JP2006053260A - Optical waveguide, ferrule for optical waveguide and optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ferrule for optical waveguide which has a small size and a sufficient strength, to provide an optical waveguide fitted to the ferrule for optical waveguide and to provide an optical connector made by integrating them. <P>SOLUTION: The optical waveguide comprises an optical waveguide core of transmitting an optical signal and a planar clad part of surrounding the optical waveguide core. Therein, the optical waveguide has a linear recessed part extended in the direction inclined by 0.1 to 15° from the extension direction of the optical waveguide core on at least either one surface of the clad part. The optical waveguide is fitted to the ferrule for optical waveguide and the optical connector is made by integrating the ferrule for optical waveguide and the optical waveguide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical waveguide used in the fields of optical communication and optical information processing, an optical waveguide ferrule for fitting the optical waveguide, and an optical connector in which the optical waveguide is fitted to an optical waveguide ferrule.

In recent years, the demand for large-capacity and high-speed data transmission is increasing due to the spread and development of information transmission means such as the Internet. In order to transmit large amounts of data at high speed, optical fibers that can send enormous amounts of information to farther distances with less transmission loss are known. A multi-core optical connector that connects multiple optical fibers at once is known. It is used.
This multi-core optical connector is connected to the multi-core optical fiber connector. At this time, it is necessary to align the optical axis of the optical waveguide of the multicore optical connector and the optical axis of the waveguide of the multicore optical fiber connector so as to be concentric. As the alignment method, for example, the optical waveguide is moved with respect to the multi-core connector so that the strongest light enters the optical waveguide of the multi-core optical connector in a state where the waveguide of the multi-core optical fiber connector emits light. There is active alignment that adjusts the position.

  However, since the alignment work in this active alignment is performed manually, the cost is high. In order to reduce the cost, it is required that the alignment operation is simplified or can be manufactured without alignment.

  Therefore, as shown in FIG. 7, positioning grooves 110 (or steps) are formed at both ends of the optical waveguide 108 in which the optical waveguide core 104 and the clad portion 106 surrounding the optical waveguide core 104 are formed on the substrate 102. Is formed parallel to the extending direction of the optical waveguide core 104, and the positioning groove 110 is engaged with the convex portion 114 formed on the connector 112 connecting the optical waveguide 122, so that the optical waveguide core 104 is connected to the connector 112. The structure which positions with respect to is disclosed (for example, refer patent documents 1-3).

  However, by forming the groove 110 at both ends of the optical waveguide 108, the dimension of the spectral waveguide 108 in the width direction becomes large. Along with this, the size of the opening 116 connecting the optical waveguide 108 of the connector 112 also increases, and the size of the connector 112 increases. In addition, since the mechanical strength of the connector 112 is reduced due to the increase in the size of the opening 116, the connector 112 is bent when pressed by the spring clamp 118, and the optical waveguide 108 is also affected by the bending and the optical connection loss is increased. There is a fear.

  Further, since the groove 110 is formed in parallel with the extending direction of the optical waveguide core 104, when the optical waveguide 108 is connected to the connector 112, the direction orthogonal to the extending direction of the optical waveguide core 104 (the width direction of the optical waveguide). However, the position of the optical waveguide core 104 in the extending direction is not restricted. For this reason, when the optical waveguide 108 is connected to the connector 112, and the connector 112 is connected to the optical fiber connector 120, the end surface of the optical waveguide core 104 must be abutted against the end surface of the optical waveguide 122 of the optical fiber connector 120 and aligned. I must. For this reason, the end face of the optical waveguide core 104 is damaged, and the optical connection loss increases.

  As a method for solving these problems, a method is disclosed in which a tapered surface is formed on an optical waveguide and a connector to perform positioning (see, for example, Patent Document 4). Briefly, the side surface in the width direction of the optical waveguide is used as a positioning surface, and a tapered surface is formed on one side surface with respect to a surface parallel to the optical waveguide core. A tapered surface is also formed on the surface of the connector facing this tapered surface. When the optical waveguide is inserted into the fitting portion of the connector, the optical waveguide is positioned at the fitting portion by receiving a reaction from the tapered surface formed on the connector.

However, in this configuration, when the optical waveguide is formed on a silicon substrate, a glass substrate, or the like, or when the optical waveguide is formed of a polymer compound having insufficient mechanical strength, the optical waveguide is connected to the fitting portion of the connector. It is conceivable that when inserted, the optical waveguide is bent by the reaction force generated when the alignment is performed by the taper, and the optical connection loss increases.
JP-A-8-248269 (Section 3-4, Fig. 1) Japanese Patent Laid-Open No. 9-105838 (term 4, FIG. 1) Japanese Patent Laid-Open No. 2001-324631 (4th item, FIG. 3) Japanese Patent Laid-Open No. 2002-020498 (4th item, FIG. 1)

In view of the above facts, the present invention aims to achieve the following objects. That is,
The objective of this invention is providing the ferrule for optical waveguides which is small in size and sufficient intensity | strength, the optical waveguide fitted to this, and the optical connector which integrated these.

<1> An optical waveguide having an optical waveguide core for transmitting an optical signal, and a plate-like clad portion surrounding the optical waveguide core, wherein the optical waveguide core is provided on at least one surface of the clad portion. An optical waveguide characterized by having a linear recess extending in a direction inclined by 0.1 to 15 ° with respect to the extending direction.
According to the invention described in <1>, the optical waveguide core is surrounded by the plate-like clad portion, and at least one surface of the clad portion is 0.1 to 15 from the extending direction of the optical waveguide core. A linear recess extending in a tilted direction is provided. This linear concave portion engages with a linear convex portion provided in an optical waveguide ferrule (described later), and the concave / convex engagement is inclined as the optical waveguide is inserted into the opening of the optical waveguide ferrule. The optical waveguide abuts against the opening side wall of the optical waveguide ferrule, the gap between the side surface of the optical waveguide and the opening side wall of the optical waveguide ferrule disappears, and the amount of insertion of the optical waveguide into the optical waveguide ferrule is restricted. The optical waveguide core is positioned with respect to the ferrule for the optical waveguide.

  As a result, only by connecting an optical connector (described later) to the optical fiber connector, the optical axis of the optical waveguide core coincides with the optical axis of the connector optical waveguide core of the optical fiber connector. For this reason, the connection work is not complicated, and the cost can be kept low.

