JPH04246931A - Light communication system - Google Patents

Abstract

PURPOSE:To enable both a short distance communication and a long distance communication by a system of the same constitution. CONSTITUTION:A transmitting part A is equipped with an electric/optical converter 11 which converts a main signal(electric signal) into an optical signal, and a light output control part 12 which outputs a control signal to this electric/ optical converter 11, and controls the size of the output of the electric/optical converter 11. On the other hand, a receiving part B is equipped with an optical/ electric converter 17 which converts the transmitted main signal(optical signal) into the electric signal, and an excess light input detector 19 which detects the size of the optical signal inputted to this optical/electrical converter 17. The size of the output of the electric/optical converter 11 is controlled based on the detected result of this excess light input detector 19.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an optical communication system.
In particular, it relates to optical communication systems using optical fiber cables.

0002

2. Description of the Related Art A conventional optical communication system is constructed as shown in FIGS. 2 and 3. FIG. 2 shows the case of long-distance transmission, and this system consists of an electric-to-optical converter 21 on the transmitting side, an optical-to-electrical converter 22 on the receiving side, and these electric-to-optical converters 21 and optical - an optical fiber cable 23 connecting an electrical converter 22; In this system, on the transmission side, an electrical signal is converted into an optical signal by an electrical-to-optical converter 21, and the optical signal is transmitted by an optical fiber cable 23 and returned to an electrical signal by an optical-to-electrical converter 22. In this case, the transmitted optical signal is considerably attenuated by the long-distance optical fiber cable 23, and the received light power on the receiving side becomes weak.

Next, FIG. 3 shows the case of short-distance transmission, and this system connects an electric-to-optical converter 21 on the transmitter side, an optical-to-electrical converter 22 on the receiver side, and connects them. optical fiber cable 23 and this optical fiber cable 2
3 and a fixed optical attenuator 24 disposed in the middle of the optical attenuator 3. In this system, compared to the case of a long-distance transmission system, an optical attenuator 2 is attached to the optical fiber cable 23.
4 is inserted, but if the configuration were the same as in the case of the long-distance system in Figure 2, this would be because the length of the optical fiber cable 23 is short, so the optical signal would not be attenuated as much and would not reach the receiving side. This is because the light-to-electricity conversion cannot be performed normally. Therefore, in the case of short-distance transmission such as within the same station building, it is necessary to install an optical attenuator 24.

0004

[Problems to be Solved by the Invention] In conventional optical communication systems, in order to perform normal communication, it is necessary to change the configuration of the communication system depending on the transmission distance as shown in FIG. 2 or 3. The work of installing the optical attenuator 24 between the transmitter and receiver was complicated.

The present invention has been made in view of the above problems, and an object thereof is to provide an optical communication system that can perform short-range communication and long-distance communication with the same configuration.

[0006]

[Means for Solving the Problems] The optical communication system of the present invention includes a transmitter having an electrical-to-optical signal converter that converts an electrical signal into an optical signal and outputs the same, and an optical signal output from the transmitter. An optical communication system comprising: a receiving section having an optical-to-electrical signal converter that receives the signal and converts it into an electrical signal; and an optical fiber cable that transmits the optical signal from the transmitting section to the receiving section. an optical input detection means for detecting the magnitude of the optical signal and outputting a control signal based on the magnitude to the transmitter via the optical fiber cable; The present invention is characterized in that an optical output control means is provided for controlling the output of the electric-to-optical signal converter based on a control signal output from the electric-to-optical signal converter.

With such a configuration, the optical communication system of the present invention can perform short-range communication and long-distance communication with the same configuration.

[0008]

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

FIG. 1 is a block diagram showing the configuration of an optical communication system according to an embodiment of the present invention. In this system, the receiver A includes an electro-optical converter 11 that converts the main signal (electrical signal) into an optical signal, and a control signal (optical signal) transmitted from the receiver B side that converts the control signal (optical signal) into an electrical signal. an optical-to-electrical converter 13 that outputs an output signal; and a control signal is output to the electric-to-optical converter 11 in response to the output signal of the optical-to-electrical converter 13, and the magnitude of the output of the electric-to-optical converter 11 is controlled. and a light output control section 12.

