JPS6047588A - Time-division type optical exchange - Google Patents

Abstract

PURPOSE:To suppress the number of channels to a rate of linear proportion and increase channels in number easily by coupling (n-1) sets of optical delay elements which delay channel time intervals and optical switches alternately in series, and using the delay circuit to interchange light signals between optional channels. CONSTITUTION:The optical delay elements 62-1-62(n-1) which have a specific delay time and delay time-division multiplex light signals of plural channels inputted from an incidence highway 1 and 2X1 optical switches 63-63(n-2) are coupled alternately in series to constitute a serial optical delay circuit 6. Light signals of optional channels from the highway 1 are distributed by an optical distributing circuit 3 to optional switches 63-63(n-2) of the delay circuit 6. The operation timing of optical switches 63-63(n-2) of the delay circuit 6 and the circuit 3 is controlled by a control circuit 7. Then, light signals are interchanged between optional channels on the highway 1, and the number of channels for ain increase in the number of channels in a frame is suppressed to a rate of linear proportion.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an optical switch that exchanges optical signals in time-division multiplexed channels with their optical levels intact.

(Background Art) Conventionally, a time-division optical switch exchanges n-channel optical signals time-division multiplexed within a frame between arbitrary channels, as shown in Fig. 1. In order to, let the channel time interval be T, OT, I
n types of optical delay elements 5-1 to 5-(n-1) giving respective delays of T, -1--, (n-1)T, and a predetermined delay to the optical signal of each channel of the joining highway 1. an optical distribution circuit 3 that distributes the optical signal to any one of the optical delay elements 5-1 to 5-(n-1) in order to provide time; and an optical distribution circuit 3 that distributes the optical signal to any one of the optical delay elements 5-1 to 5-(n-1), and multiplexes the optical signal delayed by the optical delay element again onto the Idemitsu highway. It was composed of an optical multiplexing circuit 4. Here, n is the number of multiplexed channels within a frame, and T is the channel time interval.

Therefore, the total delay time required for the optical delay elements 5-1 to 5-(n-1) is OT+ l T+ ---+(n
-1) T or n(n-1) T/2, 7L
/- When the number n of channels per unit increases, it is approximately proportional to the square of the number n of channels. Therefore, for example, when using an optical fiber delay line whose scale increases in proportion to the delay time as an optical delay element, the overall scale of the optical delay element in a time division type optical switch increases in proportion to the square of the number of channels. There were drawbacks.

(Problem to be solved by the invention) The present invention provides a delay of channel time interval T (n-1)
It is characterized by exchanging optical signals between arbitrary channels using a serial type optical delay circuit in which optical delay elements and optical switches are coupled in series in alternating order, and its purpose is to increase the number of channels n in a frame. The purpose of this invention is to suppress the increase in the scale of the optical delay circuit caused by this to a ratio linearly proportional to the number of channels n, compared to the square of the number of channels n in the case of the prior art.

(Structure and operation of the invention) FIG. 2 shows an embodiment of the invention, in which CH per frame,
〜CHtt is an input highway consisting of n channels, 2 is an output highway, 3 is an optical distribution circuit consisting of lXn optical switches, 31-O~31-(n-1) is the output of the optical distribution circuit 3, the same (31 -n is the input of the optical distribution circuit 3, 6 is the serial optical delay circuit, 61-0 to 61-(n-1) is the input of the serial optical delay circuit 6, and 61 to n are the inputs of the serial optical delay circuit 6. Output, 62-1 to B2-(n-1) is the channel time interval T
Optical delay elements 63-0 to B3- (n-
2) is a 2×1 optical switch; 7 is an optical switch 63-O to fi in the optical distribution circuit 3 and the serial optical delay circuit 6;
This is a control circuit that controls the operation of 3-(n-2). In the figure, double lines represent light paths, and solid lines represent control signal lines.

The present invention will be explained in detail below.

The serial optical delay circuit 6 has an input 8l-i (O≦1≦n
-1] to one optical delay element 62-1.
~ 62-1, and has a function of finally giving an iT time delay and outputting it to the output 81-n. At this time, in order to input the optical signal from the input 61-1 into the serial delay circuit 6, the control circuit 7 connects the optical switch 83-1 to the optical switch 83-1 via the control signal line.
is controlled to transfer the optical signal to the optical delay element 62-1. In a normal state, each optical switch 63-1 (O<i<n-2) is controlled by the control circuit 7 so as to receive an optical signal from the upper optical delay element 82-(i+1).

