JP2018004830A - High heat-resistant optical fiber module and manufacture method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high heat-resistant optical fiber module connected to a planar lightwave circuit and an optical fiber so as to maintain the characteristics even under a high-temperature environment, and a manufacture method of the same.SOLUTION: An optical fiber module 100 obtained by optically coupling a planar lightwave circuit 120 and at least one core of optical fibers 111 comprises: a planar lightwave circuit including an optical waveguide 121 on a substrate 123; at least one or more cores of optical fibers; an optical fiber connection component 112 for fixing and connecting the at least one or more cores of optical fibers to the planar lightwave circuit; a conductive thin film 101 formed in a portion, except for at least light propagating portion, between a surface of the optical fiber connection component closer to the planar lightwave circuit and a surface of the planar lightwave circuit closer to the optical fiber connection component. The conductive thin film connects the planar lightwave circuit to the optical fiber connection component by being heated by microwave.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical fiber module in which a planar lightwave circuit and an optical fiber are connected and a method for manufacturing the same, and more particularly to a high heat resistant optical fiber module having an increased heat resistant temperature and a method for manufacturing the same.

  In most cases, a planar lightwave circuit component having a planar optical waveguide made of a quartz-based material, silicon, and a semiconductor is used in a state where an optical fiber is connected as an input / output end of light rather than being used alone. In order to connect the planar lightwave circuit and the optical fiber, components for connecting the optical fiber are required. Here, as an optical fiber connecting part for connecting a planar lightwave circuit and an optical fiber, a V-groove is formed on a glass substrate, and the optical fiber is aligned and fixed with an adhesive at a desired position of the V-groove. Blocks are widely used.

  The process procedure for connecting the planar lightwave circuit and the optical fiber block is performed as follows as an example. First, the planar lightwave circuit is arranged on a fixed base, and the optical fiber block is fixed on the fine movement base. Here, an optical fiber connected to a light source is provided on one end side of the optical fiber block, and a photodiode (PD) is installed on the side opposite to the optical fiber block side of the planar lightwave circuit.

  Next, a UV curable adhesive is applied to the gap between the planar lightwave circuit and the optical fiber block in a state where the optical fiber block is brought close to one end side (optical fiber block side) of the planar lightwave circuit (generation of an adhesive layer). . Thereafter, the fine movement table on which the optical fiber block is installed is moved so that the light receiving intensity of the PD becomes maximum. When the maximum light receiving intensity is obtained in the PD, ultraviolet rays are irradiated to cure the UV curable adhesive and fix the adhesive layer.

  If necessary, an optical fiber block can be connected to the other end of the planar lightwave circuit by a similar process. At this time, instead of disposing the PD at the end of the planar lightwave circuit, the output from the already connected optical fiber may be incident on the PD.

  As described above, the planar lightwave circuit and the optical fiber block are fixed by using a UV curing adhesive that is cured by ultraviolet rays in most cases for reasons such as low cost, low loss, and shortening of the curing time. Yes.

JP-A-7-253520 International Publication No. 2014/196444 JP 2006-269984 A

  Many of the optical fiber modules having a planar lightwave circuit are used as components supporting large-capacity optical communication, but on the other hand, they are also widely used as optical sensors. When an optical fiber module is used as an optical sensor, it may be used under conditions that are more severe than in the case of optical communications, for example, in a car engine room (300 ° C) or at high geothermal temperatures (300 ° C) in a mine. The

  However, the heat resistant temperature of the UV curable adhesive determines the heat resistant temperature of the assembled optical fiber module. Therefore, there is a problem that the characteristics of the optical fiber module cannot be maintained in a high temperature environment exceeding the heat resistant temperature of the UV curable adhesive when the optical fiber module is used as an optical sensor.

