JP2016001286A - Optical fiber connection component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber connection component capable of strengthening connection of an optical fiber and a PLC and improving connection characteristics of a core of the optical fiber and an optical waveguide of the PLC.SOLUTION: An optical fiber connection component for connecting an optical fiber 103 to a planar lightwave circuit comprises: a capillary 101 having a through hole in which the optical fiber 103 can be inserted from one end face thereof and projected from the other end face thereof; and a film 102 fixed to the other end face of the capillary 101.

Description

  The present invention relates to an optical fiber connecting component, and more particularly to an optical fiber connecting component for optically coupling an optical fiber and an optical waveguide in a planar lightwave circuit.

Conventionally, a planar lightwave circuit (PLC) in which an optical waveguide mainly composed of SiO ₂ glass is formed on a silicon (Si) substrate is known. As members for optically coupling an optical waveguide and an optical fiber in a planar lightwave circuit, members such as a V-groove fiber block and a capillary are known.

  FIG. 1 shows an optical fiber connecting method using a conventional capillary. A PLC 12 is formed on the Si substrate 11. A capillary 14 for inserting the optical fiber 15 is fixed to the incident / exit end face of the optical waveguide (see, for example, Patent Document 1). In addition, a reinforcing glass plate 13 is installed on the input / output end face to which the capillary 14 is fixed so as to be flush with the input / output end face on the upper surface of the PLC 12.

  First, the optical fiber 15 is inserted into the through hole of the capillary 14 and fixed with an adhesive. Next, an adhesive is applied to the end face of the capillary 14 where the end face of the optical fiber 15 is exposed, or the end face of the PLC 12 and the edge 13 where the end face of the optical waveguide is exposed. The capillaries 14 are fixed to the PLC 12 and the sheath 13 by adjusting the positions of the core of the optical fiber 15 and the core of the optical waveguide of the PLC 12.

JP 2012-68532 A

  However, since the end face of the optical fiber and the end face of the capillary are not aligned, there are the following problems.

  When forming the end face of an optical fiber, generally, it is not necessarily perpendicular to the optical axis and is cut at a slight angle. The fact that the end face of the optical fiber is inclined with respect to the optical axis is functionally advantageous because reflected light generated at the end face of the optical fiber does not return to the optical fiber or the optical waveguide. However, when the optical fiber is inserted into the capillary, a part of the end face of the optical fiber may protrude from the end face of the capillary.

  In such a case, the end face of the capillary and the entrance / exit end face of the PLC are not parallel due to the protrusion of the optical fiber. In other words, the capillary may be fixed obliquely with respect to the incident / exit end face of the PLC. At this time, the thickness of the adhesive between the end face of the capillary and the entrance / exit end face of the PLC varies depending on the position. As a result, there is a problem that stress concentration occurs due to a temperature change, which induces peeling of the adhesive layer and deteriorates optical characteristics.

  An object of the present invention is to provide an optical fiber connecting component for strengthening the connection between an optical fiber and a PLC and improving the connection characteristics between the core of the optical fiber and the optical waveguide of the PLC.

  In order to achieve such an object, according to a first embodiment, in an optical fiber connecting part for connecting an optical fiber to a planar lightwave circuit, the optical fiber is inserted from one end face and protrudes from the other end face. A capillary having a through hole made possible and a film fixed to the other end face of the capillary are provided.

  According to a second embodiment, in an optical fiber connecting component for connecting an optical fiber to a planar lightwave circuit, a capillary having a through hole in which the optical fiber is inserted from one end face and protruded from the other end face; In the other end face of the capillary, a part of the through hole is blocked and a spacer fixed to the other end face is provided.

  According to a third embodiment, in an optical fiber connecting part for connecting an optical fiber to a planar lightwave circuit, a capillary having a through hole in which the optical fiber is inserted from one end face and protruded from the other end face; And a spacer fixed to the other end face of the capillary, wherein the optical fiber has a thickness equal to a length protruding from the other end face.

  When the optical fiber and the PLC are connected using the optical fiber connecting component described above, the incident / exit end surface of the PLC and the other end surface of the facing optical fiber connecting component are parallel to each other. Accordingly, since a uniform adhesive layer is formed between the PLC and the optical fiber connecting component, the connection between the optical fiber and the PLC is strengthened, and the connection characteristics between the optical fiber core and the optical waveguide of the PLC deteriorate. Can be prevented.

