JPS6240402A - Manufacture of optical multiplexer and demultiplexer - Google Patents

Abstract

PURPOSE:To mass-produce optical multiplexer and demultiplexer of multiple wavelength and low loss simply by manufacturing single body of several kinds of optical waveguide path parts by working a fiber glass rod and combining and connecting the optical waveguide path parts and several kinds of interference filters. CONSTITUTION:The first block is a part that emits light of wavelength lambda2, lambda4, lambda6, lambda8, lambda10 in fiber glass rods 4 and 7 side, that is, left side of interference film filters 9 and 11, and the second block is a group of fiber glass rods in opposite side of the first block and emits light of wavelength lambda1, lambda3, lambda5, lambda7, lambda9. A part of fiber glass rod between the first and second block is the third block. It is both possible to provide the interference filter 11 by vapor deposition on the fiber glass rod 7 or by vapor deposition on the fiber glass rod 6. As structure of the third block is complicated, it is desirable to form it by combining unit parts. When the third block is formed, a multiple wavelength multiplexer and demultiplexer is completed by bonding fiber glass rods of the first and second blocks on both sides.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical multiplexer/demultiplexer that is small, has low loss, is capable of multiplexing and demultiplexing multiple waves, is easy to mass produce, and is economical. be.

[Conventional technology]

As for the conventional optical multiplexer/demultiplexer, a collimated type that guides the light beam in parallel is considered to be a promising practical option (IEICE Communications System Study Group Material C!885-11).

The multiplexer/demultiplexer has a glass block inside, and an interference film filter is provided on the end face of the glass block, so that collimated light beams pass therethrough to perform multiplexing and demultiplexing. The above multiplexer/demultiplexer has extremely good loss characteristics, and the multiplexer/demultiplexer created before this (Research and Practical Application Report No. 3, page 487)
It has the advantage that it is smaller in size, has comparable characteristics, has a simpler assembly process, and can be assembled as a light-emitting and light-receiving element. Furthermore, assuming a monolithic type in the future, a waveguide-type optical multiplexer/demultiplexer may be considered, and from this point of view, an optical multiplexer/demultiplexer in which a quartz waveguide, which is thought to have low propagation loss, is formed on a silicon substrate has been proposed. (Special application 1982-
No. 72153).

[Problem that the invention seeks to solve]

The former optical multiplexer/demultiplexer in the conventional example above is for multi-mode use, and the accuracy of positioning etc. is rougher than for single-mode use, and there are some problems with temperature characteristics because the interference film filter is glued to the glass block. The latter type of optical multiplexer/demultiplexer involves inserting an interference filter from the outside into the branch point of the waveguide, which poses some problems in terms of practical reliability. The problem is that it is difficult and takes time to put into practical use.

[Means for solving problems]

To solve the above problems, a waveguide-type optical multiplexer/demultiplexer with an optical fiber embedded inside has been proposed (Japanese Patent Application No. 59-7755
No. 6, Japanese Patent Application No. 59-123608), the above optical multiplexer/demultiplexer is based on a silica glass rod that has the same characteristics as an optical fiber, and has extremely low loss as a waveguide, and Low-loss coupling can also be expected with fibers. In the present invention, unit parts are created by processing an optical waveguide rod made of quartz glass, mainly having an optical fiber structure, and an optical multiplexer/demultiplexer is created by combining several types of unit parts and a plurality of interference filters. , it is possible to combine and demultiplex any number of light waves, including two or more waves.

