JPS61112445A - Optical fiber data link - Google Patents

Abstract

PURPOSE:To adjust automatically received optical power by multiplexing a code corresponding to the input optical power onto the reception signal of a photodetector and retransmitting the signal through a coder connected to a optical transmitter. CONSTITUTION:The output information signal of the photodetector 1 is transmit ted to a reception information signal line 4, a reception optical power signal corresponding to the reception optical power of the photodetector 1 is transmit ted to a reception optical power signal line 5 and they are inputted respectively to the coder 2. The coder 2 multiplexes the inputted signal and the result is transmitted to a transmission information signal line 6 as the transmission information signal. The transmitted information signal is transmitted again as the optical signal by the optical transmitter 3. Thus, the signal corresponding to the received optical power is multiplexed in the inside of the transmitted optical signal so as to adjust automatically the received optical power.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical fiber data link in optical digital communications.

(Prior Art) Recently, optical fiber data links, which apply optical fiber communication to data transmission, have rapidly become popular and are being expanded into local area networks (LANs). When configuring a network using an optical fiber data link, it becomes necessary for multiple stations to receive the transmitted signal from one station, but since optical signal distribution involves loss, it is necessary to transmit the optical signal to an optical receiver. An optical repeater is required to convert the signal back into an electrical signal and then transmit it again using an optical transmitter.

However, expanding the permissible fluctuation range (dynamic range) of received optical power is not preferable in configuring an optical receiver because it leads to an increase in circuit scale and current consumption.

Therefore, measures have been taken to insert an optical attenuator or to adjust the output optical power of an optical transmitter on-site in order to adjust the received optical power according to an increase or decrease in the optical fiber length.

(Problems to be Solved by the Invention) Adjustment of received optical power using the conventional method requires parts such as optical attenuators and may need to be carried out on-site, resulting in increased costs when installing data links. , or that it is difficult to respond to line changes.

An object of the present invention is to multiplex a code corresponding to the input optical power to the optical receiver into the received signal of the optical receiver using a BV in an optical fiber data link consisting of an optical receiver and an optical transmitter. It is an object of the present invention to provide an optical fiber data link configured to eliminate the above-mentioned drawbacks and automatically adjust the power of received light by retransmitting the data using an encoder connected to the optical transmitter.

(Means for Solving the Problems) The optical fiber data link according to the present invention includes an optical receiver, an encoder, and an optical transmitter.

The optical receiver receives optical information from an optical fiber, converts it into corresponding electrical information, and identifies optical power.

The encoder generates a code corresponding to the optical power and multiplexes it with the received optical information.

The optical transmitter converts the output of the encoder into corresponding optical information and transmits it to another optical fiber.

(Example) Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing the basic configuration of an optical fiber click according to the present invention.

In FIG. 1, 1 is an optical receiver, 2 is an encoder, and 3 is an optical transmitter. In FIG. 1, the output information signal of the optical receiver 1 is sent to the received information signal line 4, and the received optical power signal corresponding to the received optical power of the optical receiver 1 is sent to the received optical power signal line 5. The signal is input to the encoder 2 for multiplexing. The signal multiplexed by the encoder 2 later becomes a transmission information signal and is sent to the transmission information signal line 6. The transmitted information signal is transmitted again as an optical signal by the optical transmitter 3.

FIG. 2 is a block diagram showing an embodiment of the invention. In FIG. 2, the light emitted from the optical fiber 10 on the receiving side passes through a photodiode 11, an amplifier 12, and a first discriminator 13.
This becomes a received information signal and is sent onto the signal line 4. In the end, a portion of the output signal of the amplifier 12 is branched off to the second output signal.
is input to the discriminator 14 of Here, the second discriminator 14
By selecting the response speed of the first discriminator 13 to be sufficiently slow compared to the response speed of the first discriminator 13, it becomes possible to detect only the variation in the received optical power, and the output signal on the signal line 5 corresponds to the received optical power. It becomes what it is.

Here, for the sake of simplicity, a configuration example will be described assuming that a binary signal is obtained in which the received optical power is higher or, in some cases, lower than the specified value. Received information signal on signal line 4 and signal line 5
The above received optical power signal 5 is multiplexed by the encoder 2 to become a transmission information signal on the signal line 6, and is sent to the drive amplifier 18.
The light is outputted to an optical fiber 20 on the transmitting side by an optical transmitter 3 composed of a light emitting element 19 and a light emitting element 19 . FIG. 3 is a timing diagram showing the sequence of operations of the encoder 2 in FIG.

Here, the received optical information signal on the signal line 4 is assigned to the first half of the time slot, and the received optical power signal on the signal line 5 is assigned to the second half of the time slot. In FIG. 3, a transmission information signal having a code as shown is obtained on signal line 6 from the waveform on signal line 4.5.

(Effects of the Invention) As explained above, in the present invention, in an optical fiber data link consisting of an optical receiver and an optical transmitter, the code corresponding to the input optical power to the optical receiver is After multiplexing the received signal, the encoder connected to the optical transmitter retransmits the signal, thereby eliminating the above disadvantages and multiplexing a signal corresponding to the received optical power into the transmitted optical signal, allowing the other station to This has the effect that it becomes possible to automatically adjust the transmitted light power on the side.

Therefore, fluctuations in the received optical power of the optical receiver are suppressed, so there is an effect that an optical receiver with a narrow dynamic range can be used.

That is, since the configuration of the optical receiver can be simplified, reliability can be improved and current consumption can be reduced.The practical value of the present invention is extremely high.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of an optical fiber data link according to the present invention. FIG. 2 is a block diagram illustrating one embodiment of a fiber optic data link according to the present invention. FIG. 3 is a timing diagram showing an example of the operation of the encoder in FIG. 2. 1... Optical receiver 2... Encoder 3... Optical transmitter 10.20... Optical fiber 11... Photodiode 12, 18... Amplifier 13.14
...Discriminator 19...Light emitting device patent applicant
NEC Co., Ltd. agent Bengoshi Inoro Gosai Figure 1 Figure 3 (Moment)

Claims (1)

[Claims] an optical receiver for receiving optical information from an optical fiber and converting it into corresponding electrical information and identifying optical power; and for generating a code corresponding to the optical power and multiplexing it with the received optical information. An optical fiber data link comprising: an encoder; and an optical transmitter for converting the output of the encoder into corresponding optical information and transmitting it to another optical fiber.