JP2014010334A - Optical fiber guide component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber guide component in which clearance is substantially reduced for achieving connection with reduced size, cost and loss.SOLUTION: An optical fiber guide component according to the invention comprises: a V-shaped groove substrate with at least one first V-shaped groove and a pair of second V-shaped grooves; spacer fibers accommodated in the second V-shaped grooves; and a flat substrate for bonding them onto the V-shaped substrate via the spacer fibers. While the spacer fibers are accommodated in the second V-shaped grooves, the V-shaped groove substrate and flat substrate are joined by an elastic adhesive layer formed from elastic adhesive. The diameter of the inscribed circle of a guide hole is smaller than the diameter of an optical fiber inserted in the first V-shaped groove when the optical fiber is not inserted in the first V-shaped groove.

Description

  The present invention relates to an optical fiber guide component for positioning an optical fiber to be inserted in an application of connecting an optical fiber and an optical fiber or an optical fiber and a planar optical waveguide.

  With the progress of optical communication networks, the number of optical devices mounted on the optical communication apparatus responsible for the transmission processing has increased, that is, the device mounting density has increased. Multi-channel optical devices such as optical transceivers, optical distributors, optical exchangers, and wavelength multiplexers / demultiplexers based on planar optical waveguides (hereinafter referred to as “PLCs”) on optical communication devices are based on semiconductors. This is an important device that constitutes an optical device along with the light receiving and emitting elements. Hereinafter, such a waveguide-based optical device is simply referred to as an optical device.

  Usually, an optical device is integrated with an optical fiber by a component called a fiber array or a fiber block, and the optical fiber portion is called a pigtail fiber. When optical devices are connected to each other on a board in an optical communication apparatus, it is necessary to connect pigtail fibers to each other, and they are usually connected by fiber fusion using arc discharge.

  In recent years, along with the increase in device mounting density (increase in the number of devices) in optical communication devices, the optical fiber wiring for connecting them has become large-scale and complicated, and the number of optical fiber connection points on and between boards has increased. It is increasing. Even at present, it is necessary to connect several tens of optical fibers on the board. However, the above-mentioned fusion work and the fiber management for that are difficult, and factors that hinder downsizing and cost reduction of the equipment. It has become. As optical fiber connection points are expected to increase further in the future, instead of the above fusion splicing, optical connections such as small multi-fiber optical connectors for connecting pigtail fibers more compactly and easily Parts are required.

  Conventionally, as a multi-fiber optical connector, an MT connector using a multi-fiber ferrule and a fitting pin and an MPO connector based on the MT connector are known.

  On the other hand, a new type of multi-fiber optical connector that does not use a ferrule has also been proposed, and this multi-fiber optical connector is inserted with a fiber of bare clad glass (hereinafter referred to as bare fiber) and a bare fiber. And an optical fiber guide component having a plurality of fine through holes. In this system, the fibers are connected by inserting the fibers into holes provided at both ends of the optical fiber guide component. Such a bare fiber type multi-fiber optical connector is smaller and thinner than a connector using the ferrule, and is suitable for optical fiber connection on the aforementioned board.

  Further, in the future, not only the connection between the pigtail fibers on the board but also a technology for eliminating the pigtail fibers is required. As a means therefor, there has been proposed an optical connecting component that can easily and directly connect an optical device and an optical fiber, that is, an optical connector for connecting an optical device to an optical fiber. As a method for realizing this, for example, Patent Document 1 proposes a connection method using a multi-fiber ferrule and a connection method between a bare fiber and a device using an optical fiber guide component, as well as connection between optical fibers. Has been. Hereinafter, both the connection between optical fibers and the optical device-optical fiber connection are simply referred to as “optical fiber connection”.

JP-A-9-90171 JP 2004-240323 A JP 2004-78028 A

Ryo Nagase, Shuichiro Ninagawa, Masaru Kobayashi, Yuki Abe, “16-fiber SF optical connector for board mounting”, IEICE Technical Report, The Institute of Electronics, Information and Communication Engineers, 2009, p.11-14

  Here, in the optical fiber connection, it is necessary to connect more simply and with low loss. In order to realize a low-loss connection, it is necessary to align (align) the core position of the optical fiber and the core position of the pair of optical fibers (or the waveguide core position of the optical device) with high accuracy. If the deviation in the direction perpendicular to the longitudinal direction of the fiber from the center of both cores is called axial deviation, in the case of a single mode type optical fiber (core diameter: about 10 μm) introduced in a normal optical communication system, the axis of 1 μm The shift causes a connection loss of about 0.10 to 0.15 dB, and the loss increases exponentially. For this reason, in order to realize a low-loss connection, it is necessary to suppress the amount of axial deviation to 1 μm or less. Therefore, the hole for inserting the fiber in the ferrule part or the optical fiber guide part needs to be formed with very high accuracy. In multi-fiber optical fiber connection, it is required to connect all fibers at once and with low loss, so that the technical difficulty is higher than the connection between single-fiber optical fibers.

  In the case of optical fiber connection using a multi-core ferrule, a method is adopted in which a large number of through-holes having a circular cross section are formed in the same ferrule. In this method, as the number of fiber connections, that is, the number of holes increases, the position error of the holes with respect to the ferrule is accumulated. In addition to this, the difference between the ferrule hole and the fiber diameter, the pin hole diameter, and the pin position error also accumulate and cause an axis deviation. Therefore, it becomes difficult to realize a low-loss connection as the number of fiber cores increases.

  On the other hand, in the case of optical fiber connection using bare fibers and fiber guides, as described above, each fiber is aligned in each hole even if the number of fiber connections increases, so the hole position error for the component affects the connection loss. Give almost no. Therefore, in order to obtain a low-loss connection, the fiber guide may be manufactured with high accuracy so that the hole diameter of the fiber guide matches the fiber diameter.

