the amount of convergent light applied to the mirror 16 can be increased by adjusting the distance between the condenser lens 8 and the mirror 16. In order to adjust the separation distance between the condenser lens 8 and the mirror 16, the thickness of the adhesive layer 5 and the thickness of the cladding layer 12 may be adjusted.

  Although the shape of the condensing lens 8 is not specifically limited, For example, convex lenses, such as a planoconvex lens, a biconvex lens, a convex meniscus lens, and a Fresnel lens, are mentioned. Moreover, the compound lens which combined the convex lens and the concave lens may be sufficient.

  Moreover, the constituent material of the condensing lens 8 should just be a translucent material, for example, inorganic materials like quartz glass, borosilicate glass, sapphire, fluorite, silicone resin, fluorine resin, carbonate resin. And organic materials such as olefin resins and acrylic resins.

  On the other hand, the optical waveguide module 10 shown in FIG. 8B is the same as in the second embodiment except that it has a condensing lens 8 provided on the lower surface of the light emitting element 3 so as to protrude into the opening 10L. It is. The condensing lens 8 condenses the signal light emitted from the light emitting element 3, and can increase the optical coupling efficiency.

<< Fourth Embodiment >>
Next, a fourth embodiment of the optical waveguide module of the present invention will be described.

  FIG. 9 is a diagram showing a fourth embodiment of the optical waveguide module of the present invention, and is a perspective view (partially shown through) in which only the optical waveguide is taken out and inverted upside down. In FIG. 9, dense dots are attached to the core portion 14 in the core layer 13, and sparse dots are attached to the side cladding portion 15.

  Hereinafter, although the fourth embodiment will be described, the description will focus on the differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 9, the same components as those of the first embodiment are denoted by the same reference numerals as those described above, and detailed description thereof is omitted.

  The fourth embodiment is different from the first embodiment except that the shape of the core portion 14 and the side clad portion 15 in the core layer 13 is different and the formation position of the mirror 16 is formed so as to cross the side clad portion 15. It is the same.

An optical waveguide 1 shown in FIG. 9A is the optical waveguide 1 according to the first embodiment.
In this optical waveguide 1, the mirror 16 is configured by a part of a side surface of a V-shaped space 160 formed so as to partially penetrate the optical waveguide 1 in the thickness direction. This side surface is planar and is inclined 45 ° with respect to the axis of the core portion 14.

  9A, the processed surfaces of the cladding layer 11, the core layer 13, and the cladding layer 12 are exposed, and the processed surface of the core portion 14 is located almost at the center of the mirror 16. And the processing surface of the side clad part 15 is located in the right and left.

  On the other hand, the optical waveguide 1 shown in FIG. 9B is the optical waveguide 1 according to the fourth embodiment (this embodiment).

  In the optical waveguide 1 shown in FIG. 9B, the core portion 14 does not reach the end surface of the optical waveguide 1 at one end portion, and is interrupted in the middle. And the side clad part 15 is provided from the location where the core part 14 interrupted to the end surface. A portion where the core portion 14 is interrupted is referred to as a core portion missing portion 17.

  In FIG. 9B, the mirror 16 is formed in the core portion defect portion 17. Since the mirror 16 formed in the core missing part 17 is located on the extension line of the optical axis of the core part 14, the signal light reflected by the mirror 16 is along the extension line of the optical axis of the core part 14. Propagate and enter into the core part 14.

  By the way, in the mirror 16 shown in FIG. 9B, the processed surfaces of the cladding layer 11, the core layer 13, and the cladding layer 12 are exposed. Of these, the processed surface of the core layer 13 has a side cladding. Only the processed surface of the portion 15 is exposed. Such a mirror 16 has uniform smoothness because the processed surface of the core layer 13 is composed of only a single material (a constituent material of the side clad portion 15). This is because, when the space 160 is processed, a single material is processed for the core layer 13, so that the processing rate becomes uniform. Moreover, since the clad layers 11 and 12 positioned above and below the core layer 13 are made of a clad material, the constituent material of the side clad portion 15 is close to the processing rate. As a result, the processing rate is uniform over the entire surface of the mirror 16, and the mirror 16 has excellent reflection characteristics and low mirror loss.

