JPH0572437A - Light fiber - Google Patents

Abstract

(57) [Abstract] [Purpose] Regarding the structure of an optical fiber used in an optical communication system, in particular, the structure of the input / output end face of light, the spatially propagating light condensed using a lens is incident on the cladding layer. An object of the present invention is to provide an optical fiber that can reduce the amount and stabilize optical communication. [Structure] In an optical fiber 3 in which the end face of the tip of the core 1 is a plane orthogonal to the optical transmission line, the clad layer 2 is tapered at the tip so that only the core 1 remains.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an optical fiber used in an optical communication system, and more particularly to a structure of a light input / output end face.

[0002]

2. Description of the Related Art In optical communication, an optical fiber is used as a means for propagating spatially propagating light emitted from a semiconductor light emitting device to a light receiving device. The central portion of this optical fiber is called a core, and is formed of quartz glass or the like having germanium mixed therein to increase the refractive index. The outer peripheral portion thereof is called a clad layer and is formed of quartz glass or the like having a smaller refractive index than the core.

The spatially propagating light emitted from the semiconductor light emitting device is condensed using a lens, is incident on the core of the optical fiber, and is propagated to the light receiving device. The end face of the optical fiber tip is normally orthogonal to the optical transmission line, but the end face is inclined with respect to the optical transmission line in order to reduce reflection of incident light in the direction of the semiconductor light emitting device, or A method is known in which the end face has a convex curved surface.

[0004]

When the spatially propagating light emitted from the semiconductor light emitting device is condensed using a lens and is incident on the core of the optical fiber, a part of the light is incident on the cladding layer. Since the intensity of the light propagating through the clad layer fluctuates greatly due to the influence of bending of the optical fiber, etc., stable optical communication becomes impossible when the fluctuation component is coupled to the light propagating through the core at the light receiving end.

An object of the present invention is to eliminate this drawback, and to reduce the amount of spatially propagating light condensed using a lens to enter the clad layer and stabilize optical communication. To provide fiber.

[0006]

The above object is to provide an optical fiber (3) in which the end facet of the core (1) is a plane perpendicular to the optical transmission line, and the clad layer (2) is tapered at the tip end. Achieved by an optical fiber that has been molded so that only the core (1) remains.

[0007]

In the optical fiber according to the present invention, since only the core exists on the end face which is in contact with the semiconductor light emitting device and the semiconductor light emitting device and the clad layer are separated from each other, the semiconductor light emitting device condensed by the lens is used. The probability that the spatially propagating light generated by the incident light enters the cladding layer is reduced, and the fluctuation component of the intensity of the propagating light due to bending of the optical fiber is significantly reduced. Further, by making the emitting end face have the same shape, it is possible to reduce the probability that the light propagating through the cladding layer is coupled with the light propagating through the core at the light receiving end. Further, since the area of the incident end face is the area of only the core, the amount of reflection is reduced, and stable coupling between the semiconductor light emitting device and the optical fiber becomes possible.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing an optical fiber according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, the core 1 and the cladding layer 2 are
The negative resist 4 is applied to the tip end of the optical fiber 3 made of and a mask 6 having a light-transmitting region 5 having the same shape as the shape of the end face of the core 1 is formed. Overlap so that they match, and develop.

As a result, as shown in FIG. 3, the resist film 4 remains on the core 1 on the end face of the optical fiber 3.
When the tip portion of the optical fiber 3 is etched using a hydrofluoric acid-based etchant and the resist film is removed, the cladding layer 2 at the tip portion of the optical fiber 3 is tapered to form a core, as shown in FIG. Only 1 remains.

[0011]

As described above, in the optical fiber according to the present invention, since the clad layer at the tip of the optical fiber is tapered and only the core remains, the light is emitted from the semiconductor light emitting device and the Since the probability that the condensed spatially propagating light is incident on the cladding layer is reduced and the probability that the light propagating in the cladding layer is incident on the semiconductor light receiving device is also reduced, the intensity of the propagating light is reduced by bending the optical fiber. The fluctuation can be remarkably reduced, and stable optical communication can be performed.

[Brief description of drawings]

FIG. 1 is a sectional view of the tip of an optical fiber according to the present invention.

FIG. 2 is a manufacturing process diagram of an optical fiber according to the present invention.

FIG. 3 is a manufacturing process diagram of an optical fiber according to the present invention.

[Explanation of symbols]

 1 core 2 clad layer 3 optical cable 4 resist layer 5 transparent region 6 mask

Claims (1)

[Claims] 1. An optical fiber (3) in which the end facet of the tip of the core (1) is a plane orthogonal to the optical transmission line, the clad layer (2) is tapered to form the tip of the core (1) only. An optical fiber characterized by remaining.