It is a figure which shows the optical fiber connection method using the conventional capillary. It is a figure which shows the optical connection component concerning the 1st Embodiment of this invention. It is a figure which shows the application example of the optical connection component of 1st Embodiment. It is a figure which shows the optical fiber connection method using the optical connection component of 1st Embodiment. It is a figure which shows the preparation methods of the optical connection component of 1st Embodiment. It is a figure which shows the optical fiber connection method using the optical connection component concerning the 2nd Embodiment of this invention. It is a figure which shows the application example of the optical connection component of 2nd Embodiment. It is a figure which shows the optical connection component concerning the 3rd Embodiment of this invention.

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

(First embodiment)
FIG. 2 shows an optical connection component according to the first embodiment of the present invention. As shown in FIG. 2A, the optical connection component 100 includes a capillary 101 and a film 102. The capillary 101 has a through hole into which the optical fiber 103 can be inserted from one end face and protrude from the other end face. The optical fiber 103 is inserted so that its end face is flush with the other end face, and is fixed with an adhesive at one end face.

  The thickness of the film 102 is usually 1 to 20 μm, and as described below, the portion protruding from the end face of the optical fiber 103 is made thick enough to absorb. The size of the film 102 may be the same as or larger than the cross section of the capillary 101. The material of the film 102 can be an epoxy resin, an acrylic resin, a polyurethane resin, a silicon resin, or the like, in addition to a polyester film such as polyethylene naphthalate. In the capillary 101, the film 102 is fixed to the other end surface from which the optical fiber 103 protrudes with an adhesive such as epoxy. The refractive index of the adhesive is the same as that of the optical fiber and the core portion of the PLC.

  When the above-mentioned material is used as the film 102, as shown in FIG. 2 (b), the portion protruding from the end surface of the optical fiber 103 is recessed, so that the film 102 facing the input / output end surface of the PLC is always in the direction of the PLC. Parallel to the exit end face. That is, even when the end face of the capillary 101 and the end face of the optical fiber 103 are not uniform, the unevenness can be absorbed.

  FIG. 3 shows an application example of the optical connection component of the first embodiment. FIG. 3A is a cross-sectional view seen from the side, and FIG. 3B is a plan view seen from the surface facing the input / output end surface of the PLC. The film 112 is usually 1 to 20 μm in thickness, larger in size than the capillary 101 cross section, and its outer shape is different from the capillary 101 cross sectional shape. The size of the film 112 is preferably smaller than the incident / exit end face constituted by the connected PLC and the end.

  FIG. 4 shows an optical fiber connection method using the optical connection component of the first embodiment. A PLC 202 is formed on the Si substrate 201. An optical connection component 100 is fixed to the incident / exit end face of the optical waveguide. Further, a reinforcing glass plate 203 is installed on the input / output end face to which the optical connecting component 100 is fixed so as to be flush with the input / output end face on the upper surface of the PLC 202.

  As an optical fiber connecting method, first, the capillary 101 and the film 102 are bonded, and the optical fiber 103 is inserted into the through hole from one end face of the capillary 101 and fixed with an adhesive. Next, an adhesive 204 is applied to the end face of the PLC 202 and the edge 203 where the end face of the film 102 or the end face of the optical waveguide is exposed. Application of the adhesive 204 forms an adhesive layer by attaching an adhesive film or spraying a resin by ink jetting. The optical connection component 100 is fixed by adjusting the positions of the core of the optical fiber 103 and the core of the optical waveguide of the PLC 202. An epoxy-based adhesive or the like is used for fixing the optical connection component 100.

  According to the first embodiment, the incident / exit end face of the PLC 202 and the end face of the capillary 101 opposed via the film 102 are parallel to each other. Therefore, since a uniform adhesive layer is formed between the PLC and the capillary, the connection between the optical fiber and the PLC is strengthened, and the connection characteristics between the core of the optical fiber 103 and the optical waveguide of the PLC 202 are prevented from deteriorating. be able to.