  In addition, by forming the linear concave portion that engages with the linear convex portion of the ferrule for the optical waveguide and performs positioning on the surface orthogonal to the side surface of the cladding portion, a space for forming the concave portion is not required separately. The dimension in the width direction of the optical waveguide does not increase. Therefore, even if the number of optical waveguide cores increases, the dimension in the width direction can be suppressed by the size of the optical waveguide cores arranged in parallel, and an increase in optical connection loss such as optical axis misalignment can be suppressed, Even if the optical waveguide is formed of a material that does not have sufficient mechanical strength, such as a silicon substrate or a glass substrate, bending is less likely to occur. Furthermore, when connecting the optical fiber connector and the optical connector, it is not necessary to align the end face of the optical waveguide core against the end face of the connector optical waveguide core of the optical fiber connector. There is no need to worry about increased optical connection loss.

  In addition, in an optical waveguide in which a plurality of optical waveguide cores are formed along the width direction of the cladding portion, a concave portion is formed on at least one of the upper and lower surfaces of the cladding portion, so that the surface of the cladding portion having a large area can be obtained. It will be engaged with the ferrule for optical waveguide. Therefore, the optical waveguide core can be stably engaged with the optical waveguide connector.

<2> The optical waveguide according to <1>, wherein a cross-sectional shape of the linear recess is rectangular.
According to the invention described in the above <2>, by processing the shape of the cross section of the linear concave portion to be rectangular, it is easy to process the mold for forming the linear concave portion. This leads to a reduction in manufacturing cost.

<3> The optical waveguide according to <1>, wherein a cross-sectional shape of the linear recess is substantially V-shaped.
According to the invention described in <3>, the linear concave portion of the optical waveguide is engaged with the V-shaped linear convex portion of the optical waveguide connector by making the cross-sectional shape of the linear concave portion substantially V-shaped. When doing so, the linear concave portion is supported by the linear convex portion on two sides, so that the alignment accuracy is easily obtained.
Further, in the case of a substantially V-shaped linear recess as compared with a rectangular linear recess, it is not necessary to cut out and taper a mold for forming the linear recess. As a result, the mold structure is simplified, and the incidence of molding defects such as mold release defects can be reduced, leading to a reduction in manufacturing costs.

<4> The optical waveguide according to any one of <1> to <3>, wherein at least one of the optical waveguide core and the clad portion is formed of a polymer compound.
According to the invention described in <4>, at least one of the optical waveguide core and the clad portion is formed of a polymer compound without being formed of a silicon substrate or a glass substrate, so that the material cost is kept low. This leads to a reduction in manufacturing costs. In addition, by using a polymer compound, for example, a plastic material, it becomes easy to obtain an arbitrary shape when molding the optical waveguide core and the clad portion.

<5> A ferrule for an optical waveguide, characterized by having a concave-convex relationship with the optical waveguide according to any one of <1> to <4>, and having an opening into which the optical waveguide is fitted.
According to the invention described in <5>, the ferrule for an optical waveguide has an opening having a shape that forms a concavo-convex relationship with the optical waveguide described in any one of <1> to <4>. The optical waveguide engages with the optical waveguide ferrule, and the optical waveguide can be easily positioned with respect to the optical waveguide ferrule.

<6> The ferrule for an optical waveguide according to <5>, wherein the optical waveguide ferrule has a linear convex portion that fits into the linear concave portion of the optical waveguide when the optical waveguide is inserted into the opening. It is.
According to the invention described in <6>, the optical waveguide is engaged with the ferrule for the optical waveguide by having an opening having a shape that is uneven with the optical waveguide, so that the ferrule for the optical waveguide of the optical waveguide is obtained. Can be easily positioned.

<7> An optical waveguide ferrule having an opening with which the optical waveguide is fitted is fitted into the optical waveguide according to any one of <1> to <4>. This is an optical connector.
According to the invention described in <7>, the linear waveguide is formed with a linear concave portion that is positioned by being engaged with the linear convex portion of the optical waveguide ferrule, so that the gap between the optical waveguide and the optical waveguide ferrule is determined. Even if the adhesive penetrates and cures and cure shrinkage occurs, there is no fixed part so that it does not displace, so the force that brings the optical waveguide and the ferrule for the optical waveguide closer due to cure shrinkage works equally, and bending is difficult to occur Become. As a result, an increase in optical connection loss such as optical axis misalignment can be suppressed.

<8> In the above <7>, when the optical waveguide is fitted into the optical waveguide ferrule, the distal end surface of the optical waveguide and the distal end surface of the optical waveguide ferrule are flush with each other. It is an optical connector of description.
According to the invention described in <8>, an opening is formed in the ferrule for an optical waveguide, and the opening is engaged with a linear recess provided in the optical waveguide to form the ferrule for the optical waveguide. A linear convex portion for positioning the optical waveguide core is formed. As a result, only by connecting the optical waveguide connector to the optical fiber connector, the optical axis of the optical waveguide core and the optical axis of the connector optical waveguide core of the optical fiber connector coincide with each other, so that the alignment work becomes unnecessary. For this reason, the connection work is not complicated, and the cost can be kept low.

  ADVANTAGE OF THE INVENTION According to this invention, the ferrule for optical waveguides which is small in size and has sufficient intensity | strength, the optical waveguide fitted to this, and the optical connector which integrated these can be provided.

Initially, the manufacturing process of the optical waveguide of this invention is demonstrated in order of a process using FIG.
1) Step of preparing a mold that is formed from a cured resin layer of a mold-forming curable resin and has a concave portion corresponding to the core convex portion. The production of the mold is a convex corresponding to the optical waveguide core (hereinafter referred to as “core”). However, the present invention is not limited to this. In the following, a method using the master will be described.

<Preparation of master>
A conventional method such as a photolithography method or an RIE method can be used without particular limitation for producing the master 10 (shown in FIG. 1A) on which the convex portions 12 corresponding to the core are formed. Further, the method (Japanese Patent Laid-Open No. 2002-333538) for producing an optical waveguide by the electrodeposition method or the photo-deposition method previously filed by the present applicant can also be applied to produce the master 10.

  The size of the convex portion 12 corresponding to the core formed on the master 10 is generally about 5 to 500 μm square, preferably about 40 to 200 μm square, and is appropriately determined according to the use of the optical waveguide. For example, in the case of a single mode optical waveguide, a core of about 10 μm square is generally used, and in the case of a multimode optical waveguide, a core of about 50 to 100 μm square is generally used. An optical waveguide having a larger core of about μm square is also used.

<Production of mold>
Next, a process for producing the mold 20 will be described.
As shown in FIG. 1 (B), a mold-forming curable resin is applied or cast onto the surface of the master 10 produced as described above corresponding to the core 12 as shown in FIG. 1B. The layer 20a is formed, and if necessary, a drying treatment is performed to cure the curable resin layer 20a. Then, by separating the cured curable resin layer 20a from the master 10, the mold 20 in which the concave portion 22 corresponding to the convex portion 12 is formed is produced.

