JPS63253308A - Optical demultiplexing and branching device - Google Patents

Abstract

PURPOSE:To obtain an optical demultiplexing and branching device which is simple in constitution and is low in loss and cost by integrally constituting a demultiplexing means and branching means by using glass blocks, half mirror and band-pass filters. CONSTITUTION:Two wavelength light multiplexed with wavelength lambda1 and lambda2 is converted to parallel light by a near parabolic rod lens 5 and is guided to the glass block 1 when said light is inputted to an input port P0. A filter F1 is used for branching or demultiplexing. The half mirror is provided thereto in the case of branching and the band-pass filter (BPF) in the case of demultiplexing. The two wavelength light is branched to two beams which are guided to the filters F2 and F3 if, for example, the half mirror is used for the filter F1. The filters F2 and F3, constituted of BPF, allow transmission of specific wavelength light and reflect the other wavelength light and, therefore, the branched light is separated to the wavelengths lambda1 and lambda2. Said light is converted to beam light by near parabolic rod lenses 6-9. The beam light is obtd. at output ports P1-P4. The optical coupling loss is thereby decreased and the cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical demultiplexer/brancher used in optical fiber communications and the like.

Conventional technology In optical fiber transmission using wavelength multiplexing, a multiplexer is installed at the transmitting end of an optical fiber transmission line, and a demultiplexer is installed at the receiving end. When performing relay transmission in two-wavelength multiplex transmission, as shown in FIG. 4, wavelengths λl and λ2 are wavelength-multiplexed by a multiplexer 10 in a transmitter A and transmitted to a repeater B via an optical fiber. In the relay section B, after the wavelengths λl and λ2 are separated by the splitter 11, each wavelength light is split into two by the splitter 12, one branched light is photoelectrically converted by the O/E converter, and the other branched light is The branched light is transmitted to the receiver C through two optical fibers.

Problems to be Solved by the Invention In the conventional repeater, a branching filter 11 and a branching filter 12 are required, which complicates the device configuration and causes an increase in cost. Furthermore, since the branching filter 11 and the branching device 12 are optically coupled using optical fibers, the number of connection points increases, leading to an increase in transmission line loss.

In order to solve the above problems, the present invention is easy to configure, and
The purpose is to provide a low-loss, low-cost optical demultiplexer/brancher.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention uses a glass block, a half mirror, and a divided pass filter as the demultiplexing (or branching) means. It has an integrated configuration.

Effect: According to the above configuration, an optical demultiplexer/splitter with a simple configuration, low loss, and low cost can be realized.

Embodiment FIGS. 1, 2, and 3 are block diagrams showing an embodiment of the present invention. 1.2.3.4 is glass block, 5.6
．． 7.8.9 is a focusing rod lens that converts beam light into parallel light and parallel light into beam light, Fl is a filter provided on the joint surface of glass blocks 1 and 2, and F2 is a filter between glass blocks 2 and 3. A filter provided on the joint surface, F3 is a filter provided on the joint surface of glass blocks 1 and 4, P
O is input port (optical fiber), Pl, F2, F3, F
4 is an output port (optical fiber).

The operation of the embodiment will be described below with reference to the drawings.

When a two-wavelength light multiplexed with wavelengths λ1 and λ2 is input to the input boat PO, it is converted into parallel light by a converging rod lens 5 and guided to the glass block 1. Filter Fl
is for branching or demultiplexing, and in the case of branching, a half mirror is provided, and in the case of demultiplexing, a band pass filter (hereinafter abbreviated as BPF) is provided. When a half mirror is used as the filter Fl, the two-wavelength light is split into two and guided to the filters F2 and F3. Filters F2 and F3
is composed of a BPF, which transmits light of a specific wavelength and reflects light of other wavelengths, so the branched light is separated into wavelengths λ1 and λ2, and converted into a beam of light by the focusing rod lens 6.7.8.9. and are obtained on output ports P1, F2, F3, and F4.

On the other hand, when a BPF is used as the filter Fl, light of a specific wavelength is transmitted to the filter F2, and light of other wavelengths is reflected to the filter F3. When half mirrors are used for filters F2 and F3, the demultiplexed light is split into two output ports Pi, P2, F3, and F4.
can be obtained.

Table 1 shows the types of wavelength light obtained from each output boat when a half mirror is used as the filter Fl and BPFs are used as the filters F2 and F3.

Further, Table 2 shows the types of wavelength light obtained at the output port when a BPF is used as the filter Fl and half mirrors are used as the filters F2 and F3.

Effects of the Invention As described above, according to the present invention, since the demultiplexing and branching means are integrated, optical coupling loss can be reduced and an optical demultiplexer/brancher with easy optical axis adjustment can be realized. , it becomes possible to lower the price.

[Brief explanation of the drawing]

1, 2, and 3 are block diagrams showing the structure of an optical demultiplexer/brancher according to an embodiment of the present invention, and FIG. 4 is a block diagram showing the structure of a conventional optical fiber transmission system. 1.2.3.4...Glass block, 5.6.7.8
．． 9...Focusing rod lens, Fl, F2, F3...
・Filter, PO...Input port, PI, F2, F
3.F4...Output boat. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2

Claims (1)

[Claims] first, second, third, and fourth glass blocks;
and a first filter for demultiplexing (or branching) provided on the joint surface of the second and second glass blocks, and a first filter for demultiplexing (or demultiplexing) provided on the joint surface of the second and third glass blocks. 2 filter, and a third filter for branching (or demultiplexing) provided on the joint surface of the first and fourth glass blocks, and a third filter for branching (or demultiplexing) the light from the first glass block through a focusing rod lens. Input two different wavelengths of light, the first,
An optical demultiplexer/brancher characterized in that each of the second, third, and fourth glass blocks outputs demultiplexed/branched light through focusing rod lenses.