JP6513583B2 - Optical fiber side input / output device and method of manufacturing the same - Google Patents

Description

  The present invention relates to an optical fiber side input / output device that inputs and outputs light from the side of a bent optical fiber and a method of manufacturing the same.

  As a technique for inputting and outputting an optical signal to the optical fiber without cutting the optical fiber, the existing optical fiber (input-side optical fiber) is bent, and another bent optical fiber (probe optical fiber is provided at the bent portion) Optical fiber side-way input / output technology for receiving an optical signal from the tip of the probe optical fiber and receiving the optical signal emitted from the input-side optical fiber at the tip of the probe optical fiber It is done.

  As a method of manufacturing an optical fiber side-to-side input / output device, as in the first related art, a bent portion is formed on an optical fiber by sandwiching an optical fiber with a concave surface portion formed in a concave block and a projecting portion of a convex block. The void formed in the concave block is filled with ultraviolet curing resin, the probe optical fiber is inserted into the void, alignment with respect to the bent portion is performed, and finally the ultraviolet light is applied to the ultraviolet curing resin in the void. A manufacturing method has been proposed in which the probe optical fiber is fixed by irradiating it and curing the ultraviolet curing resin (see, for example, Patent Document 1).

  However, in the method described in the first related art, there is a problem that the input / output efficiency is degraded after the probe optical fiber is fixed. The reason for the degradation of the input / output efficiency is that, as shown in the second related art, the input / output efficiency is significantly degraded only by the deviation of about several μm of the probe optical fiber. This is because the probe optical fiber deviates from the optimum position due to the contraction (see, for example, Non-Patent Document 1).

JP-A-2015-57628 "Method of manufacturing optical fiber side input / output device", Nippon Telegraph and Telephone Corporation

"Study on the position fixing accuracy of the local optical I / O device," Kawano et al., Shinbun Technical Report, OFT, Applied Technology of Optical Fiber 114 (269), 29-32, 2014-10-16. http: // www. technohands. co. jp / products / um-tula. html

  Therefore, an object of the present invention is to provide a method of manufacturing an optical fiber side input / output device that enables position fixing of a probe optical fiber without deterioration of input / output efficiency in an optical fiber side input / output device. It is in.

  In order to solve the above problems, the present invention moves the probe optical fiber by the estimated displacement amount in the estimated displacement direction and irradiates the ultraviolet light, thereby optimizing the probe optical fiber when the ultraviolet curable resin is cured. The purpose is to fix in position.

  In order to achieve the above object, according to the present invention, a probe optical fiber whose contact surface is enlarged by blocking the tip of the probe optical fiber is a concave block of an optical fiber side input / output device filled with an ultraviolet curing resin. The probe optical fiber is fitted to the fitting portion, and the probe optical fiber is aligned to maximize the coupling efficiency.

Specifically, the optical fiber side input / output device according to the present invention is
A concave block having a concave surface portion,
A convex block in which a bending optical fiber having a projection and which inputs and outputs light from the side is sandwiched between the concave surface of the concave block and the projection;
And a fixing block that holds the bending optical fiber and a probe optical fiber that performs light input / output, defines an optical axis direction of the probe optical fiber, and can be fixed to the concave block.

Specifically, a method of manufacturing an optical fiber side input / output device according to the present invention is
A method of manufacturing an optical fiber side input / output device according to the present invention, comprising
Forming a probe optical fiber block by defining and fixing the position of the probe optical fiber in the direction of the optical axis with a fixing block;
An adhesive is applied to the contact surface where the probe optical fiber block and the bottom surface and the side surface of the concave block are in contact, the probe optical fiber block is disposed according to a predetermined adjustment value, and the probe optical fiber is used with the adhesive. And fixing the block and the concave block.

In the method of manufacturing an optical fiber side input / output device according to the present invention,
The adhesive is
An ultraviolet curable resin may be used.

In the method of manufacturing an optical fiber side input / output device according to the present invention,
Bending the optical fiber between a concave block and a convex block to form a bent optical fiber;
The probe optical fiber is disposed in the direction opposite to the misregistration direction according to the adjustment value estimated beforehand so that the coupling efficiency of the optical signal input / output between the bending optical fiber and the probe optical fiber is maximized. A placement step of applying a UV curable resin,
And an irradiation step of irradiating the ultraviolet curing resin with ultraviolet light to fix it.