  For example, a fiber guide is manufactured by forming a through-hole having a circular cross-section by injection molding as shown in Patent Document 2 or a V-groove substrate as shown in Patent Document 1 and Patent Document 3. A triangular guide hole comprising a space between the V-groove of the V-groove substrate and the flat substrate is formed by covering the V-groove with a flat substrate such as glass via a spacer fiber and bonding them with an adhesive. What has been formed has been proposed so far. Hereinafter, a triangular hole formed by a space between the inner wall surface of the V groove of the V groove substrate and the surface of the flat substrate is referred to as a guide hole.

  In either system, the hole is made to have a diameter slightly larger than the diameter of the insertion fiber so that the bare fiber can be inserted into the hole. Here, if the difference between the size of the hole diameter and the diameter of the bare fiber to be inserted is called a clearance, the clearance needs to be at least 0.2 μm or more in order to easily insert the bare fiber. On the other hand, if the clearance is too large, it leads to an increase in axial deviation, that is, a deterioration in connection loss. Therefore, it is preferable to make it as small as possible.

  Here, a commercially available multi-core fiber is handled on the board as a tape fiber taped to a specific pitch, but the practical outer diameter of the cladding of the tape fiber varies by about 0.1 to 0.5 μm. There is. For this reason, it is necessary to produce an optical fiber guide component with all the tape fibers inserted into the hole and with as small a hole diameter as possible. However, it is difficult to produce such a component at a low cost and with a high yield. A method of selecting fibers with the same cladding diameter without using a tape fiber and forming a tape again so as to have a specific pitch can be considered, but this leads to an increase in mounting cost, which is not preferable.

  Here, as shown in Patent Document 2, it is difficult to produce an optical fiber guide component having the above-described high-precision hole by injection molding because the hole diameter accuracy is limited only by injection molding. In addition, because of the very high cost of molds and the need to prepare a large number of molds according to the number of fiber cores and fiber diameters used, it is possible to produce high-precision optical fiber guide parts at low cost. There are challenges.

  On the other hand, as shown in Patent Document 3, a V-groove type optical fiber guide component in which a flat substrate is bonded to a V-groove substrate via two spacer fibers can be manufactured by combining inexpensive components such as glass components. In addition, since several tens of units of optical fiber guide parts can be manufactured and processed in a lump, high-precision parts can be manufactured at a relatively low cost. Also, the V-groove can be formed by dicing, and the hole diameter of the optical fiber is determined by the diameter of the V-groove and the spacer fiber, so that it is possible to produce a fiber guide according to the number of fiber cores to be applied and the fiber diameter. And excellent in flexibility.

  However, since the V-groove type optical fiber guide component as shown in Patent Document 3 is configured with a triangular guide hole made of a V-groove, an axis misalignment tends to occur with respect to the clearance. Here, assuming that the clearance is ΔL and the amount of axis deviation is Δd, the worst value Δdmax of the axis deviation amount of the 60 ° V groove is Δdmax = √3 × ΔL, which is excellent in low cost and flexibility, It is necessary to control the hole diameter with higher accuracy than that.

  Here, spacer fibers are used to control the hole diameter, but in order to allow all bare fibers to be inserted into the holes, the diameter of the spacer fiber is slightly larger than the maximum diameter of the bare fiber of the tape fiber. The diameter must be selected. Therefore, there is always a clearance.

  Furthermore, in practice, it is difficult to suppress the amount of axial deviation to 1 μm or less for all hole diameters, including a manufacturing error of about 0.1 μm at the maximum in the depth direction of the V-groove. In addition, while the spacer fiber diameter and the insertion fiber diameter are the same, a method is also possible in which the V-groove that accommodates the fiber is set slightly deeper than the pair of V-grooves that accommodate the spacer fiber diameter. In this method as well, it is difficult to suppress the amount of axis deviation to 1 μm or less for the same reason as described above. Further, there is a problem that the fluctuation of the loss increases due to the fluctuation of the fiber in the hole due to the presence of the clearance even at the time of impact or heat change.

  The present invention has been made in view of such problems, and an object of the present invention is to achieve a small, low-cost and low-loss connection in optical fiber connection parts such as connector connection of multi-core fibers. Accordingly, it is an object of the present invention to provide an optical fiber guide component having a significantly reduced clearance.

  An optical fiber guide component according to claim 1 of the present invention is an optical fiber guide component for positioning an optical fiber inserted into a guide hole, and is at least one formed to insert the optical fiber. A V-groove substrate comprising a first V-groove and a pair of second V-grooves formed at both ends of the first V-groove, spacer fibers respectively accommodated in the second V-groove, A flat substrate for bonding onto the V-groove substrate via the spacer fiber, and the V-groove substrate and the flat substrate are in a state where the spacer fiber is accommodated in the second V-groove. The diameter of the inscribed circle of the guide hole, which is joined by an elastic adhesive layer made of an elastic adhesive and is composed of the inner wall surface of the first V-groove and the surface of the flat substrate, is in the first V-groove. In a state where the optical fiber is not inserted There and is smaller than the diameter of the optical fiber to the insert.

  An optical fiber guide component according to a second aspect of the present invention is the optical fiber guide component according to the first aspect of the present invention, wherein the depth of the second V groove is greater than that of the first V groove. It is characterized by being deeply set.

  An optical fiber guide component according to claim 3 of the present invention is the optical fiber guide component according to claim 1 of the present invention, wherein the diameter of the spacer fiber is equal to or less than the cladding diameter of the optical fiber to be inserted. It is characterized by being.

An optical fiber guide component according to a fourth aspect of the present invention is the optical fiber guide component according to any one of the first to third aspects of the present invention, wherein the elastic adhesive layer has a storage elastic modulus at 20 ° C. It consists of an elastic adhesive having elasticity of 5 × 10 ⁸ Pa or less.

