JPH04179392A - Optical self-routing circuit - Google Patents

Abstract

PURPOSE:To constitute an optical self-routing circuit by a simple constitution by operating a routing by using an optical gate which allows an optical signal to pass or reflects it only when the optical signal and an electric pulse signal are simultaneously impressed. CONSTITUTION:Optical packet signals A and B inputted to optical waveguides 101 and 102 are respectively branched into two by light branching equipments 103 and 104, and respectively made incident to optical gates 105, 106, 107 and 108. The output optical signals of the optical gates 106 and 108 are multiplexed by an optical multiplexer 109, the output optical signals of the optical gates 106 and 108 are multiplexed by an optical multiplexer 110, and respectively emitted from optical waveguides 111 and 112. An electric pulse generating circuit 113 impresses and supplies the same electric pulses to the optical gates 105 and 107, and the different electric pulses to the optical gates 106 and 108, and the optical gates 105-108 allow the optical signals to pass only when the optical signals and the electric pulse signals are simultaneously impressed. Thus, the optical self-routing circuit can be obtained by the simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical self-routing circuit that performs routing according to the header portion of an optical packet signal.

(Prior art) Optical communication using optical fibers as transmission paths has advantages such as being able to transmit a large amount of information because the optical fiber has a wide band, and that the optical fiber is not subject to induced noise. Therefore, it is expected that it will be widely used in the future. The switch used in this optical communication is preferably an optical switch that can exchange optical signals in the optical domain. Among these, optical packet switching equipment that handles packetized optical signals is seen as promising because it can efficiently exchange information at various signal speeds. Such an optical packet switch requires an optical self-routing circuit that reads the header portion of an optical packet signal and performs routing accordingly. As such a circuit, the one shown in FIG. 5 has been known. In FIG. 5, an optical packet signal input to an optical waveguide 501 is branched into two by an optical splitter 502, one of which is connected via an optical waveguide 503 to an optical link consisting of an optical splitter 505, an optical delay quantum 506, and an optical combiner 507. 500, and the other is an optical waveguide 504.
The signal is then sent to the optical switch 512. Optical correlator 500
generates a large optical correlation signal if the head portion of the optical packet signal is the same as a predetermined pattern, and generates only a small correlation signal if it is not the same. The output of the optical correlator 500 is converted into an electrical signal by a photoelectric converter 508 and applied to a control electrode of an optical switch 512 via an amplifier 509. Therefore, the optical switch 512 switches depending on whether the header part of the optical packet signal matches the predetermined pattern of the optical correlator 500, and the optical bucket signal is output to the optical waveguide 510 or the optical waveguide 511. Some routing is performed. For more information on such optical self-routing circuits, see Suji Ringer. Series in Electronics and Photonics (Springer 5eries 1nE
electronics and photonics)
Volume 25, Photonic Switching (Photon
ic Switching) pages 193-195.

(Problem to be solved by the invention) In the conventional optical self-routing circuit, the optical correlator 500
, a photoelectric converter 508 , an amplifier 509 , and other circuits are required.

An object of the present invention is to provide an optical self-routing circuit with a simple configuration.

(Means for Solving the Problems) A first optical self-routing circuit of the present invention has n
an optical branching device, n×m optical gate elements connected to the output ends of the n optical branching devices and to which electric pulse signals are applied, and n optical gate devices belonging to different systems of the m optical branching devices; It is composed of m number of n optical combiners that combine the outputs of the optical gates, and the optical gate element is characterized in that it allows the optical signal to pass through only when the optical signal and the electric pulse signal are applied at the same time. Further, a second optical self-routing circuit of the present invention includes n m-optical splitters, and n×m optical directivity circuits in which the output ends of the n m-optical splitters are connected to a first terminal. a separator, n×m optical gate elements to which second terminals of the n×m optical directional separators are respectively connected and electrical pulses are applied, and different systems of the m optical splitters. belonging n
m optical directional separators combine the output optical signals from the third terminals of the optical directional separators; A signal is output from the second terminal but not from the third terminal, and the optical signal input to the second terminal is output from the third terminal, and the optical gate element is configured to output the optical signal and the electric pulse signal. The feature is that the optical signals are reflected thereafter only when they are applied at the same time.

(Function) The optical self-routing circuit of the present invention can perform optical routing using an optical gate that passes or reflects the optical signal only when an optical signal and an electric pulse signal are applied simultaneously. Self-routing circuits can be constructed.

(Example) FIG. 1 shows a first embodiment of the invention.

In FIG. 1, optical packet signals A and B input to optical waveguides 101 and 102 are transmitted to optical branchers 103 and 104, respectively.
split into two optical gates 105.106 and 107.108
is incident on the Output optical signals from the optical gates 105 and 107 are combined by an optical combiner 109 and output from an optical waveguide 111. The output optical signals of the optical gates 106 and 108 are sent to the optical combiner 1.
10 and output from an optical waveguide 112. The electric pulse generating circuit 113 applies and supplies the same electric pulse to the optical gates 105 and 107 and another electric pulse to the optical gates 106 and 108.