In the method of manufacturing an optical fiber side input / output device according to the present invention,
Measuring the amount of decrease in coupling efficiency between the bending optical fiber and the probe optical fiber when the probe optical fiber is displaced;
An irradiation step of centering the probe optical fiber so as to maximize coupling efficiency, and irradiating the ultraviolet curing resin applied in the disposing step to fix the ultraviolet curing resin;
And the estimation step of estimating the shift amount of the probe optical fiber as the adjustment value from the decrease amount of the coupling efficiency.

  The above inventions can be combined as much as possible.

  According to the present invention, the probe optical fiber is moved in the estimated displacement direction by moving the probe optical fiber by the estimated displacement amount, and the ultraviolet light is irradiated to fix the probe optical fiber at the optimum position when the ultraviolet curable resin is cured. it can. Further, by estimating the direction of displacement and the amount of displacement at the time of fixation and correcting in the opposite direction, the position of the probe optical fiber can be fixed without deterioration of the input / output efficiency.

An example of the top view of the optical fiber side input-output device concerning this embodiment is shown. An example of the side view of an optical fiber side input-output device provided with the bending optical fiber of the single-fiber core which concerns on this embodiment is shown. An example of the side view of the optical fiber side way input-output device provided with the 4 core tape fiber which concerns on this embodiment is shown. An example of the block diagram of the convex block which concerns on this embodiment is shown. An example of the block diagram of the concave block which concerns on this embodiment is shown. An example of the top view and the side view which were block-ized using the to-be-bent fiber of the single core wire which concerns on this embodiment is shown. An example of the top view and side view which were block-ized using the to-be-bent fiber of 4 core tape fiber which concerns on this embodiment is shown. An example of the configuration conditions of the optical fiber side input / output device concerning this embodiment is shown. An example of the configuration conditions of the optical fiber side input / output device concerning this embodiment is shown. An example of a top view and a side view of an optical fiber side way input-output device concerning this embodiment is shown. The relationship between the shift amount μm in the Z-axis direction from the optimum position and the decrease amount db of the coupling efficiency is shown. An example of the measuring method of the coupling efficiency in the optical fiber side input-output device which concerns on this embodiment is shown. An example of fixation of the probe optical fiber in the optical fiber side input-output apparatus which concerns on this embodiment is shown. An example of a fixed result of a probe optical fiber in an optical fiber sideways input-output device concerning this embodiment is shown.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below. These implementation examples are merely illustrative, and the present invention can be implemented in various modifications and improvements based on the knowledge of those skilled in the art. In the present specification and drawings, components having the same reference numerals denote the same components.

(Embodiment 1)
A top view of the optical fiber side input / output device according to the present embodiment is shown in FIG. The optical fiber side input / output device includes a concave block 11, a convex block 12, an ultraviolet curing resin 14, a fixing block 15, and a probe optical fiber 16. Specific functions of the optical fiber side input / output device will be described below.

  In the optical fiber sideward input-output device, the concave block 11 and the convex block 12 are used to form the desired bending shape by sandwiching the optical fiber 13 to be bent. The concave block 11 and the convex block 12 have curved portions so as to have a desired bending shape. The concave block 11 has a counterbore for installing the blocked probe optical fiber 16. The counterbore is a fitting portion with the fixed block 15. The counterbly can move the fixed block 15 by the estimated displacement direction and amount.

  For the concave block 11, it is desirable to use a material that can be bonded with an optical plastic or quartz glass, such as acrylic or polycarbonate, which is transparent in the used wavelength range, and an ultraviolet curing resin 14. The blocked probe optical fiber 16 is placed at a position where it can receive most of the leaked light from the bent fiber 13, and is fixed to the bottom of the concave block 11 by the ultraviolet curing resin 14.

  The UV curable resin 14 is filled only between the side of the blocked probe optical fiber 16 and the side of the recessed block 11 as shown in FIG. 1 and between the blocked probe optical fiber 16 and the bottom of the recessed block 11 (application ).