  For example, in the case of a quartz-based planar lightwave circuit, the waveguide is made of a quartz-based material, while the planar lightwave circuit is also made of a quartz-based material, so that the characteristics can be maintained even at temperatures exceeding 500 ° C. It is done. However, as described above, when the optical fiber block is fixed using the UV curable adhesive, the heat resistance temperature of the assembled optical fiber module is limited by the heat resistance temperature of the UV curable adhesive. Generally, when the temperature exceeds the heat resistance temperature of the optical fiber module, the UV curable adhesive is softened, and the optical axis that has been aligned is shifted, leading to an increase in optical loss of the optical fiber module. In addition, when the temperature is higher, the adhesive layer becomes brittle due to carbonization of the UV curable adhesive, and the bonded optical fiber block is detached from the planar lightwave circuit (for example, see Patent Document 1). Therefore, in the case of an optical fiber module using a conventional quartz-based planar lightwave circuit using a UV curable adhesive, the characteristics cannot be maintained at a temperature exceeding 500 ° C. which is higher than the heat resistant temperature of the UV curable adhesive.

  On the other hand, as another technique for fixing optical fibers, there is a fusion splicing technique for connecting by fusion. This is the most common connection method as a technique for permanently connecting quartz optical fibers, and since glass is directly bonded to each other, it can be used even in a high temperature region. Applying this method to a quartz-based planar lightwave circuit, research and development has also been conducted to directly fuse and connect the planar lightwave circuit and the optical fiber.

  However, since the difference between the heat capacity of the planar lightwave circuit board and the heat capacity of the optical fiber is large, the glass constituting the waveguide of the planar lightwave circuit does not melt at the melting temperature of the optical fiber. On the other hand, when the heating temperature is raised so as to melt the glass constituting the waveguide of the planar lightwave circuit, the optical fiber itself may be damaged. Therefore, it is difficult to connect the planar lightwave circuit and the optical fiber by fusion. In addition, in the case of a quartz-based planar lightwave circuit, a technique called fusion cannot be taken, but in the first place, a planar lightwave circuit made of silicon and a semiconductor cannot fix an optical fiber by using this fusion technique. .

  Accordingly, an object of the present invention is to provide a highly heat-resistant optical fiber module that maintains characteristics of an optical fiber module in which a planar lightwave circuit and an optical fiber are connected even under a high temperature environment, and a method for manufacturing the same. To do.

  In order to achieve such an object, the first aspect of the present invention fixes a planar lightwave circuit having an optical waveguide on a substrate, at least one optical fiber, and at least one optical fiber. An optical fiber connecting component for connecting the optical fiber to the planar lightwave circuit, a surface of the optical fiber connecting component on the planar lightwave circuit side, and a surface of the planar lightwave circuit on the optical fiber connecting component side. A conductive thin film formed at a portion excluding at least a portion where light propagates between, and the conductive thin film is heated by microwaves to connect the planar lightwave circuit and the optical fiber connecting component. The planar lightwave circuit and the optical fiber having at least one core are optically coupled.

  According to a second aspect of the present invention, there is provided an optical fiber module according to the first aspect, the surface of the optical fiber connection component on the planar lightwave circuit side, and the surface of the planar lightwave circuit on the optical fiber connection component side. It further includes a resin filled in a portion where the light propagates between the surfaces.

  According to a third aspect of the present invention, there is provided the optical fiber module according to the first and second aspects, wherein the conductive thin film is a thin film made of conductive particles such as metal and carbon, or semiconductor particles, or a conductor. Alternatively, it is a thin film of ink and paste-like dispersion in which a semiconductor is dispersed.

  According to a fourth aspect of the present invention, there is provided a method of manufacturing an optical fiber module in which a planar lightwave circuit having an optical waveguide on a substrate and at least one optical fiber are optically coupled. A portion of the end face on the planar lightwave circuit side of the optical fiber connection component for connecting an optical fiber of a core or more to the planar lightwave circuit, at least a portion where light is propagated, on the optical fiber connection component side of the planar lightwave circuit A portion of the end face excluding at least a portion where light propagates, or a portion of the end face of the optical fiber connection component on the planar lightwave circuit side excluding at least a portion where light propagates, and an end face of the planar lightwave circuit on the side of the optical fiber connection component Patterning a conductive thin film that can be heated by microwave irradiation on at least a portion excluding a portion where light propagates; and Aligning the optical fiber and the planar lightwave circuit so as to enable optical connection between the fiber and the planar lightwave circuit, contacting the conductive thin film and the planar lightwave circuit, and microwaves. And heating the conductive thin film by irradiation to connect the optical fiber connecting component and the planar lightwave circuit.

