JPS594340A - Optical multiplex communication system - Google Patents

Abstract

PURPOSE:To extend freely slave devices connected and multiplied to a master station device, by converting optically transmission information after being modulated at a frequency assigned to each slave station and using optical signal of the same wavelength for transmitting and receiving. CONSTITUTION:A signal inputted from an input terminal A and transmitted to slave station devices 2a, 2b, 2c is modulated in frequencies f1, f2, f3 at a frequency modulator provided in a signal converter 3 of the master station device 1, converted at an optoelectric converter 4 in the lump and outputted as optical signals. The signals are branched or transmitted at directional separators 5a, 5b of the devices 2a, 2b and inputted to optoelectric converters 7a, 7b, 7c, where the signal is converted into an electric signal and demodulated at signal converters 8a, 8b, 8c.

Description

Detailed Description of the Invention (a) Technical Field of the Invention The present invention provides multiplexing between a plurality of slave station devices multi-connected to a 23λ station-1ts via an optical fiber and the master station device. This article concerns the communication system for transmitting and receiving information, and in particular, the optical multiplex communication system that allows multiple connection of a large number of slave stations.

(b) Technical background In recent years, with the rise of information technology in the field of communications,
The number of communication lines is increasing. Optical multiplex communication systems that transmit and receive multiplexed information between multiple slave stations connected to a master station via optical fibers and the master station are no exception, and the increase in information ψ is no exception. Accordingly, there is a need for a system that can increase the number of slave station devices that can be multi-connected.

The figure is a diagram showing a configuration example of an optical multiplex communication system.

In the figure, 1 is a master station device, 2a, 2b, 2c are slave station devices, 3 is a signal converter, 4 is an optical/electrical converter, and 5a.

5b is a directional separator, 6a and 6b are directional couplers, 7a
, 7b, 7c are optical/electrical converters, 8a, 8b, 8c
are signal converters, 9a, 9b, 9c are received data 17 power terminals (hereinafter referred to as output terminals), 10a, 10b, 1
0c is a transmission data input terminal (hereinafter referred to as input terminal), A
B is a transmission data input terminal (hereinafter referred to as an input terminal), and B is a reception data output terminal (hereinafter referred to as an output terminal).

There is a (-J1 optical wavelength division multiplex communication system) as a conventional optical multiplex communication system, and the optical wavelength division multiplex communication system will be explained below.

In optical wavelength division multiplexing communication systems, each slave station device (j 2 a
.

2b and 2c have different frequencies λ8. λ2. λ3?
ijl! +I'm guessing. That is, slave station devices 2a, 2
b.

In the gas-liquid exchangers 7a, 7b, and 7c, the light of wavelength λ7. λ2. It has a light emitting element that outputs an optical signal of λ3. Additionally, the optical-to-electrical converter 4 of the master station device 1 has a wavelength λ1.1 assigned to each slave station device 2a, 2t, 2C. λ2. It has three types of light emitting elements that output an optical signal of λ3. Furthermore, the directional separator 5a reflects the wavelength λ2, which is applied to the slave station device 2a, of the optical signal output from the master station device 1 to the G/C-electrical converter 7a, and transmits other waves. λ2. It allows light of λ3 to pass through. Unfortunately, the directional separator 5b returns the optical signal of wavelength λ2 that has passed through the directional coupler 5a to the optical-to-electrical converter 7b, and converts the optical signal of wavelength λ2 back to the optical signal of wavelength λ2. It is transparent. The directional coupler 6b couples the signal with the wavelength λ3 from the slave station device 2c and the optical signal with the wavelength λ2 output from the optical-to-electrical converter 7b in the slave station device 2b, and also performs directional coupling. vessel 6a
is for coupling the optical signal from the directional coupler 6b with the optical signal of wavelength λ1 output from the optical to optical converter 7a in the slave station N2a.

First, a case will be described in which the master station device 1 is used as the transmitting side. The signal input from input terminal A and sent to each slave station device 2a, 2b+2c is transmitted to each slave station i within optical-to-electrical converter 4.
Locations 2a, 2b, 2c K assigned wavelengths λ1.
λ2. With three light emitting elements that output an optical signal of λ3,
After electrical-to-optical conversion, the signals are combined and output to a transmission optical fiber. The output light of this master station device 1 is transmitted through a directional separator 5a.
Only the signal of the wavelength λ assigned to the slave station device 2a is reflected by the optical-to-electrical converter 7a. The optical-to-electrical converter 7a converts the optical signal with the wavelength λ into an electrical signal and outputs it as received data at the output terminal 9a, 1:#).The optical signal transmitted through the directional separator 5a is Sex separation? +'5b, only the optical signal with the wavelength λ assigned to the slave station device 2h is reflected and input to the i(]...4Q converter 7b. Converts optical signals to electrical signals and outputs terminals 9b, l:
D Output as received data. The optical signal transmitted through the directional separator 5b is an optical signal of wavelength λ3 that is relatively focused on the slave station device 2c, and this optical signal is sent to the optical-to-electrical converter 7c as a direct signal. and output as received data from the output terminal 9c.