Next, as shown in FIG. 1C, the mold 20 is provided with an inlet 26 for filling the recess 22 with the core-forming curable resin, and an outlet 28 for discharging the resin from the recess 22. Formed by punching.
In addition to the configuration in which the entrance 26 and the discharge port 28 are previously provided in the mold 20 by punching, various methods can be used. As another method, for example, after forming a cured resin layer of a curable resin for forming a mold on a master, a mold is prepared by peeling the curable resin layer from the master, and then the recesses are exposed at both ends of the mold. And a method of forming the inlet and the outlet by cutting into two. Thus, the formation method of the entrance 26 and the discharge port 28 is not particularly limited.

  By providing the inlet 26 and the outlet 28 communicating with the concave portion 22 of the mold 20 at both ends of the concave portion 22, the inlet 26 can be used as a liquid (resin) reservoir, and the outlet 28 has a vacuum suction pipe therein. By inserting, the inside of the recess 22 can be connected to a vacuum suction device. It is also possible to connect the inlet 26 to the core-forming curable resin injection pipe and pressurize and inject the resin from the inlet 26 into the recess 22. When there are a plurality of recesses 22, the discharge port 28 may be provided corresponding to each recess 22, or may be provided with one hole that communicates with each recess 22 in common.

  The thickness of the cured resin layer is appropriately determined in consideration of the handleability of the mold 20, but generally about 0.1 to 50 mm is appropriate. Further, by performing release treatment such as application of a release agent on the master 10 in advance, the curable resin layer 22a can be easily peeled from the master 10 and the peeling of the master 10 and the mold 20 is promoted.

  As the mold forming curable resin, the cured product can be easily peeled off from the master 10, the mold 20 (repetitively used) has a certain level of mechanical strength and dimensional stability, and is a hard resin that maintains the shape of the recess 22. It is preferable that it has thickness (hardness) and has good adhesion to the clad substrate 30 described later. Various additives can be added to the mold-forming curable resin as necessary.

  The mold-forming curable resin can be applied or cast onto the surface of the master 10, and the protrusions 12 corresponding to the individual cores formed on the master 10 must be accurately transferred. Therefore, it is preferable to have a viscosity below a certain limit, for example, about 500 to 7000 mPa · s. (Note that the “mold-forming curable resin” used in the present invention also includes a resin that becomes a rubber-like body having elasticity after curing.) In addition, the solvent is used for viscosity adjustment, and the adverse effect of the solvent. Can be added to the mold-forming curable resin to such an extent that does not occur.

  The mold-forming curable resin includes silicone rubber (silicone elastomer) or silicone resin after curing in terms of peelability, mechanical strength / dimensional stability, hardness, and adhesion to the base material for clad (clad part). A curable organopolysiloxane is preferably used. The curable organopolysiloxane preferably contains a methylsiloxane group, an ethylsiloxane group, or a phenylsiloxane group in the molecule. Further, the curable organopolysiloxane may be a one-component type or a two-component type used in combination with a curing agent, and may be a thermosetting type or a room temperature curable type (for example, one that is cured by moisture in the air). ), And other types of curing (such as ultraviolet curing) may be used.

  As curable organopolysiloxane, what becomes silicone rubber after hardening is preferable. As the silicone rubber after curing, what is usually called liquid silicone rubber (“liquid” includes those having a high viscosity such as a paste) is used. The liquid silicone rubber is preferably a two-pack type used in combination with a curing agent. Among them, the addition type liquid silicone rubber is preferably used because the surface and the inside are uniformly cured in a short time, and there are no or by-products, and the mold release property is excellent and the shrinkage rate is small.

  Among liquid silicone rubbers, liquid dimethylsiloxane rubber is particularly preferred from the viewpoints of adhesion, peelability, strength and hardness controllability. In addition, a cured product of liquid dimethylsiloxane rubber generally has a refractive index as low as about 1.43. Therefore, a mold formed using this is used as it is as a clad substrate without being peeled off from the clad substrate. be able to. In this case, it is necessary to devise such that the mold, the filled core forming resin, and the clad substrate are not peeled off.

  The viscosity of the liquid silicone rubber is 500 from the viewpoint of accurately transferring the convex portion 12 corresponding to the core and facilitating defoaming by reducing the mixing of bubbles, and forming a mold having a thickness of several millimeters. The thing of about -7000 mPa * s is preferable, Furthermore, the thing of about 2000-5000 mPa * s is more preferable.

  Further, the surface energy of the mold 20 is in the range of 10 dyn / cm to 30 dyn / cm, particularly 15 dyn / cm to 24 dyn / cm, so that the adhesion with the base film and the penetration rate of the curable resin for core formation From the point of view, it is preferable.

The shear rubber hardness of the mold 20 may be 15 to 80, and 20 to 60 is particularly preferable from the viewpoint of mold taking performance, maintenance of the concave shape, and peelability.
The surface roughness (root mean square roughness (RMS)) of the mold 20 is 0.5 μm or less, preferably 0.1 μm or less, more preferably 0.05 μm or less, so that the optical waveguide characteristics of the formed core are obtained. The optical loss can be greatly reduced. The surface roughness is preferably 1/2 or less of the wavelength of the light to be used, and when it is 1/10 or less, the waveguide loss due to the core surface roughness of the light becomes almost negligible.

Moreover, it is preferable that the casting_mold | template 20 is a light transmittance in an ultraviolet region and / or a visible region. Since the mold 20 is light transmissive in the visible region, positioning can be easily performed when the mold 20 is brought into close contact with the clad substrate 30 (see FIG. 1D) in the step 2) described later. Further, it can be observed that the core-forming curable resin is filled in the concave portion 22 of the mold 20 in the step 3) described later, and the completion of filling can be easily confirmed.
Further, it is preferable that the mold 20 is light transmissive in the ultraviolet region in order to perform ultraviolet curing through the mold 20 when an ultraviolet curable resin is used as the core-forming curable resin. Therefore, the transmittance of the mold 20 in the ultraviolet region (300 nm to 400 nm) is preferably 80% or more.

