JP2006031052A - Ferrule - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ferrule which can be utilized in an optical waveguide module having stable temperature characteristics and moist heat characteristics even in a severe use environment. <P>SOLUTION: The ferrule is a ferrule which can be utilized in the optical waveguide module for optically coupling an optical fiber which constitutes at least part of a transmission line with a waveguide component having an optical waveguide on a waveguide substrate made of silicon or silica glass as the first material, and which is made of a plastic material as the second material, in which through holes which specify the installation position of the end of the optical fiber are provided, The second material satisfies a relationship of ¾ΔL/(E1/E2)¾<3.0×10<SP>-6</SP>(°C<SP>-1</SP>) with respect to the first material forming the waveguide substrate, where ΔL is a difference in thermal expansion coefficient between the first material and the second material, E1 is a modulus of elasticity of the first material, and E2 is a modulus of elasticity of the second material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a ferrule that holds one end of an optical fiber, and optically couples the optical fiber with a waveguide component as an optical component having an optical waveguide on a substrate made of a material different from the ferrule. In particular, the present invention relates to a ferrule capable of obtaining excellent temperature and wet heat characteristics in relation to the substrate material.

  With the development of optical communication technology in recent years, there is an increasing demand for branching elements, multiplexing / demultiplexing elements and the like for branching or multiplexing light of a predetermined wavelength. Further, in order to satisfy the demand for higher density of these optical components, quartz glass-based optical planar waveguide circuits (waveguide components) have been used. This planar optical waveguide has low waveguide loss (transmission loss associated with optical branching) and enables low-loss connection with an optical fiber.

  As the above planar optical waveguide, for example, in Patent Document 1, after a glass film is formed by a flame hydrolysis method (FHD method) or the like, a circuit pattern is formed by a reactive ion etching method (RIE method) which is an application of semiconductor technology. There is disclosed a buried-type quartz optical waveguide obtained by forming a clad portion and forming a clad portion.

  When such a waveguide component is used for an optical component (for example, an optical waveguide module), an input / output optical fiber is generally connected to the optical waveguide formed in the waveguide component. For connection between the waveguide component and the optical fiber, for example, as shown in Non-Patent Document 1, a quartz ferrule with precision processing and an optical fiber arranged and fixed is used. A method of adhering and fixing to the end face of the waveguide component using an ultraviolet curable adhesive is generally used.

Further, for example, in Patent Document 2, a ferrule is made of quartz glass that transmits ultraviolet rays, and the end face of the ferrule and the end face of the waveguide part are solidified uniformly and in a short time, thereby shortening the working time and each of these end faces. A technique for reducing the possibility of shifting is disclosed.
JP 58-105111 A JP-A-6-51155 IEEE Photonic Technology Letters, vol.4, No.8, (1992), pp. 906-908

  When optically connecting an optical fiber and an optical waveguide built into a waveguide component, the most important thing is that the connecting portion is misaligned (the core end face of the optical fiber and the core end face via an adhesive). In other words, it is necessary to reduce transmission loss (hereinafter referred to as transmission loss at the connecting portion) due to misalignment of the optical waveguide end faces facing each other. For example, the diameter (core diameter) of the optical waveguide built in the waveguide component is 10 μm or less, and the coupling loss between such an optical waveguide and an optical fiber (core of the optical fiber) is made less than 0.3 dB. In this case, the amount of displacement at the connecting portion must be suppressed to within 1 μm. On the other hand, in the case of an optical waveguide module in which a waveguide component (particularly a waveguide substrate) and a ferrule each made of a material having a different coefficient of thermal expansion are bonded and fixed with an adhesive having a predetermined strength, the connection portion is In this case, each core end face is displaced.

Therefore, an optical waveguide module that can be used in a harsh environment (as a temperature characteristic specification of components used indoors, 10 cycles (48 hours) with a temperature variation of −10 ° C. to 60 ° C. is common. For example, Bellcore In order to obtain 42 cycles (336 hours) with a temperature variation of −40 ° C. to 75 ° C. in the temperature characteristic specification of TR-NWT-001209 manufactured by the company, a ferrule that holds the end of the optical fiber is introduced as described above. In general, it is made of quartz glass having substantially the same thermal expansion coefficient as the constituent material of the waveguide substrate to obtain desired temperature characteristics and wet heat characteristics.
FIG. 29 is a diagram showing the relationship between the amount of misalignment between the end face of the optical waveguide and the core end face of the optical fiber and the transmission loss of the single mode optical waveguide having a mode field diameter of 10 μm.

  However, paying attention only to the ferrule manufacturing technology, when manufacturing a ferrule using the above-mentioned quartz glass, as disclosed in the above-mentioned literature, a material that is difficult to process such as glass is highly accurate within 1 μm. It is necessary to process (processing of the position fixing groove for the optical fiber), and further, it is necessary to configure the optical fiber end portion by a plurality of constituent members (the optical fiber end portion is composed of two upper and lower quartz plates). Sandwiched between glass plates). On the other hand, for example, when a ferrule is formed of a plastic material, it is shown in, for example, “DEVELOPMENT OF 16-FIBER CONNECTORS FOR HIGH-SPEED LOW-LOSS CABLE CONNECTION” (INTERNATIONAL WIRE AND CABLE SYMPOSIUM PROCEEDINGS 1993, pp. 244-249). In this way, plastic molding can be performed in one step, and through holes (with continuous inner walls) that define the installation position by inserting the end of the optical fiber are also made with high precision during this plastic molding. Can do. When the ferrule is made of a plastic material in this way, it is not necessary to prepare a plurality of members and grip the fiber end in order to obtain a gripping structure of the optical fiber end (at the same time as the end of the optical fiber during plastic molding). Since a through-hole that can precisely define the installation position can be formed, there is no need to sandwich and hold the tip of the optical fiber from the top and bottom, and high-precision processing technology is not required (the through-hole is each Since each optical fiber is made with high accuracy, there is no need for precision processing such as forming a position fixing groove for the optical fiber in the holding member), and the plastic material is suitable as a constituent material of the ferrule.

  In view of the above-mentioned circumstances, the present invention relates to a ferrule made of a plastic material that is easy to perform continuous molding and high-precision processing at a low cost instead of a material that is difficult to process such as glass. A ferrule for obtaining an optical waveguide module having stable temperature characteristics and wet heat characteristics even in a severe use environment in an optical waveguide module including waveguide components (particularly, a waveguide substrate) and ferrules made of different materials. The purpose is to provide.