An optical fiber guide component according to a fifth aspect of the present invention is the optical fiber guide component according to any one of the first to third aspects of the present invention, wherein the elastic adhesive layer has a storage elastic modulus at 20 ° C. It consists of an elastic adhesive in the range of 1 × 10 ⁷ Pa to 1 × 10 ⁸ Pa.

  An optical fiber guide component according to a sixth aspect of the present invention is the optical fiber guide component according to any one of the first to fifth aspects of the present invention, wherein the fiber insertion port end surface of the guide hole has an inclination. A chamfering process is formed.

  An optical fiber guide component according to a seventh aspect of the present invention is the optical fiber guide component according to any one of the first to sixth aspects of the present invention, wherein between the V-groove substrate and the flat substrate, A rubber film having a thickness equal to or less than the fiber diameter is provided.

  According to the optical fiber guide component of the present invention, the optical fiber to be connected is pressed against the inner wall of the V-groove by the restoring force of the elastic resin in the optical fiber connection component such as the connector connection of the multi-fiber, thereby reducing the size and cost. In addition, a low-loss connection can be achieved and the clearance can be greatly reduced.

It is a figure which shows sectional drawing of the optical fiber guide component 50 which concerns on this invention. It is a schematic diagram of the optical fiber guide component 50 which concerns on this invention. It is a figure for demonstrating the optical fiber guide component 100 which concerns on Example 1 of this invention. It is a figure for demonstrating the optical fiber guide component 200 which concerns on Example 2 of this invention. It is a figure for demonstrating the manufacturing method of the optical fiber guide component 200 which concerns on Example 2 of this invention. It is a figure for demonstrating the optical fiber guide component 300 which concerns on Example 3 of this invention. It is a figure which shows typically the mechanism in which one bare fiber is inserted in the guide hole of the optical fiber guide component which concerns on this invention. It is a figure which shows the example of the method of applying external force to the optical fiber guide part which concerns on this invention. It is a figure which shows the example which applied the optical fiber guide component which concerns on this invention to the bare fiber type connection form. It is the photograph after connecting an optical fiber using the optical fiber guide part which concerns on this invention. It is a figure which shows the example which applied the optical fiber guide component which concerns on this invention to the connection of an optical device and an optical fiber.

  Hereinafter, an exemplary embodiment of the optical fiber guide component 50 according to the present invention will be described. FIG. 1 shows a cross-sectional view of an optical fiber guide component 50 according to the present invention. As shown in FIG. 1, the optical fiber guide component 50 according to the present invention includes a V-groove substrate 10, a flat substrate 20, and a spacer fiber 30. As shown in FIG. 1, on the upper surface of the V-groove substrate 10, there are eight first V-grooves 1 and a pair of spacer fibers 30 positioned at both ends of the eight-core first V-groove 1. A second V-groove 2 that is a V-groove is formed. In the V-groove substrate 10, an elastic adhesive is applied to the space formed by the flat substrate 20 and the spacer fiber 30 where the first V-groove 1 and the two second V-grooves 2 are not formed. The elastic adhesive layer 40 is formed by filling.

  In the conventional optical fiber guide component, it is necessary to use a spacer fiber having a fiber diameter equal to or larger than the maximum value of the tape fiber diameter to be inserted. However, in the optical fiber guide component 50 according to the present invention, contrary to the conventional case, the spacer fiber 30 having a fiber diameter equal to or smaller than the minimum value of the tape fiber diameter to be inserted is selected, or the second V-groove 2 is selected. Is set deeper than the depth of the first V-groove 1. That is, in the optical fiber guide component 50 of the present invention, the diameter of the inscribed circle (hereinafter referred to as the hole diameter) of each guide hole before fiber insertion is set smaller than the diameter of the optical fiber.

  Since the diameter of each guide hole before fiber insertion is smaller than the diameter of the optical fiber, it is difficult to insert the optical fiber as it is. However, in the optical fiber guide component 50 of the present invention, the V-groove substrate 10 and the flat substrate 20 Are bonded by an elastic adhesive layer 40 made of an elastic adhesive having a certain elastic modulus. Thereby, the thickness of the elastic adhesive layer 40 is displaced by the insertion force or the like applied when the fiber is inserted, and the flat substrate 20 is displaced. Therefore, the hole diameter of the guide hole is temporarily enlarged, and the optical fiber can be inserted.

  After the optical fiber is inserted into the guide hole and the bare fiber is accommodated, the bare fiber is pressed at two points on the inner wall surface of the first V-groove 1 of the V-groove substrate 110 by the pressing force due to the elastic restoration of the elastic adhesive layer 40. And a total of three points in contact with one point on the surface of the flat substrate 20 can be maintained. Thereby, the optical connection in a state where the clearance in the guide hole is substantially zero can be realized. As a result, it is possible to realize an optical fiber connection with a much lower loss than before.

  Here, it is ideal that the elastic adhesive layer 40 can be elastically deformed only by the insertion force of the fiber. Hereinafter, the elastic modulus of the elastic adhesive layer 40 for causing elastic deformation only by the fiber insertion force is defined.

FIG. 2 is a schematic view of an optical fiber guide component 50 according to the present invention. FIG. 2 shows the V-groove substrate 10, the flat substrate 20, and the optical fiber 35. As shown in FIG. 2, the flat substrate 20 includes a guide portion 60 having an obliquely inclined surface for inserting the optical fiber 35.
The optical fiber guide component 50 is connected to the PLC.

  2, the diameter of the optical fiber 35 is d, the elastic second moment of the optical fiber 35 is E, the inclination angle of the guide portion 60 with respect to the x-axis direction in FIG. 2 is α, the protruding length of the optical fiber 35 is L, the light The number of cores of the fiber 35 is N, the storage elastic modulus of the elastic adhesive layer 40 is G, the strain amount of the elastic adhesive layer 40 is δ, and the static (dynamic) friction coefficient between the optical fiber 35 and the V-groove substrate 10 or the flat substrate 20 is μ, the bonding cross-sectional area of the elastic adhesive layer 40 with respect to the V-groove substrate 10 and the flat substrate 20 is S, and the maximum value of the insertion force F that is orthogonal to the fiber longitudinal direction and acts on the flat substrate 20 in the z-axis direction in FIG. Is Fmax, (Equation 1) is a condition for the flat substrate 20 to be elastically deformed only by the insertion force of the fiber.