  According to a fifth aspect of the present invention, there is provided an optical fiber module manufacturing method according to the fourth aspect, wherein after the step of connecting the optical fiber connection component and the planar lightwave circuit, the optical fiber connection component The method further includes the step of filling resin in a portion where the light propagates between a surface on the planar lightwave circuit side and a surface on the optical fiber connection component side of the planar lightwave circuit.

  According to a sixth aspect of the present invention, there is provided a method of manufacturing the optical fiber module according to the fourth or fifth aspect, wherein the conductive thin film is a thin film made of conductive particles such as metal and carbon, or semiconductor particles. Or a thin film of an ink and a paste-like dispersion in which a conductor or a semiconductor is dispersed.

  According to the present invention, it is possible to provide an optical fiber module having high heat resistance in which a planar lightwave circuit and an optical fiber are connected so as to maintain characteristics even under a high temperature environment.

It is a figure which shows the basic composition of the optical fiber module which concerns on this invention. (A) shows sectional drawing of the optical waveguide direction of the optical fiber module, (b) shows sectional drawing in AA 'of (a), (c) in BB' of (a). A cross-sectional view is shown. It is a figure which shows the optical fiber module which concerns on Example 1 of this invention. (A) shows sectional drawing of the optical waveguide direction of an optical fiber module, (b) shows sectional drawing in CC 'of (a), (c) shows in DD' of (a). A cross-sectional view is shown. It is a figure which shows the optical fiber module which concerns on Example 2 of this invention. (A) shows sectional drawing of the optical waveguide direction of the optical fiber module, (b) shows sectional drawing in EE 'of (a), (c) shows in FF' of (a). A cross-sectional view is shown.

  Hereinafter, the configuration of the present invention will be described in detail with reference to the drawings.

[Basic configuration]
FIG. 1 is a diagram showing a basic configuration of an optical fiber module according to the present invention. FIG. 1 (a) shows a cross-sectional view of the optical fiber module in the light guiding direction, and FIG. 1 (b) shows FIG. FIG. 1C is a cross-sectional view taken along the line BB ′ of FIG. 1A. 1A includes an optical fiber 111 having at least one core, a planar lightwave circuit 120, an optical fiber connection part 112 for connecting the optical fiber 111 to the planar lightwave circuit 120, and a planar lightwave. The electroconductive thin film 101 which joins the circuit 120 and the optical fiber connection component 112 is provided. Here, the planar lightwave circuit 120 includes a substrate 123, an optical waveguide 121 on the substrate 123, and a Yatoi plate 122 on the optical waveguide 121. The optical waveguide 121 includes a core 121-1, and a clad 121-2 around the core 121-1.

  The planar lightwave circuit 120 is made of a quartz material or silicon. The conductive thin film 101 is formed on at least a portion of the end face of the optical fiber connection component 112 on the side of the planar lightwave circuit 120 excluding a portion where light is propagated. In the optical fiber module 100 according to the present invention, the conductive thin film 101 is used as an adhesive layer for joining the planar lightwave circuit 120 and the optical fiber connection component 112. Thereby, the planar lightwave circuit 120 and the optical fiber connection part 112 can be joined via the conductive thin film 101, and the planar lightwave circuit 120 and the optical fiber 111 can be optically coupled.

  Here, the conductive thin film 101 is a thin film made of conductive particles or semiconductor particles such as metal and carbon, or a thin film of an ink or paste-like dispersion in which the conductive or semiconductor is dispersed (see Patent Document 2). The temperature can be instantaneously increased by microwave irradiation.

  When joining the planar lightwave circuit 120 and the optical fiber connection part 112, when using a heat-resistant adhesive that is heat-treated using a furnace or the like as in the prior art, the reaction / curing of the heat-resistant adhesive is at least several minutes or more. Heat treatment is required. Therefore, the planar lightwave circuit 120 and the optical fiber connecting part 112 to be joined and the parts connected thereto are heated. Then, the relative position between the planar lightwave circuit 120 and the optical fiber connecting part 112 is shifted due to the difference in thermal expansion coefficients of the members constituting these parts. Therefore, when the planar lightwave circuit 120 and the optical fiber connecting part 112 are joined using a method such as a furnace that requires long-time heat treatment, the planar lightwave circuit 120 and the optical fiber 111 cannot be coupled with low loss. .

