JPS62247636A - Optical fiber transmission system - Google Patents

Abstract

PURPOSE: To form a main signal system and a MODEM circuit for auxiliary signals independently of each other by multiplexing the optical signal which is modulated by an auxiliary signal having a satisfactorily low transmission speed to another optical signal which is modulated by the main digital signal and transmitting those multiplexed signals. CONSTITUTION:A main digital signal 101 undergoes code conversion via a main signal optical transmitter 11 and is converted into an optical signal after elimination of the low frequency component. This optical signal is sent to a multiplexer 13. While an auxiliary digital signal 102 of a low speed is converted into an optical signal by an auxiliary signal optical transmitter 12 and outputted to the multiplexer 13. These optical signals multiplexed by the multiplexer 13 are sent to the receiver side. At the receiver side, a demultiplexer 14 branches the received optical signals in a proper ratio and converts them into electric signals via a main signal optical transmitter 15 and an auxiliary signal optical receiver 16 with operations adverse to those carried out at the transmitter side.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an optical fiber transmission system, and in particular to an optical fiber transmission system that multiplexes and transmits auxiliary signals with a sufficiently low transmission speed for a high-speed main signal transmission system. Regarding fiber transmission methods.

[Prior art: 1 Conventionally, in this type of optical fiber system, for example, on the transmitting side, the number of bits of the auxiliary signal is inserted into the bit array of the digital signal of the main signal, and on the receiving side, the number of bits of the auxiliary signal is inserted into the bit array of the digital signal of the main signal. A method of extracting the auxiliary signal by separating the bi and soto signals has been put into practical use.

[Problem that the invention seeks to solve]

In the conventional optical fiber transmission system described above, even though the transmission speed of the auxiliary signal is sufficiently lower than that of the main signal system, it is necessary to cause the circuit to operate at the same speed as the main signal. Therefore, as the transmission speed of the main signal system increases, the conventional optical fiber transmission method has the disadvantage that the circuit scale and power consumption increase.

[Means for Solving the Problems] The optical fiber transmission system of the present invention is an optical fiber transmission system in which an auxiliary signal having a sufficiently low transmission speed is multiplexed and transmitted with respect to a high-speed main signal using an optical fiber. , an optical combiner and an optical demultiplexer formed by utilizing the difference in the wave number bands occupied by the main signal and the auxiliary signal are provided as multiplexing means.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the main parts of an embodiment of the present invention. As shown in FIG. 1, this embodiment includes a main signal optical transmitter 11, an auxiliary signal optical transmitter 12, an optical combiner 13, an optical demultiplexer 14, and a main signal optical receiver. 15, and an auxiliary signal optical receiver 16.

In FIG. 1, a main signal digital signal 101 is balanced through code conversion in a main signal optical transmitter 11, low frequency components are removed, and then converted into an optical signal, which is sent to an optical multiplexer 13. sent to. On the other hand, the auxiliary signal digital signal 102 is converted into an optical signal by the same procedure in the auxiliary signal optical transmitter 12 and input to the optical multiplexer 13. In the optical multiplexer 13, the main signal transmitter 1
The optical signals inputted by the auxiliary signal transmitter 1 and the auxiliary signal transmitter 12 are multiplexed and sent to the receiving side via a predetermined optical transmission path. In this case, since the two optical signals have different modulation frequency bands, the combined optical signals are combined with their frequency bands separated. On the receiving side, the multiplexed optical signals sent from the transmitting side are split at an optimal ratio by the optical demultiplexer 14, and are split into optical signals corresponding to the main signal and the auxiliary signal, respectively. The signal is input to the optical receiver 15 and the auxiliary signal optical receiver 16, converted into an electrical signal, and output.

Next, FIG. 2 shows a block diagram of another embodiment in which the present invention is applied to an intermediate repeater, in which an optical demultiplexer 21,
A main signal optical receiver 22, an auxiliary signal optical receiver 23,
A main signal optical transmitter 24, an auxiliary signal optical transmitter 25,
An optical multiplexer 26 is provided.

In FIG. 2, an optical signal 103 sent via a predetermined optical transmission line is demultiplexed by an optical demultiplexer 21 into a main signal optical signal and an auxiliary signal optical signal, each of which is used as a main signal. The signal is input to an optical receiver 22 and an auxiliary signal optical receiver 23. The main signal digital signal converted into an electrical signal by the main signal optical receiver 22 is converted into an optical signal by the main signal optical transmitter 24 and input to the optical multiplexer 26 .

On the other hand, in the auxiliary signal optical receiver 23, the optical demultiplexer 2
The optical signal of the auxiliary signal input from 1 is converted into an electrical signal and output. Further, the auxiliary signal digital signal inputted to the auxiliary signal optical transmitter 25 is converted into an optical signal, inputted to the optical multiplexer 26, and multiplexed with the main signal optical signal in the separated frequency range. and sent out to the optical transmission line.

As seen in each of the embodiments shown in FIGS. 1 and 2 above, the optical signal modulated by the auxiliary signal is combined with the optical signal modulated by the main digital signal, An optical signal is transmitted via a predetermined optical transmission path.

〔Effect of the invention〕

As explained above, the present invention combines an optical signal modulated by a main signal digital signal with an optical signal modulated by an auxiliary signal having a sufficiently low transmission speed, and transmits the combined signal. It is now possible to configure the modulation/demodulation circuits of the auxiliary signal system independently, and when inserting the auxiliary signal into the main signal transmission system, the circuits can operate at the same high speed as the main signal system. This has the effect of reducing circuit scale and power consumption compared to conventional optical fiber transmission systems.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a main part of one embodiment of the present invention, and FIG. 2 is a block diagram showing a main part of another embodiment in which the present invention is applied to an intermediate relay device.

Claims (1)

[Claims] In an optical fiber transmission system that multiplexes and transmits an auxiliary signal with a sufficiently low transmission speed on a high-speed main signal using an optical fiber, it is formed using the difference in the occupied frequency bands of the main signal and the auxiliary signal. An optical fiber transmission system comprising an optical combiner and an optical demultiplexer as multiplexing means.