  A side view of an optical fiber side input / output device according to the present embodiment will be described with reference to FIGS. FIG. 2 shows a side view of an optical fiber side input / output device comprising a single-fiber bent optical fiber 13. FIG. 3 shows a side view of an optical fiber side input / output device comprising a to-be-bent optical fiber 13 of four-core tape fiber.

  The optical fiber side input / output device shown in FIGS. 2 and 3 includes a concave block 11, a convex block 12, a bent optical fiber 13, an ultraviolet curing resin 14, a fixing block 15, and a probe optical fiber 16; A guide rail 19 and a base 21 are provided. The optical fiber side input / output device shown in FIGS. 2 and 3 will be described below.

  In the optical fiber side input / output device according to the present embodiment, the concave block 11 is provided with a guide groove in advance so as to guide the bent optical fiber 13 to a predetermined height. Thus, even after the probe optical fiber 16 is fixed to the concave block 11, the axes in the height direction of the bendable optical fiber 13 and the probe optical fiber 16 can be made to coincide with each other. By means of the guide rails 19 adjacent to the bottom surface of the concave block 11, the convex block 12 is movable in the lateral direction of the drawing, and can hold or bend the optical fiber 13 to be bent.

  As shown in FIG. 3, when the optical fiber 13 to be bent is a four-core tape fiber, a four-core fiber array in which four probe optical fibers 16 are arranged at predetermined intervals is fixed to the concave block 11. The ultraviolet curing resin 14 is filled only between the side surface and the bottom surface of the probe optical fiber 16 blocked with the fixing block 15 as shown in FIGS. 2 and 3 and the concave block 11.

  As a result, the positional deviation of the probe optical fiber 16 due to the contraction of the ultraviolet curing resin 14 may be considered only in the height direction and the longitudinal direction of the probe optical fiber 16 (right direction in the figure). It becomes easy to estimate the displacement amount. The length in the height direction of the gap between the bottom surface of the concave block 11 and the blocked probe optical fiber 16 is preferably short. This is because the shorter one can reduce the amount of misalignment due to the cure shrinkage of the ultraviolet curable resin 14. The UV curable resin 14 desirably has a high light transmittance and a low cure shrinkage.

  The configuration diagrams of the convex block 12 and the concave block 11 in the optical fiber side input / output device according to the present embodiment will be described with reference to FIGS. 4 and 5, respectively. FIG. 4 is shown in (a) as a top view of the convex block 12 and in (b) as a side view in the case of using a single-fiber bent optical fiber 13, wherein the bent optical fiber 13 of a four-core tape fiber is shown. (C) is shown as a side view in the case of using. FIG. 5 is shown in (d) as a top view of the concave block 11 and in (e) as a side view.

  Blocking of the probe optical fiber 16 using the fixing block 15 will be described below with reference to FIGS. 6 and 7. 6 shows a top view (f) and a side view (g) in the case where the probe optical fiber 16 is a single cored wire, and FIG. 7 shows a top view (h) and a side view in the case where the probe optical fiber 16 is a four-core tape fiber. Figure (i) is shown. By blocking the probe optical fiber 16 using the fixing block 15 described above, the strength can be improved by increasing the contact surface with the ultraviolet curing resin 14, and the probe optical fiber 16 itself can be reinforced. it can.

Here, a method of manufacturing the optical fiber side input / output device according to the present embodiment will be described.
1: Estimate the direction of misalignment and the amount of misalignment when fixed.
The ultraviolet curing resin 14 is fixed in the opposite direction of the positional deviation direction estimated in 2: 1 in the state of being displaced by the estimated positional deviation amount.
As a result, after fixation, the probe optical fiber moves to the optimum position where the coupling efficiency is maximized by the contraction of the ultraviolet curing resin 14, and it is possible to manufacture a device with a small deterioration of the coupling efficiency.

The estimation method of the displacement direction and the displacement amount at the time of fixation will be described below.
1. The bent optical fiber 13 is sandwiched between the concave block 11 and the convex block 12 to form a bend.
2. The blocked probe optical fibers 16 are aligned to maximize coupling efficiency.
3. The amount of decrease in coupling efficiency when the probe optical fiber 16 is displaced in the direction in which it can be displaced is measured.
4. The probe optical fiber 16 is positioned so as to maximize the coupling efficiency, and the ultraviolet curing resin 14 is irradiated and fixed.
5. The shift amount of the probe optical fiber 16 is estimated from the decrease amount of the coupling efficiency.

