JPH0548537A - Parallel optical transmitter - Google Patents

Abstract

PURPOSE:To obtain the parallel optical transmitter from which parallel data synchronized with each other are sent even when the optical signal is sent in parallel by using plural optical lines whose length differs from each other. CONSTITUTION:An optical transmission system 1 is provided, from which optical signals synchronized with each other for plural N channels are outputted. The system is provided with optical wires 9-1 to N through which N-channels of optical signals are sent, and provided with light receiving elements 5-1 to N converting the optical signal into an electric signal, and optical signal delay circuits 6-1 to N adjusting the delay of the optical signals to make the total delay between the N channels of optical signals equal and to be sent to an electric signal processing circuit 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel optical transmission device for transmitting a plurality of optical signals in parallel.

[0002]

2. Description of the Related Art Conventionally, as one type of data transmission, parallel data transmission has been used in which a plurality of electrical signals are transmitted in parallel as electrical signals using a plurality of electrical wirings. In recent years, in the field of various communication devices and computers,
With the increasing demand for high-speed and large-capacity data transmission, problems such as limitation of transmission speed and limitation of the number of I / Os have become apparent in conventional parallel data transmission in which electric signals are transmitted in parallel. Therefore, a parallel optical transmission as shown in FIG. 4 has been proposed in which an electrical signal is converted into an optical signal and then the optical signal is transmitted in parallel by using a plurality of optical wirings.

[0003]

However, if there are differences in the lengths of a plurality of optical wirings that connect the optical transmission system and the optical reception system, as shown in FIG. There is a problem that the delay time when reaching the point is different, and there is a difference in the delay time between the electric signals reproduced based on this optical signal, that is, a synchronization shift occurs and accurate parallel data transmission cannot be performed. . In particular, as shown in FIG. 6, in a parallel optical transmission device configured such that an optical signal input to one optical receiving system 4 is output from a plurality of optical transmitting systems 1-1 to M,
The difference in the length of the plurality of optical wirings connecting the optical transmission systems 1-1 to M and the optical reception system 4 is large, and the difference in the delay time between the channels becomes a very serious problem. As a method for making the delay times of a plurality of signals uniform, equalizing the length of the optical wiring is effective, but the length of the optical wiring at that time is determined by the length of the longest optical wiring. That is, in order to connect the transmitting and receiving systems that are close to each other, an optical wiring having the same length as the longest optical wiring among the plurality of optical wirings in the parallel optical transmission apparatus is required. In order to do that, there was a problem that a considerable space was required. Further, when the optical wiring is manufactured on the substrate, there is a problem that it is very difficult to design the optical wiring to have the same length.

The present invention has been made in view of the above circumstances. Even when parallel transmission of optical signals is performed using a plurality of optical wirings having different lengths, parallel data transmission in which signals are synchronized can be performed. An object is to provide a possible parallel optical transmission device.

[0005]

A parallel optical transmission apparatus of the first invention is an optical transmission system for outputting a plurality of optical signals, a plurality of optical lines for transmitting the optical signals, and an optical line for transmitting the optical signals. And a light receiving element for converting the optical signal into an electric signal, and an electric signal delay circuit for adjusting the electric signal converted by the light receiving element to a set delay amount. A parallel optical transmission apparatus according to a second aspect of the present invention compares the parallel optical transmission apparatus according to the first aspect of the present invention with a delay time of an electric signal whose delay amount is adjusted and outputs a control signal to the electric signal delay circuit. A circuit is provided, and the electric signal delay circuit sets a delay amount based on the control signal.

[0006]

According to the parallel optical transmission apparatus of the present invention, a plurality of optical signals transmitted from the optical transmission system through the optical wiring are converted into electric signals by the light receiving element, and then the delay amount of the electric signals is changed to the electric signals. Adjusted by the delay circuit. That is, the difference in the delay time of each optical signal generated due to the difference in the length of the optical wiring is adjusted and synchronized.

[0007]

FIG. 1 shows a first embodiment of a parallel optical transmission device according to the present invention. In this embodiment, the electric signal delay circuit 6-1
.. 6-N, the optical signals input to the receiving system 4 are converted into electrical signals using the light receiving elements 5-1 to 5-N, and then input to the electrical signal delay circuits 6-1 to 6-N. Then, the delay amounts of the electric signal delay circuits 6-1 to 6-N are set so that the total delay amounts of the signals of the respective channels become equal. Thereby, the signals of the plurality of channels are synchronized. In this case, the delay amounts of the electric signal delay circuits 6-1 to 6-N may be set using a control signal from the outside or a control signal generated inside.