  From the above, the optical waveguide module 10 according to the present embodiment has a particularly high optical coupling efficiency.

<Method for manufacturing optical waveguide module>
Next, an example of a method for manufacturing the optical waveguide module as described above will be described.

  An optical waveguide module 10 shown in FIG. 1 is manufactured by preparing an optical waveguide 1, a circuit board 2, a light emitting element 3, and a semiconductor element 4, and mounting them.

  Among these, the circuit board 2 is formed by forming a conductor layer so as to cover both surfaces of the insulating substrate 21 and then removing (patterning) unnecessary portions to leave the conductor layers 22 and 23 including the wiring pattern. The

  Examples of the method for producing the conductor layer include chemical vapor deposition methods such as plasma CVD, thermal CVD, and laser CVD, physical vapor deposition methods such as vacuum vapor deposition, sputtering, and ion plating, plating methods such as electrolytic plating and electroless plating, Examples include a thermal spraying method, a sol-gel method, and a MOD method.

  Moreover, as a patterning method of a conductor layer, the method which combined the photolithography method and the etching method is mentioned, for example.

  The circuit board 2 thus formed and the prepared optical waveguide 1 are bonded and fixed by the adhesive layer 5.

  Next, the light emitting element 3 and the semiconductor element 4 are mounted on the circuit board 2. As a result, the conductor layer 23 is electrically connected to the electrode 32 of the light emitting element 3 and the electrode 42 of the semiconductor element 4.

  This electrical connection is performed, for example, by supplying solder or brazing material in the form of bumps or balls, or in the form of solder paste (brazing material paste), and melting and solidifying by heating.

Thereafter, the sealing materials 61 and 62 are supplied and sealed.
The optical waveguide module 10 is obtained as described above.

<Optical waveguide manufacturing method>
Here, an example of the manufacturing method of the optical waveguide (the manufacturing method of the optical waveguide of the present invention) will be described.

  The optical waveguide 1 includes a laminated body (base material) formed by laminating a clad layer 11, a core layer 13 and a clad layer 12 in this order from below, and a mirror 16 formed by removing a part of the laminated body. And an uneven pattern 100 formed on the upper surface of the cladding layer 12.

≪First manufacturing method≫
First, the 1st manufacturing method of the optical waveguide 1 is demonstrated.

  FIG. 10 is a view (longitudinal sectional view) for explaining a first method of manufacturing the optical waveguide shown in FIG.

  Hereinafter, the first manufacturing method will be described by dividing into [1] a step of forming the laminated body 1 ′, [2] a step of forming the uneven pattern 100, and [3] a step of forming the mirror 16.

  [1] A laminate (base material) 1 ′ shown in FIG. 10A is formed by sequentially forming a clad layer 11, a core layer 13 and a clad layer 12, or the clad layer 11 and the core layer 13 In addition, after the clad layer 12 is formed on the base material in advance, the respective layers are manufactured by a method of peeling them off from the substrate and bonding them together.

  Each of the clad layer 11, the core layer 13 and the clad layer 12 is formed by applying a composition for formation on a substrate to form a liquid film, and then homogenizing the liquid film and removing volatile components. It is formed.

  Examples of the coating method include a doctor blade method, a spin coating method, a dipping method, a table coating method, a spray method, an applicator method, a curtain coating method, and a die coating method.

  In order to remove volatile components in the liquid film, a method of heating the liquid film, placing the liquid film under reduced pressure, or spraying a dry gas is used.

  In addition, as a composition for formation of each layer, the solution (dispersion liquid) formed by melt | dissolving or disperse | distributing the constituent material of the clad layer 11, the core layer 13, or the clad layer 12 in various solvents is mentioned, for example.

  Here, examples of a method for forming the core portion 14 and the side clad portion 15 in the core layer 13 include a photobleaching method, a photolithography method, a direct exposure method, a nanoimprinting method, and a monomer diffusion method. It is done. In any of these methods, the refractive index of the core layer 13 is relatively different from that of the core portion 14 having a relatively high refractive index by changing the refractive index of the partial region of the core layer 13 or changing the composition of the partial region. A side cladding portion 15 having a low height can be formed.

  [2] Next, the concave / convex pattern 100 is formed on the surface of the multilayer body 1 ′ (the upper surface of the clad layer 12).