[Function] The present invention involves processing a fiber glass rod made of quartz glass and having a core portion equivalent to an optical fiber inside to fabricate several types of single optical waveguide components, and eliminating several types of interference with the optical waveguide components. By combining and connecting filters, it is possible to easily mass-produce multi-wavelength, low-loss optical multiplexers/demultiplexers, and the difference from conventional technology is that:
``Even when optical multiplexing and demultiplexing of a very large number of wavelengths is performed, the loss is low, the manufacturing method is simple, and mass production is possible. In the prior art, the form of the optical multiplexer/demultiplexer had to be changed as the wavelength of light increased, and the manufacturing method had to be changed to match the form. Furthermore, although the conventional optical multiplexer/demultiplexer has a multimode waveguide, the optical multiplexer/demultiplexer of the present invention can also be manufactured as a single mode optical multiplexer/demultiplexer. In addition, there is a manufacturing method in the prior art that has optical properties equivalent to those of the present invention, in which the optical fiber itself is processed into an optical multiplexer/demultiplexer (Wav
e-/ength-DiVision Multi D
emultiplexers for'I'wo-Ch
anne/ Single-Mode Transmi
ssion Systems A, Rechelt,
Journal of the Light Union, vol, LT2x A 5, □ct, 1984, p.
, 695). The above method constructs an optical multiplexing/demultiplexing circuit by embedding the optical fiber in a jig with an adhesive or the like, and questions remain regarding processing accuracy, handling, and reliability. In contrast, in the present invention,
Since the outer diameter is considerably thicker than that of an optical fiber, it is easy to process and handle, and there is a possibility that it can be fabricated by matching the outer diameter, making it easy to mass-produce.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an optical multiplexer/demultiplexer according to the present invention, and FIG. 2 is a block diagram showing the central part of the above embodiment.
FIG. 3 is a diagram showing an example of unit parts constituting the above embodiment. In FIG. 1, 1 and 3 to 7 indicate fiber glass rods having a core portion 2 of an optical fiber structure therein, and 8 to 11 indicate interference film filters, respectively.

Fiberglass rods 1 and 3 constituting the present invention
~7 have a core portion 2 equivalent to a multimode or single mode optical fiber inside, and interference filters 8~1 are provided between the fiber glass rods 1 and 3~7, respectively.
It is connected with 1 in between.

Thus, for example, the wavelength λ, to λ,. Ten waves of light are made to enter the fiber glass rod 1 from the lower left side of the figure.

First, it is coupled to the fiberglass rod 1,
In this case, if the outside is also an optical fiber, the optical fiber and the optical multiplexer/demultiplexer can be fused and spliced, and the coupling loss can be extremely reduced. The incident light reaches the interference film filter 8, but the interference film filter 8 transmits the light of wavelength λ2 to λ.

Since the fiberglass rod 3 reflects light with a wavelength of λ, only light with a wavelength of λ can be extracted from the fiber glass rod 3.

The light with wavelengths λ2 to λ1o reflected by the interference film filter 8 transmits the light with wavelengths λ2 to the interference film filter 9, and the light with wavelengths λ3 to λ
,. reflects the light of In this way, each time it enters each interference film filter, only the light of a specific wavelength is extracted, and the light of other wavelengths is reflected while proceeding. When the light of wavelength λ9 is extracted by interference film filter 0, the remaining wavelength is λ,.

can be extracted from the fiberglass rod 7. In other words, by selecting an interference film filter, 1
It is possible to extract one wavelength from two interference film filters, and when performing optical multiplexing, the above operation can be performed in reverse.

Furthermore, it is naturally possible to perform multiplexing and demultiplexing simultaneously.

Next, a method of manufacturing the optical multiplexer/demultiplexer shown in FIG. 1 will be explained. When the optical multiplexer/demultiplexer is broken down into its parts, it can be roughly divided into three blocks. The first block is λ2, λ4, λ6 on the fiber glass rod 4 and 7 side in FIG.
λ8, λ□. The second block emits light with a wavelength of λ0, λ3, λ- on the opposite side of the first block.
This is a group of fiber glass rods that emit light with wavelengths of 5, λ7, and λ9. The central portion of the fiberglass rod sandwiched between the first and second blocks is the third block. Since the interference film filter is inserted at the boundary of each block, it does not matter which block the interference film filter belongs to, but it is desirable that the interference film filter be close to the reflective surface. In terms of manufacturing method, it is possible to provide the interference filter 11 by vapor deposition on the fiber glass rod 7 or by vapor deposition on the fiber glass rod 6. The interference film filter portions in the first block and the second block are as follows: Since they are each made of the same type of fiber glass rod, mass production is high. If the interference film filter is deposited on a large number of fiber glass rods for each wavelength, the yield will be high and it will be economical.