A specific operation of the parallel optical transmission apparatus according to this embodiment will be described with reference to the signal waveforms shown in FIG. First, a synchronized N-channel optical signal is output from the optical transmission system 1 (output optical signal). This optical signal is sent to the optical wiring 9-1 to 9-N.
Is input to the optical receiving system 4. When reaching the optical receiving system 4, a difference in signal delay amount occurs in each channel due to a difference in length of each optical wiring 9-1 to 9-N (input optical signal). The input optical signal input to the optical receiving system 4 is converted into an electric signal in the light receiving elements 5-1 to 5-N. At that time, the difference in the delay time of the optical signal appears as it is as the difference in the delay time of the electric signal (light → electricity). This electric signal is input to the electric signal delay circuits 6-1 to 6-N,
Delay each signal. At that time, the electric signal delay circuit 6
The delay amounts of the electric signal delay circuits 6-1 to 6-N are set so that the total delay amounts of the signals output from -1 to 6-N are equal (electric signal (delay)). Here, the electric signals having the same delay time are directly input to the electric signal processing circuit 8 in the subsequent stage (electrical signal). After performing the above operation and adjusting the delay time between each channel, if signal transmission for actual processing is performed, synchronized parallel signal transmission can be performed without equalizing the optical transmission path. It will be possible.

Next, the second parallel optical transmission device according to the present invention will be described.
An example of the above is shown in FIG. The parallel optical transmission apparatus according to the present embodiment is a phase comparison circuit for automatically setting the delay amounts of the electric signal delay circuits 6-1 to 6-N in the parallel optical transmission apparatus according to the first embodiment. By adding 7, a control signal for controlling the delay amount of the electric signal delay circuits 6-1 to 6-N is generated inside the optical receiving system. The operation of the phase comparison circuit will be described below. The phase comparison circuit 7 includes an electric signal delay circuit 6-1.
~ 6-N with the delayed electrical signal as input,
The control signals of the electric signal delay circuits 6-1 to 6-N are generated so that the delay times of the respective electric signals are compared with each other so as to obtain the delay amount necessary to equalize the total delay amounts of the respective channels.
The electric signal delay circuits 6-1 to 6-N set the delay amount of the electric signal based on the control signal to make the total delay time of the signals of all channels uniform and synchronize.

[0010]

When the parallel optical transmission device of the present invention is used,
Since the signal phase adjustment is performed by a circuit, it is not necessary to make the optical wiring equal in length. That is, the length of the optical wiring connecting the optical transmission system and the optical reception system can be arbitrarily set. Therefore, it is only necessary to use the minimum required optical wiring, the amount of optical wiring used is small compared to the conventional parallel optical transmission device, and the optical wiring can be saved. In addition, since there is no redundant optical wiring, neat connection and mounting between optical input / output terminals can be performed. Furthermore, when the optical transmission system has a hybrid configuration,
The difference in the delay amount due to the difference in the wiring length due to the mounting form of the electric circuit and the light emitting element can be adjusted in a circuit manner.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a parallel optical transmission device of the present invention using an electric signal delay circuit.

FIG. 2 is a diagram showing a signal propagation state for explaining the operation of the parallel optical transmission apparatus shown in FIG.

FIG. 3 is a diagram showing a configuration of a parallel optical transmission device of the present invention using an electric signal delay circuit having a function for automatically adjusting a signal delay amount.

FIG. 4 is a diagram showing a configuration of a conventional parallel optical transmission device.

5 is a diagram showing a signal propagation state of the parallel optical transmission device shown in FIG.

FIG. 6 is a diagram showing a configuration of a parallel optical transmission device in which an optical signal input to one optical receiving system is output from a plurality of optical transmitting systems.

[Explanation of symbols]

1, 1-1 to M Optical transmission system 2 Electric signal processing circuit 3-1 to N Light emitting element or light emitting element + electrical signal processing circuit 4 Optical receiving system 5-1 to N Light receiving element or light receiving element + electrical signal processing circuit 6 -1 to N electrical signal delay circuit 7 phase comparison circuit 8 electrical signal processing circuit 9-1 to N optical wiring

Claims (2)

[Claims] 1. An optical transmission system for outputting a plurality of optical signals, a plurality of optical wirings for transmitting the optical signals, a light receiving element for converting the optical signals transmitted by the optical wirings into electric signals, and the light receiving device. A parallel optical transmission device comprising: an electric signal delay circuit that adjusts the electric signals converted by the elements to set delay amounts. 2. A phase comparison circuit that compares the delay times of the electric signals whose delay amounts have been adjusted and outputs a control signal to the electric signal delay circuit, wherein the electric signal delay circuit comprises:
2. The parallel optical transmission device according to claim 1, wherein a delay amount is set based on the control signal.