  Fmax can be approximately expressed by (Equation 2) from the calculation by the material dynamic model.

  (Expression 2) is obtained by decomposing the force in the vertical direction when the maximum value I of the compressive force in the x-axis direction is applied to the obliquely inclined surface of the guide portion 60 when the fiber is a beam. The maximum value I of the compression force is expressed as (Equation 3).

  It is known that when a force equal to or greater than the maximum value I shown in (Equation 3) is applied to the fiber, the fiber buckles. In the present invention, it is preferable to select a fiber guide shape and an elastic adhesive that satisfy (Expression 1) and (Expression 2).

  As shown in (Expression 2), when the angle α of the flat substrate with respect to the x-axis direction is 90 °, that is, when there is no guide portion 60, the insertion force is almost zero. Therefore, it is necessary to form the guide part 60 by performing insertion guide processing on the flat substrate 20. This insertion guide processing can be formed by dicing or the like, similarly to the method disclosed in Patent Document 3. As α is smaller, the value of F increases. However, since a dicing blade having an angle of 60 ° is generally used as a commercial product, α is 60 ° / 2, that is, 30 ° from the viewpoint of low cost. It is preferable to make it about or less.

  In addition, the smaller the protruding length L of the optical fiber 35 is, the larger F is. However, if L is too small, the length of the guide portion 60 in the x-axis direction must be shortened, and the guide portion 60 is shortened. Therefore, it becomes difficult to manufacture and grip the guide portion 60.

When the guide part 60 was actually produced, it was confirmed that practical handling was difficult when L was 1 mm or less. Therefore, L is fixed to 1 mm, d = 125 μm, E = 76 × 10 ⁹ Pa, α = 30 °, static friction coefficient μ = 0, and N = 1 (minimum value), using the above (formula 2). When the insertion force Fmax is calculated, the insertion force Fmax is approximately 58N. That is, a force of about 58 N is applied to the flat substrate 20 with the insertion of one fiber. In order to displace the flat substrate 20 with this force, an elastic modulus G satisfying (Equation 1) is required.

The bonding cross-sectional area S is the fiber protruding length L and the length L ′ in FIG. 1, that is, y other than the portion where the first V-groove 1 and the second V-groove 2 are formed in the V-groove substrate 10. Determined by axial length. The latter is determined by the width of the PLC component or connector structure, but from the viewpoint of miniaturization, it is difficult to set it to approximately 2 mm or more at both ends. The maximum bonding cross-sectional area is S = 2 × L × L ′. When L = 1 mm and L ′ = 2 mm, S = 4 mm ² .

Further, what is generally called an elastic adhesive usually has an elongation of 10% or more (JIS K6301), but in the present invention, other than what is generally called an elastic adhesive, elastic deformation against strain An adhesive having a large range can also be used (including the latter, it is called an elastic adhesive in the present invention). In the elastic adhesive including the latter definition, the region where the adhesive maintains elasticity is approximately 3% or less as the existing adhesive. If it exceeds that, elastic recovery will occur, but there will be a considerable amount of viscoelastic components, and the influence of relaxation time and the like will increase. Therefore, 3% is assumed as the maximum strain. At this time, when the storage elastic modulus required for displacement is calculated by (Equation 1), it is about 5 × 10 ⁸ Pa. If the elastic modulus is less than this value, the flat substrate 20 can be displaced and the clearance can be reduced to zero with only the insertion force of one fiber, which is excellent in practicality. In actual production, the thickness and displacement amount of the adhesive layer may be set as appropriate so that the elastic strain region is taken into consideration.

However, even if the elastic modulus is equal to or greater than this value, means other than displacing the flat substrate only by the fiber insertion force, for example, the first V-groove 1 and the second V-groove 2, and the dummy V-groove An external force that temporarily expands the fiber diameter may be applied only during insertion, for example, by inserting a metal rod having the same diameter as the fiber diameter to be inserted. The conventional adhesive uses a hard UV curing adhesive, and its storage elastic modulus is about 1 × 10 ⁹ to 1 × 10 ¹¹ Pa, which is suitable for insertion with the insertion force of the fiber. Absent.

As described above, from the viewpoint of fiber insertion property, the lower the storage elastic modulus, the more suitable, for example, a silicone adhesive or a modified silicone adhesive of about 1 × 10 ⁶ Pa. However, as described in Patent Document 3, considering that mass production is performed by dicing the fiber guide by dicing, if the storage elastic modulus is too low, the shear bond strength and the like are reduced accordingly, so that the V-groove substrate 10 There is a concern that displacement between the flat substrate 20 and the flat substrate 20 may occur. As a preliminary study, when two slide glasses were bonded together and cut out by dicing, it was confirmed that the two plates were shifted or peeled at an elastic modulus of 1 × 10 ⁷ or less. On the other hand, when the elastic modulus was in the range of 1 × 10 ⁷ Pa to 1 × 10 ⁸ Pa, it was confirmed that there was almost no peeling or displacement. Therefore, the elastic modulus is preferably 1 × 10 ⁷ Pa to 1 × 10 ⁸ Pa in order to reduce the relative displacement between the V-groove substrate 10 and the flat substrate 20 and increase the accuracy in batch processing. With the above elastic modulus, the flat substrate 20 can be minutely displaced only by the fiber insertion force, and mass productivity can be ensured.

