JPH03175754A - Optical data link - Google Patents

Abstract

PURPOSE:To make it possible to widely apply an optical data link also to a different system by allowing the optical data link itself to convert a serial data signal into the prescribed number of parallel data signals and transmit the converted signals. CONSTITUTION:A serial signal outputted from a parallel/serial(P/S) converter 1 in a transmission side device A is inputted to an S/P converter 2 in the optical data link B and optical signals converted into parallel signals corresponding to three buses are sent to an optical cable 4 by optical transmitters 3a to 3c. On the receiving side, the parallel signals received from the optical cable 4 are converted into electric signals by optical receivers 5a to 5c and then inputted to a P/S converter 6. The received parallel signals are converted to the original serial signal, which is inputted to an S/P converter 7 in a device C.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to optical data links. More specifically, the present invention relates to a novel configuration of an optical data link that uses an optical transmission line such as an optical fiber as a medium and exchanges data using a digital signal converted into an optical signal.

BACKGROUND OF THE INVENTION A typical application of optical fibers is optical data transmission using optical fibers as a transmission medium. Among these uses, in particular, data transmission of digital data handled by computers and the like is a field that is attracting the most attention as the field of use of digital data expands.

By the way, when handling digital data, for example, when transferring one word of data consisting of multiple bits, there is a serial method in which each bit is sequentially transmitted one by one, and a serial method in which each bit constituting one word is transmitted multiple times. There is a parallel method in which data is transferred simultaneously via two transmission lines.

FIG. 4 is a diagram showing the basic configuration of a serial optical data link.

As shown in the figure, when configuring an optical data link using a serial transmission method, transmission data output from a serial interface including a parallel/serial converter 41 provided at the output end of the transmission side is transmitted to an optical transmitter. 42 into an optical signal, and transmits it to an optical receiver 44 on the receiving side via only one optical transmission line 43. The optical receiver 44 inputs transmission data as an electrical signal to a serial interface including a serial/parallel converter 45 provided at the input end.

In such a serial optical data link, the number of transmission lines can be reduced by utilizing the broadband characteristics of optical fibers. However, since the transmission speed within the transmission path 43 increases, the optical modulator is required to operate at high speed.

On the other hand, FIG. 5 is a diagram showing the basic configuration of a parallel optical data link.

As shown in the figure, in a parallel optical data link, a plurality of optical transmitters 528 to 5
2p1 optical fibers 53a to 53p and optical receiver 54a
~54p is used and no signal conversion takes place within the digital signal processing device. However, as is clear from FIG. 5, a plurality of transmission buses are required depending on the format of digital data to be handled, and the same optical data link cannot be applied to systems of different formats.

In addition, as shown by the dotted lines in Figures 4 and 5,
The serial or parallel data to be transmitted is generated by the interface of the digital equipment that handles that data, and the optical data link itself is responsible only for optical-to-electrical or electro-optical conversion of data signals and for transmitting and receiving optical signals. .

Problems to be Solved by the Invention As described above, conventional optical data links transmit data using either a serial method or a parallel method. However, as mentioned above, the serial method requires a wideband transmission line and transmitter/receiver, and to improve the transmission speed, expensive high-speed modem equipment and wideband fiber must be used. Furthermore, this is currently approaching its limits. Furthermore, in the case of the parallel system, the number of transmission lines varies depending on the system, making it impossible to use general-purpose equipment, and also requiring a lot of effort to install, resulting in high costs.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a novel optical data link that solves the problems of the prior art described above, is applicable to different systems, and is capable of realizing high-speed data transmission at low cost. is its purpose.

According to the present invention, an optical data link that transmits a digital signal as an optical signal between a pair of digital data processing devices has a serial interface of a digital data processing device on the transmitting side. Serial/
a parallel converter, an optical transmitter that sends the parallel signal output from the serial/parallel converter as an optical signal to an optical transmission line, an optical transmission line that transmits the parallel optical signal sent out from the optical transmitter, and An optical receiver receives a parallel optical signal from an optical transmission line and converts it into an electrical signal, and a parallel receiver converts the parallel signal output from the optical receiver into a serial signal.
An optical data link is provided, comprising a serial converter and configured to perform data transmission using a parallel transmission method between the serial interfaces of the pair of digital data processing devices.