  On the other hand, when microwave heating is used, only the conductive thin film 101 can be selectively heated in a short time. Since the conductive thin film 101 is instantaneously heated by the microwave irradiation, the planar lightwave circuit 120 and the optical fiber connection component are hardly changed without changing the relative position between the aligned planar lightwave circuit 120 and the optical fiber connection component 112. 112 can be joined. Therefore, the conductive thin film 101 can be used as an adhesive layer for joining the planar lightwave circuit 120 and the optical fiber connection component 112.

  According to the present invention, by using the conductive thin film 101 as a bonding material for each component of the optical fiber module, the heat resistance in which the optical fiber and the planar lightwave circuit are connected so as to maintain the characteristics even in a high temperature environment is high. An optical fiber module can be provided. Embodiments according to the present invention will be described below.

[Example 1]
FIG. 2 is a diagram illustrating the optical fiber module according to the first embodiment of the present invention. FIG. 2A is a cross-sectional view of the optical fiber module in the light guiding direction, and FIG. FIG. 2C is a cross-sectional view taken along the line CC ′ of FIG. 2A, and FIG. 2C is a cross-sectional view taken along the line DD ′ of FIG. The optical fiber module 200 of FIG. 2A includes a single-core optical fiber 211, a planar lightwave circuit 220, a glass capillary 212 for connecting the optical fiber 211 to the planar lightwave circuit 220, a planar lightwave circuit 220, and glass. A conductive thin film 201 that joins the capillary 212 is provided. Here, the planar lightwave circuit 220 includes a substrate 223, an optical waveguide 221 on the substrate 223, and a Yatoi plate 222 on the optical waveguide 221. The optical waveguide 221 includes a core 221-1 and a clad 221-2 around the core 221-1. In addition, a resin 202 is filled in a gap between light transmitting portions of the end surface of the glass capillary 212 on the side of the planar lightwave circuit 220 and the end surface of the optical fiber 211 and the end surface of the planar lightwave circuit 220 on the side of the glass capillary 212.

In this embodiment, the planar lightwave circuit 220 uses a quartz-based material as the material of the substrate 223. When a quartz-based material is used as the material of the substrate 223, generally, an optical waveguide 221 having a high refractive index is formed on a flat substrate made of quartz (glass) or silicon, and a splitter or an arrayed waveguide diffraction grating ( AWG) or the like. In this embodiment, a lower clad layer and a core layer are sequentially formed on a quartz substrate 223, and etching is performed with the core layer leaving a portion to be an optical waveguide 221 to deposit an upper clad layer mainly composed of SiO _2. Thus, the planar lightwave circuit 220 is produced.

  Glass capillaries 212 that can be generally procured from the market can be used, and many of them are made by drawing a glass base material and producing an insertion hole with a precise dimension in the same manner as the optical fiber manufacturing technology. It is. In addition, it may be produced by injection molding or machining. In this embodiment, the glass capillary 212 is made of glass having a heat-resistant temperature of 550 ° C. and a coefficient of thermal expansion that is substantially the same as that of semiconductor silicon.

  The optical fiber 211 is inserted into the insertion hole 212-1 of the glass capillary 212, and the conductive thin film 201 is patterned on the end surface of the glass capillary 212 on the planar lightwave circuit 220 side. The glass capillary 212 has a flat end face on the planar lightwave circuit 220 side, and a counterbore 212-2 is provided on the end face opposite to the end face face on the planar lightwave circuit 220 side. When inserting the optical fiber 211 into the glass capillary 212, it is very difficult to insert a thin optical fiber into an insertion hole having substantially the same diameter without the countersink 212-2. It is easy to insert the optical fiber 211 itself. Further, when the optical fiber 211 is inserted into the insertion hole 212-1, the end of the coating 211-2 of the optical fiber 211 can be finally stored. If the optical fiber 211 is only a strand (core) 211-1 (the glass is exposed), it is easy to break, but if a part of the coating 211-2 is also housed in the insertion hole 212-1 of the glass capillary 212, the optical fiber 211. Can be made difficult to break.