Example 1
The optical fiber guide component 100 according to the first embodiment of the present invention will be described with reference to FIG. In FIG. 3, an optical fiber guide component 100 including a V-groove substrate 110 having a first V-groove 1 and a second V-groove 2, a flat substrate 120, a spacer fiber 130, and an elastic adhesive layer 140 is shown. It is shown. The optical fiber guide component 100 has a structure in which both ends of the V-groove substrate 110 protrude from the flat substrate 120 in the x-axis direction, which is the longitudinal direction of the V-grooves 1 and 2. Hereinafter, a method for producing the optical fiber guide component 100 according to the first embodiment of the present invention will be exemplified.

  First, an insertion fiber diameter for connecting an optical fiber is measured. Usually, the clad diameter of an optical fiber used for optical communication is 125 μm (± 0.5 μm). From the measurement results, the clad diameter of the tape fiber used this time is 124.6 to 125.0 μm.

  Next, by machining, an 8-core first V-groove 1 with an angle of 60 degrees is machined on an 8 × 5 × 1 mm quartz glass plate, and the ends of the 8-core first V-groove 1 are similarly processed. A V-groove substrate 110 was produced by processing the second V-groove 2. At this time, the total depth of the ten V-grooves 1 and 2 in the V-groove substrate 110 was set to be the same, and the value was 160 μm. The pitch of the V grooves was set to 250 μm. In addition, it is possible to process the V-groove with a predetermined pitch with an accuracy of ± 0.1 μm by a conventional technique. In machining, the interval between the V-grooves can be freely set. Therefore, a fiber guide having an arbitrary pitch can be easily manufactured.

  Next, a fiber having a cladding diameter of 124.0 μm, which is smaller than the optical fiber to be inserted, is selected as the spacer fiber 130, and this is accommodated in the second V-groove 2, and then 8 × 4 × 1 mm. It was covered with a flat substrate 120 made of a quartz glass plate. At this time, as shown in FIG. 3, in the x-axis direction in FIG. 3, both end portions in the x-axis direction of the V-groove substrate 110 are made approximately 1 mm longer than the flat substrate 120. The structure protruded against.

Next, an elastic adhesive is applied to the space formed by the flat substrate 120 and the spacer fiber 130 in the V-groove substrate 110 where the first V-groove 1 and the second V-groove 2 are not formed. The elastic adhesive layer 140 is formed by filling and curing. That is, the elastic adhesive layer 140 is formed between the flat substrate 120 and the portion other than the V-groove forming portion of the V-groove substrate 110 so as to be separated by the spacer fiber 30. When the elastic adhesive is cured, the flat substrate 120 is pressed using a jig, the pressing force is adjusted so that the spacer fiber 130 and the flat substrate 120 are in contact with each other, and the state is maintained and cured. It was. As an elastic adhesive for the elastic adhesive layer 140, a modified silicone elastic adhesive (stored elastic modulus at 20 ° C .: ˜1.0 × 10 ⁷ Pa) that causes condensation and curing by mixing two liquids is used. Filled low, then cured at room temperature for half a day. As a result, a guide hole composed of a triangular space is formed in the gap between the V groove 1 of the V groove substrate 110 and the flat substrate 120, and the diameter of the inscribed circle of the guide hole is approximately 124 μm.

  A guide portion 160 having a predetermined guide angle was formed by grinding a groove near the end face into which the fiber is inserted in the flat substrate 120 with a micro drill. The guide angle at this time was about 30 °.

  In the optical fiber guide component 100 manufactured as described above, the spacer fiber 130 includes three points on the inner wall surface of the second V-groove 2 of the V-groove substrate 110 and one point on the surface of the flat substrate 120. It will be in the state which touched at the point. Further, the height from the bottom of the first V-groove 1 and the second V-groove 2 of the V-groove substrate 110 to the flat substrate 120 is approximately 186 μm [= (124/2) × 3]. That is, the thickness of the elastic adhesive layer 140 is approximately 26 μm. In addition, as shown in FIG. 3, since both ends of the V-groove substrate 110 are projected in the x-axis direction with respect to the flat substrate 120 and are also subjected to guide processing, a structure in which a fiber can be easily inserted. It has become.

(Example 2)
An optical fiber guide component 200 according to Embodiment 2 of the present invention will be described with reference to FIG. 4 shows an optical fiber guide component 200 including a V-groove substrate 210 having a first V-groove 1 and a second V-groove 2, a flat substrate 220, a spacer fiber 230, and an elastic adhesive layer 240. It is shown. Hereinafter, the manufacturing method of the optical fiber guide component 200 according to the second embodiment of the present invention will be illustrated with reference to FIG. 5 by extracting differences from the manufacturing method shown in the first embodiment.

  The clad diameter of the tape fiber used is 124.6 μm to 125.0 μm, as in the case of Example 1. First, in order to manufacture a plurality of optical fiber guide components at once, two quartz glass plates having a size corresponding to several tens of optical fiber guide components are prepared. As shown in FIG. 5A, the V-groove processing of the V-groove substrate 210 is performed by machining one quartz glass plate, and the 8-core first V-groove 1 having a V-groove angle of 60 ° is processed. The V-groove substrate 210 is manufactured by processing the second V-groove 2 in the same manner at both ends of the eight-core first V-groove 1. Here, the depth of the first V-groove 1 was set to 160 μm, while the depth of the second V-groove 2 was set to 161.5 μm. A total of 70 V-grooves were formed in the same manner on the same glass plate, with a total of 10 first V-grooves 1 and 2 V-grooves 2 serving as basic unit rows. Eight V-grooves were formed on the same glass plate as marks for separating the seven rows.