The optical data link according to the present invention is configured such that the optical data link itself converts a serial data signal output from a device connected to the data link into a predetermined number of parallel data signals and transmits the converted data signals. Its main characteristic is that it exists.

That is, the optical data link according to the present invention includes a serial/parallel converter in the data link itself, and after transmitting input serial data as parallel data,
It is configured to output serial data again using its own parallel/serial converter. Therefore,
Although the transmission line itself is a parallel transmission line, it can be treated as a serial optical data link to the outside.

In this way, the optical data link according to the present invention is used by being connected to the serial interface of equipment connected thereto, and therefore can be widely applied to different systems.

In addition, the optical data link itself has multiple transmission paths, and the serial data output from the transmitting side is parallelized and transmitted according to the number of transmission paths, so the bandwidth of the transmission path and the optical transceiver Signal transmission can be performed under advantageous conditions regarding the modulation speed and the like.

Hereinafter, the present invention will be described in more detail with reference to the drawings, but the following disclosure is only one embodiment of the present invention, and does not limit the technical scope of the present invention in any way.

FIG. 1 is a diagram schematically showing the configuration of an optical data link according to the present invention.

As shown in the figure, this optical data link is a data link B for transmitting data between a pair of digital data processing devices A and C.

Here, the digital data processing devices A and C each include a serial/parallel converter 1 and a parallel/serial converter 7 as serial transmission interfaces. Therefore, optical data link B connects device A
It is configured such that serial data is input on the device C side, and the serial data is output again on the device C side. Generally, the serial transmission interface of the device C on the receiving side is equipped with a timing circuit for extracting the tarok signal from the input serial signal.

On its transmission side, the optical data link B comprises a serial/parallel converter 2 connected to a serial/parallel converter 1 and optical transmitters 3a, 3b and 3C. Optical transmitters 3a, 3b and 3C are connected via optical fiber cables 4 to optical receivers 5a, 5b and 5C, respectively. Optical receivers 5a, 5b and 5c are connected to parallel/serial converter 6. This parallel/
The serial converter 6 is connected to a serial/parallel converter 7 provided at the serial transmission interface of the device C. In this embodiment, the optical cable 4 has 3
It is composed of optical fibers S1, S2, and S3.

The optical data link configured as described above operates as follows.

First, a serial signal output from the parallel/serial converter 1 of the device A on the transmitting side is input to the serial/parallel converter 2 of the optical data link B. serial/
In the parallel converter 2, the optical signals converted into parallel signals corresponding to three buses in this embodiment are sent to the optical cable 4 by optical transmitters 3a, 3b and 3C.

On the receiving side, on the other hand, the parallel signals received from the optical cable 4 are converted into electrical signals by optical receivers 5a, 5b, and 5C, and then input to the parallel/serial converter 6. Here, the received parallel signal is converted into the original serial signal and input to the serial/parallel converter 7 of device B.

In addition, in a normal serial optical data link, the transmitting side is supplied with a clock signal from the connected digital data processing device, and the receiving side extracts the clock signal from the received signal and uses it for signal reproduction. The structure is as follows. Also in the method of the present invention as described above, on the transmitting side, the connected device A
However, at the receiving end in the data link, it is not possible to extract the clock signal in a serial manner. Therefore, in this embodiment, a parallel conversion method that allows parallel/serial conversion to be performed without a clock signal on the receiving side is exemplified.

FIGS. 2(a) to 2(f) are signal waveform diagrams for explaining the operation of the optical data link shown in FIG. 1.

In the optical data link shown in FIG. 1, the serial/parallel converter 2 of the optical data link C receives a serial data signal Dlh as shown in FIG. 2(a) from the parallel/serial converter 1 to the device. Man-powered.

Here, the serial/parallel converter 2 includes three signal detection circuits that detect transitions of the signal Din for every three bits. The first signal detection circuit monitors the transition of the signal D l h every 3 bits from the start of the signal DI, .
When the signal D1□ is transitioning, the state of its own neutral signal is transitioned. This output signal is converted into an optical signal by the optical transmitter 3a, and outputted to the optical fiber S1 as a signal as shown in FIG. 2 (6). The second signal detection circuit provided in the serial/parallel converter 2 is connected to the first signal detection circuit described above.
The same processing is executed one bit later than the signal detection circuit. Therefore, a signal as shown in FIG. 2(C) is output to the optical fiber S2. The third signal detection circuit also executes similar processing with a delay of one bit from the second signal detection circuit, and a signal as shown in FIG. 2(d) is output to the optical fiber S3. In addition, these figures 2 (a) to (C
) is 1/1 of the transmission speed of the original realistic signal.
It is possible to transmit at a transmission rate of 3.