In the third block, the part where the fiber glass strands etc. are present has a folded structure and is complicated, so it is desirable to construct it by a combination of unit parts as shown in FIG. There are two types of parts: the entrance part part 12 and the final output part 13 have the same shape, and all other parts have the shapes shown in 14.

Moreover, since the above-mentioned input part part 12, output part part 13, and part 14 all have folded parts of the same shape, the 0 part 14, which can be manufactured by the same method at the time of manufacture, is as shown in FIG. It consists of 15 and 16 individual parts bounded by dotted lines, and the dotted line parts are adhesive parts. Although an adhesive may be used for adhesion, it is desirable to use optical adhesion without using an adhesive if possible. If you are concerned about strength, strong adhesion can be achieved by heat-pressing at approximately 1100°C in an electric furnace. ・Technically difficult points in manufacturing the part 14 shown in Fig. 3 are the individual parts 15. Since the cores 17 and 18 of each of the 16 cores must be aligned and the core passages must be aligned at the end faces, care must be taken in the polishing technique. This point has already been described in Japanese Patent Application No. 59-77556, and is carried out while optically measuring or under a microscope. Further, if the core portion of the fiberglass rod is not eccentric with respect to the outer diameter of the rod, it is also possible to adjust the outer diameter of the rod. Also each unit part 12.13.14 in a ready-made mold
It is also possible to assemble by fitting and gluing.

Since the interference film filter is preferably vapor-deposited on the end face of the component 14, it is desirable that the bonding surfaces of the individual components 15 and 16 be bonded using an adhesive that can withstand high temperatures or optical bonding.

After the third block shown in FIG. 2 is formed as described above, the fiber glass rods of the first and second blocks are bonded to both sides to complete the multi-wavelength optical multiplexer/demultiplexer.

The above optical multiplexer/demultiplexer has a normal optical waveguide loss of 1 dB/c.
The loss was about rrL, whereas the loss was more than 5 orders of magnitude lower.

〔Effect of the invention〕

As described above, the method for manufacturing an optical multiplexer/demultiplexer according to the present invention involves processing an optical waveguide rod that has an optical fiber structure and is entirely made of silica glass to produce a plurality of types of unit parts. By combining a unit part and multiple interference film filters with different transmission wavelengths and combining them to obtain the desired multiplexing or demultiplexing, the basic parts are the same and the unit part They can be manufactured using the same manufacturing method, and by combining them, a multi-wavelength optical multiplexer/demultiplexer can be realized with extremely low loss, and it is economically promising because it can be mass-produced.

Further, the fiberglass rod used in the present invention has an outer diameter of i
If it is on the order of mm, it can be manufactured in large quantities and at low cost using optical fiber drawing technology, so if the above manufacturing method is used, the coupling and branching circuits of various optical components can be economically advantageous in the same way as the optical multiplexer/demultiplexer. production is possible.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of an optical multiplexer/demultiplexer according to the present invention, and FIG. 2 is a block diagram showing the central part of the above embodiment.
FIG. 3 is a diagram showing an example of unit parts constituting the above embodiment. 1.3-7... Optical waveguide rod (fiber glass rod), 2.17.18... Core, 8-11... Interference film filter, 12-14... Unit component.

Claims (1)

[Claims] An optical waveguide rod, which has an optical fiber structure at its center and is entirely made of silica glass, is processed to produce multiple types of unit parts, and each of the above unit parts is combined with multiple interference film filters each having a different transmission wavelength. A method for manufacturing an optical multiplexer/demultiplexer by combining the above so as to obtain desired multiplexing or demultiplexing.