As the spacer fiber 230, fibers having a cladding diameter of 124.6 μm, which is the same as the minimum value of the tape fiber, are selected and accommodated in the second V groove 2 of the V groove substrate 210. It was covered with a flat substrate 220 made of the other quartz glass plate having almost the same area. After that, as shown in FIG. 5 (a), an elastic adhesive is applied to portions other than the V-groove forming portion of the V-groove substrate 210, and the flat substrate 220 is bonded and fixed while uniformly applying a pressing force to the elastic adhesive. Then, the elastic adhesive layer 240 was formed between the portion other than the V groove forming portion of the V groove substrate 210 and the flat substrate 220 by curing. As the elastic adhesive, a two-component mixed silylated urethane adhesive having a storage elastic modulus of 6 × 10 ⁷ Pa at 20 ° C. was used. At the time of curing, a guide for inserting a fiber between the first V-groove 1 and the rubber layer 340 by pressing the flat substrate 220 using a jig and maintaining the state to cure. A hole was formed. The inscribed circle diameter of the guide hole is set to be approximately 1.5 μm smaller than the fiber diameter.

  After bonding and fixing, the V-groove substrate 210 and the flat substrate 220 are subjected to dicing so that the size becomes 8 × 5 × 2 mm as shown in FIG. Make a batch of minutes. Thereafter, as shown in FIG. 5C, V-groove dicing is performed on the fiber insertion ports on both ends of the V-groove substrate 210. As a result, a guide portion 260 having an insertion assist groove structure that facilitates fiber insertion as shown in FIG. 4 was formed. Regarding the formation of the insertion assist structure, referring to Patent Document 3, the grinding amount on the V-groove side was reduced, and the V-grooves 1 and 2 were substantially protruded in the x-axis direction. At this time, the groove is inclined at 30 degrees on both the flat substrate side and the V-groove substrate side with respect to the x-axis direction, and a deeper groove is formed on the V-groove substrate side. The structure is easy to apply fiber insertion force.

(Example 3)
FIG. 6 shows a cross-sectional view of an optical fiber guide component 300 according to Embodiment 3 of the present invention. As shown in FIG. 6, the optical fiber guide component 300 according to the third embodiment includes a V-groove substrate 310, a flat substrate 320, a spacer fiber 330, an adhesive layer 340, and an elastic film layer 350. A 16-core first V-groove 1 and a second V-groove 2 for a pair of spacer fibers 340 located at both ends of the first V-groove 1 are formed on the upper surface of the V-groove substrate 310. . The elastic film layer 350 can be a rubber film having a thickness equal to or less than the fiber diameter. The manufacturing method of the optical fiber guide component 300 according to Example 3 of the present invention was performed in the same procedure as the manufacturing method shown in Example 1. Differences from the manufacturing method shown in Example 1 are extracted and described below.

  The clad diameter of the 16-fiber tape fiber to be used is 124.6 to 125.0 μm as in the first embodiment. First, a 16-core first V-groove 1 having an angle of 60 degrees is machined into a quartz glass plate by machining, and two second V-grooves 2 are similarly formed at both ends of the 16-core first V-groove 1. The V-groove substrate 310 is manufactured by processing. Here, the total depth of the 18 V grooves 1 and 2 was set to 160 μm.

As the spacer fiber 330, a fiber having a cladding diameter of 124.0 μm, which is smaller than the minimum value of the tape fiber, is selected and accommodated in the second V-groove 2, and then a low-hardness silicone rubber sheet having a thickness of about 100 μm. The spacer fiber 330 is covered with a flat substrate 320 to which an elastic film layer 350 made of is bonded. Thereafter, an epoxy adhesive having a storage elastic modulus of 2 × 10 ¹⁰ Pa is filled in a space formed by the portion other than the V-groove forming portion of the V-groove substrate 310, the spacer fiber 330, and the elastic film layer 350, Cured. At the time of curing, the flat substrate 320 is pressed using a jig, the pressing force is adjusted so that the spacer fiber 330 and the rubber layer 340 are in contact with each other, and the state is maintained and cured, whereby the first A guide hole for inserting a fiber was formed between the V groove 1 and the rubber layer 340. The diameter of the inscribed circle of the guide hole is approximately 124 μm. After that, as in Example 2, the insertion guide structure was formed by applying groove processing for facilitating insertion to both ends of the V-groove substrate 310.

  According to the optical fiber guide component 300 according to the third embodiment, in addition to the effect of the elastic restoring force by the elastic adhesive layer 340 as described above, the elastic restoring force by the elastic film layer 350 fixed to the flat substrate 320 is further increased. It is added to the fiber individually in the -z-axis direction. Therefore, there is no influence of the V-groove depth error, a further reduction in loss can be realized, and there is an effect of making the clearance smaller (zero). At this time, the elastic adhesive layer 340 does not necessarily need to use an elastic adhesive, and may use a normal epoxy adhesive.

  FIG. 7 is a diagram schematically showing a mechanism in which one bare fiber is inserted into the guide hole of the optical fiber guide component according to the present invention. FIG. 7A shows a cross-section during insertion of a bare fiber, and FIG. 7B shows a cross-section after connection. The bare fiber to be inserted is chamfered, and the optical fiber guide is subjected to the insertion guide processing as in the second embodiment. Here, the optical fiber guide component 200 according to the second embodiment is basically described, but the same applies to the optical fiber guide components 50, 100, and 300 according to the present invention.

  As shown in FIG. 7A, the bare fiber portion of the optical fiber 35 is easily inserted along the first V-groove 1 of the V-groove substrate 210 by the fiber chamfering and the insertion assist structure. However, with the flat substrate 220, the fiber chamfered portion can be inserted after a-a 'in FIG. 7A, but insertion other than the chamfered portion is temporarily stopped, and only the fiber tip is sandwiched. Here, when a force is applied to further insert the bare fiber into the guide hole, a force for pushing up the flat substrate 220 to increase the hole diameter is generated, and an insertion force is generated at each position of the flat substrate 220 accordingly. The bare fiber is inserted while the elastic adhesive layer 240 is deformed. In the optical fiber guide component 200, the elastic adhesive layer 240 made of the elastic adhesive having the elastic modulus described in the second embodiment only needs to displace the flat substrate 220 by 1.5 μm. It is possible to spread only with. The amount of displacement of about 1.5 μm at this time is about 5% of elongation with respect to the thickness of the elastic adhesive layer 240 (about 25 μm), but the silylated urethane resin used did not elastically break. .

