JPH10246833A - Connecting member for optical fiber and its manufacture, and connection structure of optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To fix an optical fiber to the input/output end surface of an optical element without variance in connection angle even if the light input/output end surface slants to an optical waveguide. SOLUTION: The optical fiber connecting member 10 is used which is constituted by forming a flat part 12 for rotating direction position display at part of the outer periphery of a tubular body having a connection end surface 10a oblique to the direction of a through hole 11 for optical fiber insertion, the optical fiber 4 is inserted into the through hole 11, and the optical fiber connecting member 10 is adhered to the light input/output end surface 3 of the optical element with a ultraviolet-ray setting adhesive 13 together with the optical fiber 4; and the direction of the connection angle between the light guide 2 of the optical element 1 and the optical fiber 4 can easily be set to a correct direction by referring to the direction of the flat part 12 for rotating direction position display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber connecting member for connecting a waveguide type optical element having an optical waveguide to an optical fiber, a method for manufacturing the same, and an optical fiber connecting structure.

[0002]

2. Description of the Related Art An optical device using a waveguide type optical element is:
Since it can be reduced in size and cost, it is an indispensable component in optical fiber communication.

The input of light to this type of optical device is
In many cases, this is performed by directly fixing an optical fiber to the end face of the waveguide-type optical element that has been cut and polished, with a light-transmitting adhesive such as an ultraviolet-curing adhesive. In this case, since the optical fiber has a small diameter and does not have a sufficient connection strength as it is, the strength is usually increased by using a reinforcing member such as a glass tube or a small piece together. For example, JP-A-1-302
In the fixing structure of an optical waveguide and an optical fiber described in Japanese Patent Publication No. 211, there is disclosed a structure in which an optical fiber penetrates a reinforcing pipe and is fixed to an end face of an optical element with an ultraviolet curable resin. In the method of connecting an optical fiber described in Japanese Patent Publication No. 5-71922, an optical fiber is fixed to an end face of an optical waveguide substrate using a small piece together with an adhesive.

Incidentally, the light input / output end face (connection end face) of an optical element having an optical waveguide is sometimes cut obliquely (non-perpendicular plane) with respect to the optical waveguide in order to prevent reflected light returning to the optical fiber. However, at this time, the optical axis of the optical fiber needs to be inclined in consideration of refraction at the oblique end face.

FIG. 6 shows an optical fiber connection structure in such a case. In this figure, reference numeral 1 denotes a waveguide type optical element having an optical waveguide, and an optical input / output end face (connection end face) 3 from which the optical waveguide 2 is exposed is formed to be oblique (non-perpendicular) to the optical waveguide 2. Have been. Reference numeral 4 denotes an optical fiber to be connected to the optical waveguide 2, and reference numeral 5 denotes a glass tube as a reinforcing member. The glass tube 5 has a shape as shown in FIG.
That is, it has a connection end face 5a that is inclined with respect to the direction of the through hole for inserting the optical fiber 4.

In FIG. 6, the position of the solid line P of the glass tube 5 is when the glass tube 5 is correctly arranged with respect to the light input / output end face 3 of the waveguide type optical element 1.
In this state, the light is guided correctly, the loss at the time of connection is small, and the reflected return light to the optical fiber 4 can be prevented.

[0007]

However, the glass tube 5 as a reinforcing member has a small diameter in practice, so that it is difficult to confirm the inclination direction of the connection end face 5a, and when the optical fiber 4 and the glass tube 5 are fixed. In addition, since the glass tube 5 rotates, the connection state of the light input / output end face 3 to the end face of the optical waveguide varies. For example, if the glass tube 5 in FIG. 6 is turned into a virtual line Q by rotation and the connection end surface 5a is inclined in the opposite direction, the virtual line R may be in an incorrect posture when bonded with an ultraviolet curing adhesive. As a result, the glass tube 5 is fixed, which causes an increase in loss at the time of connection and an increase in reflected light returning to the optical fiber 4.