Next, the joining process of the glass capillary 212 and the planar lightwave circuit 220 of the optical fiber module of the present embodiment will be described.
First, one or a plurality of glass capillaries 212 are held in a jig that can be held so that the surface of the glass capillary 212 on the planar lightwave circuit 220 side is horizontal, and screen printing is performed on the end surface of the glass capillary 212 on the planar lightwave circuit 220 side. The conductive thin film 201 was patterned at once. The thickness of the conductive thin film 201 was 0.3 μm.

  Thereafter, the glass capillary 212 is fixed on an L-shaped jig made of ceramic, the optical fiber 211 is inserted into the insertion hole 212-1 of the glass capillary 212, and the optical fiber 211 is placed on the vertical surface of the L-shaped jig. The glass capillary 212 was abutted. By performing the butting, the surface position of the surface of the laser frit glass and the surface of the optical fiber 211 can be matched. In this example, the optical fiber was intentionally lowered by 5 μm from the state where the surface positions of both surfaces coincided by performing abutment. This is because, when the glass capillary 212 and the planar lightwave circuit 220 are connected later, a slight empty wall is intentionally provided between the planar lightwave circuit 220 and the optical fiber 211 in the glass capillary 212. . Since the coupling tolerance is very wide with respect to the propagation direction of light, the optical fiber 211 is pulled down to create a relief, so that the optical expansion due to volume expansion can be performed against the temperature change of the parts such as when the outside air temperature changes. Fluctuations can be reduced. If there is no escape in the light propagation direction, the planar lightwave circuit 220 and the optical fiber 211 collide, and in some cases, the optical fiber 211 may move in the normal direction of the substrate of the planar lightwave circuit 220, and the optical connection loss increases. , Become a factor of fluctuation. However, the optical fiber 211 may be connected by matching with the planar lightwave circuit 220 without lowering the optical fiber 211.

  Next, in order to fix the glass capillary 212 and the optical fiber 211, a resin 203 was dropped on the optical fiber 211 to fill a gap between the glass capillary 212 and the optical fiber 211. Thereafter, the optical fiber module 200 was heated in an oven at 350 ° C. for 1 hour while maintaining this state. In this embodiment, an optical fiber having a coating made of polyimide and a heat-resistant temperature of 300 ° C. (instantaneous 400 ° C.) is used. As the resin 203, BCB (Benzocyclobutene) that cures when heat of 300 ° C. or more is applied is not limited to this, and any resin that can obtain heat resistance may be used. In addition, a method of metalizing and fixing the inside of the glass capillary 212 and the optical fiber 211 may be used.

  Subsequently, the planar lightwave circuit 220 is fixed on the stage, the glass capillary 212 to which the optical fiber 211 is fixed is held on the six-axis positioning stage, and the planar lightwave circuit 220 and the optical fiber 211 can be optically connected. Alignment was performed. The alignment method for optical connection between the planar lightwave circuit 220 and the optical fiber 211 is the same as the alignment method of the conventional optical fiber block fixed with the UV curing adhesive. When aligning, while adjusting the parallelism, the end face of the planar lightwave circuit 220 and the conductive thin film 201 patterned on the end face of the glass capillary 212 are brought into contact with each other, a gap of 5 μm is provided, and the glass capillary 212 is moved. Alignment was performed in a state where possible. Then, after the light was most transmitted through alignment, the glass capillary 212 was moved in the light propagation direction to bring the planar lightwave circuit 220 and the glass capillary 212 into contact with each other.

  Thereafter, using a microwave heating apparatus, the module was irradiated with microwaves having a wavelength of 2.45 GHz, and only the conductive thin film 201 patterned on the end face of the glass capillary 212 was instantaneously and selectively heated. By this heating, the planar lightwave circuit 220 and the glass capillary 212 to which the optical fiber 211 was fixed were diffusion bonded via the conductive thin film 201. When the conductive thin film 201 formed on the glass capillary 212 is irradiated with microwaves, the conductive thin film 201 is instantaneously heated to 1000 ° C. or higher, while the temperature of each component of the planar lightwave circuit 220 does not rise. Accordingly, unidirectional diffusion occurs from the conductive thin film 201 side to the planar lightwave circuit 220 side, and solid solution / adhesion of the conductive thin film material component and the planar lightwave circuit component material component occurs at the interface. Also, in the conductive thin film 201 and the glass capillary 212, the conductive thin film 201 is heated, but the temperature of the glass capillary 212 does not rise. Accordingly, the diffusion from the conductive thin film 201 side to the glass capillary 212 occurs, and the conductive thin film material component and the glass capillary material component are dissolved and adhered at the interface. Thereby, the planar lightwave circuit 220 and the glass capillary 212 are fixed with sufficient strength.