  When no external force is applied, the elastic adhesive layer 240 is elastically deformed and deformed so as to restore its original shape as it is after the bare fiber is inserted, so that the fiber is always pressed in the −z-axis direction, and the bare fiber is The state where the inner wall surface of the groove 1 and the surface of the flat substrate 220 are in contact with each other at three points is maintained. When the elastic film layer 350 is used as in the third embodiment, the bare fiber is kept in contact with the inner wall surface of the first V groove 1 and the surface of the elastic film layer 350 at three points. Even when an external force is applied as described later, if the external force is released after the insertion, the bare fiber is similarly pressed in the −z-axis direction.

  When it is difficult to insert only with the fiber insertion force, a method of applying an external force to the flat substrate 220 as described above may be used. For example, when the difference in hole diameter is large or when the number of fiber cores is small, an external force that enlarges the hole diameter may be temporarily applied as described below.

  As a method of applying an external force, there is a method of holding and holding a flat substrate from both ends by using a jig or the like and pushing it up slightly in the z-axis direction. Another example of a method for applying an external force is the method shown in FIG. FIG. 8 shows an optical fiber guide component 400 including a V-groove substrate 410, a flat substrate 420, a spacer fiber 430, and an elastic adhesive layer 440. As shown in FIG. 8A, the V-groove substrate 410 is formed with a first V-groove 1, a second V-groove 2, and a third V-groove 440.

  As shown in FIG. 8B, two or more third V-grooves 450 are formed in addition to the first V-groove 1 into which the bare fiber is inserted and the second V-groove 2 into which the spacer fiber 430 is inserted. A dummy fiber 460 having a diameter approximately equal to or slightly larger than the fiber diameter is inserted into the third V-groove 450. As a result, the elastic adhesive layer 440 can be temporarily elastically deformed to expand the fiber insertion port in advance, and after inserting the bare fiber tape fiber, the dummy fiber 460 is pulled out to be elastic. The adhesive layer 440 can be elastically restored. The dummy fiber 460 can be a metal pin, a polymer rod, a glass rod, or the like.

  With the optical fiber guide component according to the present invention having the elastic restoring mechanism as described above, the fiber is always fixed at a predetermined position in the V-groove, and there is no clearance after insertion. In the conventional structure, there is a clearance even after insertion, so the bare fiber, the V-groove, and the flat substrate can contact only one point or two points. there were. In the optical fiber guide component according to the present invention, since the position of the fiber is determined only by the groove accuracy, the axial deviation due to the clearance can be almost eliminated. Further, as described above, since the bare fiber is aligned in each hole as described above, the pitch error of the V-groove is not affected, so that the permanent connection is achieved by the optical fiber guide component of the present invention. The same extremely low loss optical fiber connection becomes possible.

Example 4
Next, Example 4 which shows the example which applied the optical fiber guide component which concerns on this invention to the bare fiber type connection form is demonstrated using FIG. In the fourth embodiment, an example in which the optical fiber guide component 200 according to the second embodiment is used will be described. However, the same effect can be realized even when the optical fiber guide components 50, 100, 300, and 400 according to the present invention are used. .

  FIG. 9A shows a cross section in which an 8-core tape fiber 510 having a cladding diameter of 124.6 μm to 125.0 μm is inserted and connected to the first V-groove 1 from opposite ends. FIG. 9B is a diagram viewed from the direction of the arrow in FIG. As shown in FIG. 9 (b), the two eight-fiber tape fibers are attached to the common optical fiber housing behind the optical fiber guide component 200 and the conventional bare fiber type optical fiber connecting component, respectively. . At the time of insertion, the 8-fiber tape fiber 510 is inserted into each pair from both ends by displacing the flat substrate 220 by about 1.5 μm by the fiber insertion force. In FIG. 9A, the spacer fiber 230 is omitted for simplification. Further, only one fiber is inserted in FIG. 9A, but actually eight fibers are similarly inserted in the depth direction of the drawing.

  After the connection was completed by inserting the fibers from both ends, the fitting state was maintained with housing parts similar to the optical fiber housing as described in Non-Patent Document 1, and the connection of the two tape fibers was completed. In addition, a refractive index matching agent was applied in advance to the tip of the fiber to prevent a reduction in reflection. FIG. 12 shows a photograph after optical fiber connection. After the connection, as shown in FIG. 12, the whole is sandwiched and a clip part to be fixed is attached, thereby providing a mechanism for preventing loss fluctuation caused by subsequent thermal fluctuation.

  As described above, five 8-fiber optical fiber connecting parts were produced, and the connection loss was measured. As a result, an excessively low connection loss of 0.05 dB on average was obtained. Also, it was confirmed that a high reflection attenuation was obtained by the refractive index matching agent with an average reflection attenuation of 40 dB. On the other hand, the fluctuation of excess loss when the thermal fluctuation was performed at −40 ° C. to 85 ° C. could be suppressed to an average of 0.1 dB or less.

  In this example, the connection form is based on a refractive index matching agent. However, it is also possible to use a method in which the fiber end faces are connected to each other by applying a pressing force, and in this case, after fiber insertion is completed. In addition, it is only necessary to press one side of the tape fiber portion in the direction of further insertion to develop a buckling force.

(Example 5)
Next, Example 5 which shows the example which applied the optical fiber guide component which concerns on this invention to the connection of an optical device and an optical fiber is demonstrated using FIG. In the fifth embodiment, an example in which the optical fiber guide component 200 according to the second embodiment is used will be described, but the same effect can be realized even when the optical fiber guide components 50, 100, 300, and 400 according to the present invention are used. .