In the ferrule according to the present invention, an optical fiber constituting at least a part of a transmission line and an optical waveguide constituting at least a part of the transmission line on a waveguide substrate made of silicon or quartz glass as a first material And an optical waveguide module for optically coupling an optical functional component that realizes a predetermined function, and is made of a second material different from the first material, and the optical fiber A through-hole that defines the installation position of the end is provided. For example, a plastic material is suitable as the second material.
When the ferrule is used in an optical waveguide module, for example, in order to optically couple one end of the optical fiber and one end of the optical waveguide, the ferrule holds the one end of the optical fiber (an end portion of the optical fiber). Is installed in a state of being inserted into a through-hole having a continuous inner wall), and is fixed so that its end face faces the end face of the waveguide component by an adhesive having a predetermined strength. The optical fiber is composed of a core for propagating light of a predetermined wavelength and a clad covering the core. Usually, the clad surface is coated with an acrylate resin, or the surface is made of plastic. Used in a state covered with The optical fiber is not limited to a single-core fiber, and a plurality of optical fibers (each optical fiber may be coated with an acrylate resin colored in a different color) are integrally covered with a plastic material. Tape type fibers are also included.

In particular, when the ferrule is applied to an optical waveguide module, an optical waveguide module whose coupling loss is 0.3 dB or less even under severe temperature fluctuations (for example, temperature fluctuation in the range of −40 ° C. to + 75 ° C.) is realized. Therefore, the first material constituting the substrate part of the waveguide component and the second material constituting the ferrule have a difference between the thermal expansion coefficient of the first material and the second material. Is ΔL, the elastic modulus of the first material is E1, and the elastic modulus of the second material is E2.
| ΔL / (E1 / E2) | <3.0 × 10 ⁻⁶ (° C. ⁻¹ ) (1)
Satisfies the relationship.

When the plastic material constituting the ferrule according to the present invention is a phenolic epoxy resin containing a predetermined amount of quartz filler, its thermal expansion coefficient may be 10 × 10 ⁻⁶ (° C. ⁻¹ ) or less, but it is even better. In order to obtain a high temperature characteristic, the thermal expansion coefficient is preferably 6 × 10 ⁻⁶ (° C. ⁻¹ ) or less.

Further, the content of the quartz filler contained in the phenolic epoxy resin may be 85% by weight or more and 95% by weight or less, but in order to obtain more excellent wet heat characteristics, the content is 90% by weight. The content is preferably 95% by weight or less. At this time, the elastic modulus of the above-described phenolic epoxy resin is 5000 (kg / mm ² ) or less.

When an optical waveguide module is configured using each constituent member made of different materials, such as a waveguide substrate made of silicon or quartz glass and a ferrule made of a plastic material, the above formula (1) As shown, by making the effective thermal expansion coefficient of the ferrule constituent material with respect to the constituent material of the waveguide substrate less than 3 × 10 ⁻⁶ (° C. ⁻¹ ), the deviation amount of each core end face caused by temperature fluctuation can be reduced. 1 μm or less, that is, the coupling loss can be suppressed to 0.3 dB or less. At least the inventors contain at least 75 wt% or more of a quartz filler in order to obtain the ferrule applicable to the quartz glass substrate constituting a part of the waveguide component (to satisfy the above condition). In order to obtain a ferrule made of a plastic material (coefficient of thermal expansion of 3 × 10 ⁻⁶ ° C. ⁻¹ or more and 10 × 10 ⁻⁶ ° C. ⁻¹ or less) and applicable to a silicon substrate, at least 85% by weight or more It was confirmed that it was necessary to comprise a plastic material containing a quartz filler (having a thermal expansion coefficient of 3 × 10 ⁻⁶ ° C. ⁻¹ or more and 6 × 10 ⁻⁶ ° C. ⁻¹ or less). At this time, it was also confirmed that the optical waveguide module having the above configuration can obtain good temperature characteristics.

On the other hand, the theoretical limit value of the quartz filler that can be contained in the plastic material is 96 volume% in the December 1994 issue of industrial materials (Vol. 42, No. 15, pp. 112-116). The inventors have already obtained a plastic ferrule containing 94% by weight of quartz filler. Furthermore, when the wet heat characteristics of the optical waveguide module comprising a quartz glass waveguide substrate and a plastic ferrule were evaluated under predetermined conditions, the lower limit value of the quartz filler contained in the plastic material was 80% by weight to 90%. It has also been confirmed that it exists between weight percent. Moreover, since the theoretical limit value of the quartz filler content is 96% by volume, the lower limit value of the thermal expansion coefficient of the plastic material as the constituent material of the ferrule is 3 × 10 ⁻⁶ (° C. ⁻¹ ) ( (See FIG. 19). In addition, volume% and weight% are substantially in agreement.

  Therefore, regardless of whether a silicon substrate or a quartz glass substrate is used, by applying a plastic material containing at least 85 wt% to 95 wt% quartz filler as a constituent material of the ferrule, temperature characteristics and wet heat characteristics In either case, a good optical waveguide module can be obtained.

In particular, a phenolic epoxy resin containing a predetermined amount of quartz filler and having a thermal expansion coefficient of 10 × 10 ⁻⁶ (° C. ⁻¹ ) or less is applied to the quartz glass substrate as a constituent material of the ferrule. In addition, the silicon substrate includes a phenolic epoxy resin containing a predetermined amount of quartz filler as a constituent material of the ferrule and having a thermal expansion coefficient of 6 × 10 ⁻⁶ (° C. ⁻¹ ) or less. Thus, the temperature characteristic specifications of the parts used in the room (10 cycles (48 hours) with a temperature fluctuation of −10 ° C. to 60 ° C.), and further the temperature characteristic specifications of Bellcore TR-NWT-001209 (− An optical waveguide module satisfying 42 cycles (336 hours) at a temperature variation of 40 ° C. to 75 ° C. is obtained.

  In addition, by adjusting the content of the quartz filler in the ferrule to 90 wt% or more and 95 wt% or less, the wet heat characteristic specification of TA-NWT-001221 manufactured by Bellcore (75 ° C., 90 ± 5 RH, 500 hours) ) Is reliably obtained.

  An embodiment of the present invention will be described below with reference to FIGS. In addition, the same code | symbol is attached | subjected to the same part in a figure, and description is abbreviate | omitted.

  (First embodiment)

  First, before describing the ferrule according to the present invention, an optical waveguide module in which the ferrule is used and a manufacturing method thereof will be described. FIG. 1 is a view for explaining an assembly process of an optical waveguide module using a ferrule according to the present invention, and FIG. 2 is a perspective view showing a configuration of the entire optical waveguide module using the ferrule. In this method of manufacturing an optical waveguide module, first, a ferrule 3 bonded and fixed by an adhesive 5 with the end portion of the input / output optical fiber 4 inserted into the through hole, and light of a predetermined wavelength on the waveguide substrate. And a waveguide component 1 having an optical waveguide (core) that propagates through the substrate. Furthermore, in order to obtain sufficient adhesive strength between the ferrule 3 and the waveguide component 1, a reinforcing member 2 is prepared. The reinforcing member 2 has a bottom surface 2b that is bonded and fixed to the upper surface 1b of the waveguide component 1 with an adhesive, and a side surface 2a that faces the bonded end surface 3c of the ferrule 3.