Next, a case where the slave station devices 2a, 2b, and 2c are on the transmitting side will be explained. Assuming that a data signal is input from the input terminal 10c of the slave station device 2c, this data signal is converted into optical signal No. 1- of wavelength λ3 by the optical/electrical converter 7c and output. At this time, when a data signal is input from the input terminal 10b of the slave station device 2b, this data 1 word is converted into an optical signal of wavelength λ4 by the optical/electrical converter 7b and output. This optical signal of wavelength λ2 is combined with the optical signal of wavelength λ3 from slave station device 2c at the directional coupler 6b and output.

At this time, if there is no optical signal output from the slave station device 2a, and if an optical signal that is a combination of an optical signal with wavelength λ2 and an optical signal with wavelength λ3 is input, this data signal is The electric conversion circuit 7a converts the optical signal into an optical signal having a wavelength λ, and the directional coupler 6a combines the signal with the optical signal from the directional coupler 6b, which is then input to the master station device 1. In such a master station device 1, the wavelengths λl, λ2 . An optical signal obtained by combining the optical signals of λ3 is converted into an electric signal by a light receiving element in the optical-to-electrical converter 4, and outputted from an output terminal B.

However, such conventional optical multiplex communication systems, ie, optical wavelength multiplex communication systems, have the following drawbacks. In other words, in conventional optical multiplex communication systems, when adding multiple slave stations to a master station, a wavelength is required to be assigned to the additional slave stations, but the wavelength range of a laser diode is 0.8 microns. Since it is 1.3 microns from 0.8 microns to 1.3 microns, even if you try to thinly divide the wavelength range from 0.8 microns to 1.3 microns and allocate wavelengths to each slave station,
It was difficult to manufacture a laser diode to realize this. Therefore, there is a limit to the number of slave stations that can be multi-connected to the master station, and the system cannot be expanded.

In addition, since conventional optical multiplex communication systems require directional couplers, directional separators, and light emitting elements with various characteristics, the process for manufacturing them is different and is suitable for mass production. ', it also had the disadvantage of high manufacturing costs.

(d) Purpose of the Invention In view of the drawbacks of the conventional optical multiplex communication system, the present invention has the following objectives:
An optical multiplex communication system that does not require different characteristics for the directional coupler and directional separator 1 light-emitting elements, that is, allows the use of directional couplers and directional separator 1 light-emitting elements that have the same characteristics. The purpose of the present invention is to expand the system by providing a system that allows the user to freely add slave stations that are multi-connected to a master station.

(e) Structure of the Invention In order to achieve the above object, the present invention provides a method for transmitting and receiving multiplexed information between a plurality of slave station devices that are multi-connected to a master station device via optical fibers, and the master station device. In an optical multiplex communication system that performs
electrical/optical converting means for converting the signal modulated by the modulating means into an optical signal; t-electrical converting means for converting the optical signal sent from the master station device into an electrical signal; Extracting means for extracting only the frequency band assigned to the own station device from the output of the PLM conversion means, demodulating means for demodulating the output of the extraction means at the frequency assigned to the own station device, A modulation means for modulating information sent to each of the plurality of slave station devices in a master station device at a frequency assigned to each of the plurality of slave station devices, and a signal modulated by the modulation means is collectively converted into an optical signal. electrical/optical conversion means for converting, the plurality of slave station devices,
The output of the light-to-air conversion means, which converts the optical signals sent from the A demodulating means is provided for modulating the signal from each slave station device at a frequency assigned to each slave station device, and a demodulating means is provided to modulate the signal from each slave station device obtained by the extraction means ((). This system is characterized by transmitting and receiving information between the station remaining device and a plurality of slave station devices.

(f) Embodiment of the Invention An embodiment of the optical multiplex communication system of the present invention will be described below with reference to the drawings.

First, a case where the master station device 1 is on the transmitting side will be explained. still,
Here, a case will be explained taking as an example a case where three slave station devices are multi-connected to the master station device M.