On the other hand, the receiving section B includes an optical-to-electrical converter 17 that converts the main signal (optical signal) into an electrical signal, and the magnitude of the optical signal input to this optical-to-electrical converter 17 (excessive input). It is comprised of an excessive light input detector 19 that detects the excessive light input, and an electric-to-optical converter 18 that receives the detection output of the excessive light input detector 19 as an input and outputs a control signal (optical signal).

[0011] The transmitting section A and the receiving section B are connected by an optical fiber cable 15. A WDM (wavelength division multiplexing) filter 14 is provided on the transmitting section A side of this optical fiber cable 15, and a WDM filter 16 is disposed on the receiving section 8 side.

Next, the operation of this transmitting/receiving system will be explained. First, in the case of long-distance communication, since the received light power on the receiver B side is weak, the excessive light input detector 19 detects this and outputs a control signal (electrical signal) to that effect. The electrical-to-optical converter 18 converts this control signal into an optical signal and sends it to the optical fiber cable 15 via the WDM filter 16. The control signal (optical signal) sent to the optical fiber cable 15 is transmitted to the transmitter A via the WDM filter 14.
The signal is input to the optical-to-electrical converter 13 and converted into an electrical signal. The optical output control section 12 receives this control signal and outputs electricity.
A control signal is output to the optical converter 11 to maximize the optical output. This increases the output of the electro-optical converter 11 and transmits a suitable optical signal.

On the other hand, in the case of short-distance communication, the received light power on the receiver B side increases, and if a light stronger than that which can be received by the receiver B is received, the excessive light input detector 19 This is detected and a control signal to that effect is output. The control signal (electrical signal) output from this excessive optical input detector 19 is converted into an optical signal by an electrical-to-optical converter 18, and then, as in the case of long-distance transmission, a WDM filter 16
The signal is transmitted to the transmitter A side via the optical fiber cable 15, and is converted into an electrical signal by the optical-to-electrical converter 13. The optical output control section 12 receives this control signal and outputs a control signal to the electro-optical converter 11 to lower the optical output. As a result, the output of the electro-optical converter 11 is reduced, and a suitable optical signal is transmitted.

In this way, the optical communication system of this embodiment can perform normal communication in both long-distance and short-distance communication.

[0015]

As explained above, according to the optical communication system of the present invention, the receiving section is provided with an optical input detecting means for detecting the magnitude of input light, and the transmitting section is provided with an optical input detecting means for detecting the magnitude of input light. Accordingly, an optical output control means is provided to control the magnitude of the optical output signal according to the transmission distance.
There is no need to change the configuration of the communication system depending on whether the transmission distance is long distance, such as between stations, or short distance, such as within a station building, and there is no need for the optical attenuator required for short distance communication. This has the effect of

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an optical communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of an optical communication system used for conventional short-range communication.

FIG. 3 is a block diagram showing the configuration of an optical communication system used for conventional long-distance communication.

[Explanation of symbols]

11 Electrical-optical converter 12 Optical output control unit 13 Optical-electrical converters 14, 16 WDM (wavelength multiplexing) filter 15 Optical fiber cable 17 Optical-electrical converter 18 Electrical-optical converter 19 Excessive light input detection unit

Claims (1)

[Claims] Claim 1: A transmitting unit including an electrical-to-optical signal converter that converts an electrical signal into an optical signal and outputs the same; and an optical-electrical signal that receives the optical signal output from the transmitting unit and converts it into an electrical signal. In an optical communication system that includes a receiving section having a converter and an optical fiber cable that transmits an optical signal from the transmitting section to the receiving section, the receiving section detects the magnitude of the optical signal input to the receiving section. Optical input detection means is provided for outputting a control signal based on the optical fiber cable to the transmitting section via the optical fiber cable, and the transmitting section is provided with a control signal based on the control signal output from the optical input detecting means.
An optical communication system comprising an optical output control means for controlling the output of an optical signal converter.