  Next, the following steps are performed on the bonded end surface 1a of the waveguide component 1 in which the reinforcing member 2 is already bonded and fixed to the upper surface 1b and the bonded end surface 3c of the ferrule 3 holding the end of the optical fiber 4, respectively. Optical polishing is performed in order. The bonding surface (side surface) 2 a of the reinforcing member 2 is polished at the same time when the end surface of the waveguide component 1 is polished, and the core end surface of the optical fiber 4 is also polished at the same time when the end surface of the ferrule 3 is polished.

First step (rough polishing step): exposing each end face with 800-2000 # rough polishing paper Second step (medium polishing step): removing surface scratches on each end face with 6-9 μm diamond abrasive grains Third Process (finish polishing process): Further remove surface scratches on each end face with 1 to 3 μm diamond abrasive grains. Fourth process (buff polishing process): each with 0.3 μm or less cesium oxide abrasive grains or silicon dioxide abrasive grains. In this polishing step, the propagation direction of light in the bonding portion 13 (this direction is the direction of the optical fiber 4 to the ferrule 3 is removed. The angle of each end face may be shifted from 90 degrees. The angle adjustment in this case is performed in the first step. In addition, since polishing methods other than the above-described polishing methods are known, the polishing method is selected as necessary.

Subsequently, the optical input / output end face 1 a of the waveguide component 1 and the adhesive end face 3 c of the ferrule are bonded to each other with the adhesive 6, and then the end face of the optical waveguide formed in the waveguide part 1 and the optical fiber 4 are bonded. Align the core end face. At this time, the optical fiber 4 is already fixed to the ferrule 3 with the adhesive 5 having a predetermined strength. Further, between the bottom surface 2b of the reinforcing member 2 and the top surface 1a of the waveguide component 1, and between the bonding surface 2a of the reinforcing member 2 and between the bonding surface 1a of the waveguide component 1 and the bonding surface 3c of the ferrule 3, It is bonded with an ultraviolet curable or thermosetting adhesive having an adhesive strength of 50 kg / cm ² or more, preferably 100 kg / cm ² or more.

  The alignment of the optical waveguide end face of the waveguide component 1 and the core end face of the optical fiber 4 is supported by a precision moving stage as shown in, for example, US Pat. No. 4,744,619. In this state, light of a predetermined wavelength is incident from one input / output end face of the optical waveguide of the waveguide component 1 and is emitted from the optical fiber 4 optically connected to the other input / output end via the adhesive. This is performed while monitoring the intensity of the emitted light. That is, alignment is performed by moving the waveguide component 1 or the ferrule so that the light intensity of the emitted light is maximized.

  An optical waveguide end face of the waveguide component 1 (which constitutes a part of the input / output end face of the waveguide part 1) and a core end face of the optical fiber 4 (a part of the adhesive end face 3c of the ferrule 3) When the alignment is completed, the adhesive is solidified by irradiating the bonded portion with ultraviolet light or heating to a predetermined temperature. The ferrule according to the present invention as shown in FIG. 2 is used by performing this series of operations (adhesion of each end face in the bonding portion 13 -alignment-solidification of the adhesive) on both input / output end faces of the waveguide component 1. The obtained optical waveguide module is obtained.

  Next, the structure of the ferrule 3 according to the present invention will be described with reference to FIGS. FIG. 3 is a development view showing the structure of the ferrule 3. In the figure, 3a indicates the upper surface of the ferrule 3, 3b indicates the side surface, 3c indicates the front surface (adhesion surface), 3d indicates the bottom surface, and 3e indicates the back surface (the side on which the optical fiber 4 is inserted). On the upper surface 3 a of the ferrule 3, a window 310 is provided in advance on the ferrule 3 with the tip of the optical fiber 4. A guide groove 330 a is provided in advance in the base portion 330 visible from the window 310 in order to facilitate the insertion of the tip of the optical fiber 4 into the through hole 340. Further, since the tip of the optical fiber 4 and the ferrule 3 are bonded and fixed at the pedestal portion, the window 310 also functions as an adhesive inlet. The rear surface 3e of the ferrule 3 is provided with an opening 320 for inserting the tip portion of the optical fiber 4 into the ferrule. In addition, an opening 340 a of a through-hole 340 formed in advance is located on the front surface 3 c of the ferrule 3 (a surface directly facing the input / output end surface 1 a of the waveguide component 1).

  4 is a diagram showing a cross-section along the line C-C of the ferrule 3 shown in FIG. 3. The tip portion of the optical fiber 4 is the ferrule from the back surface 3e toward the front surface 3c in the direction of the arrow H. Inserted inside. 5 is an enlarged view of the cross section of the through-hole 340 in the ferrule cross-sectional view shown in FIG. 4, and the inside of the through-hole 340 is the tip of the optical fiber 4 as can be seen from this figure. In order to prevent insertion of the portion 340b having a considerably larger diameter than the diameter of the optical fiber and the installation position of the tip portion of the optical fiber 4 (horizontal displacement relative to the front surface 3c), The portion 340 c has a diameter substantially equal to the diameter of the optical fiber 4.

  As already described, the first material (for example, silicon, quartz glass, etc.) suitable for constituting the substrate of the waveguide component 1 and the second material (for example, plastic) suitable for constituting the ferrule 3 are used. Material). Therefore, even if the alignment is performed accurately and the waveguide component 1 and the ferrule 3 are bonded and fixed, for example, in an environment where a temperature variation of about −40 ° C. to + 75 ° C. occurs, the difference is caused by the difference in thermal expansion coefficient of each material. As a result, a positional shift between the optical waveguide end face of the waveguide component 1 and the core end face of the optical fiber 4 occurs (coupling loss increases).

Therefore, in the present invention, the effective thermal expansion coefficient for the first material suitable for the waveguide substrate of the waveguide component 1 is used so that the coupling loss is 0.3 dB or less even under the above temperature fluctuation. | ΔL / (E1 / E2) | is composed of a second material having a ^{value of} less than 3 × 10 ⁻⁶ ° C.− ¹ . In the above equation showing the effective thermal expansion coefficient, ΔL is the difference between the thermal expansion coefficient of the first material and the thermal expansion coefficient of the second material, E1 is the elastic modulus of the first material, and E2 is the second material. Elastic modulus.

In particular, the inventors have a waveguide substrate made of silicon or quartz glass, a phenolic epoxy resin (including a predetermined amount of quartz filler) having a thermal expansion coefficient of 10 × 10 ⁻⁶ ° C. ⁻¹ or less, Is an optical waveguide module having excellent temperature characteristics by combining with a ferrule 3 composed of a phenolic epoxy resin (including a predetermined amount of quartz filler) having a thermal expansion coefficient of 6 × 10 ⁻⁶ ° C. ⁻¹ or less. Got. In addition, when the ferrule 3 is configured with a phenol-based epoxy resin, the content of the quartz filler is preferably 85% by weight to 95% by weight, but in order to obtain an optical waveguide module further excellent in wet heat characteristics. It was also confirmed that the content of the quartz filler is preferably 90% by weight to 95% by weight. In addition, the elasticity modulus of these phenol type epoxy resins is 5000 kg / mm < ² > or less.