FIG. 2 is a diagram for explaining one structure of the optical gates 105 to 108 in FIG. 1. In FIG. 2, the light gate has one end surface 220 and the other end surface 230 of the light guide layer 210, an input optical signal 200 is input to one end surface 220 of the light guide layer 210, and an output signal is output from the other end surface 230. An optical signal 250 is output. Furthermore, a control signal V is applied via an electrode 240. This light gate is V=VH
When the input optical signal 200 is input at the time of V =
While a voltage of VI, (VI, < VH) is applied, the input optical signal is amplified and output. Details of such an optical gate are described in the proceedings of the 1990 Autumn Conference of the Japan Society of Applied Physics, page 754, lecture number 26p-H-2.

FIG. 3 is a time chart for explaining the operation of FIG. 1. In FIG. 3, 301 is the optical gate 1 of FIG.
05.107 is shown, and the time t1 to t
VI is maintained at vH between t2 and t6. 302
represents the electric pulse applied to the optical gates 106 and 108 in FIG. 1, which is vH between times t2 and t3 and maintained at vL between t3 and t6.

The optical packet signal A input to the optical gates 105 and 106 in FIG. 1 is transmitted from time t1 to t2 as shown at 303 in FIG.
The header optical signal exists only during this period. Therefore, in the optical gate 105, the time when the electric pulse is at vH coincides with the time when the header optical signal exists, but in the optical gate 106, they do not coincide. Therefore, the data part of the optical packet signal A passes only through the optical gate 105 and is routed to the leading wavepath 111 via the optical combiner 109. - direction, light gate 10
In the optical packet signal B input at 7.108, the header optical signal exists only between times t2 and t3, as shown at 304 in FIG. Therefore, in the optical gate 108, the time when the electric pulse is at vH coincides with the time when the header optical signal exists, but in the optical gate 107, they do not coincide. Therefore, the data part of the optical packet signal B passes only through the optical gate 108 and is routed to the optical waveguide 112 via the optical combiner 110. In this way, in the optical self-routing circuit of FIG. 1, the header part of the optical bucket signal is
Alternatively, self-routing is performed to the optical waveguide 111 or 112 depending on whether the signal is present between t2 and t3.

FIG. 4 is a diagram showing a second embodiment of the present invention, in which the same numbers as in FIG. 1 are given to the same components and the operations are the same. The optical signal from the optical splitter 103 is sent to the half mirror 40
The optical signal from the optical splitter 104 is also input to the optical gate 107.108 via the half mirror 401. light gate 10
5 to 108 have reflective films 402 to 405 added, so
If the time when the header part of the optical packet signal exists and the time when the electric pulse is at vH match, the passed optical signal data part is reflected by the reflective film and is optically guided from the optical combiner 109 and 110 via the half mirror 401. Wave paths 111 and 112 are routed. Therefore, in this embodiment as well, self-routing can be performed to the leading wavepath 111 or 112 depending on whether the header section is located between times t1 and t2 or between t2 and t3.

Note that the half mirror 401 is connected to the optical splitter 103.10.
This is to prevent the optical signal from 4 from entering the optical combiner 109 and 110, so instead, use a directional optical coupler,
Optical couplers and optical circulators may be used.

(Effects of the Invention) As described above, according to the present invention, an optical self-routing circuit can be obtained with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a first embodiment of the present invention, FIG. 2 is a structural diagram of the optical gates 105 to 108 in FIG. 1, FIG. 3 is a time chart for explaining the operation of FIG. 1, and FIG. FIG. 4 shows a second embodiment of the present invention, and FIG. 5 shows a conventional optical self-routing circuit. In the figure, 101.102.111.112.501
．． 503.504.510.511 is an optical waveguide, 103
．． 104.502.505 is an optical splitter, 105-108
is a light gate, 109.110.507 is a light combiner, 11
3 is an electric pulse generation circuit, 401 is a half mirror, 4
02 to 405 are reflective films, 500 is an optical correlator, 506 is an optical delay element, 508 is a photoelectric converter, 509 is an amplifier, 51
2 is a light switch.

Claims (2)

[Claims] (1) n m-optical splitters, n×m optical gate elements connected to the output ends of the n m-optical splitters to which electric pulse signals are applied, and different m-optical splitters and m optical combiners that combine the outputs of n optical gates belonging to the system, and the optical gate element only allows optical signals to pass through when an optical signal and an electric pulse signal are applied at the same time. Optical self-routing circuit featuring: (2) n m optical splitters, n x m optical directional separators in which the output ends of the n m optical splitters are connected to the first terminal, and n×m optical gate elements to which the second terminals of the optical directional splitters are respectively connected and electric pulses are applied, and n×m optical gate elements belonging to different systems of the m optical splitters
and n optical combiners that combine the output optical signals from the third terminals of the optical directional separators, and the optical directional separators combine the optical signals input to the first terminals. is output from the second terminal but not from the third terminal, and the optical signal input to the second terminal is output from the third terminal, and the optical gate element receives the optical signal and the electric pulse signal. An optical self-routing circuit characterized by reflecting optical signals only when applied simultaneously.