Second Embodiment
An example of the specific configuration conditions of the optical fiber side input / output device according to the present embodiment will be described below with reference to FIGS. The bending radius and angle of the curved surface portion of the concave block 11 and the convex block 12 are 1.825 mm and 90 degrees. As the optical fiber 13 to be bent, a single core of 0.25 mm in diameter is used. The material of the concave block 11 may be polycarbonate. The counterbore provided in the concave block 11 has a flat surface perpendicular to the optical axis of the probe optical fiber 16 so that the optical axis direction of the probe optical fiber 16 held by the fixing block 15 is maintained. The angle θ of the flat surface of the counterbore in FIG. 8 is, for example, 37 degrees.

  As the probe optical fiber 16, a single-mode fiber with a gradient index lens connected to the tip is used, and a lens diameter of 0.125 mm, a beam waist diameter of 25 μm, and a beam waist distance of 1 mm are used. Acrylic was used for the probe optical fiber reinforcing block that functions as the fixing block 15. As shown in FIG. 9, the distance between the reinforcing block and the bottom of the concave block 11 was designed to be 0.5 mm. The UV curable resin 14 used had a light transmittance of 92% and a cure shrinkage of 4%.

  The estimation of the direction of displacement and the amount of displacement when the probe optical fiber 16 is fixed in the optical fiber lateral input / output device according to the present embodiment will be described below with reference to FIGS. 10 and 11, respectively. In FIG. 10, (j) is shown as a top view of the optical fiber side input / output device, and (k) is shown as a side view.

  With regard to the estimation of the displacement direction, in the optical fiber side input / output device mentioned as the present embodiment, the displacement direction of the reinforcing block may be regarded as the negative direction of the Z axis. This is because the UV curing resin is filled so as to be symmetrical with respect to the Y-axis direction, and the reinforcing block is sufficiently close to 10 μm or less to the side surface of the concave block in the X direction, so shrinkage occurs. The amount is 0.1 μm and can be ignored.

  In addition, the side faces of the concave block and the reinforcing block are designed to be perpendicular also in the φ direction, so they do not change, and there is a point that the ultraviolet curing resin 14 changes in the negative direction of the Z axis because it shrinks after curing It is for.

  FIG. 11 shows the relationship between the shift amount μm in the Z-axis direction from the optimum position and the decrease amount db of the coupling efficiency. In FIG. 11, in the estimation of the positional displacement amount, the amount of decrease in coupling efficiency was measured when the positional displacement was made in the positional displacement direction (in the present embodiment, in the Z-axis direction) before fixing. After the measurement, the probe optical fiber 16 was aligned at a position where the coupling efficiency is maximized, and was irradiated with ultraviolet light to cure and fix the ultraviolet curing resin 14.

  As a result, the coupling efficiency after fixation was reduced by about 1.8 dB as compared to that before fixation. Since the amount of decrease in coupling efficiency is 1.8 dB, as shown in FIG. 11, it can be estimated that the displacement by −6 μm in the Z-axis direction (the displacement calculated based on the cure shrinkage of the ultraviolet curable resin 14 is − It is 6.8 μm and almost agrees with the calculation result).

  An example of a method of measuring the coupling efficiency in the optical fiber side input / output device according to the present embodiment will be described below with reference to FIG. In the optical fiber sideward input / output device in FIG. 12, the light source 22 is connected to the end of the optical fiber 13 to be bent, and the power meter 23 is connected to the probe optical fiber 16. As shown in FIG. 12, the probe optical fiber 16 is moved, and alignment is performed so that the power of light received by the power meter 23 is maximized. The alignment method moves the probe optical fiber with a resolution of about 1 μm by using a commercially available ultrasonic linear actuator or the like.

  Immobilization of the probe optical fiber 16 in the optical fiber side input / output device according to the present embodiment will be described below with reference to FIG. As shown in FIG. 13, based on the positional displacement amount estimated above, a new concave block 11, convex block 12 and blocked probe optical fiber 16 are prepared, and the reinforcing block is arranged in the Z axis direction +6 μm. Ultraviolet rays are irradiated in a state where only the position is shifted, and the ultraviolet curing resin 14 is cured and fixed.