  Ferrule 3 composed of the above materials is shown in, for example, “DEVELOPMENT OF 16-FIBER CONNECTORS FOR HIGH-SPEED LOW-LOSS CABLE CONNECTION” (INTERNATIONAL WIRE AND CABLE SYMPOSIUM PROCEEDINGS 1993, pp.244-249). Further, it is obtained by a plastic molding method. That is, two upper and lower molds having a predetermined shape are prepared, and a metal core pin for forming a through-hole of the ferrule 3 is sandwiched between the molds. It is obtained by injecting the above resin into the cavity.

On the other hand, when the optical waveguide module shown in FIG. 2 is manufactured using the ferrule 3 having the structure shown in FIGS. However, as pointed out, it is difficult to evenly bond the end faces of the bonding portion 13 without causing a positional shift between the end face of the optical waveguide 130 and the core end face of the optical fiber 4. However, even in such a case, by previously forming a guide pin hole 350 as shown in FIG. 6 in the ferrule 3, the above-described alignment operation can be omitted, and further, the adhesive can be solidified. Even if time is required, it is possible to avoid a positional shift between the end face of the optical waveguide of the waveguide component 1 and the end face of the core of the optical fiber 4 held by the ferrule 3. A method of manufacturing a plastic ferrule having a hole for the guide pin is disclosed in, for example, “HIGH FIBER COUNT OPTICAL CONNECTORS” (INTERNATIONAL WIRE AND CABLE SYMPOSIUM PROCEEDINGS 1993, pp. 238-243). In this case, both ends of the guide pin 100 are respectively inserted into holes provided in the waveguide component 1 (particularly the waveguide substrate) and holes 350 provided in the ferrule 3, and the adhesion end surface 1 a of these waveguide components 1 and the ferrule are inserted. 3 is bonded to the bonding end face 3c by the above-mentioned adhesive (an ultraviolet curable or thermosetting adhesive having an adhesive strength of at least 50 kg / cm ² or more with respect to quartz glass), thereby making the alignment operation unnecessary. . An alignment method using this guide pin is disclosed in, for example, Japanese Patent Laid-Open Nos. 2-125208 and 5-333231. Moreover, the cross section along the DD line of the ferrule 3 shown in FIG. 6 corresponds with the ferrule cross section shown in FIG.

  The optical fiber 4 held with its end inserted in the through-hole 340 of the ferrule 3 generally has a core that propagates light of a predetermined wavelength, covers the core, and has a refractive index lower than the refractive index of the core. It is comprised from the clad which has a rate. In this embodiment, a tape type fiber in which a plurality of optical fibers are coated with plastic as shown in FIGS. 7 and 8 is used. In this case, each bare fiber 410 (consisting of the core 410a and the clad 410b) is individually coated with the acrylate resin 420, and the ribbon portion 430 in which the fibers coated with the acrylate resin are bundled in a row is coated with plastic. Configured. When the optical fiber 4 is bonded and fixed to the ferrule 3, the plastic coating 430 at the tip of the optical fiber 4 is peeled off (and the acrylate coating 420 is also peeled off), and the opening 320 provided on the back surface 3e of the ferrule 3 is removed. It is attached to a through hole 340 provided corresponding to each optical fiber, and is bonded and fixed by the adhesive 5 at the pedestal portion 330 of the ferrule 3. The ferrule 3 may be directly attached with an optical fiber constituting another transmission line, or an input / output optical fiber is separately attached in consideration of connection with the other transmission line. Also good. In either case, the optical fiber attached to the ferrule 3 constitutes a part of the transmission line.

  The structure of the waveguide component 1 is shown in FIG. This figure corresponds to a cross section of the waveguide component 1 along the line AA of the optical waveguide module shown in FIG. The waveguide component 1 includes a waveguide substrate 110 made of silicon or quartz glass, a lower cladding layer 120 (glass material layer) formed on the waveguide substrate 110, and a predetermined shape on the lower cladding layer 120. And an upper clad layer 140 (glass material layer) covering the optical waveguide 130, and the clad layers 120 and 140 are based on the refractive index of the optical waveguide 130. Also have a low refractive index. The structure of the waveguide component 1 used in the optical waveguide module is not limited to the buried type waveguide as shown in FIG. 9, for example, an optical integrated circuit (issued by Ohm Company, February 25, 1985, p.204) is applicable to waveguide components having various structures (for example, ridge-type waveguides).

FIG. 10 is an enlarged cross-sectional view of the connecting portion 13 between the embedded waveguide component 1 having the cross-sectional structure shown in FIG. 9 and the ferrule 3 having the above-described structure. This cross-sectional view coincides with the cross section taken along the line BB shown in FIG. As shown in this figure, between the upper surface 1b of the waveguide component 1 and the bottom surface 2b of the reinforcing member 2, the adhesive surface 1a of the waveguide component 1 and the adhesive surface 3c of the ferrule 3 (surface including the core end surface of the optical fiber 4). ) And between the side surface 2a of the reinforcing member 2 and the adhesive surface 3c of the ferrule 3 are each an ultraviolet curable or thermosetting adhesive having an adhesive strength of 50 kg / cm ² or more with respect to quartz glass. 6 is bonded and fixed. The alignment described above is an operation for matching the end surface of the core 410a of the optical fiber 4 whose tip is held by the ferrule 3 with the end surface of the optical waveguide 130 in the light propagation direction. Indicates a portion where the optical fiber 4 and the optical waveguide 130 are optically connected.

  Further, the connecting portion 13 between the waveguide component 1 and the ferrule 3 in this optical waveguide module is structurally reinforced by the reinforcing member 2 as shown in FIGS. The present invention is not limited only to the embodiment. For example, as shown in FIGS. 11 and 12, the waveguide component 1 may be fixed to the support member 10 to reinforce the strength of the bonding portion 13 with the ferrule 3. The support member 10 is also made of the same material as the waveguide substrate 110, for example, silicon or quartz glass. In addition, the cross section of the waveguide component 1 along the FF line | wire in this figure corresponds with the cross section of the embedded type waveguide component shown in FIG.

  (Second Embodiment)

  Next, as shown in FIG. 12, a case where the ferrule according to the present invention is applied to an optical waveguide module according to another embodiment will be described. In order to explain the structure of the connecting portion 13 of this optical waveguide module, a cross-sectional view along the line GG in the drawing is shown in FIG. In this optical waveguide module, the waveguide component 1 and the support member 10 are bonded and fixed by an adhesive 6, and the bonded end surface 10 a of the support member 10 is polished at the same time as the end surface polishing of the waveguide component 1 described above. .