The optical distribution circuit 3 sends the optical signals of each channel sent in a time-divisional manner via the light input highway 1 to predetermined inputs 6L (however, 0<1<n-1) of the serial optical delay circuit 6. In order to transfer, the optical signal is output 3l-1 (however, 0≦1<
n-1).

The optical signal of the channel arriving from the optical highway I is
(However, when delaying by O≦l≦n-1), the control circuit 7 selects the output 31-i of the optical distribution circuit 3.
controls.

Next, the present invention will be explained in detail using FIG. 3.

The light input highway 1 is channel CH as shown in the figure.

A frame is composed of n channels of ~CHn, and each optical signal is designated as D1~Dn. Here, time-convert channel C) (I to channel CHn, channel CHn to channel CH, and other channels CH2 to CH
Consider the case where no time conversion is performed for n-1. Therefore, the optical signal DI-D of each channel on the light input highway
The delay time required for n is the optical signal of channel CH,
For (n-1)T, optical signal Dn of channel CHn
IT for, and the remaining channels CH2~CHn
-+ optical signals D2 to Dn-1 are OT.

At the time of channel CH1, optical signal D1 has (n-1
) The output 31- of the optical distribution circuit 3 to provide a delay of T
(n-1) is selected, and the input 81 of the serial optical delay circuit 6
-(n-1), the optical signal D1 is transmitted to the optical delay circuit 82-
(n-1). Thereafter, the optical signal passes through the serially coupled optical delay elements 82-(n-2) to 62-1 and finally reaches the channel CH on Idemitsu Highway 2.
will be exchanged.

Similarly, at the time of channel CHn, the output 31-1 of the optical distribution circuit 3 is used to give an IT delay to the optical signal Dn.
is selected, and the optical signal Dn is transferred to the optical delay element 62-1 via the input 61-1 of the serial optical delay circuit 6. Thereafter, it is output onto Idemitsu Highway 2 at the time of channel CH1.

At each point in time of the remaining channels CH2-CH old, the output 31-0 of the optical distribution circuit 3 is selected in order to give the respective optical signals D2 to Drhl an OT delay, that is, no delay. D2 to Dn-2 are transferred to the input 61-0 of the serial optical delay circuit 6, and immediately transferred to the same channel on the Idemitsu Highway 2 via the optical switch 63-0.

(Effects of the Invention) As explained above, the present invention uses a series optical delay circuit in which (n-1) optical delay elements and optical switches are alternately connected in series to generate an optical signal consisting of n channels per frame. The optical signal of any channel on the highway can be time-divisionally exchanged to any channel, and even if the number of channels per frame n increases, the overall scale of the optical delay circuit can be suppressed to a proportion proportional to n. This has the advantage that when using an optical delay circuit that occupies a large volume, such as an optical fiber delay line, the circuit scale of the optical delay circuit in a time-sharing optical switch can be kept smaller than before. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a conventional time-sharing optical switch, FIG. 2 is a configuration diagram of an embodiment of the present invention, and FIG. 3 is an example of the time-sharing optical switch in the embodiment of FIG. FIG. 1...Imitsu Highway, 2...Idemitsu Highway, 3
... Optical distribution circuit, 31-O to 31-(n-1) ... Optical distribution circuit output, 3
1-n... optical distribution circuit input, 4... optical multiplexing circuit,
5-0 to 5-(n-1)... Conventional optical delay element, 6.
...Series type optical delay circuit, 61-0~81-(n-1)...Serial type optical delay circuit input, 61-n...Serial type optical delay circuit output, 62-1~
62-(n-1)... Optical delay element, 63-(n-2)
=・Z

Claims (1)

[Claims] A series type optical delay circuit in which optical delay elements and optical switches having a fixed delay time are alternately coupled in series to give an arbitrary delay to optical signals of multiple time-division multiplexed channels input from an input highway. , an optical distribution circuit that distributes optical signals of arbitrary channels of the optical highway to arbitrary optical switches of the serial optical delay circuit, and operation timings of the optical switches of the serial optical delay circuit and the optical distribution circuit. and a control circuit for controlling the optical highway, and is characterized by being capable of exchanging optical signals between any channels on the optical highway.