  When the +6 μm position is deviated in the Z-axis direction, the distance between the reinforcement block and the bottom of the concave block 11 is increased by 6 μm to 506 μm, and the position deviation due to curing shrinkage is considered to increase. Since it is 0.1 μm or less compared to the case of, it can be ignored.

  The immobilization result of the probe optical fiber 16 in the optical fiber side input / output device according to the present embodiment will be described below with reference to FIG. As a result of fixation of the probe optical fiber 16, the coupling efficiency after fixation had a decrease of 0.1 dB or less compared to when it was centered at the optimum position. As a result of measuring the coupling efficiency 10 times with the optical fiber lateral input / output device manufactured by the manufacturing method of the present embodiment, the average value was almost equal to the coupling efficiency when aligned to the optimum position.

  Specifically, FIG. 14 shows the time course of the coupling efficiency during immobilization (during UV irradiation). In “A.” in FIG. 14, the UV curable resin 14 is moved by −6 μm in the Z-axis direction along with the curing of the UV curable resin 14 so that it returns to the optimum position and converges to the coupling efficiency when aligned to the optimum position. Further, “B.” in FIG. 14 shows the coupling efficiency when moved by +6 μm in the Z-axis direction.

  The above-described embodiment is an example. Although the displacement amount and direction differ depending on the dimensions and materials of the concave block 11 and the convex block 12 and the probe optical fiber 16, they can be fixed by the same procedure and method as in the embodiment. The four-core tape fiber can be immobilized by the same procedure and method as the embodiment. It is applicable also to adhesives other than ultraviolet curing resin 14.

  The present invention can be applied to the information communication industry.

11: concave block 12: convex block 13: bent optical fiber 14: ultraviolet curing resin 15: fixed block 16: probe optical fiber 19: guide rail 21: base 22: light source 23: power meter

Claims (4)

A concave block having a concave surface portion and a counterbore ,
A convex block in which a bending optical fiber having a projection and which inputs and outputs light from the side is sandwiched between the concave surface of the concave block and the projection;
A fixed block which holds the bending optical fiber and a probe optical fiber that performs light input / output, defines an optical axis direction of the probe optical fiber, and is fitted to the counterbore of the concave block;
Equipped with
The counterbore of the concave block has a bottom surface parallel to the optical axis direction of the probe optical fiber and a flat surface perpendicular to the optical axis direction of the probe optical fiber,
The fixed block has its tip end butted against the flat surface,
An optical fiber side input / output device characterized in that an adhesive is uniformly filled on both sides of the fixed block in the optical axis direction of the probe optical fiber . A method of manufacturing an optical fiber side input / output device according to claim 1, wherein
And forming a fixed Mr probe optical fiber block said probe optical fiber in the fixing block,
Measuring the relationship between the amount of decrease in coupling efficiency between the bending optical fiber and the probe optical fiber with respect to the positional deviation of the probe optical fiber block in the direction perpendicular to the bottom surface of the counterbore;
An aligning step of determining an optimum position of the probe optical fiber block such that the coupling efficiency is maximized in a direction perpendicular to the bottom surface of the counterbore;
A curing step of uniformly filling and curing the adhesive on both sides of the fixed block in the optical axis direction of the probe optical fiber;
The bonding efficiency is measured again to measure the amount of reduction from the maximum value, and from the amount of reduction and the relationship, the displacement due to the curing of the adhesive is detected, and the displacement is estimated as an adjustment value. Estimation step,
A method of manufacturing an optical fiber side input / output device characterized in that The adhesive is applied to a contact surface where another probe optical fiber block and the bottom surface and flat surface of the counterbore of the other concave block are in contact with each other, and from the optimum position in the direction opposite to the displacement direction. Arranging the probe optical fiber block at a position shifted by an adjustment value;
A fixing step of curing the adhesive to fix the probe optical fiber block and the concave block;
The method of manufacturing an optical fiber side input / output device according to claim 2, further comprising: The adhesive is
UV curable resin,
The method according to claim 3 , wherein the ultraviolet curable resin is cured by irradiating ultraviolet light.

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