  Furthermore, the shape of the various optical waveguides 130 built in the said waveguide component 1 is shown in FIGS. These drawings show a state in which the waveguide component 1 from which the upper cladding layer 140 is removed is viewed from above. As described above, the shape of the optical waveguide 130 formed in the waveguide component 1 can be in various modes such as one-to-many (FIG. 14), many-to-many (FIG. 15), or two-to-many (FIG. 16). There are optical waveguide patterns for realizing optical communication (including optical branching and optical coupling functions).

  The optical waveguide module using the ferrule according to the present invention naturally functions as a part of the optical communication system. Therefore, as shown in FIG. 17, this optical waveguide module includes an input / output optical fiber 4 in order to easily realize optical coupling with other transmission paths 20a and 20b. In this case, the optical waveguide module includes the above-described waveguide component 1, the ferrule 3 bonded and fixed to the waveguide component 1, and an adhesive in a state where the tip is inserted into the through hole 340 of the ferrule 3. 5 includes an input / output optical fiber 4 (in this embodiment, a multi-core tape type fiber) that is bonded and fixed by means of 5. In particular, the other end of each input / output optical fiber 4 is bonded and fixed to another ferrule 30 with an adhesive 50 in order to enable optical coupling with the other transmission paths 20a and 20b. The transmission lines 20a and 20b include optical fibers 210 and 220 for propagating optical signals, respectively, but also include elements such as a transmitter, an optical amplifier, an optical multiplexer / demultiplexer, and a receiver. It consists of

  As described above, the optical waveguide module optically coupled to the other transmission paths 20a and 20b constitutes a part of the transmission path. In addition, the optical waveguide module installed as a part of the transmission line in this way is a case of a predetermined shape as disclosed in, for example, Japanese Patent Application Laid-Open No. 62-73210, in order to protect the connection portion 13. It is stored in. Further, this optical waveguide module may be protected by resin molding, as disclosed in European Patent Publication No. 0422445A1.

  Next, materials that constitute each of the waveguide substrate 110 and the ferrule 3 that constitute a part of the waveguide component 1, particularly the thermal expansion coefficient and elastic modulus of these materials will be mainly described.

First, the variation in coupling loss due to the thermal expansion of each material of the connection portion 13 of the ferrule 3 that holds the waveguide component 1 and the tip portion of the optical fiber 4 will be described. Here, eight linear optical waveguides (core diameter: core diameter: 250 μm pitch) are formed on a silicon (Si) substrate so as not to consider the loss fluctuation (transmission loss due to optical branching) caused by the optical waveguide 130. A planar waveguide component on which 7 μm × 7 μm, relative refractive index difference: 0.3%) was formed was prepared. The optical waveguide shape in this waveguide component is shown in FIG. A ferrule 3 made of a plastic material having a thermal expansion coefficient different from that of the waveguide component 1 having the silicon substrate is prepared, and the optical fiber core held by the ferrule 3 is opposed to the optical waveguide 13 for alignment. After that, it was fixed with an ultraviolet curable adhesive to produce several types of samples (optical waveguide modules for characteristic comparison). In order to avoid fluctuations due to insufficient strength of the adhesive as much as possible, the breaking strength of the adhesive was 100 kg / cm ² or more with respect to quartz glass. The adhesive strength may be at least 50 kg / cm ² .

  Table 1 shows the materials used for the ferrule 3 and the physical properties thereof.

The physical property values of plastics 1 to 4 shown in Table 1 are shown in FIGS. In particular, in FIG. 19, the horizontal axis represents the amount of quartz filler contained (wt%, indicated by wt% in the figure), the vertical axis represents the relationship of the thermal expansion coefficient (/ ° C.) of the plastic material, and FIG. The amount of the quartz filler contained (wt%, indicated by wt% in the figure), and the vertical axis indicates the elastic modulus (kg / mm ² ) of the plastic material. As can be seen from these figures, when the content of the quartz filler increases, the coefficient of thermal expansion of the plastic material decreases, while its elastic modulus tends to increase. FIG. 21 shows the effective thermal expansion coefficient | ΔL / (E1 / E2) | of each plastic material with respect to the amount (wt%) of the quartz filler contained. A curve 501 (plotted with a black circle) in the figure indicates an effective thermal expansion coefficient of each plastic material with respect to silicon (Si), and a curve 502 (plotted with a circle) indicates the effective of each plastic material with respect to quartz glass (SiO 2). The coefficient of thermal expansion is shown. In the relational expression showing the effective thermal expansion coefficient, ΔL is the difference between the thermal expansion coefficients of silicon or quartz glass (the constituent material of the waveguide substrate) and each plastic material (the constituent material of the ferrule), and E1 is the silicon or quartz glass. E2 is the elastic modulus of each plastic material. Therefore, from this figure, in order to obtain a plastic material having an effective coefficient of thermal expansion of less than 3 × 10 ⁻⁶ ° C. ⁻¹ with respect to the silicon substrate, it is necessary to contain 85 wt% or more of quartz filler, In order to obtain a plastic material having an effective coefficient of thermal expansion of less than 3 × 10 ⁻⁶ ° C. ⁻¹ with respect to the quartz glass substrate, it is understood that it is necessary to contain 75 wt% or more of quartz filler.

The thermal expansion coefficient of a plastic material containing 75% by weight or more of quartz filler is 10 × 10 ⁻⁶ ° C.− ¹ or less, and the thermal expansion coefficient of a plastic material containing 85% by weight or more of quartz filler is 6 × 10. ^-6 ° C ^-1 or less. On the other hand, as described above, the theoretical limit value of the content of the quartz filler is 96% by volume (substantially coincident with the weight%), and thus the thermal expansion coefficient of each plastic material is 3 × 10 ⁻⁶ ° C. ^−1. This is the end (see FIG. 19).

  Changes in loss due to temperature fluctuations were evaluated using the measurement system shown in FIG. The optical waveguide module 123 to be measured is housed in a thermostatic chamber 250 in the environmental device 200, and light of a certain intensity from the LED 230 is optically connected to one input / output optical fiber (the input side end face of the optical waveguide). The intensity of the light passing through the optical waveguide and further passing through the other input / output optical fiber (optically connected to the output end face of the optical waveguide 130) is measured by the optical power meter 220. By doing so, the fluctuation amount of the coupling loss due to the temperature fluctuation is measured. The optical power meter 220 is controlled by a personal computer 210. The temperature in the thermostat 250 is adjusted by the temperature control means so as to change as shown in FIG. This temperature control means 240 is also controlled by the personal computer 210. That is, the temperature varies between −40 ° C. and + 75 ° C., and the rate of change is ± 1.5 ° C./min. Table 2 shows the fluctuation amount due to the above temperature change with respect to the coupling loss between the waveguide component and the ferrule.

  The number of samples prepared for this measurement is four for each material combination.