Curable organopolysiloxanes, especially liquid silicone rubbers that become silicone rubbers after curing, have excellent contradictory properties of adhesion to the clad substrate 30 and peelability, have the ability to transfer nanostructures, silicone rubber and clad Even when the base material 30 is brought into close contact, it is possible to prevent even the liquid from entering. The mold 20 using such silicone rubber transfers the shape of the master 10 with high accuracy and adheres firmly to the clad substrate 30. For this reason, it becomes possible to efficiently fill the core forming resin only in the recesses 22 between the mold 20 and the clad substrate 30. Further, the clad substrate 30 and the mold 20 can be easily peeled off. Therefore, an optical waveguide whose shape is maintained with high accuracy can be manufactured from the mold 20 very simply.
Further, when the cured resin layer, particularly the cured resin layer has rubber elasticity, a part of the cured resin layer, that is, a part other than the part to which the convex portion 12 of the master 10 is transferred can be replaced with another rigid material. The handling property of the mold 20 is improved.

2) The process of making the clad substrate 30 adhere to the mold 20 The clad substrate 30 is stuck to the mold 20. As the clad substrate 30, a glass substrate, a ceramic substrate, a plastic substrate or the like can be used without limitation. By using a polymer compound such as a plastic substrate for the clad substrate 30, it is easy to obtain an arbitrary shape when the clad portion is molded.

  Moreover, what coated these base materials with resin for refractive index control is also used. The clad substrate 30 has a refractive index smaller than 1.55 and more preferably smaller than 1.50. In particular, the refractive index of the core 32 (see FIG. 1F) needs to be smaller than 0.01. Further, the clad substrate 30 is preferably flat, excellent in adhesion to the mold 20, and in the case where the both are brought into close contact with each other, there is no void other than the concave portion 22 of the mold 20.

  Among plastic substrates, optical waveguides using flexible film substrates can be used as couplers, optical wiring between boards, optical demultiplexers, and the like. Depending on the application of the optical waveguide to be produced, the film base material has optical properties such as refractive index, light transmission, mechanical strength, heat resistance, adhesion to the mold, flexibility (flexibility) Etc. are selected.

  Materials for the film base include acrylic resins (polymethyl methacrylate, etc.), alicyclic acrylic resins, styrene resins (polystyrene, acrylonitrile / styrene copolymers, etc.), olefin resins (polyethylene, polypropylene, ethylene / propylene, etc.) Copolymer), alicyclic olefin resin, vinyl chloride resin, vinylidene chloride resin, vinyl alcohol resin, vinyl butyral resin, arylate resin, fluorine-containing resin, polyester resin (polyethylene terephthalate, polyethylene naphthalate) Etc.), polycarbonate resin, cellulose di- or triacetate, amide resin (aliphatic, aromatic polyamide, etc.), imide resin, sulfone resin, polyether sulfone resin, polyether ether ketone resin, polyphenylenes Fido resins, polyoxymethylene-based resin or a mixture of resins, and the like.

  When the film substrate is not very good in adhesion to the mold 20 and the core 32, treatment with an ozone atmosphere and ultraviolet irradiation treatment with a wavelength of 300 nm or less may be performed to improve the adhesion between the mold 20 and the core 32. desirable.

  In addition, as the alicyclic olefin resin, those having a norbornene structure in the main chain and those having a norbornene structure in the main chain and an alkyloxycarbonyl group in the side chain (the alkyl group having 1 to 6 carbon atoms or cyclohexane) And those having a polar group such as an alkyl group). Among them, an alicyclic olefin resin having a norbornene structure in the main chain and a polar group such as an alkyloxycarbonyl group in the side chain has a low refractive index (refractive index is around 1.50, core 32, clad group It has excellent optical characteristics such as a difference in the refractive index of the material 30) and high light transmittance, is excellent in adhesion to the mold 20, and is excellent in heat resistance.

The refractive index of the film substrate is preferably smaller than 1.55 and more preferably smaller than 1.53 in order to ensure a difference in refractive index from the core 32.
The thickness of the film substrate is appropriately selected in consideration of flexibility, rigidity, ease of handling, and the like, and is generally preferably about 0.1 mm to 0.5 mm.

3) Step of filling the concave portion 22 of the mold 20 with the clad substrate 30 in close contact with the core-forming curable resin, as shown in FIG. 1 (D), the core is provided at the entrance 26 formed at one end of the concave portion 22. The forming curable resin is injected, and suctioned under reduced pressure from the discharge port 28 formed at the other end of the recess 22, and the recess 22 is filled with the core forming curable resin.
The method for filling the concave portion 22 with the core-forming curable resin is not limited to the above method. For example, the entrance 26 is filled with a small amount of core-forming curable resin by utilizing a capillary phenomenon, or the core-forming curable resin is pressure-filled from the entrance 26 into the recess 22, or the recess 28 is provided with a recess. There is a method of filling the concave portion 22 with the core-forming curable resin by, for example, vacuuming the inside of the chamber 22 or performing both pressure filling and vacuum suction. When using pressure filling and vacuum suction together, it is preferable to synchronize them. As a result, with the mold 20 being stably fixed, the pressure is gradually increased in the pressure filling, and the pressure is gradually decreased in the vacuum suction, so that the curable resin for core formation is made faster. The reciprocity law to inject can be made compatible. Further, when the concave portion 22 is filled with the core-forming curable resin by utilizing the capillary phenomenon, the inside of the concave portion 22 is preferably decompressed to about 0.1 to 100 kPa in order to promote filling. Furthermore, in order to promote filling, in addition to reducing the pressure in the recess 22, it is also an effective means to lower the viscosity by heating the core-forming curable resin filled from the inlet 26 of the mold 20. is there.

  As the core-forming curable resin, resins such as ultraviolet curable, radiation curable, electron beam curable, and thermosetting can be used. Of these, ultraviolet curable resins and thermosetting resins are preferably used. As the ultraviolet curable resin or thermosetting resin for forming the core, an ultraviolet curable or thermosetting monomer, an oligomer, or a mixture of a monomer and an oligomer is preferably used. Moreover, epoxy type, polyimide type, and acrylic type ultraviolet curable resin are preferably used as the ultraviolet curable resin. Thus, by forming the core with a polymer compound without forming it with a silicon substrate, a glass substrate or the like, the material cost can be kept low, leading to a reduction in manufacturing cost. Moreover, it becomes easy to obtain arbitrary shapes by molding the core with a polymer compound such as ultraviolet curable, radiation curable, electron beam curable, or thermosetting resin.

  The core-forming curable resin is required to have a low viscosity in order to fill the voids (recesses 22) formed between the mold 20 and the clad substrate 30. By setting the viscosity of the curable resin to 10 to 2000 mPa · s, preferably 100 to 1000 mPa · s, and more preferably 300 to 700 mPa · s, the filling speed is increased, and a core having a high accuracy is obtained. Loss can be reduced.