In the first embodiment, the combination of the Si substrate 201 and the PLC 202 is shown. However, an optical waveguide layer made of LiNbO _{3 or} a semiconductor waveguide layer can also be applied as a lightwave circuit.

  FIG. 5 shows a method for manufacturing the optical connecting component of the first embodiment. First, a plurality of capillaries 121 a to 121 f are fixed to the film 122. Next, the optical fibers 103a to 103f are inserted into the through holes of the capillaries 121a to 121f, respectively, and fixed with an adhesive. Finally, when the film 122 is cut, a plurality of optical connecting parts can be obtained. In this way, there is an advantage that a plurality of optical connection parts can be efficiently manufactured.

(Second Embodiment)
FIG. 6 shows an optical fiber connection method using the optical connection component according to the second embodiment of the present invention. A PLC 202 is formed on the Si substrate 201. An optical connection component 300 is fixed to the incident / exit end face of the optical waveguide. The optical connection component 300 includes a capillary 301 and spacers 302a and 302b. In addition, a reinforcing glass plate 203 is installed on the input / output end face to which the optical connecting component 300 is fixed so as to be flush with the input / output end face on the upper surface of the PLC 202.

  As an optical fiber connection method, first, a spacer 302 is formed on the other end face of the capillary 301, and the optical fiber 303 is inserted into the through hole from one end face of the capillary 301 and fixed with an adhesive. Next, an adhesive 204 is applied to the other end face of the capillary 301 or the end face of the PLC 202 and the sheath 203 where the end face of the optical waveguide is exposed. The optical connection component 300 is fixed by adjusting the positions of the core of the optical fiber 103 and the core of the optical waveguide of the PLC 202. An epoxy-based adhesive is used to fix the optical connection component 300.

  The spacers 302 provided between the other end face of the capillary 301 and the entrance / exit end face of the PLC 202 have the same thickness. When the optical fiber 303 is inserted into the capillary 301, the end face of the optical fiber comes into contact with the spacer 302 and stops. In this state, the optical fiber 303 and the capillary 301 are fixed. Thereby, the incident / exit end face of the PLC and the end face of the facing capillary 301 become parallel.

  FIG. 7 shows an application example of the optical connection component of the second embodiment. FIGS. 7A to 7D show how the spacer 302 is mounted on the incident / exit end face formed by the PLC 202 and the sheath 203. A plurality of spacers are provided, and the spacers 302, 312, and 322 in FIGS. 7A to 7C are arranged so as to contact the core of the optical fiber 303. That is, the other end face of the capillary 301 is fixed so as to block a part of the through hole into which the optical fiber 303 is inserted.

  As shown in FIG. 7D, the spacer 332a that contacts the core of the optical fiber and the spacer 332b that contacts the capillary may be divided and arranged. The arrangement pattern can be arranged point-symmetrically with respect to the center of the core, or can be arranged line-symmetrically with respect to an axis passing through the center of the core.

  As an optical fiber connecting method using such a capillary with a spacer, first, a spacer 302 coated with an adhesive only on one side is arranged on an appropriate work table as shown in FIG. The capillary 301 is adhered to the upper surface of the spacer 302 to which the adhesive is applied, while maintaining the positional relationship shown in FIG. In the case of FIG. 7D, only the spacer 332a to be bonded to the capillary 301 is bonded. Next, the optical fiber 303 is inserted into the through-hole from one end face of the capillary 301, the optical fiber 303 and the capillary 301 are fixed with an adhesive, and then the optical fiber 303 and the spacer 302 are bonded and fixed.

  An adhesive 204 is applied to the end surfaces of the capillary 301 and the optical fiber 303 on the side to which the spacer 302 is bonded, or the end surfaces of the PLC 202 and the edge 203 where the end surfaces of the optical waveguide are exposed. Application of the adhesive 204 forms an adhesive layer by attaching an adhesive film or spraying a resin by ink jetting. The optical connection component 300 is fixed by adjusting the positions of the core of the optical fiber 303 and the core of the optical waveguide of the PLC 202. An epoxy-based adhesive is used to fix the optical connection component 300.

The material of the spacer may basically be anything as long as it is hard, for example, a metal thin film such as gold or silver, a metal foil such as copper alloy or nickel alloy, a metal glass thin film such as silicon or Pd-Cu-Si, TiN Materials for optical devices such as ceramic thin film, hard plastic, quartz glass, and LiNbO ₃ can be used.