  Ideal if the waveguide substrate 110 and ferrule 3 are the same material (for example, Si / Si: when the substrate material is silicon and the ferrule material is also silicon), there is no difference in thermal expansion due to temperature fluctuations. However, in such a case, the fluctuation amount of the coupling loss should be approximately less than 0.1 dB. In the case of “Si / Si” shown in Table 2 as an example of such a case, the fluctuation amount of the coupling loss is 0.08 dB. In addition, when the difference in coefficient of thermal expansion between the materials is large, for example, in the case of “Si / plastic 1” shown in Table 2, it is obvious that the amount of fluctuation of the coupling loss is remarkably large.

  FIG. 24 shows a graph showing the amount of misalignment between the cores of the optical waveguide 1 and the optical fiber 4 obtained by calculation based on the fluctuation amount of the coupling loss in relation to the thermal expansion coefficient. In FIG. 24, a line segment on which the calculated value of the positional deviation amount is plotted is indicated by 503, and a line segment on which the experimental value is plotted is indicated by 504. As can be seen from this figure, the actual positional deviation amount is smaller than the value obtained from the calculation. This is considered due to the fact that the amount of displacement becomes relatively small due to the elastic deformation of both the waveguide substrate material and the ferrule material.

  The proportion at which the amount of displacement due to elastic deformation is suppressed is determined by the ratio of the elastic modulus between the constituent material of the waveguide substrate 110 and the constituent material of the ferrule 3 connected to the waveguide component 1. Accordingly, FIG. 25 shows the amount of displacement calculated in consideration of the ratio of elastic moduli of the constituent materials of the waveguide substrate 110 and the ferrule 3. In FIG. 25, a line segment on which the calculated value of the positional deviation amount is plotted is indicated by 505, and a line segment on which the experimental value is plotted is indicated by 506. By taking into account the elastic deformation in this way, the amount of positional deviation obtained from the calculation is in good agreement with the actual value. In FIG. 25, the horizontal axis represents the effective thermal expansion coefficient (the difference between the thermal expansion coefficients of the waveguide substrate material and the ferrule constituent material and the ratio of the elastic modulus of the waveguide substrate material and the elastic modulus of the ferrule material. Ratio).

  From the above examination results, even when the ferrule 3 is configured using a material having a coefficient of thermal expansion different from that of the material forming the waveguide substrate 110, the actual displacement can be reduced by utilizing the elastic deformation of each material. It is understood that is possible. Therefore, according to the relationship shown in FIG. 29, if the amount of positional deviation is about 1 μm, the amount of fluctuation in coupling loss can be suppressed to about 0.3 dB.

The allowable amount of misalignment also depends on the interval between the cores of the optical fiber 4 (multi-core tape type fiber in this embodiment) held by the ferrule 3. For example, in the case where 16 cores are arranged at a pitch of 250 μm, the distance between the cores at both ends is 3.75 mm. For example, in order to suppress the displacement amount within 1 μm in an environment with a temperature difference of 100 ° C., It is necessary to satisfy the conditions already mentioned. That is, the difference between the thermal expansion coefficient of the constituent material of the waveguide substrate 110 and the thermal expansion coefficient of the constituent material of the ferrule 3 is ΔL, the elastic modulus of the constituent material of the waveguide substrate 110 is E1, and the elastic modulus of the constituent material of the ferrule 3 Is set to E2, the effective thermal expansion coefficient | ΔL / (E1 / E2) | of the constituent material of the ferrule 3 with respect to the constituent material of the waveguide substrate 110 is less than 3.0 × 10 ⁻⁶ ° C. ^−1. There is a need to. Desirably, it should be less than 2.7 × 10 ⁻⁶ ° C. ⁻¹ .

  In general, silicon or quartz glass is used as a constituent material of the waveguide substrate 110 constituting a part of the waveguide component 1. Development of an embedded quartz glass-based waveguide formed on this waveguide substrate is under active development because of its low coupling loss with the optical fiber and low internal transmission loss. The physical properties of these materials are shown in Table 1 above.

On the other hand, as a material often used when manufacturing the ferrule 3, there is a phenol-based epoxy resin containing a quartz glass filler. The thermal expansion coefficient of this material can be changed by changing the filler content and the like, and by adjusting this content, the elastic modulus of the epoxy resin can be adjusted in the range of 1500 to 5000 Kg / mm ² . Assuming that the waveguide substrate 1 is made of silicon or quartz glass, and the ferrule 3 is manufactured using a material whose elastic modulus is within the range of the above effective thermal expansion coefficient, the thermal expansion coefficient of this material Needs to be 10 × 10 ⁻⁶ ° C. ⁻¹ or less.

Further, from this examination result, not only the above-mentioned phenol-based epoxy resin but also other resins have a sufficiently small elastic modulus, for example, a material having a relatively large thermal expansion coefficient (for example, 20 × 10 5 if it is 500 kg / mm ² or less). ^{Even at −6} ° C. ⁻¹ ), it can be seen that the core misalignment due to temperature fluctuations can be sufficiently suppressed. For example, when the waveguide substrate 110 is manufactured from quartz glass, the difference between the thermal expansion coefficient of this material and that of quartz glass is assumed that the elastic modulus of the material constituting the ferrule 3 is 50 Kg / mm ² or less. Is about 4 × 10 ⁻⁴ ° C.− ¹ , the effective thermal expansion difference considering the actual elastic deformation is less than 3 × 10 ⁻⁶ ° C.− ¹ . An example of a resin having a thermal expansion difference of this level is LCR305 manufactured by ICI.

  As a problem predicted when the ferrule 3 is configured using such a resin, since the elastic modulus of the material itself is low, elastic deformation occurs due to fixing to a jig or the like during alignment, and the position of the core This means that there is a possibility of shifting. In such a case, it can be solved by improving the handling method (for example, fixing the surface to a jig).

  A plurality of optical waveguide modules manufactured based on the above examination will be described in detail below.

Sample 1
In this sample 1, as a constituent material of the ferrule 3, a phenolic epoxy resin material having a thermal expansion coefficient of 6.0 × 10 ⁻⁶ ° C. ⁻¹ and an elastic modulus of 2500 kg / mm ² was used. The effective coefficient of thermal expansion of this material for silicon is 2.25 × 10 ⁻⁶ ° C. ⁻¹ . In addition, the waveguide component 1 was formed by forming an 8-branch single mode optical waveguide 130 formed on the silicon substrate 110 by combining the FHD method and the RIE method. The waveguide shape of the manufactured optical waveguide 130 is shown in FIG. Next, a ferrule 3 holding a one-core optical fiber (the tip of the optical fiber is fixed to the ferrule by an adhesive) and a tape-type fiber in which eight-core optical fibers are arranged and fixed at a pitch of 250 μm The held ferrule 3 (the tip portion of the tape-type fiber is fixed to the ferrule with an adhesive) is connected to the input / output end faces 1a and 1c of the waveguide component 1, respectively, and the optical waveguide module 5 of the sample 1 is connected. Created. The alignment is performed by the method already described. The adhesive used for bonding the waveguide component 1 and each ferrule 3 is heated by adding a thermosetting catalyst to an ultraviolet curable adhesive having an adhesive strength of 100 kg / cm ² or more to quartz glass. What provided sclerosis | hardenability was used.