[0008] A first object of the present invention is to solve the above problems,
Optical fiber connecting member capable of fixing an optical fiber to the optical input / output end face without variation in connection angle even when the optical input / output end face of the optical element is inclined with respect to the optical waveguide, and a method of manufacturing the same Is to provide.

A second object of the present invention is to use an optical fiber connection member together with an optical input / output end face of an optical element formed to be inclined with respect to an optical waveguide, and to connect an optical fiber without variation in connection angle. An object of the present invention is to provide an optical fiber connection structure that can be fixed to the optical input / output end face.

[0010] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0011]

In order to achieve the above object, a connecting member for an optical fiber according to the present invention comprises a through hole for inserting an optical fiber and a connecting end face inclined with respect to the direction of the through hole. And a flat part formed on a part of the outer periphery of the tubular body.

In the above-mentioned optical fiber connecting member, it is preferable that the tubular body has a property of transmitting ultraviolet light.

Further, in the optical fiber connecting member, a conical recess may be formed on an end surface of the tubular body opposite to the connection end surface, and the through hole may be opened at a center of the conical recess. .

In the method for manufacturing an optical fiber connection member according to the present invention, the cylindrical tubular body having a through hole is cut obliquely with respect to the direction of the through hole while the cylindrical tubular body having the through hole is fixed by fixing means. And a step of forming a flat portion on a part of the outer periphery of the tubular body by polishing the upper portion of the cylindrical tubular body after cutting in such a fixed state so as not to reach the through hole. I have.

In the optical fiber connection structure according to the present invention, in the configuration in which an optical fiber is connected to the optical waveguide of an optical element having an optical waveguide formed therein, the tubular structure has a connection end face inclined with respect to the direction of the through hole. An optical fiber is inserted into the through hole of the optical fiber connecting member having a flat portion formed on a part of the outer periphery of the body, and the optical fiber connecting member is put together with the optical fiber on the light input / output end face of the optical element. It is characterized by being adhered with a translucent adhesive.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a connecting member for an optical fiber according to the present invention;

FIG. 1 shows the overall configuration of an embodiment of the present invention, FIGS. 2 and 3 show an optical fiber connecting member used in this embodiment, and FIG. 4 shows a method of manufacturing the optical fiber connecting member. Show.

1 to 3, a waveguide type optical device 1
The light input / output end face (connection end face) 3 is formed oblique (non-perpendicular) to the optical waveguide 2 as in the case of FIG. The optical fiber connecting member 10 serving as a reinforcing member at the time of connecting the optical fiber is made of a glass tubular body having an ultraviolet transmitting property, that is, a glass tube, and has an optical fiber insertion through hole 11 penetrating the center thereof. It has a connection end face 10a that is inclined with respect to the center axis of the glass tube, that is, the direction of the optical fiber insertion through hole 11. Further, a flat portion 12 for displaying a rotational direction position is formed on a part of an outer peripheral surface formed as a circumferential surface of the glass tube. The rotation direction position display flat portion 12 is formed so as to have a predetermined specific positional relationship with respect to the optical fiber insertion through hole 11. For example, in the example of FIGS. When the connection end face 10a of the optical fiber connection member 10 is brought into contact with the light input / output end face 3 of the optical element 1 so as to be in the normal through-hole direction with respect to the optical element 1, the rotation direction position display flat portion 12 is formed. Is located directly beside.

The optical fiber connecting member 10 shown in FIGS.
As shown in FIG. 1, the optical fiber 4 is inserted into the through-hole 11 of the optical fiber connecting member 10 and the connection end face 10a of the optical fiber connecting member 10 is connected thereto. The optical fiber connecting member 10 is bonded and fixed to the optical element 1 together with the optical fiber 4 with an ultraviolet curing adhesive 13 in a state where the optical fiber 1 is in contact with the light input / output end face 3 of the optical element 1. At the time of this bonding, the direction of the connection angle between the optical waveguide 2 and the optical fiber 4 is changed by adjusting the rotation direction of the optical fiber connection member 10 with reference to the position of the rotation direction position display flat portion 12. Can be easily set to the correct orientation,
Variations in the connection state between the optical waveguide 2 and the optical fiber 4 can be greatly reduced. For this reason, the above configuration enables optical fiber connection with good reproducibility.