  Thereafter, a resin 202 is filled in an air layer between the connection end faces of the planar lightwave circuit 220, the glass capillary 212, and the optical fiber 211. By filling the resin 203 between the connection end surfaces of the planar lightwave circuit 220 and the glass capillary 212 and the optical fiber 211, the connection strength between the planar lightwave circuit 220 and the glass capillary 212 is increased. Further, it is possible to reduce the loss of the optical connection between the planar lightwave circuit 220 and the optical fiber 211 and reduce the reflection. After filling, the resin 202 is cured by heat treatment.

  According to the configuration of this embodiment in which the conductive thin film 201 is used for bonding the planar lightwave circuit 220 and the glass capillary 212, it is not necessary to use a UV curing adhesive when connecting the planar lightwave circuit 220 and the optical fiber 211. Since all materials have a heat resistance of 300 ° C. or higher, the heat resistance of the optical fiber module 200 assembled as compared with the conventional method can be greatly improved. Of course, it is possible to provide a smaller and lower price than heat-resistant optical fiber modules made through expensive metal cases or lens mounting.

  In addition, since quartz-based glass is transparent to microwaves, the glass capillary 212 and the planar lightwave circuit 220 themselves are not heated even when irradiated with microwaves. Therefore, only the conductive thin film 201 is locally and instantaneously heated and diffusion-bonded, and can be fixed without changing the relative positions of the glass capillary 212 and the planar lightwave circuit 220.

  The apparatus for aligning the planar lightwave circuit 220 and the glass capillary 212 includes a light source and a transmission intensity measuring instrument in addition to a six-axis stage, but only the stage portion is set in the microwave heating apparatus. The fiber is taken in and out through an opening provided in the microwave irradiation apparatus. The stage is made of a material that does not absorb microwaves, such as ceramic or plastic.

  Furthermore, in this embodiment, the glass capillary 212 whose end face is vertically polished is connected to the planar lightwave circuit 220 whose end face is also vertically polished. However, when it is desired to reduce reflection by the connection end face, each is several degrees (8 °). If the surface is tilted and polished, the return loss can be further reduced.

[Example 2]
In the first embodiment, an example in which a single-core glass capillary and a planar lightwave circuit are connected is shown. In the second embodiment, an example in which a multicore optical fiber block and a planar lightwave circuit are connected is shown.

  FIG. 3 is a diagram illustrating an optical fiber module according to Embodiment 2 of the present invention. FIG. 3A is a cross-sectional view of the optical fiber module in the light guiding direction, and FIG. FIG. 3C is a cross-sectional view taken along the line EE ′ of FIG. 3A, and FIG. 3C is a cross-sectional view taken along the line FF ′ of FIG. The optical fiber module 300 of FIG. 3A includes at least one optical fiber 311, a planar lightwave circuit 320, a V-groove substrate 312 for connecting the optical fiber 311 to the planar lightwave circuit 320, and an optical fiber 311. And a conductive thin film 301 that joins the planar lightwave circuit 220 and the V-groove substrate 312 to each other. Here, the planar lightwave circuit 320 includes a substrate 323, an optical waveguide 321 on the substrate 323, and a Yatoi plate 322 on the optical waveguide 321. The optical waveguide 321 includes a core 321-1 and a clad 321-2 around the core 321-1. In addition, a resin 302 is filled in a space between the end surface of the V-groove substrate 312 and the lid 313 on the planar lightwave circuit 320 side and the end surface of the optical fiber 311 and the end surface of the planar lightwave circuit 320 on the V-groove substrate 312 side. ing.

