DE2708606A1 - Communications system with optical fibres - uses optical fibres both for communications and for switching signals and power transmission - Google Patents

Abstract

The communications system uses optical fibres not only for transmitting communications signals, but also for sending the signals needed for setting up and cancelling connections. The power supply to the subscribers terminals is also transmitted via the optical fibres in the form of light energy. The latter is transmitted as unmodulated light whose frequency differs from the fundamental frequency of the light signals transmitted from the central station to subscribers.

Description

Communication system

The present invention relates to a communication system that provides information transmits optically via optical fibers.

In recent years, optical fibers made of glass fibers have become have been developed that allow broadband signals with comparatively lower levels Transferring attenuation.

These properties make fiber optic cables particularly suitable for Use in higher network levels of Xelephonsystemen in which a larger number of telephone signals in time division multiplex z the frequency division multiplex technology be transmitted. Are the transmission lines in higher network levels made of fiber optic cables built up, but also for reasons of the application of a uniform one transmission technology, the use of fiber optic cables in the lower network levels up to the individual participant stations of interest. This is especially true albeit a need for a higher frequency bandwidth for the subscriber lines exists than the usual electrical telephone subscriber lines available can ask.

The present invention is based on the object of a communication system indicate the information table transmits via fiber optics and in the Provision has been made to ensure that the signals required to establish the connection are also provided are transmitted and the individual subscriber stations are supplied with energy.

To solve this problem, the invention proposes a communication system before, which transmits information optically via optical fibers and in the case of the erfindungsgedB the optical fibers not only for the transmission of the communication signals but also for the transmission the signals required to establish and clear connections and for transmission of energy in the form of light to supply energy to the subscriber stations.

The subscriber station is advantageously supplied with energy in such a way that also unmodulated light on the optical fiber to the subscriber is transmitted, the frequency of this unmodulated light preferably being different is chosen as the fundamental frequency of the light signals transmitted in the same direction. The unmodulated light can then be in the subscriber station by means of a frequency separator separated from the light signals.

In the following an Äusfürrungsbeispiel the invention is based on the Figure described.

The figure shows a subscriber line consisting of an optical waveguide 1, which the subscriber station shown on the right with that on the the center shown on the left. The subscriber station includes one Device 12 in which an opto-electrical converter is integrated with an alarm device is, an optoacoustic transducer 13 and an acoustooptic modulator 14. Der Optoacoustic transducer 13 can, for example, consist of an optoelectrical transducer exist, e.g. a photodiode and a thrush coupled to it. For the acousto-optical Modulator of the known construction comes into consideration, in which - due to the elasto-optical Effect light is scattered on an acoustic wave.

Furthermore, a fork 3 is also provided in the subscriber station Merging or separation of outward and return channels, a crossover network 10, the the incoming light signal via the hook switch 8 of the alarm device 12 or the optoacoustic transducer 13 and supplies the unmodulated incoming light via the optical changeover switch 9 to the acousto-optical converter 14 or leads back to the optical waveguide 1 via the coupling member 5 and the fork 3. In the Central a control device 15 and a switching matrix 16 are provided, furthermore a fork 2 for bringing together or separating the outward and return channels, a coupling element 4, two electro-optical converters 11 and 12 and two opto-electrical converters 17 and 18, an optical switch 6, the useful information signals to the optoelectrical Umwandlder 18 and the operating signals required to set up and clear the connections to the opto-electrical converter 17 conducts, as well as an electrical switch 7, the depending on the switch position the outgoing operating signals or the outgoing Useful information signals on the electro-optical converter 11 conducts.

Instead of one optical fiber, two can also be used, each one for there and back. The forks 2 and 3 can then be omitted.

Should be based on a request from a third person arriving at the headquarters Subscriber established a connection to the subscriber shown in the figure are, so in the control center of the control device 15 is the electro-optical Converter 12, which like the electro-optical converter 11 from a light source, e.g. a light emitting diode can exist, controlled. A light signal comes through this Via the coupling member 4 and the fork 2 and the optical waveguide 1, the fork 3, the crossover network 10, the hook switch 8 to the alarm clock device 12. At The hook switch becomes the acceptance of the communication request by the subscriber 8 flipped and at the same time the optical switch 9 switched so that it has the acousto-optical Modulator 14 supplied with light. Before this switchover, the coupling point is given 5 and thus the light guide 1 is the unmodulated output from the frequency separator 10 Light fed directly, while after switching this light via the acousto-optical Modulator 14 is conducted. The light intensity is thus changed by this switching degraded. This reduction in intensity is carried out in the control center by the control device recognized and then switched through the connection.

Should be based on the communication request of the participant shown a connection are established, the switch 9 is briefly in a position brought in which it is possible to provide information about a communication request To send headquarters. The unmodulated light arriving from the control center is used for this purpose returned to the control center via switch 9.

Thereafter, the switch 9 is on the supply of the acousto-optical modulator 14 switched and at the same time the hook switch 8 from its rest position in its operating position switched.

In the control center, the operational readiness is established by the control device 15 of the subscriber is recognized, the connection request is forwarded and the switch 6 and 7 switched to transmission of the useful information.

1 Figure 4 claims L e r s e i t e

Claims (4)

Claims (1) gomplunikationssystem, the information optically transmits via optical fibers, thereby g e k e n n n z e i c h -n e t that the optical fibers in addition to the transmission of communication signals, also for the transmission of the verb signals required for building up and breaking down applications and for the transmission of energy serve in the form of light to supply energy to the subscriber station. 2. Communication system according to claim 1, characterized in that g e -k e n n z e i c h n e t that the energy for supplying the subscriber station in the form of unmodulated Light is transmitted. 3. Komiminikationasystem according to claim 2, characterized g e -k e n n z e i c h n e t that the frequency of the transmitted unmodulated light differs from the fundamental frequency of the light signal transmitted from the control center to the subscriber station deviates. 4. Communication system according to claim 2, characterized in that g e -k e n n z e i c h n e t that in the subscriber station for the light arriving from the control center a crossover is arranged, which the incoming modulated light over a Fork holder and an opto-electrical converter to the Eörmuschel or the alarm device and directing the unmodulated light to the acousto-optic modulator.