  In addition, in order to reproduce the original shape of the convex portion 12 corresponding to the core formed on the master 10 with high accuracy, it is necessary that the volume change before and after curing of the curable resin is small. For example, a reduction in volume causes waveguide loss. Accordingly, it is desirable that the curable resin has a volume change as small as possible, and a resin having a volume change of 10% or less is used. Preferably, the volume change is in the range of 0.01 to 4%. Lowering the viscosity of the curable resin using a solvent is preferably avoided if possible because the volume change before and after curing is large. In a material having a volume shrinkage of 0.01% or less or a material that expands in volume, the peeling efficiency from the mold 20 decreases, and surface degradation such as surface breakage occurs when peeling from the mold 20. This is not preferable because the smoothness of the optical waveguide decreases and the optical waveguide loss increases.

  In order to reduce the volume change (shrinkage) after curing of the core-forming curable resin, a polymer can be added to the resin. The polymer is preferably compatible with the core-forming curable resin and does not adversely affect the refractive index, elastic modulus, and transmission characteristics of the resin. In addition to reducing the volume change by adding a polymer, the viscosity and the glass transition point of the cured resin can be highly controlled. Examples of the polymer include acrylic, methacrylic acid, and epoxy polymers, but are not limited thereto.

  The refractive index of the cured product of the core-forming curable resin is in the range of 1.2 to 1.6, more preferably in the range of 1.4 to 1.6, and the refractive index of the cured product falls within the range. Resins having different refractive indexes are used.

  The refractive index of the cured product of the core-forming curable resin needs to be larger than that of the film base material (including the clad layer in the step 5 below) to be the base material 30 for clad. The difference in refractive index between the core and the clad (clad base material and clad layer) is 0.01 or more, preferably 0.05 or more.

4) Step of curing filled core-forming curable resin In the step of 3), the core-forming curable resin filled in the recesses 22 is cured. In order to cure the ultraviolet curable resin, an ultraviolet lamp, an ultraviolet LED, a UV irradiation device or the like is used. Further, heating in an oven or the like is used to cure the thermosetting resin.

5) Step of peeling the mold 20 from the clad substrate 30 After the step 4), the mold 20 is peeled from the clad substrate 30. As shown in FIG. 1E, on the peeled clad substrate 30, a resin portion cured in the core 32, the entrance 26 and the exit 28 is formed. Then, as shown in FIG. 1 (F), the cured resin portion in the entrance 26 and the exit 28 is removed by grinding or the like. Thus, the core 32 (optical waveguide core) is obtained. The end surface of the core 32 has mirror smoothness.
Further, the mold 20 used in the steps 1) to 4) can be used as it is for the cladding layer as long as the conditions such as the refractive index are satisfied. In this case, it is not necessary to peel off the mold and it can be used as it is as the cladding layer. To do. In this case, the mold is preferably subjected to ozone treatment in order to improve the adhesion between the mold and the core material.

6) Step of forming a clad layer on the clad substrate 30 on which the core 32 is formed As shown in FIG. 1G, the clad layer 34 is formed on the clad substrate 30 on which the core 32 is formed. Form. As the clad layer 34, a film (for example, a clad base material used in the step 2) is used, a layer obtained by applying and curing a clad curable resin, a solvent for a polymer material Examples thereof include a polymer film obtained by applying a solution and drying. As the curable resin for cladding, an ultraviolet curable resin or a thermosetting resin is preferably used. For example, an ultraviolet curable or thermosetting monomer, an oligomer, or a mixture of a monomer and an oligomer is used.

In order to reduce the volume change (shrinkage) after curing of the curable resin for clad formation, a polymer (for example, methacrylic acid) that is compatible with the resin and does not adversely affect the refractive index, elastic modulus, and transmission characteristics of the resin. Can be added to the clad curable resin (ultraviolet curable resin or thermosetting resin).
When a film is used as the clad layer 34, it is bonded using an adhesive. At this time, it is desirable that the refractive index of the adhesive is close to the refractive index of the film. As the adhesive to be used, an ultraviolet curable resin or a thermosetting resin is preferably used. For example, an ultraviolet curable or thermosetting monomer, an oligomer, or a mixture of a monomer and an oligomer is used. In addition, a polymer similar to the polymer added to the clad layer 34 can be added to this film in order to reduce the volume change (shrinkage) after curing of the ultraviolet curable resin or the thermosetting resin.

  The difference in refractive index between the clad substrate 30 and the clad layer 34 is preferably small, and the difference is within 0.1, preferably within 0.05, more preferably within 0.001 from the viewpoint of light confinement. Most preferably, the difference should be eliminated.

7) Step of curing the clad layer 34 The clad layer 34 obtained in the step 6) is obtained by applying and drying a solution of a clad curable resin and a polymer solution, followed by drying. The polymer film is bonded and cured using an adhesive or the like (ultraviolet curable resin or thermosetting resin) that bonds the base film for cladding. In order to cure the ultraviolet curable resin, an ultraviolet lamp, an ultraviolet LED, a UV irradiation device or the like is used. Moreover, in order to harden a thermosetting resin, the heating etc. in oven are performed.
Through the above steps, the optical waveguide 38 is formed.

8) Step of forming linear recess 36 in optical waveguide 38 As shown in FIG. 1 (H), a machine such as polishing the linear recess 36 on the clad substrate 30 of the optical waveguide 38 formed by the above steps. Formed by processing.
In addition, the formation method of the linear recessed part 36 is not limited to machining. For example, a concave shape may be formed when the clad substrate 30 is molded. In this case, as a method of forming the linear recess 36 in the clad substrate 30, a mold having a convex shape is formed in the same manner as in step 1), and the clad substrate material is spin coated on the upper surface thereof. There is a method of applying by a method, then curing and peeling off. There is also a method of forming a convex shape by providing a convex shape on the rolling roll and pressing the clad substrate with the rolling roll.

As shown in FIG. 2, the linear recess 36 is set to extend in a direction (angle θ in FIG. 2) inclined by 0.1 to 15 ° from the extending direction of the optical waveguide 66. This linear concave portion engages with a linear convex portion provided on an optical waveguide ferrule (described later), and the concave / convex engagement is inclined as the optical waveguide is inserted into the opening of the optical waveguide ferrule. The optical waveguide abuts against the opening side wall of the optical waveguide ferrule, the gap between the side surface of the optical waveguide and the opening side wall of the optical waveguide ferrule disappears, and the amount of insertion of the optical waveguide into the optical waveguide ferrule is restricted. The optical waveguide core is positioned with respect to the ferrule for the optical waveguide.
If the inclination of the linear concave portion from the extending direction of the optical waveguide is less than 0.1 °, the optical waveguide or the optical waveguide ferrule is lighted by the elasticity or the like when the optical waveguide comes into contact with the opening side wall of the optical waveguide ferrule. The insertion amount of the waveguide with respect to the optical waveguide ferrule is likely to be misaligned, and positioning is not performed. If the angle is 15 ° or more, it is necessary to make the opening of the optical waveguide ferrule long in the width direction. Therefore, if the optical waveguide ferrule is made thin, the strength decreases. Need to produce. The inclination of the linear recess from the extending direction of the optical waveguide is preferably 0.5 to 10 °, and more preferably 1 to 5 °.