  Specifically, a mold 110 corresponding to the uneven pattern 100 to be formed is prepared. And as shown in FIG.10 (b), the shaping | molding die 110 is pressed on the surface of laminated body 1 '. As a result, the mold of the mold 110 is transferred to the laminate 1 ′, and the mold pattern 110 is formed by releasing the mold 110 (FIG. 10C).

  At this time, the mold 110 is pressed in a heated state, and this time, the mold 110 is cooled while maintaining the state. Thereby, the transferability of the shape of the laminated body 1 ′ can be improved, and the shape retention after transfer can be improved, and the concavo-convex pattern 100 with high dimensional accuracy can be formed.

  In this case, the heating temperature of the molding die 110 is preferably higher than the softening point of the constituent material of the cladding layer 12, and the cooling temperature of the molding die 110 is preferably lower than the softening point of the constituent material of the cladding layer 12. Thereby, the shape transferability can be further improved.

  When the mold 110 is pressed, the constituent material of the cladding layer 12 is softened, and the softened material is deformed along the mold of the mold 110. At this time, depending on the shape of the mold, deformation occurs such that the surface is recessed or protrudes from the surface, and a recess or a protrusion is formed.

  As the mold 110, for example, a metal, silicon, resin, glass, or ceramic mold is used, and a mold release agent is preferably applied to the molding surface.

  The mold 110 can be formed by a method such as a laser processing method, an electron beam processing method, or a photolithography method.

  The mold 110 may be a duplicate of the master mold (original mold). Examples of such a replication mold include a film having a mold replicated on the surface.

  [3] Next, a digging process for removing a part from the lower surface side of the clad layer 11 is performed on the stacked body 1 ′. The inner wall surface of the space (cavity) thus obtained becomes the mirror 16.

  The digging process on the stacked body 1 ′ can be performed by, for example, a laser processing method, a dicing method using a dicing saw, or the like.

  As described above, the laminate (base material) 1 'and the mirror 16 formed thereon are obtained. Thereby, the optical waveguide 1 is obtained.

«Second manufacturing method»
Next, a second manufacturing method of the optical waveguide 1 will be described.

  FIG. 11 is a view (longitudinal sectional view) for explaining a second method of manufacturing the optical waveguide shown in FIG.

  Hereinafter, the second manufacturing method includes the steps of [1] forming the clad layer 11 (first clad layer), [2] forming the core layer 13, and [3] forming the concave / convex pattern 100. The step of forming the (second clad layer) and the step of [4] forming the mirror 16 will be described separately.

[1] First, the clad layer 11 is formed in the same manner as in the first manufacturing method.
[2] Next, the core layer 13 is formed on the clad layer 11 in the same manner as in the first manufacturing method (FIG. 11A).

  [3] Next, a composition for forming the clad layer 12 is applied on the core layer 13 to form a liquid film 121.

  Next, the mold 110 is pressed against the liquid coating 121 (FIG. 11B). In this state, the liquid coating 121 is cured (mainly cured). As a result, the liquid coating 121 is cured, the clad layer 12 is formed, and the laminate 1 ′ is obtained. Further, the mold 110 is transferred onto the upper surface of the clad layer 12, and the uneven pattern 100 is formed by releasing the mold 110 (FIG. 11C).

  With such a method, since the mold 110 is transferred to the liquid coating 121, good transferability can be obtained. As a result, the concavo-convex pattern 100 having particularly high dimensional accuracy can be formed.

  The liquid coating 121 is cured by a thermosetting method, a photocuring method, or the like, although it varies depending on the composition of the composition for forming the cladding layer 12.

  Further, before the mold 110 is pressed, the liquid coating 121 may be in a semi-cured state (dry film), and the mold 110 may be pressed against this dry film. Thereby, a moldability and mold release property can be improved more. The dry film is formed by removing a part of the solvent in the liquid coating 121, and is richer in flexibility and plasticity than the cured product.

  [4] Next, the mirror 16 is formed on the laminate 1 ′ in the same manner as in the first manufacturing method. Thereby, the optical waveguide 1 is obtained.

≪Third manufacturing method≫
Next, the 3rd manufacturing method of the optical waveguide 1 is demonstrated.