  The V-groove substrate 312 is formed by machining a glass substrate having a thickness of 1 mm, a width of 3 mm, and a length of 8 mm using machining, and then machining a countersink at a location where an optical fiber coating is accommodated in a portion 4 mm from the tip. It is produced by forming. The optical fiber 311 is a heat-resistant optical fiber whose coating is formed of polyimide, and specifically, one having a heat-resistant temperature of 300 ° C. (instantaneous 400 ° C.) is used. The lid 313 is formed of a glass substrate similar to the V-groove substrate 312 having a width of 3 mm and a length of 4 mm.

  In the second embodiment, the V-groove substrate 312 is manufactured by machining, but the V-groove substrate 312 is not different from that used in conventional communication, and may be prepared by press working or the like. . In addition, the V-groove substrate 312 has a plurality of V-grooves aligned, but a single V-groove may be provided in order to connect a single-core optical fiber as in the first embodiment. For the V-groove substrate 312 and the lid 313, a glass substrate having a heat-resistant temperature of 550 ° C. and a thermal expansion coefficient substantially the same as that of semiconductor silicon is used, but the present invention is not limited to these.

  Next, the bonding process between the V-groove substrate 312 and the planar lightwave circuit 320 of the optical fiber module of this embodiment will be described.

  First, each of the V-groove substrate 312 and the lid 313 is polished on the surface to be finally optically connected, and the conductive thin film 301 is formed on the polished surface. The temporarily assembled V-groove substrate 312 and lid 313 (optical fiber block) are held in a jig that can hold the polished surfaces of the V-groove substrate 312 and the lid 313 horizontally, and the conductive thin film 301 is screen-printed. Form. The conductive thin film 301 has the polishing surface of the lid 313 except for the outer periphery of the polishing surface of 50 μm, and the polishing surface of the V-groove substrate 312 except for the vicinity of the V-groove where the optical fiber 311 is inserted and the outer periphery of 50 μm. Formed on the part. The thickness of the conductive thin film 301 is 0.3 μm.

  The formed V-groove substrate 312 is placed on a stage in which a vacuum hole that can be heated is formed, and the optical fiber 311 that has been cleaved by stripping the tip coating is placed in the V-groove of the V-groove substrate 312 as shown in FIG. After the insertion, the optical fiber 311 is pressed by the lid 313. The cleaved surface of the optical fiber 311 and the surface of the V-groove substrate 312 and the lid 313 on which the conductive thin film 301 is formed are mechanically held while pressed against an arbitrary reference surface, and the assembled V-groove substrate 313, The resin 303 is inserted from one side of the side surfaces of the optical fiber 311 and the lid 313 to fill the gap. Thereafter, the assembled V-groove substrate 312, optical fiber 311 and lid 313 were heated to 250 ° C. and then left for 60 minutes to fix these members.

  Next, an optical fiber block according to Example 2 was manufactured by fixing the optical fiber 311 together with the coating using a heat-resistant resin at a countersink portion of the V-groove substrate 312 that accommodates the coating of the optical fiber 311.

  The produced optical fiber block and the planar lightwave circuit 320 provided with a multi-core input / output waveguide on the quartz substrate 323 are aligned by the same method as in the first embodiment, and are subjected to microwave irradiation to thereby form a conductive thin film. 301 was instantaneously selectively heated and fixed.

  Even in the case of using an optical fiber block in which a multi-core optical fiber 311 is inserted as in the present embodiment, the optical fiber module having greatly improved heat resistance using the conductive thin film 301 according to the present invention. Can be provided.

  In Examples 1 and 2, the conductive thin film is formed by patterning on the optical fiber block or glass capillary side, but conversely, the conductive thin film is formed on the planar lightwave circuit side and fixed after alignment. Needless to say.

[Modification]
In Examples 1 and 2, the substrate of the planar lightwave circuit is made of a quartz-based material. However, when the substrate is made of silicon, microwave energy absorption occurs because silicon is not transparent to microwaves. The absorbed energy is converted into heat, which raises the temperature of the planar lightwave circuit around the substrate for a short time. Since the volume expansion of the planar lightwave circuit including the substrate occurs due to this temperature rise, it can be considered that the optical axis of the aligned optical fiber is shifted. When the mode field at the connection point between the planar lightwave circuit and the optical fiber is large, a slight deviation (<1 μm) is not a problem, but when the mode field is small, it can be said that the temperature rises instantaneously. May be.