  The cross-sectional shape of the linear recess in FIGS. 1 and 2 is a rectangular shape, but is not limited to the shape of the present invention, and may be substantially V-shaped as shown in FIG. In either case, the cross-sectional shape of the linear convex portion of the ferrule for optical waveguide described later is set to have a concave-convex relationship.

<Ferrule for optical waveguide and optical connector>
The ferrule for an optical waveguide of the present invention is characterized by having an uneven relationship with the optical waveguide of the present invention and having an opening into which the optical waveguide is fitted.
Further, the optical connector of the present invention is characterized in that an optical waveguide ferrule having an opening portion into which the optical waveguide is fitted is fitted to the optical waveguide. .

  As shown in FIG. 4, the ferrule 70 for an optical waveguide has an opening 44 for connecting the optical waveguide 38. The opening 44 is formed with a linear convex portion 46 with high accuracy with which the linear concave portion 36 formed in the optical waveguide 38 is engaged. When the optical waveguide 38 is inserted and fitted into the opening 44 of the optical waveguide ferrule 70, the linear concave portion 36 of the optical waveguide 38 and the linear convex portion 46 of the optical waveguide ferrule 70 are The front end surface of 38 and the front end surface of the optical waveguide ferrule 70 are set to be flush with each other.

  As a material used for the ferrule 70 for an optical waveguide, an epoxy resin, polyphenylene sulfide, or the like is used. Further, when an inorganic glass powder such as quartz is added to these materials, the mechanical strength and the shape accuracy are improved. These materials are used to form by injection molding, transfer molding, injection molding or the like.

  FIG. 5 is a partial cross-sectional perspective view when the cross-sectional shapes of the linear concave portion 36 of the optical waveguide 38 and the linear convex portion 46 of the ferrule 70 for the optical waveguide are rectangular, unlike FIG. As shown in FIG. 5, the opening 44 of the optical waveguide ferrule 70 is formed with a linear protrusion 46 that engages with the linear recess 36 formed in the optical waveguide 38. When inserted into the opening 44 of the waveguide ferrule 70, as shown in FIG. 5B, the linear concave portion 36 of the optical waveguide 38 and the linear convex portion 46 of the optical waveguide ferrule 70 are in contact with each other. The front end surface of the optical waveguide 38 and the front end surface of the ferrule 70 for the optical waveguide are fitted to be flush with each other. In this way, the optical waveguide 38 and the optical waveguide ferrule 70 are fitted together to form the optical connector 50 of the present invention.

  When the optical waveguide 38 is inserted into the opening of the optical waveguide ferrule 70, the linear convex portion 46 of the optical waveguide ferrule 70 and the linear concave portion 36 of the optical waveguide 38 are engaged, and the side surface of the optical waveguide 38 is further engaged. Comes into contact with the side surface of the opening 44 of the ferrule 70 for the optical waveguide, and insertion is restricted. The insertion is regulated, and an adhesive is poured between the optical waveguide ferrule 70 and the optical waveguide 38 to fix the optical waveguide 38 to the optical waveguide ferrule 70. It is preferable to use an adhesive that does not apply a force such as bending or distortion to change the relative position of the optical waveguide 38 and the optical waveguide ferrule 70 by volume change (shrinkage). The adhesive used for bonding 30 (see FIG. 1G) is preferably used.

A pin hole 42 is formed in the connection surface of the optical waveguide ferrule 70. One end of the pin 45 is inserted into the pin hole 42, and the other end of the pin 45 is inserted into the pin hole 43 of the optical fiber connector 41 to be connected. Insert. Thereby, the optical waveguide ferrule 70 is positioned and connected to the optical fiber connector 41, and the optical axis of the core 66 of the optical waveguide ferrule 70 coincides with the optical axis of the optical waveguide 38 of the optical fiber connector 41.
And the ferrule 70 for optical waveguides and the optical fiber connector 41 are fixed using the spring clamp which is not shown in figure.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[Example 1]
<Preparation of master>
A thick film resist (manufactured by Micro Chemical Co., Ltd., SU-8) was applied to the silicon substrate 52 by spin coating, prebaked at 80 ° C., exposed through a photomask, and developed. As a result, as shown in FIG. 6A, eight core convex portions 54 (width: 50 μm, height: 50 μm, length: 150 mm, proximity width 250 μm) having a square cross section were formed. This was post-baked at 120 ° C. to produce a master 56 for core production.

<Production of mold>
Next, after the release material is applied to the master 56, as shown in FIG. 6B, a thermosetting liquid dimethylsiloxane rubber (manufactured by Dow Corning Asia Ltd .: SYLGARD 184, viscosity 5000 mPa · s) and a mold material are used. A mixture of the curing agents (molding material 58) is poured and cured by heating at 120 ° C. for 30 minutes. Then, the mold material 58 is peeled from the master 56, and as shown in FIG. 6C, a mold 60 (a mold thickness of 3 mm) in which a core recess 62 is formed is produced. Next, an entrance for filling the ultraviolet curable resin (see FIG. 1C) and an outlet for discharging the resin (ultraviolet curable resin) so that both ends of the core recess 62 are exposed. A discharge port was formed.

  The mold 60 had a surface energy of 22 dyn / cm, a shear rubber hardness of 60, a surface roughness of 10 nm or less, an ultraviolet transmittance of 80% or more, and was transparent and well observed.

<Production of Clad Base Material and Optical Waveguide Core>
As shown in FIG. 6D, a clad base material 64 (manufactured by JSR Corporation, Arton film, refractive index 1.510) having a thick film of 188 μm that is slightly larger than the mold 60 was adhered to the mold 60. .

Next, a few drops of UV curable resin (JSR Co., Ltd., PJ3001) with a viscosity of 1300 mPa · s are dropped at the entrance at one end of the mold 60, and by capillary action, as shown in FIG. The recess 62 was filled with an ultraviolet curable resin. Then, 50 mW / cm ² of UV light was irradiated through the mold 60 for 5 minutes to cure the ultraviolet curable resin, and the mold 60 was peeled from the clad substrate 64.