  As a processing method of the spacer, a desired size can be obtained by a normal fine processing method, that is, cutting by precise machining. A material such as silicon can be processed by etching. Regarding the control of the thickness of the spacer, for example, a desired thickness can be obtained by stretching a metal thin film or the like, or by using a metal glass etching method.

(Third embodiment)
FIG. 8 shows an optical connection component according to the third embodiment of the present invention. In the second embodiment, the spacer is disposed so as to contact both the optical fiber and the capillary, so that the light incident / exit end surface of the PLC and the end surface of the facing capillary are parallel to each other. In the third embodiment, the spacers are arranged so as to contact only the capillaries, and the input / output end surfaces of the PLC and the end surfaces of the facing capillaries are parallel to each other. In the third embodiment, a case will be described in which the end face of the optical fiber is polished obliquely with respect to the optical axis in advance in order to suppress the return light due to the end face reflection of the optical fiber. In general, since the optical fiber with a diameter of 125 μm is inclined by 8 degrees from the perpendicular to the optical axis, the end face of the optical fiber is compared with the end face of the capillary when the oblique end face portion protrudes completely. And a maximum of 18 μm.

  Therefore, spacers 342, 352, and 362 having a thickness of approximately 20 μm, which are substantially equal to the length of the optical fiber protruding from the end face of the capillary, are formed on the end face of the capillary. A capillary with a spacer is placed on a flat plate with the surface on which the spacer is formed facing down, and the optical fiber 303 is inserted into the through hole of the capillary 301 and fixed with an adhesive. An adhesive is applied to the end face of the capillary or the end face of the PLC where the end face of the optical waveguide is exposed. The position of the core of the optical fiber and the core of the optical waveguide of the PLC is adjusted to fix the optical connection component. Thereby, the incident / exit end face of the PLC and the end face of the facing capillary are parallel to each other.

  The manufacturing method of the capillary with such a spacer is the same as that of the second embodiment.

(Confirmation of effect)
A PLC and an optical fiber were connected using the optical connection component of the first to third embodiments, and a heat cycle test (−45 to 85 ° C., 100 times) was performed. The deterioration of the optical characteristics caused by the peeling of the adhesive layer formed between the PLC and the capillary respectively decreased. Compared with the optical fiber connection method using the conventional capillary shown in FIG. 1, both optical insertion loss and light reflection loss were improved by several percent.

11, 201 Si substrate 12, 202 PLC
13,203 Reinforced glass plate (Yatoi)
14, 101, 121, 301 Capillary 15, 103, 303 Optical fiber 100, 300 Optical connecting part 102, 112, 122 Film 204 Adhesive 302, 312, 322, 332, 342, 352, 362 Spacer

Claims (7)

In an optical fiber connecting part for connecting an optical fiber to a planar lightwave circuit,
A capillary having a through hole in which the optical fiber is inserted from one end face and protruded from the other end face;
An optical fiber connecting part comprising: a film fixed to the other end face of the capillary.   The optical fiber connecting component according to claim 1, wherein the film is made of a polyester film containing polyethylene naphthalate. In an optical fiber connecting part for connecting an optical fiber to a planar lightwave circuit,
A capillary having a through hole in which the optical fiber is inserted from one end face and protruded from the other end face;
An optical fiber connecting component comprising: a spacer fixed to the other end surface of the capillary at a part of the through hole at the other end surface of the capillary. In an optical fiber connecting part for connecting an optical fiber to a planar lightwave circuit,
A capillary having a through hole in which the optical fiber is inserted from one end face and protruded from the other end face;
A spacer fixed to the other end face of the capillary, the spacer having a thickness equal to the length of the optical fiber protruding from the other end face.   5. The optical fiber connection component according to claim 3, wherein the spacer includes a plurality of spacers and is arranged point-symmetrically with respect to a center of the core of the optical fiber.   5. The optical fiber connecting component according to claim 3, wherein the spacer includes a plurality of spacers, and is arranged in line symmetry with respect to an axis passing through a center of the core of the optical fiber. .   7. The optical fiber connection part according to claim 3, wherein the spacer is made of quartz glass.

Images