Each slave station device 1lf2 a+ 2 input from input terminal A
The signals sent to be2c have frequencies h f+ , f2 . fs
The frequency shifter modulates the same wave number f
After being modulated by l+b and fs, the signals are combined at the 'air level' and output. The output of the signal converter 3 is collectively converted by an optical iL electrical converter and output as an optical signal. The output of this master station device 1 is branched or transmitted through directional separators 5a and 5b of slave station devices 2a and 2b, respectively.
Light 1 is also Kihenkyuki 7B, 7b.

7c. And an optical/electrical converter 7a.

At 7b and 7c, the input optical signal ff is converted into an electrical signal and outputted to signal conversion □+3a, 8b, and 8c. That is, the outputs of the light exchangers 7a, 7b, and 7c become electrical signals equivalent to the output of the signal converter 3 in the master station device 1. And signal converters 8a, 8b
, 8c, the outputs of the optical-to-electrical converters 7a, 7b, and 7c are assigned to the frequency band f assigned to each slave station device.
l.

f! After extracting the signal to the own station using a filter that extracts +f8, divide it for each slave station device! It demodulates at the currently set frequency using a modulator, and outputs the data to its own station through output terminals 9a and 9c, respectively.

Next, a case where the slave station devices 2a, 2b, and 2c are on the transmitting side will be described.

In each slave station device 2a, 2b, 2c, each data signal inputted from each input terminal 10a, iob, 10c is converted into a frequency f1. f! Modulated by l fB, the light
Electrical converter 7a.

7b and 7c convert it into an optical signal. The optical signals from the slave station devices 2a, 2b, 2c thus obtained are combined by directional couplers 6a, 6b connected to optical fibers and sent to the master station device. These optical signals have the same wavelength, and are input to the master station device 1 in a combined form. In the master station device 1, the combined optical signals are collectively converted into electrical signals by an optical-to-electrical converter 4. This electrical signal is transmitted to the frequency bands fl and f assigned to the slave station devices by the signal converter 3.
After the signals are extracted for each slave station device t2a, 2b+2a by a filter that allows only the Hf3 signal to pass, the signals are outputted from the tone output terminal B, respectively.

In this way, in the optical multiplex communication system of the present invention, optical signals of the same wavelength are used to transmit and receive multiplexed signals between the master station and the counting slave station.

(g) Effects of the Invention As explained in detail above, according to the 〉' communication system of the present invention, the master station sr h
Since signals are being sent and received between +i number of slave station devices,
Circuits and elements having the same characteristics can be used as the light emitting elements of the directional coupler and directional separator 9 provided in the master station device and the slave station device.

Therefore, only the steps 1 <+HIi are required for manufacturing, and since it is suitable for mass production, the manufacturing cost can be reduced. In addition, since the optical multiplex communication system of the present invention can transmit and receive optical signals of the same wavelength, there is no need to use optical signals of multiple wavelengths as in the conventional optical multiplex communication system, and the light emitting element ( laser diode) is also 1
There are only a few types, and there are no difficulties in manufacturing. Therefore, it is possible to freely add slave station devices that are multi-connected to the master station device, and it is possible to expand the system.

[Brief explanation of the drawing]

The figure shows fI! of the optical multiplex communication system. FIG. In the figure, 1 is a master station device t, 2a, 2b, 2c are slave station devices, 3 is a signal converter, 4 is an optical/electrical converter, and 5a
, 5b is a directional separator, 6a and 6b are directional couplers, 7
a, 7b, 7c are light-W gas exchangers; 8a; 8b and 8c are signal converters; 9a, 9b, and 9c are reception data output terminals; 10a, 10b, and 10c are transmission data input terminals; A is a transmission data input terminal; and B is a reception data output terminal.

Claims (1)

[Claims] In an optical multiplex communication system in which multiplexed information is sent and received between a plurality of slave stations t connected to a master station via optical fibers and the master station, A modulation means for modulating information to be sent to each of the slave station devices at a frequency assigned to the own station device; A light-to-electric conversion means that converts the optical signal sent from the device into an optical signal. A demodulating means is provided for demodulating the output of the means at a frequency assigned to the own station device, and information to be sent to each of the plurality of slave station devices is sent to the master station device at a frequency assigned to each of the plurality of slave station devices. A modulating means for modulating. An electrical/optical converting means for collectively converting the signals modulated by the modulating means into optical signals, and an electrical/optical converting means for collectively converting the optical signals sent from the plurality of slave station devices into one optical signal. an optical/electrical conversion means for converting, an extraction means for extracting the output of the optical/electrical conversion means for each frequency band assigned to each slave station -Jk position, and each slave station device that has been converted by the extraction means; A demodulating means is provided for demodulating the signal from the master station at a frequency assigned to each slave station, and information is transmitted and received between the master station and a plurality of slave stations using optical signals of the same growth. Characteristic optical multiplex communication system.