  As a result, as shown in FIG. 6 (F), the core 66 having the same shape as the convex portion 54 of the master 56 was formed on the clad substrate 64. In this example, the refractive index of the core 66 was 1.591.

<Clad layer creation>
Next, as shown in FIG. 6G, a clad layer 68 was bonded to the surface of the clad substrate 64 on which the core 66 was formed. For the clad layer 68, an ultraviolet curable adhesive (manufactured by JSR Corporation) having a refractive index after curing of 1.510 which is the same as that of the clad substrate 64 is used. Then, 50 mW / cm ² of UV light was irradiated through the mold 60 for 5 minutes to adhere the clad layer 68 to the clad substrate 64. In this way, the optical waveguide 38 was formed.

<Formation of linear recess>
Next, using a dicing saw (manufactured by DISCO Corporation, DAD321, blade width 0.10 mm), as shown in FIG. 6 (H), the optical waveguide 38 is positioned at 100 μm from the outermost core 66. Is ground in parallel with the extending direction of the core 66, and the dimension in the direction (width direction) orthogonal to the extending direction of the core 66 is set to 2 mm. The core 66 was ground so that the dimension in the extending direction was 100 mm.

  Then, as shown in FIG. 2, when the optical waveguide 38 is assembled on one surface of the optical waveguide 38, the width 0 of the surface in the width direction of the surface optically connected to the optical fiber, that is, a position 1 mm from the end portion, is obtained. A rectangular linear recess 36 having a thickness of 0.1 mm and a depth of 0.1 mm was formed with an inclination of 1 ° with respect to the extending direction of the core 66. The linear concave portion 36 engages with a linear convex portion 46 formed on the optical waveguide ferrule 70 described later to position the optical waveguide ferrule 70 and the optical waveguide 38.

<Production of optical waveguide ferrule>
The optical waveguide ferrule 70 was formed by transfer molding of an epoxy resin to which quartz glass powder was added. An opening 44 is formed in the ferrule 70 for the optical waveguide and has a substantially rectangular shape when viewed from one direction. As shown in FIG. 4, the optical waveguide 38 is fitted in the opening 44, and the core 66 of the optical waveguide 38 is formed on the bottom surface 44A of the opening 44 on the side optically connected to the optical fiber connector. A linear convex portion 46 having a width of 0.1 mm and a height of 0.1 mm is formed at an inclination of 1 ° with respect to the stretching direction. Further, as the linear concave portion 36 of the optical waveguide 38 and the linear convex portion 46 of the optical waveguide ferrule 70 are engaged and inserted, the side surface of the opening 44 that the optical waveguide 38 is pressed along the inclination, and the optical fiber The linear convex portion 46 is formed so that the width center of the linear convex portion 46 on the side optically connected to the connector is 1 mm. In this manner, the optical waveguide 38 and the optical waveguide connector 70 are engaged, and an ultraviolet curable adhesive (manufactured by JSR Corporation) is hung between the side surface of the opening 77 and the side surface of the optical waveguide 38, and 50 mW / The UV curable adhesive was cured by irradiating cm ² of UV light for 5 minutes, and the optical waveguide 38 was fixed to the optical waveguide connector 70.

  A pin hole 42 is formed in the connection surface of the optical waveguide ferrule 70. One end of the pin 45 is inserted into the pin hole 42, and the other end of the pin 45 is inserted into the pin hole 43 of the optical fiber connector 41 to be connected. Insert. Thereby, the optical waveguide connector 70 is positioned and connected to the optical fiber connector 41, and the optical axis of the core 66 of the optical waveguide ferrule 70 coincides with the optical axis of the optical waveguide 38 of the optical fiber connector 41.

And the optical waveguide connector 70 and the optical fiber connector 41 were fixed using the spring clamp which is not shown in figure.
In the optical waveguide 38 and the optical waveguide ferrule 70 manufactured by this manufacturing method, the linear concave portion 36 and the linear convex portion 46 are formed with an extending direction and an inclination of the core 66, whereby the optical waveguide ferrule 70 has an optical waveguide. When the optical waveguide 38 is assembled, the optical waveguide 38 is inserted into the opening 44 by engaging the linear recess 36 of the optical waveguide 38 with the linear protrusion 46 of the optical waveguide ferrule. In response to the reaction from the convex portion 46, the optical waveguide 38 is pressed against the side surface of the opening 44, and positioning is performed in the extending direction of the core 66 and the direction orthogonal to the extending direction of the core 66. Accordingly, the optical axis of the core 66 of the optical waveguide 38 and the optical axis of the optical waveguide 67 of the optical fiber connector 41 connected to the ferrule 70 for the optical waveguide coincide only by connecting the optical waveguide 38 to the ferrule 70 for the optical waveguide. This eliminates the need for alignment work. For this reason, the connection work is not complicated, and the cost can be kept low.

  Further, when the optical waveguide ferrule 70 and the optical fiber connector 41 are connected, it is not necessary to align the end surface of the core 66 against the end surface of the optical waveguide 67 of the optical fiber connector 41. Therefore, there is no worry that the optical connection loss increases.

  Further, since the linear recess 36 is formed at a position on the projection area of the core 66 on the lower surface of the optical waveguide 38, a space for forming the recess 72 is not required in the optical waveguide 38. Therefore, the width of the optical waveguide 38 is reduced. Directional dimensions do not increase. Therefore, even if the number of cores 66 is increased, the dimension in the width direction can be suppressed to a size that allows the cores 66 to be arranged in parallel. Even if the waveguide 38 is formed, bending is less likely to occur. As a result, an increase in optical connection loss such as optical axis misalignment can be suppressed.

[Example 2]
First, in the same manner as in Example 1, an optical waveguide 38 was produced.
<Formation of linear recess>
In the same manner as in Example 1, using a dicing saw (manufactured by DISCO Corporation, DAD321, blade width 0.10 mm), the optical waveguide 38 is extended in the extending direction of the core 66 at a position of 100 μm from the outermost core 66. And the dimension in the direction (width direction) orthogonal to the extending direction of the core 66 is set to 2 mm. Moreover, it grind | polished so that the dimension of the extending | stretching method of the core 66 might be set to 100 mm.

  Then, as shown in FIG. 7, when the optical waveguide 38 is assembled as an optical connector on the one surface of the optical waveguide 38, the tip shape from the center in the width direction of the surface optically connected to the optical fiber, that is, 1 mm from the end. Using a V-shaped blade (tip angle 90 °), a straight recess 36 having a width of 0.1 mm, a depth of 0.1 mm, and a tip angle of 90 ° having a substantially V-shaped cross-section is formed by extending the core 66. In contrast, it was formed with an inclination of 1 °. The V-shaped linear recess 36 is for positioning an optical waveguide ferrule 70 and an optical waveguide 38, which will be described later. In FIG. 7, the same components as those in FIG.