As described above, the parallel signals output to the three optical fibers S+, S2 and S3 are transmitted to the optical receivers 5a and 5.
After being converted into an electrical signal by b and 5c, it is input to the parallel-to-serial conversion circuit 6.

FIG. 3 is FIG. 2 showing a specific example of the configuration of the parallel/serial converter 6 in the circuit shown in FIG. 1.

As shown in the figure, this parallel/serial converter 6 is composed of two exclusive OR circuits 21 and 22. Here, the outputs of two of the optical receivers 5a, 5b, and 5c are connected to the input of the exclusive OR circuit 21, and the outputs of the two optical receivers 5a and 5b are connected to the input of the exclusive OR circuit 21, and the outputs are transmitted via the optical fibers S1 and S2. receive the signal. The input of the exclusive OR circuit 22 is connected to the output of the exclusive OR circuit 21 and the output of the optical receiver 5c.

Now, the output signal of the exclusive OR circuit 21 is S. Then,
Signal S. is an exclusive OR signal of the signals propagating through the optical fibers S1 and S2, resulting in a signal as shown in FIG. 2(e). This signal S. By obtaining the exclusive OR of and the signal propagating through the optical fiber S3 in the exclusive OR circuit 22, a signal exactly the same as the input signal Dlh for this optical data link C is obtained, as shown in FIG. DouL
can be obtained. With the above method, an external clock is not required for parallel/serial conversion processing, and the circuit can be easily configured.

In this embodiment, the optical data link C transmits parallel signals through three buses, but the present invention is of course not limited to this.

Furthermore, it goes without saying that the serial/parallel or parallel/serial conversion of the transmitted optical signal is not limited to the above-mentioned method.

As described in detail, the optical data link according to the present invention includes:
Although data transmission itself is performed in parallel, data input to the data link is performed in serial, and at the end of the optical data link, received data is output as original serial data. Therefore, this optical data link can be treated as a highly versatile serial data link in appearance.

In addition, in this optical data link, the optical data transmission itself is performed in parallel, so there is no need for a wide band on the optical cable or high-speed operation on the optical transmitter/receiver, resulting in low cost and high transmission speeds. It is possible to construct a high-speed optical data link.

[Brief explanation of drawings]

FIG. 1 is a diagram (not showing the configuration of an optical data link according to the present invention), and FIGS. 2(a) to (f) show optical data when using the circuits shown in FIGS. FIG. 3 is a signal waveform diagram showing a transmission signal in a data link; FIG. 3 is a diagram showing a specific configuration example of a parallel/serial converter that can be advantageously used in the optical data link shown in FIG. 4 is a diagram showing the configuration of a general optical data link using the serial system, and FIG. 5 is a diagram showing the configuration of a general optical data link using the parallel system. [Main reference numbers] 1.6.41...Parallel/serial converter, 2.7
．． 45... Serial/parallel converter, 3a, 3b,
3c. 42.52a-52p...Optical transmitter, 4.43
．． 53a to 53p... Optical cable (optical fiber), 5a, 5b, 5c, 44.54a to 54p... Optical receiver,

Claims (1)

[Claims] In an optical data link that transmits a digital signal using an optical signal as a medium between a pair of digital data processing devices, a serial signal output from a serial interface of a transmitting digital data processing device is specified. a serial/parallel converter for converting into parallel signals with a number of buses;
an optical transmitter that sends the parallel signal output from the serial/parallel converter as an optical signal to an optical transmission line; an optical transmission line that transmits the parallel optical signal sent out from the optical transmitter; an optical receiver that receives an optical signal and converts it into an electrical signal; and a parallel/serial converter that converts a parallel signal output from the optical receiver into a serial signal, An optical data link characterized in that data is transmitted between interfaces using a parallel transmission method using a predetermined number of buses.