JPS60186139A - Optical fiber bus communication method - Google Patents

Abstract

PURPOSE:To have a multidrop type communication through one optical fiber bus by providing a reflection part to one terminal of one optical fiber and inserting an optical directional coupler at every drop point, and demultiplexing an up and a down signal from each other. CONSTITUTION:The reflecting film 11 is provided to one terminal of one optical fiber 10 and directional couplers 8, 12, 13, and 9 are provided at respective drop points of the fiber 10. For example, a light transmit signal sent from the light emitting device 1-1 of an optical terminal device 1 after being modulated with a signal given the number of a destination optical terminal device is passed through the optical directional coupler 8 and reflected by the optical directional coupler 12 to travel upward through the optical fiber 10, and the light is reflected by the reflecting film 11 to travel downward; and the light is demultiplexed by the optical directional couplers 12 and 13 respectively and sent to photodetectors 1-2 and 2-2 of the optical terminal devices 1 and 2. Each terminal accepts only a signal addressed to the terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a multi-drop optical fiber bus communication system, and relates to an optical fiber bus communication system that enables multi-drop communication using a single optical fiber bus.

(b) Prior Art and Problems As a conventional multi-drop optical fiber bus communication system, there is a U-shaped optical fiber bus communication system described below.

FIG. 1 is a block diagram of a conventional U-shaped optical fiber bus communication system, in which each drop point of a U-shaped optical fiber bus 5 is provided with an optical coupler 3, 4 and an optical splitter 6°7. For example, an optical transmission signal modulated with a signal attached with the number of the destination optical end floor device, which is transmitted from the light emitter 1-1 of the optical end floor device 1, passes through the optical coupler 3 and is sent to the optical fiber 7 in the upstream direction. 5-
1 and a downstream optical fiber 5-2, and an optical splitter 6
．． 7I Trowel branched light end floor device t 1.2 light receiver 1
-2.2-2. Each party terminal device @1, 2 receives only the optical signal addressed to its own party terminal device among the optical signals received by the optical receiver 1-2, 2-2. In this way, the U-shaped fiber optic bus 5
I am using multi-drop communication using U.
The shaped optical fiber bus 5 includes upstream optical fibers 5-1.
Since the optical fiber 5-2 is provided in the downstream direction, there is a problem in that an optical fiber having a length twice the length of the transmission path is required between the optical terminal devices on both sides.

(c) Object of the Invention In view of the above-mentioned problem 1, the object of the present invention is to provide an optical fiber bus communication system that enables multi-drop communication using a single optical fiber bus.

(d) Structure of the Invention In order to achieve the above object, the present invention provides a reflective section at one end of one optical fiber, and inserts an optical directional coupler at each drop point of the one optical fiber. The optical transmission signal from the optical terminal equipment is reflected by the optical directional coupler at the drop point of the optical terminal equipment, travels up the single optical fiber, is reflected by the reflecting part, and is transmitted to the optical fiber. The optical fiber is characterized in that it travels down a single optical fiber and is branched off at an optical directional coupler at each drop point and sent to the light receiver of each party terminal device.

In other words, conventionally optical signals were only sent in one direction through optical fibers, but now they are sent in both directions, and a directional coupler is used to separate the upstream and downstream signals. This enables multi-drop communication over a fiber bus.

(e) Embodiment of the Invention An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram of an optical fiber bus communication system according to an embodiment of the invention, and FIG. 3 shows the configuration of an optical fiber terminal. In the figure, parts having the same functions as those in FIG.

In the case of FIG. 2, for example, the optical transmission signal modulated with the signal assigned the number of the destination optical end floor device transmitted from the light emitter 1-1 of the optical end floor device 1 is sent to the optical directional coupler 8. The light passes through the directional coupler 12, is reflected at the optical directional coupler 12, travels up the optical fiber 10, is reflected at the reflective film 11, travels down the optical fiber 11, and is branched at each of the optical directional couplers 12 and 13 to form an optical end floor device. 11.
2 is sent to the optical receiver 1-2.2-2. Each terminal device 1.2 takes in only the optical signals addressed to its own optical terminal device among the optical signals received by the optical receiver 1-2.2-2. By doing this, the length of the optical fiber can be made equal to the length of the transmission path between the optical terminal devices at both ends, and the length of the optical fiber is 0 (conventionally).
It can be reduced to 1/2.

The reflective portion can be provided at one end of the optical fiber 10 by depositing a reflective film at a vertical angle in the length direction of the optical fiber 10, as shown in FIG.

(f) Effects of the Invention As explained in detail above, according to the present invention, there is an effect that the optical fiber length can be made equal to 1/2 of the conventional length, that is, equal to the transmission path length.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional U-shaped optical fiber bus communication system, Fig. 2 is a block diagram of an optical fiber path communication system according to an embodiment of the present invention, and Fig. 3 is a front view showing the configuration of an optical fiber terminal. be. In the figure, 1.2 is a light end floor device, 1-1.2-1 is a light emitter,
1-2.2-2 is a light receiver, 3 and 4 are optical couplers, 5 is a U-shaped optical fiber bus, 6 and 7 are optical branchers, 8 and 9°12,
13 is an optical directional coupler, and 10 is an optical fiber. 11 indicates a reflective film.

Claims (1)

[Claims] In the multi-drop optical 7 Aiba bus communication system, a reflective section is provided at one end of a single optical fiber, and an optical directional coupler is inserted at each drop point of the single optical fiber. The optical transmission signal from the floor equipment is reflected by the optical directional coupler at the drop point of the optical terminal device, propagates up the one optical fiber, is reflected by the reflection part, and is connected to the one optical fiber. An optical fiber bus communication system characterized in that the optical fiber bus travels in a downward direction, is branched at an optical directional coupler at each dop point, and is sent to a light receiver of each optical end floor device.