<Production of optical waveguide ferrule>
As shown in FIG. 7, the optical waveguide ferrule 70 was formed with an opening 44 so as to have a substantially rectangular shape when viewed from one direction by injection molding using polyphenylene sulfide as a material. As shown in FIG. 7, the opening 44 is set so that the optical waveguide 38 is fitted, and the core 66 of the optical waveguide 38 is formed on the bottom surface 44A of the opening 44 on the side optically connected to the optical fiber connector. A V-shaped linear convex portion 46 having a width of 0.1 mm, a height of 0.1 mm, and a tip angle of 90 ° is formed at an inclination of 1 ° with respect to the stretching direction. The size of the opening 44 is such that the vertical dimension is several μm larger than the thickness of the optical waveguide 78 and the width dimension is 2.18 mm. Further, as the V-shaped linear concave portion 36 of the optical waveguide 38 and the linear convex portion 46 of the optical waveguide ferrule 70 are engaged and inserted, the optical waveguide 38 is pressed along the inclination of the opening 44. The V-shaped linear convex portion 46 is formed so that the width center of the linear convex portion 46 on the side in the width direction and the side optically connected to the optical fiber connector is 1 mm. As such, the optical waveguide 38 and the optical waveguide ferrule 70 are engaged, and an ultraviolet curable adhesive (manufactured by JSR Corporation) is hung between the side surface of the opening 44 and the side surface of the optical waveguide 38. The UV curable adhesive was cured by irradiating 50 mW / cm ² of UV light for 5 minutes, and the optical waveguide 38 was fixed to the ferrule 70 for the optical waveguide.

A pin hole 42 is formed in the connection surface of the optical waveguide ferrule 70. One end of the pin 45 is inserted into the pin hole 42, and the other end of the pin 45 is inserted into the pin hole 43 of the optical fiber connector 41 to be connected. Inserted. Thus, the optical waveguide ferrule 70 is positioned and connected to the optical fiber connector 41, and the optical axis of the core 66 of the optical waveguide ferrule 70 coincides with the optical axis of the optical waveguide 38 of the optical fiber connector 41.
And the ferrule 70 for optical waveguides and the optical fiber connector 41 were fixed using the spring clamp which is not shown in figure.

  In the optical waveguide 38 and the optical waveguide ferrule 70 manufactured by this manufacturing method, the linear concave portion 36 and the linear convex portion 70 are formed with the extending direction and the inclination of the core 66, whereby the optical waveguide ferrule 70 When the optical connector is assembled with the optical waveguide 38, the linear recess 36 of the optical waveguide 38 is engaged with the linear protrusion 46 of the ferrule for the optical waveguide and inserted into the opening 44. 36 receives a reaction from the linear convex portion 46 of the ferrule 70 for the optical waveguide, and presses the optical waveguide 38 against the side surface of the opening 44 and the opposite surface on which the linear convex portion 46 is formed, and the extending direction of the core 66, and Positioning is performed in a direction orthogonal to the extending direction of the core 66. Accordingly, the optical axis of the core 66 of the optical waveguide 38 and the optical axis of the optical fiber connector 41 of the optical fiber connector 41 connected to the optical waveguide ferrule 70 coincide only by connecting the optical waveguide 38 to the optical waveguide ferrule 70. This eliminates the need for alignment work. For this reason, the connection work is not complicated, and the cost can be kept low.

  Further, by making the cross-sectional shape of the positioning projections and recesses substantially V-shaped, the optical waveguide 78 faces not only the width direction of the optical waveguide ferrule 70 but also the surface on which linear convex portions are formed. Since the optical axis position accuracy can be further increased.

  In the present embodiment, the tip angles of the linear concave portions 36 and the linear convex portions 46 having a V-shaped cross section are set to 90 °, but this angle is not limited to 90 ° and may be larger than 90 °. Also, it may be smaller than 90 °.

It is a perspective view which shows the manufacturing process of the optical waveguide which concerns on one Embodiment of this invention. It is a perspective view showing an optical waveguide concerning one embodiment of the present invention. It is a perspective view which shows the optical waveguide which concerns on another embodiment of this invention. It is a perspective view which shows the manufacturing process of the optical connector which concerns on one Embodiment of this invention. 1A and 1B are a perspective view showing an optical waveguide according to an embodiment of the present invention, and a perspective view showing an optical connector. It is a perspective view which shows the manufacturing process of the optical waveguide which concerns on the Example of this invention. It is a perspective view corresponding to FIG. 4 which shows the manufacturing process of the optical connector which concerns on the Example of this invention. It is a perspective view which shows the conventional optical waveguide and the ferrule for optical waveguides.

Explanation of symbols

30 Clad base material (clad part)
36 linear recess 38 optical waveguide 41 optical fiber connector 44 opening 46 linear protrusion 50 optical connector 66 core (optical waveguide core)
67 Optical waveguide (connector optical waveguide core)
70 Ferrule for optical waveguide

Claims (8)

An optical waveguide having an optical waveguide core for transmitting an optical signal, and a plate-like clad portion surrounding the optical waveguide core,
An optical waveguide characterized in that a linear recess extending in a direction inclined by 0.1 to 15 ° from the extending direction of the optical waveguide core is formed on at least one surface of the clad portion.   The optical waveguide according to claim 1, wherein a cross-sectional shape of the linear recess is rectangular.   The optical waveguide according to claim 1, wherein a cross-sectional shape of the linear recess is substantially V-shaped.   4. The optical waveguide according to claim 1, wherein at least one of the optical waveguide core and the clad portion is formed of a polymer compound. 5.   5. A ferrule for an optical waveguide, characterized in that the optical waveguide according to any one of claims 1 to 4 has a concave-convex relationship and has an opening into which the optical waveguide is fitted.   6. The ferrule for an optical waveguide according to claim 5, further comprising a linear convex portion that fits into the linear concave portion of the optical waveguide when the optical waveguide is inserted into the opening.   The optical waveguide according to any one of claims 1 to 4, wherein an optical waveguide ferrule having an opening to which the optical waveguide is fitted is fitted to the optical waveguide. A featured optical connector.   8. The optical connector according to claim 7, wherein when the optical waveguide is fitted into the optical waveguide ferrule, a front end surface of the optical waveguide and a front end surface of the ferrule for the optical waveguide are flush with each other. .

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