  The insertion loss of the optical waveguide module (sample 1) obtained as described above is 10.1 dB on average, and the excess loss (total transmission loss including branch loss in the optical waveguide 130) is 1.1 dB. It was. Moreover, the optical waveguide module of these samples 1 was measured by the temperature change pattern shown in FIG. 23 in the temperature range of −40 ° C. to 75 ° C. using the measurement system shown in FIG. Note that light having a wavelength of 1.3 μm was used as measurement light. As a result of such measurement, it was confirmed that each optical waveguide module of Sample 1 has a good temperature characteristic with an average fluctuation amount of coupling loss of 0.2 dB and a maximum fluctuation amount of 0.3 dB.

Sample 2
Next, the case of the optical waveguide module of sample 2 manufactured using a plastic material having physical properties different from those of the ferrule of sample 1 will be described.

In this sample 2, as a constituent material of the ferrule 3, a phenol-based epoxy resin material having a thermal expansion coefficient of 4.5 × 10 ⁻⁶ ° C. ⁻¹ and an elastic modulus of 3300 Kg / mm ² was used. The effective coefficient of thermal expansion of this material for silicon is 1.74 × 10 ⁻⁶ ° C. ⁻¹ . In addition, the waveguide component 1 was formed by forming an 8-branch single mode optical waveguide 130 formed on the silicon substrate 110 by combining the FHD method and the RIE method. The waveguide shape of the manufactured optical waveguide 130 is shown in FIG. Next, a ferrule 3 holding a one-core optical fiber (the tip of the optical fiber is fixed to the ferrule by an adhesive) and a tape-type fiber in which eight-core optical fibers are arranged and fixed at a pitch of 250 μm The held ferrule 3 (the tip portion of the tape-type fiber is fixed to the ferrule by an adhesive) is connected to the input / output end faces 1a and 1c of the waveguide component 1, respectively, and the optical waveguide module 5 of the sample 2 is connected. Created. The alignment is performed by the method already described. The adhesive used for bonding the waveguide component 1 and each ferrule 3 is heated by adding a thermosetting catalyst to an ultraviolet curable adhesive having an adhesive strength of 100 kg / cm ² or more to quartz glass. What provided sclerosis | hardenability was used.

  The optical waveguide module (sample 2) obtained as described above had an insertion loss of 10.0 dB on average and an excess loss of 1.0 dB. Further, the optical waveguide modules of these samples 2 were measured by the temperature change pattern shown in FIG. 23 in the temperature range of −40 ° C. to 75 ° C. using the measurement system shown in FIG. Note that light having a wavelength of 1.3 μm was used as measurement light. As a result of such measurement, it was confirmed that each optical waveguide module of Sample 2 has a good temperature characteristic with an average fluctuation amount of coupling loss of 0.2 dB and a maximum fluctuation amount of 0.25 dB.

Sample 3
Next, an optical waveguide module in which the following plastic ferrule 3 is bonded and fixed to a waveguide component 1 composed of a quartz glass substrate will be described.

In this sample 3, a phenol-based epoxy resin material having a thermal expansion coefficient of 4.5 × 10 ⁻⁶ ° C. ⁻¹ and an elastic modulus of 3300 Kg / mm ² was used as a constituent material of the ferrule 3. The effective thermal expansion coefficient of this material for quartz glass is 1.89 × 10 ⁻⁶ ° C. ⁻¹ . Further, the waveguide component 1 is formed by forming an eight-branch single mode optical waveguide 130 formed by combining the FHD method and the RIE method on the quartz glass substrate 110. The waveguide shape of the manufactured optical waveguide 130 is shown in FIG. Next, a ferrule 3 holding a one-core optical fiber (the tip of the optical fiber is fixed to the ferrule by an adhesive) and a tape-type fiber in which eight-core optical fibers are arranged and fixed at a pitch of 250 μm The held ferrule 3 (the tip portion of the tape-type fiber is fixed to the ferrule by an adhesive) is connected to the input / output end faces 1a and 1c of the waveguide component 1, respectively, so that the optical waveguide module of the sample 3 is 5 Created. The alignment is performed by the method already described. The adhesive used for bonding the waveguide component 1 and each ferrule 3 was an ultraviolet curable adhesive having an adhesive strength of 100 kg / cm ² or more with respect to quartz glass.

  The insertion loss of the optical waveguide module (sample 3) obtained as described above averaged 10.6 dB, and the excess loss was 1.6 dB. Further, the optical waveguide modules of these samples 2 were measured by the temperature change pattern shown in FIG. 23 in the temperature range of −40 ° C. to 75 ° C. using the measurement system shown in FIG. Note that light having a wavelength of 1.3 μm was used as measurement light. As a result of such measurement, it was confirmed that each optical waveguide module of Sample 3 had good temperature characteristics with an average fluctuation amount of coupling loss of 0.11 dB and a maximum fluctuation amount of 0.18 dB. The temperature characteristics of the sample 3 are more excellent than those of the samples 1 and 2 described above. This is because the quartz substrate is used as the waveguide substrate 110, and thus the waveguide substrate 110 is used. It is considered that the stress applied to the waveguide glass layers (120, 130, 140) is reduced.

  From the above results, these samples 1 to 3 are all the temperature characteristic specifications of the parts used in the room (10 cycles (48 hours) with a temperature variation of −10 ° C. to 60 ° C.), and further, Bellcore TR- The temperature characteristic specification of NWT-001209 (42 cycles (336 hours) with a temperature variation of −40 ° C. to 75 ° C.) is satisfied.

Next, a comparative example will be described. The constituent material of the ferrule in this comparative example was a plastic material having a thermal expansion coefficient of 15.2 × 10 ⁻⁶ ° C. ⁻¹ and an elastic modulus of 2000 Kg / mm ² . The effective coefficient of thermal expansion for silicon (substrate material) of the material is 6.6 × ^{10 -6} ℃ ^-1, it exceeds 3.0 × ^{10 -6} ℃ ^-1. Similar to the above example, the waveguide component 1 having the 8-branch optical waveguide 130 and the ferrule made of the plastic material were bonded and fixed to produce five optical waveguide modules. In this case, the insertion loss at room temperature was 10.0 dB, and the excess loss was 1.0 dB, indicating low loss characteristics. However, when this optical waveguide module was placed in an environment where the temperature fluctuated in the same manner as in the previous example, the loss fluctuation amount was 0.8 dB at the maximum, which was twice or more that of the previous example. This is considered to be due to the large displacement of the core due to thermal expansion due to temperature fluctuation.

