JPS6172208A - Production of base material for optical branching device - Google Patents

Abstract

PURPOSE:To obtain an optical branching device having less variance of quality by arranging several quartz rods in a quartz pipe and forming a space among these rods and packing closely very narrow rods to be a core in this space and heating them to join quartz rods with very narrow rods into one body. CONSTITUTION:Plural sectoral quartz rods 5a, 5b, and 5c whose curvature of outside peripheral surfaces are approximately equal to the curvature of the inside surface of a quartz pipe 4 are inserted into the quartz pipe 4, and a Y-shaped space 6 is formed among rods 5a, 5b, and 5c, and many very narrow rods 7 to be a core are packed closely in this space 6, and they are heated to join quartz rods 5a, 5b, and 5c with very narrow rods 7 into one body, and this joined material is stretched until the width of the core part becomes prescribed dimensions. This stretched base material is sliced to a prescribed thickness, and a sliced piece is polished, and quartz plate is stuck to the polished surface, and the core is covered with quartz to be a clad, thus forming a waveguide of the optical branching device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The manufacturing method of the present invention is for manufacturing a base material of an optical splitter used in an optical fiber system.

(Prior art) Optical splitters that input signals from one optical fiber into multiple optical fibers have conventionally been made by combining minute prisms, half mirrors, lenses, etc., or by fusion-bonding optical fibers. There are some types, such as those that apply integrated circuit technology to form branch patterns.

(Problems with the prior art) The first two types of conventional optical splitters can only be manufactured one at a time, and in addition, delicate adjustments are required, which takes time and increases costs. ing.

The last one has a film thickness of 1 μm or less, so it is necessary to combine a prism, lens, etc. in order to connect it to a multimode fiber with a core diameter of about 50 mm. Therefore, like the first two cases, there is a drawback that adjustment takes time.

(Means for Solving the Problems) The manufacturing method of the present invention provides an optical branching device 3 for a multimode optical fiber, which is composed of three claddings la, lb, and 1c and a core 2, as shown in FIG. It is designed so that it can be easily manufactured.

As shown in FIG. 2, the present invention includes inserting into a quartz tube 4 a plurality of fan-shaped quartz rods 5a, 5b, 5c whose outer peripheral surfaces have a curvature approximately equal to the curvature of the inner diameter of the quartz tube 4. , a Y-shaped gap 6 is formed between each row 5a, 5b, 5c, a large number of ultra-thin diameter rods 7 serving as a core are densely filled in this gap 6, and then heated to form quartz rods 5a, 5b, 5C and an ultra-thin diameter rod 7 are integrated.

In order to integrate the quartz rods 5a, 5b, 5C and the ultra-thin diameter rod 7, after filling the gap 6 with the ultra-thin rod 7, one end is sealed, and while depressurizing from the other end, the sealed portion is sequentially ignited. Then, the quartz tube 4, the quartz rods 5a, 5b, 5c, and the gap 6 between the fibers are brought into close contact and integrated.

Thereafter, the core portion is stretched until the width reaches a predetermined dimension.

The cross section of the base material manufactured in this manner has the same shape in both longitudinal directions.

To form an optical splitter waveguide from the stretched base material, it is sliced to a predetermined thickness, polished, a quartz plate is attached to the polished surface, and the core is surrounded by quartz that serves as a cladding.

When actually used, remove the three parts of the quartz tube 4 near the entrance of the optical branching waveguide by grinding, etc., and fuse the optical fiber to the part, or connect the optical fiber to the same part with a connector. Then, light branching is performed so that the light incident from one location is emitted from the other two locations.

(Example) A fan-shaped quartz rod 5a is placed in a quartz tube 4 with an inner diameter of 23φ and an outer diameter of 26.6φ so that the figure-7-shaped gap 6 is 0125 mm.
, 5b, 5c, the gap 6 has a diameter of 0125φ, a refractive index of 1,
After densely filling the rods 7 with a diameter of 473, they were heated and integrated.

The outer diameter of the quartz rods 5a, 5b, and 5c after heating and integration is 2.
6.5φ, width of core part 2 is 0.20mm, length is 100mm
It was mm.

In order to use this base material as a branch for a fiber with a core diameter of 50JL, it is necessary to draw it to have an outer diameter of 6.6Φ and make it into a thin piece of 5Cg.

(Effect of the invention) According to the above embodiment, there is little variation in quality.

Since more than 100 pieces of flakes can be obtained in 10 pieces, productivity is greatly improved. Furthermore, since this method does not require lenses, prisms, etc., an inexpensive optical splitter can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an optical splitter manufactured by the method of the present invention,
FIG. 2 is an explanatory diagram of the present invention. 4 is a quartz tube 5a, 5b, 5c is a quartz rod 6 is a gap 7 is an ultra-thin diameter rod 2 5C7

Claims (1)

[Claims] Several quartz rods are arranged inside a quartz tube to form a gap between each rod, and after this gap is densely filled with the ultra-fine diameter rods that will serve as the core, the quartz rods and the ultra-fine rods are integrated by heating. 1. A method for producing a base material for an optical splitter, characterized in that the base material is made to