  FIG. 12 is a view (longitudinal sectional view) for explaining a third method of manufacturing the optical waveguide shown in FIG.

  Hereinafter, the third manufacturing method includes [1] a step of forming the clad layer 12 (second clad layer) on the mold, [2] a step of forming the core layer 13 on the clad layer 12, and [3] core. The step of forming the cladding layer 11 on the layer 13 and the step of [4] forming the mirror 16 will be described separately.

  [1] First, the molding surface of the mold 110 is arranged facing upward. Then, the liquid coating 121 is formed by applying a composition for forming the clad layer 12 on the mold 110 (FIG. 12A).

  Next, in this state, the liquid coating 121 is cured (main curing). As a result, the liquid coating 121 is cured and the cladding layer 12 is formed. Further, the mold 110 is transferred to the lower surface of the cladding layer 12 (FIG. 12B).

  With such a method, since the mold 110 is transferred to the liquid coating 121, good transferability can be obtained. As a result, the concavo-convex pattern 100 having particularly high dimensional accuracy can be formed.

  The liquid coating 121 is cured by a thermosetting method, a photocuring method, or the like, although it varies depending on the composition of the composition for forming the cladding layer 12.

[2] Next, the core layer 13 is formed on the cladding layer 12 in the same manner as in the first manufacturing method.
[3] Next, the clad layer 11 is formed on the core layer 13 in the same manner as in the first manufacturing method (FIG. 12C). Then, the mold 110 is peeled from the clad layer 12.

  [4] Next, the mirror 16 is formed on the laminate 1 ′ in the same manner as in the first manufacturing method. Thereby, the optical waveguide 1 is obtained.

<Electronic equipment>
The electronic device (the electronic device of the present invention) including the optical waveguide module of the present invention can be applied to any electronic device that performs signal processing of both an optical signal and an electric signal. For example, a router device, a WDM device, Application to electronic devices such as mobile phones, game machines, personal computers, televisions, home servers, etc. is preferable. In any of these electronic devices, it is necessary to transmit a large amount of data at high speed between an arithmetic device such as an LSI and a storage device such as a RAM. Therefore, since such an electronic device includes the optical waveguide module of the present invention, problems such as noise and signal degradation peculiar to the electric wiring are eliminated, and a dramatic improvement in performance can be expected.

  In addition, the amount of heat generated in the optical waveguide portion is greatly reduced compared to electrical wiring. Therefore, the degree of integration in the substrate can be increased to reduce the size, the power required for cooling can be reduced, and the power consumption of the entire electronic device can be reduced.

  As described above, the embodiments of the optical waveguide, the optical waveguide manufacturing method, the optical waveguide module, and the electronic device according to the present invention have been described. It can be replaced with any structure capable of performing the same function. Moreover, arbitrary components may be added, and a plurality of embodiments may be combined.

  Moreover, in each said embodiment, although the number of the channels (core part) which the optical waveguide 1 has is one, the number of channels may be two or more in the optical waveguide of this invention. In this case, the number of mirrors, concave / convex patterns, light emitting elements, etc. may be set according to the number of channels. As for the light emitting element and the light receiving element, one element having a plurality of light emitting units or a plurality of light receiving units may be used.

1 Optical waveguide 1 'Laminated body (base material)
DESCRIPTION OF SYMBOLS 10 Optical waveguide module 10L Opening 11 Cladding layer (1st cladding layer)
12 Cladding layer (second cladding layer)
121 Liquid coating 13 Core layer 14 Core part 15 Side clad part 16 Mirror 160 Space 17 Core part missing part 2 Circuit board 20 Connector 21 Insulating board 211 Opening part 22, 23 Conductive layer 221, 231 Opening part 222, 232 Air gap 3 Light emission Element 31 Light emitting part 32 Electrode 4 Semiconductor element 42 Electrode 5 Adhesive layer 51 Opening 61, 62 Sealing material 7 Light receiving element 71 Light receiving part 8 Condensing lens 100 Concave and convex pattern 101 Concave part 110 Mold

Claims (14)