  Therefore, when a silicon substrate is used for a planar lightwave circuit, a material in which metal particles and carbon particles are mixed (refer to Patent Document 2 and Patent Document 3) is conductive in order to further enhance the selective heating property of microwave heating. May be used as a conductive thin film. As a result, only the conductive thin film is selectively heated by microwave irradiation, and even in a planar lightwave circuit using a silicon substrate, temperature rise can be suppressed and positional deviation between the planar lightwave circuit and the optical fiber can be suppressed. it can.

  Even if the substrate of the planar lightwave circuit is other semiconductor material such as InP, the temperature rise is suppressed by using a material with stronger microwave absorption for the conductive thin film as in this modification, and the planar lightwave circuit and the optical A positional deviation with respect to the fiber can be suppressed.

100, 200, 300 Optical fiber module 101, 201, 301 Conductive thin film 111, 211, 311 Optical fiber 112 Optical fiber connection component 120, 220, 320 Planar light wave circuit 121, 221, 321 Optical waveguide 121-1, 212-1 321-1 Core 121-2, 221-2, 321-2 Cladding 122, 222, 322 Yatoi plate 123, 223, 323 Substrate 202, 203, 302, 303 Resin 211-1, 311-1 Core 211-2, 311-2 Coating 212 Glass capillary 212-1 Insertion hole 212-2 Countersink 312 V-groove substrate 313 Lid

Claims (6)

A planar lightwave circuit having an optical waveguide on a substrate;
An optical fiber having at least one core;
An optical fiber connecting component for fixing the optical fiber of at least one core and connecting the optical fiber to the planar lightwave circuit;
A conductive thin film formed at a portion excluding at least a portion where light propagates between a surface of the optical fiber connection component on the planar lightwave circuit side and a surface of the planar lightwave circuit on the optical fiber connection component side. The conductive thin film is heated by microwaves to connect the planar lightwave circuit and the optical fiber connection component, and the planar lightwave circuit and the optical fiber having at least one core are optically coupled. An optical fiber module.   And further comprising a resin filled in a portion where the light propagates between a surface of the optical fiber connection component on the planar lightwave circuit side and a surface of the planar lightwave circuit on the optical fiber connection component side. The optical fiber module according to claim 1.   2. The conductive thin film according to claim 1, wherein the conductive thin film is a thin film composed of particles of a conductor such as metal and carbon, or a semiconductor particle, or a thin film of an ink and a paste-like dispersion in which a conductor or a semiconductor is dispersed. 2. An optical fiber module according to 2. A method of manufacturing an optical fiber module in which a planar lightwave circuit having an optical waveguide on a substrate and at least one core optical fiber are optically coupled,
A portion of the end face on the planar lightwave circuit side of the optical fiber connection component for connecting the at least one core optical fiber to the planar lightwave circuit, at least a portion where light is propagated, and the optical fiber connection of the planar lightwave circuit A part of the end surface on the component side excluding at least a portion where light propagates, or a part of the end surface on the planar lightwave circuit side of the optical fiber connection part excluding a portion where light propagates and the optical fiber connection part of the planar lightwave circuit Patterning a conductive thin film that can be heated by microwave irradiation on at least a portion of the side end face excluding a portion where light propagates; and
Aligning the optical fiber and the planar lightwave circuit so as to enable optical connection between the optical fiber and the planar lightwave circuit;
Contacting the conductive thin film with the planar lightwave circuit;
Heating the conductive thin film by microwave irradiation, and connecting the optical fiber connecting component and the planar lightwave circuit. A method of manufacturing an optical fiber module, comprising:   After the step of connecting the optical fiber connecting component and the planar lightwave circuit, between the surface of the optical fiber connecting component on the planar lightwave circuit side and the surface of the planar lightwave circuit on the optical fiber connecting component side The method of manufacturing an optical fiber module according to claim 4, further comprising a step of filling the portion where the light propagates with a resin.   5. The conductive thin film according to claim 4, wherein the conductive thin film is a thin film made of particles of a conductor such as metal and carbon, or a semiconductor particle, or a thin film of an ink and a paste-like dispersion in which a conductor or a semiconductor is dispersed. 5. A method for producing an optical fiber module according to 5.

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