  Next, the wet heat characteristics of the optical waveguide module according to the present invention will be described. As mentioned above, the theoretical limit value of the quartz filler that can be contained in the plastic material suitable as the constituent material of the ferrule 3 is the industrial material December 1994 (Vol. 42, No. 15, pp. 112). ˜116) is shown to be 96% by volume. FIG. 27 is a conceptual diagram schematically showing a filling model with spherical fillers. Secondary spheres 600b, tertiary spheres 600c, and quadratic spheres 600d are sequentially formed in the gaps formed by the primary spheres 600a having the maximum diameter. Filled. Therefore, the theoretical value of 96% by volume means a limit value at which a resin such as plastic can be embedded in the filler gap.

  The inventors prepared ferrules 3 using phenolic epoxy resins having a quartz filler content of 70%, 80%, 90%, and 94% by weight, each having a quartz glass substrate 110. An optical waveguide module as a sample was manufactured by bonding and fixing to the branched waveguide component 1. The wet heat characteristics of each of these optical waveguide modules were measured in an environment of a temperature of 75 ° C. and a relative humidity (RH) of 95% (the wet heat characteristic specifications of TA-NWT-001221 manufactured by Bellcore are 75 ° C., 90 ± 5 RH, 500 Time), the results shown in FIG. 28 were obtained for each optical waveguide module. As can be seen from this result, good results were obtained particularly in the case of a ferrule using a material having a quartz filler content of 90 wt% to 95 wt%. In addition, it was confirmed that the sample with a large transmission loss had peeling in the adhesion part 13. FIG.

It is a figure for demonstrating the assembly process of the optical waveguide module which concerns on 1st Embodiment using the ferrule which concerns on this invention. It is a perspective view which shows the structure of the optical waveguide module which concerns on 1st Embodiment using the ferrule which concerns on this invention. It is an expanded view of the ferrule for explaining the structure of the ferrule according to the present invention. It is a figure which shows the cross-sectional structure along CC line of the ferrule shown by FIG. It is a principal part enlarged view of the ferrule cross section shown by FIG. It is a figure for demonstrating the alignment method of the optical waveguide module using the ferrule which concerns on this invention. It is a perspective view for demonstrating the structure of the front-end | tip part of a tape type fiber. It is the figure which showed the cross-section along the EE line of the tape type fiber shown by FIG. It is a figure which shows the cross-sectional structure along the AA line of the waveguide components shown by FIG. It is a figure which shows the cross-section along the BB line of the optical waveguide module shown by FIG. It is a figure for demonstrating the assembly process of the optical waveguide module which concerns on 2nd Embodiment using the ferrule which concerns on this invention. It is a perspective view which shows the structure of the optical waveguide module which concerns on 2nd Embodiment using the ferrule which concerns on this invention. It is a figure which shows the cross-section along the GG line of the optical waveguide module shown by FIG. It is a figure which shows the waveguide pattern built in waveguide components (the 1). It is a figure which shows the waveguide pattern built in waveguide components (the 2). It is a figure which shows the waveguide pattern built in waveguide components (the 3). It is a figure which shows the whole structure of the optical communication system provided with the optical waveguide module using the ferrule which concerns on this invention. It is a figure which shows the waveguide pattern of the waveguide components manufactured as a sample for experiment. It is the figure which showed the relationship between quartz filler content (weight%) and a thermal expansion coefficient (/ degreeC) as a physical-property value of the constituent material (plastic) of a ferrule. It is the figure which showed the relationship between quartz filler content (weight%) and elastic modulus (kg / mm < ² >) as a physical-property value of the constituent material (plastic) of a ferrule. It is a figure showing the relation between quartz filler content (% by weight) and effective thermal expansion coefficient (| ΔL / (E1 / E2) |) as physical property values of the constituent material (plastic) of the ferrule. It is a figure which shows the structure of the measurement system for measuring the temperature characteristic of the optical waveguide module using the ferrule which concerns on this invention. It is a figure which shows the temperature fluctuation pattern in the measurement system shown by FIG. The figure which shows the relationship between the difference (the calculated value and the measured value) of the thermal expansion coefficient in the constituent material of the waveguide substrate and the constituent material of the ferrule, and the amount of core misalignment in the bonded portion of the optical waveguide module configured using these It is. The figure which shows the relationship between the effective thermal expansion coefficient (calculated value and measured value) of the constituent material of the ferrule with respect to the constituent material of a waveguide board | substrate, and the core position shift | offset | difference amount in the adhesion part of the optical waveguide module comprised using these is there. It is a figure which shows the waveguide pattern of the manufactured waveguide components as an Example of the optical waveguide module using the ferrule which concerns on this invention. It is the conceptual diagram which showed typically the filling model of the quartz filler. It is a figure which shows the result of having measured the wet heat characteristic of the optical waveguide module using the ferrule which concerns on this invention. It is the figure which showed the coupling loss resulting from position shift with an optical fiber and an optical waveguide.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Waveguide substrate, 3 ... Ferrule, 4 ... Input / output optical fiber (tape type fiber), 6 ... Adhesive, 110 ... Waveguide substrate, 130 ... Optical waveguide, 410 ... Optical fiber, 410a ... Core, 600a, 600b, 600c, 600d ... quartz filler.

Claims (7)

An optical fiber constituting at least part of the transmission line and an optical waveguide constituting at least part of the transmission line are provided on a waveguide substrate made of silicon or quartz glass as a first material, thereby realizing a predetermined function. It can be used in an optical waveguide module for optically coupling an optical functional component to be configured, and is configured of a second material different from the first material, and defines an installation position of the optical fiber end portion A ferrule provided with a through-hole,
The second material is different from the first material constituting the waveguide substrate by a difference between the thermal expansion coefficient of the first material and the thermal expansion coefficient of the second material by ΔL, When the elastic modulus of the material is E1, and the elastic modulus of the second material is E2,
| ΔL / (E1 / E2) | <3.0 × 10 ⁻⁶ (° C. ⁻¹ )
A ferrule that satisfies the relationship   The ferrule according to claim 1, wherein the second material is a plastic material. The ferrule according to claim 2, wherein the plastic material is a phenolic epoxy resin containing a predetermined amount of quartz filler and having a thermal expansion coefficient of 10 × 10 ⁻⁶ (° C. ⁻¹ ) or less. The ferrule according to claim 2, wherein the plastic material is a phenolic epoxy resin containing a predetermined amount of quartz filler and having a thermal expansion coefficient of 6 × 10 ⁻⁶ (° C. ⁻¹ ) or less.   The ferrule according to claim 3 or 4, wherein the content of the quartz filler is 85 wt% or more and 95 wt% or less.   The ferrule according to claim 3 or 4, wherein the content of the quartz filler is 90 wt% or more and 95 wt% or less. The plastic material is a phenolic epoxy resin containing a predetermined amount of quartz filler and having an elastic modulus of 5000 (kg / mm ² ) or less. Ferrule.

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