The core,
A clad portion provided so as to cover a side surface of the core portion;
An optical path conversion unit that is provided in the middle of the core unit or on an extension line, and converts the optical path of the core unit to the outside of the cladding unit,
Of the surface of the clad portion, provided at least at a site optically connected to the core portion via the optical path changing portion, the convex portion projecting the surface locally or locally dented An optical waveguide comprising: a concave / convex pattern formed by arranging a plurality of concave portions.   The optical waveguide according to claim 1, wherein the convex portions and the concave portions are regularly arranged at regular intervals.   The optical waveguide according to claim 2, wherein an arrangement cycle of the convex portions and an arrangement cycle of the concave portions in the concave / convex pattern are equal to or less than a wavelength of the signal light incident on the optical waveguide.   4. The optical waveguide according to claim 1, wherein a height of the convex portion and a depth of the concave portion in the concave / convex pattern are equal to or less than a wavelength of signal light incident on the optical waveguide.   5. The optical waveguide according to claim 1, wherein each of the convex portion and the concave portion has a columnar shape, a conical shape, a hemispherical shape, or a shape conforming thereto.   The optical waveguide according to any one of claims 1 to 4, wherein the convex portions and the concave portions are convex or concave.   The optical waveguide according to any one of claims 1 to 6, wherein the optical path conversion unit includes a reflection surface provided so as to obliquely cross at least the core unit. The core,
A clad portion provided so as to cover a side surface of the core portion;
An optical path conversion unit that is provided in the middle of the core unit or on an extension line, and converts the optical path of the core unit to the outside of the cladding unit,
Of the surface of the cladding part, provided at least at a site optically connected to the core part by the optical path changing part, a convex part that locally protrudes the surface or a concave part that is locally recessed A method of manufacturing an optical waveguide having a plurality of concave and convex patterns,
Preparing a base material having the core part, the clad part, and the optical path changing part;
A method of manufacturing an optical waveguide, comprising: pressing a molding die against the surface of the base material to locally protrude or dent a part of the surface to form the concavo-convex pattern. .   The method for manufacturing an optical waveguide according to claim 8, wherein the uneven pattern is formed by cooling the mold after pressing the heated mold on the surface of the base material. A core layer comprising: a core portion; and a side clad portion provided adjacent to a side surface of the core portion;
A first cladding layer and a second cladding layer provided adjacent to both surfaces of the core layer;
An optical path conversion unit that is provided in the middle or on an extension line of the core unit and converts the optical path of the core unit to the outside of the second cladding layer,
Of the surface of the second clad layer, provided at least at a site optically connected to the core portion by the optical path changing portion, the convex portion protruding locally or the local depression of the surface A method of manufacturing an optical waveguide having a concavo-convex pattern formed by arranging a plurality of recesses,
Forming the first cladding layer;
Forming the core layer on the formed first cladding layer;
Applying a clad layer-forming composition on the core layer to form a liquid film;
Forming the concave / convex pattern and forming the second cladding layer by curing the liquid coating or the semi-cured product thereof while pressing a mold on the liquid coating or the semi-cured product thereof. An optical waveguide manufacturing method characterized by the above. A core layer comprising: a core portion; and a side clad portion provided adjacent to a side surface of the core portion;
A first cladding layer and a second cladding layer provided adjacent to both surfaces of the core layer;
An optical path conversion unit that is provided in the middle or on an extension line of the core unit and converts the optical path of the core unit to the outside of the second cladding layer,
Of the surface of the second clad layer, provided at least at a site optically connected to the core portion by the optical path changing portion, the convex portion protruding locally or the local depression of the surface A method of manufacturing an optical waveguide having a concavo-convex pattern formed by arranging a plurality of recesses,
Applying the composition for forming a cladding layer on a mold, forming a liquid film or a semi-cured product of the liquid film, and then curing to obtain the second cladding layer having the concavo-convex pattern formed thereon;
Forming the core layer on the formed second cladding layer;
And a step of forming the first cladding layer on the core layer. An optical waveguide according to any one of claims 1 to 7,
An optical waveguide module comprising: an optical element optically connected to the core portion through the optical path changing portion and the concave / convex pattern.   Furthermore, the optical waveguide module of Claim 12 which has a condensing lens provided between the said uneven | corrugated pattern and the said optical element.   An electronic apparatus comprising the optical waveguide module according to claim 12.

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