The optical fiber connecting member 10 and the optical fiber 4 can be fixed in advance by inserting the optical fiber 4 into the through hole 11 with an adhesive or the like. The direction of the connection member 10 can be changed by rotation, and the rotation direction of the fiber 4 can be adjusted with reference to the flat surface 12.

Since the optical fiber connecting member 10 is made of glass having an ultraviolet transmitting property, the ultraviolet curing adhesive 13 which has entered the inside of the optical fiber connecting member 10 is also quickly cured by irradiating ultraviolet rays. And sufficient adhesive strength can be ensured.

FIG. 4 shows a specific example of a method of manufacturing an optical fiber connecting member according to this embodiment. Here, a glass tube 20 having an inner diameter of 0.130 mm, an outer diameter of 1.0 mm, and a length of 10 mm is used.
Are prepared and fixed on a cutting jig 30 using a fixing wax 31 as shown in FIG. Next, as shown in FIG. 3B, the glass tube 20 is cut at an oblique angle of 3 ° with respect to a direction perpendicular to the central axis of the glass tube 20 using a rotary blade 40 (a diamond cutter or the like). After cutting, while maintaining the same fixed state, the upper surface of each glass tube 20 was polished using a rotating grindstone to such an extent that the flat portion 12 having an appropriate width was formed and did not reach the inner through hole. The optical fiber was fixed to the optical waveguide 2 of the optical element 1 as shown in FIG. 1 using the glass optical fiber connecting member 10 shown in FIG. The adjustment of the connecting member 10 for the oblique angle direction can be easily performed by referring to the rotation direction position display flat portion 12 which is a polished surface, and as a result, an increase in loss at the time of connection can be greatly reduced.

Table 1 below shows the increase in loss in the conventional example shown in FIG. Table 2 shows the increase in loss in the embodiment of the present invention shown in FIG. These were measured for 1, 2, and 3. Here, the increase in loss refers to a state in which the optical fiber is positioned at a regular position with respect to the optical waveguide by the jig (however, before the ultraviolet-curing adhesive is cured) and the glass tube of the conventional example or the optical fiber of the present invention. Compared to the state after fixing the optical fiber with the ultraviolet curing adhesive using the connecting member together, measure how much the loss increased in the latter case after fixing with the ultraviolet curing adhesive compared to the former This is the result.

Table 1 (conventional example) Sample No. Loss increase (dB) 1 0.8 2 0.2 3 1.5 Table 2 (Embodiments of the present invention) Sample No. Loss increase (dB) 1 0.1 2 0.3 3 0.2

From the comparison between Table 1 and Table 2, in the case of the embodiment according to the present invention, since the connection angle of the optical fiber to the optical waveguide of the optical element is always maintained correctly, the loss variation is small, and It can be seen that the deviation in the angle of the optical axis between the optical waveguide and the optical fiber can be kept small, so that the loss increase can be reduced as a whole.

FIG. 5 shows another embodiment of the optical fiber connecting member according to the present invention, in which the structure of the end surface opposite to the connecting end surface of the optical fiber connecting member is devised. As shown in this figure, the optical fiber connecting member 10 has a conical recess 15 formed on an end face 10b opposite to the connection end face 10a of a glass tubular body having ultraviolet light transmissivity. An optical fiber insertion through-hole 11 is opened in the portion. Other configurations are the same as those in FIGS.

In the optical fiber connecting member of FIG. 5, the operation of inserting the optical fiber 4 into the through hole 11 for inserting the optical fiber by using the conical recess 15 is facilitated, and the workability can be improved. .