  FIG. 11 shows a configuration in which an eight-core tape fiber having a cladding diameter of 124.6 to 125.0 μm is inserted into one end of the fiber guide of the optical fiber guide component 200 and connected. As shown in FIG. 11A, a planar optical waveguide made of quartz glass and having an 8-branch splitter function with a pitch of 250 μm is prepared, and an optical fiber guide component 200 manufactured on the end face thereof as shown in Example 2 is used. The 8-fiber fiber guide was attached. Here, the fiber guide is attached so that the hole and the core position of the waveguide correspond to each other.

  As a method for attaching the fiber guide to the end face of the optical waveguide, the following method was adopted. That is, a bare fiber is inserted into any two cores of the fiber guide, and light enters the optical fiber to align with the optical waveguide. When inserting this bare fiber, as described above, it was inserted by temporarily applying an external force to enlarge the hole diameter. With the external force released and the clearance removed, the hole position and waveguide core position were aligned, and then UV adhesive was dropped onto the V-groove substrate end face and the waveguide connection single face to irradiate ultraviolet rays and fixed. At this time, the flat substrate was not bonded and fixed to the optical device with UV resin. Also, UV resin was not allowed to enter the hole. This is because the adhesive wraps around the end face of the optical fiber guide component connected to the optical device by performing groove processing in the same manner as the method of forming the insertion assist groove at the boundary between the flat substrate and the V-groove substrate. Was prevented and realized. After this process, the inserted alignment optical fiber was pulled out.

  If the optical waveguide and the fiber guide are integrated in this manner, a low-loss connection can be easily performed by inserting the optical fiber into the fiber guide in an arbitrary subsequent process.

  When inserting the bare fiber, the adhesive layer was elastically deformed by the insertion force of the 8-core tape fiber by the same method as described above. A refractive index matching agent was applied to the connection surface between the optical waveguide and the fiber. After insertion, after the fiber is abutted against the waveguide end face, UV curable adhesive is infiltrated into the flat substrate, the end face of the optical device and the fiber insertion hole, and the device and the entire optical fiber guide component are bonded and fixed together. Was completed.

  In total, ten optical waveguides having fiber guides connected to the end faces were produced by such a process. An 8-fiber tape fiber was inserted into the fiber guide of each optical waveguide by the above-described method, and excess loss was measured. As a result, the average excess loss was as low as 0.08 dB. This result shows that the optical fiber guide component of the present invention is manufactured with high accuracy. The return loss was 40-50 dB in all cases.

  The connection end face may be in a PC connection state by buckling the fiber, or a refractive index matching agent may be introduced as in connection with the waveguide. The connection end face is not limited to the right end face, but may be an oblique end face in order to further improve the return loss.

  Moreover, although the silicone adhesive, the silylated urethane adhesive, etc. were used for the kind of elastic adhesive this time, it is not necessarily limited to said adhesive. As long as the adhesive has an elastic modulus range according to the claims, silicone-based, modified silicone-based, silylated urethane-based, and derivatives thereof can be applied, and rubber-based adhesives and modified silicone-type epoxy matrix systems can be applied. An adhesive, a non-crosslinkable adhesive resin such as acrylic, or a crosslinkable adhesive resin having a reduced elastic modulus by adding a filler or the like may be used.

  The diameter of the bare fiber to be inserted is not limited to around 125 μm, and the V groove depth and the spacer fiber diameter may be appropriately selected according to the diameter of the bare fiber to be inserted. Further, in the present invention, the description has been given by taking the eight-core V-groove as an example, but the number of cores of the bare fiber to be inserted is not particularly limited, and the first V-groove is processed according to the number of cores. Can be prepared.

DESCRIPTION OF SYMBOLS 1 1st V-groove 2 2nd V-groove 10, 110, 210, 310, 410 V-groove substrate 20, 120, 220, 320, 420 Flat substrate 30, 130, 230, 330, 430 Spacer fiber 35 Optical fiber 40, 140, 240, 340, 440 Elastic adhesive layer 50, 100, 200, 300, 400 Optical fiber guide component 60, 160, 260 Guide portion 350 Elastic film layer 450 Third V groove 460 Dummy fiber

Claims (7)

An optical fiber guide component for positioning an optical fiber inserted into a guide hole,
A V-groove substrate comprising at least one first V-groove formed to insert the optical fiber and a pair of second V-grooves formed at both ends of the first V-groove;
Spacer fibers respectively accommodated in the second V-grooves;
A flat substrate for bonding onto the V-groove substrate via the spacer fiber,
In a state where the spacer fiber is accommodated in the second V-groove, the V-groove substrate and the flat substrate are joined by an elastic adhesive layer made of an elastic adhesive,
The diameter of the inscribed circle of the guide hole constituted by the inner wall surface of the first V-groove and the surface of the flat substrate is the light to be inserted when the optical fiber is not inserted into the first V-groove. An optical fiber guide component having a diameter smaller than that of the fiber.   The optical fiber guide component according to claim 1, wherein a depth of the second V-groove is set deeper than that of the first V-groove.   The optical fiber guide component according to claim 1, wherein a diameter of the spacer fiber is equal to or less than a cladding diameter of the optical fiber to be inserted. The optical fiber guide component according to any one of claims 1 to 3, wherein the elastic adhesive layer is made of an elastic adhesive having a storage modulus of elasticity of 5 x 10 ⁸ Pa or less at 20 ° C. 4. The optical fiber according to claim 1, wherein the elastic adhesive layer is made of an elastic adhesive having a storage elastic modulus in a range of 1 × 10 ⁷ Pa to 1 × 10 ⁸ Pa at 20 ° C. 5. Guide parts.   6. The optical fiber guide component according to claim 1, wherein a chamfering process is formed on the end face of the fiber insertion port of the guide hole so as to have an inclination.   The optical fiber guide component according to any one of claims 1 to 6, wherein a rubber film having a thickness equal to or less than a fiber diameter is provided between the V-groove substrate and the flat substrate.