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0029]

As described above, according to the connecting member for an optical fiber according to the present invention, the tubular member having the through hole for inserting the optical fiber and the connecting end face inclined with respect to the direction of the through hole is provided. Since a flat portion is formed in a part of the outer periphery, the flat portion can be used as a rotational direction position display of the optical fiber connecting member, and the rotational direction position can be easily adjusted, so that the light input / output end face of the optical element is connected to the optical waveguide. Even when the optical fiber is inclined, the optical fiber can be fixed to the optical input / output end face without variation in the connection angle.

Further, according to the method of manufacturing a connecting member for an optical fiber according to the present invention, the cylindrical tubular body having the through hole is fixed with the fixing means, and the cylindrical tubular body is oriented with respect to the direction of the through hole. Obliquely cutting, and a step of forming a flat portion on a part of the outer periphery of the tubular body by polishing the upper portion of the cut cylindrical tubular body so as not to reach the through hole in a fixed state as it is. Thus, it is possible to efficiently manufacture an optical fiber connecting member in which the flat portion is formed on the outer periphery.

Further, according to the optical fiber connection structure of the present invention, an optical fiber connection in which a flat portion is formed on a part of the outer periphery of a tubular body having a connection end surface inclined with respect to the direction of the through hole. Insert an optical fiber into the through hole of the member,
The optical fiber connection member is bonded to the light input / output end face of the optical element together with the optical fiber with a light-transmissive adhesive, and the flat portion of the optical fiber connection member can be used as a rotational direction position display. By easily adjusting the position in the rotation direction, the optical fiber can be securely fixed to the optical input / output end face of the optical element without variation in the connection angle, and the inconvenience that the connection angle of the optical fiber fluctuates when the adhesive is cured. Can be.

[Brief description of the drawings]

FIG. 1 is a side view showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a side view showing an optical fiber connecting member in the embodiment.

FIG. 3 is a front view of the same.

FIG. 4 is a process explanatory view showing a method for manufacturing an optical fiber connecting member in the embodiment.

FIG. 5 is a side sectional view showing another embodiment of the present invention.

FIG. 6 is a side view showing a connection structure of an optical fiber to an optical element in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waveguide type optical element 2 Optical waveguide 3 Optical input / output end face 4 Optical fiber 5, 20 Glass tube 10 Optical fiber connection member 11 Optical fiber insertion through hole 12 Rotation direction position display flat part 13 Ultraviolet curing adhesive 30 Cutting Jig 31 Fixed wax

Claims (5)

[Claims] 1. A tubular body having an optical fiber insertion through-hole and a connection end face inclined with respect to the direction of the through-hole, wherein a flat portion is formed on a part of the outer periphery of the tubular body. Characteristic optical fiber connection member. 2. The optical fiber connecting member according to claim 1, wherein the tubular body has an ultraviolet transmitting property. 3. The optical fiber according to claim 1, wherein a conical concave portion is formed on an end surface of the tubular body opposite to the connection end surface, and the through hole is opened at a central portion of the conical concave portion. Connection member. 4. A step of cutting the cylindrical tubular body obliquely with respect to the direction of the through hole in a state where the cylindrical tubular body having the through hole is fixed by the fixing means, and a step of cutting the cylindrical body in the fixed state as it is. Forming a flat portion on a part of the outer periphery of the tubular body by polishing the upper portion of the tubular body so as not to reach the through hole. 5. An optical fiber connection structure for connecting an optical fiber to an optical element of an optical element having an optical waveguide formed therein, the optical element having a connection end face inclined with respect to the direction of the through hole. An optical fiber is inserted into the through-hole of the optical fiber connecting member having a flat portion formed in the portion, and the optical fiber connecting member is put together with the optical fiber on the light input / output end face of the optical element with a translucent adhesive. An optical fiber connection structure characterized by being adhered by: