JP2850550B2 - Optical self-routing circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical self-routing circuit for performing routing according to the header of an optical packet signal.

[0002]

2. Description of the Related Art Optical communication using optical fibers for transmission lines
It is expected that the optical fiber will be widely used in the future because it has the advantages of being able to transmit a large amount of information because of its wide band and the optical fiber being not affected by induced noise. As an exchange used in this optical communication, an optical exchange capable of exchanging optical signals in an optical region is desirable. In particular, optical packet switches that handle packetized optical signals
It is promising because it can exchange information of various signal speeds efficiently. Such an optical packet switch requires an optical self-routing circuit that reads a header portion of an optical packet signal and performs routing in accordance with the header portion.
Conventionally, as such a circuit, an “optical self-routing circuit” shown in FIG.
(Patent application on January 14).

In FIG. 5, optical packet signals A and B input to optical waveguides 101 and 102 are respectively divided into optical splitters 103 and 103.
Optical gates 105, 106 and 10 are divided into two at 104.
7, 108. Output optical signals from the optical gates 105 and 107 are combined by the optical combiner 109 and output from the optical waveguide 111. Output optical signals from the optical gates 106 and 108 are combined by an optical combiner 110 and output from an optical waveguide 112. The optical gate 105,
The same electrical pulse is applied to 107 and another electrical pulse is applied to optical gates 106 and 108.

FIG. 6 is a view for explaining one structure of the optical gates 105 to 108 in FIG. In FIG. 6, the optical gate has one end face 2220 of the light guide layer 2210 and the other end face 2230, and one end face 210 of the light guide layer 2210.
The input optical signal is input to 220 and the other end face 22
An output optical signal is output from 30. Further, a control signal V is applied via the electrode 2240. This optical gate is
When the input optical signal 2200 is incident when V = V _H , while the voltage of V = V _L (V _L <V _H ) is applied thereafter,
It amplifies and outputs the incident optical signal. The details of such an optical gate are described in the Abstracts of the Japan Society of Applied Physics 1990 Fall Meeting, page 754, lecture number 26p-H-2.

FIG. 7 is a time chart for explaining the operation of FIG.
It is a chart. 2300 indicates the applied electrical pulse to the optical gates 105 and 107, involves between V _L between times t ₁ ~t ₂ V _H becomes t ₂ ~t _6. 2301 is an optical gate 10
Shows the applied electrical pulse to 6,108, the time t ₂ ~t ₃
Kept between V _L between V _H becomes t ₃ ~t ₆ of. Optical gate 1
The optical packet signal A incident on the optical discs 05 and 106 is 2302
Header optical signal only during the time t ₁ ~t ₂ as shown in is present. Therefore, in the optical gate 105, the time during which the electric pulse is at V _H coincides with the time during which the header part optical symbol exists, but the optical gate 106 does not. Therefore, the data portion of the optical packet signal A passes through only the optical gate 105 and is routed to the optical waveguide 111 via the optical coupler 109.

On the other hand, the optical packet signal B incident on the optical gates 107 and 108 has a time t _{2 as} indicated by reference numeral 2303.
Header optical signal only during ~t ₃ is present. Therefore, in the optical gate 108, the time during which the electric pulse is at V _H coincides with the time during which the header part optical signal exists.
7 does not match. Therefore, the data portion of the optical packet signal B passes through only the optical gate 108 and is routed to the optical waveguide 112 via the optical coupler 110. As described above, the optical self-routing circuit of FIG. 5 performs self-routing to the optical waveguide 111 or 112 depending on whether the header portion of the optical bucket signal is at any one of the times t _{1 to} t ₂ or t _{2 to} t ₃ .

[0007]

In the conventional optical self-routing circuit, if the header part optical signals of the optical packet signals A and B input to the optical waveguides 101 and 102 exist at the same time, the optical packet signal The data parts of A and B are
Each of the optical gates 105 and 107 or the optical gate 106,
Go through 108. Therefore, in this case, the optical waveguide 111
Alternatively, there has been a problem that the data portions of the optical packet signals A and B are simultaneously output from the 112 via the optical coupler 109 or 110, and a collision of the data portions occurs.

It is an object of the present invention to provide an optical self-routing circuit which does not cause collision of a plurality of optical packet signals.

[0009]

An optical self-router according to the present invention is provided.
The switching circuit converts the optical signals from each of the n input terminals into m
N m light splitters for splitting into optical signals, and the n m light splitters
The m optical branches connected to the output end of the branching device and different from each other
N optical gates belonging to the system of vessels and to which electric pulses are applied
N ××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××××× @
m optical gate elements and each of the m optical gate element groups
Output from the n optical gate elements forming the
M n-light combiners for each of the force ends, and the m lights
An electric pulse for supplying an electric pulse to each of the gate element groups
A generator circuit, wherein the n input terminals and the m input terminals
Optical self-routing that exchanges optical signals between the output terminals
Wherein the optical signal includes a header indicating a destination.
And the following data, and the header is
corresponding to the time positions pre-assigned to the m outputs
Set, and the electric pulse generation circuit
Connected to each of the device groups via a resistor, and
The n optical gate elements constituting each of the gate element groups
Electrically cascaded through equal delay elements,
Each of the n optical gate elements has an electric pulse generating circuit.
The electric pulse signal from is delayed in time by the delay element.
The electric pulse signal is applied to each of the output terminals.
Maintains high level voltage within corresponding time positions
Then the optical signal is reduced to a lower medium level voltage.
It is held for more than the data length and then
The pressure drop is periodically repeated, and the m
The incident light in the n optical gate elements of each optical gate element group
First within the time position of the header of the optical signal
Optical gate to which a high level voltage of the electric pulse signal is applied
The intermediate level voltage of the electric pulse signal is held in the
Time from the electric pulse generation circuit through the resistor
An optical gate into which a current is injected and into which said current is first injected
An element allowing the data of the optical signal to pass and
Due to the high level voltage drop occurring at
The other of the n optical gate elements pass the data.
It is characterized in that it is suppressed. Further, the light of the present invention
A self-routing circuit is provided for each of the n inputs.
N m optical splitters for splitting an optical signal into m optical signals,
Connected to the output terminals of the n m optical splitters and different from each other.
And an electric pulse is applied.
m optical gate element groups each including n optical gate elements
N × m optical gate elements, and the m optical gates
Output of n optical gate elements constituting each of the gate element groups
M n-optical couplers for merging and emitting to each of the m output terminals
Applying an electric pulse to each of the m optical gate element groups.
And an electric pulse generating circuit for supplying the electric pulse.
Light that exchanges optical signals between m input terminals and m output terminals
A self-routing circuit, wherein the optical signal is
It consists of a header that indicates the destination and data that follows.
When the header is pre-assigned to the m output terminals
The electric pulse generation circuit is set within
connected to each of the m optical gate element groups via a resistor,
N optical gates forming each of the m optical gate element groups
The elements are electrically connected in cascade, and the n optical gate elements are
The electric pulse signal from the electric pulse generation circuit is
Signal is applied simultaneously, and the electric pulse signal is output from the output terminal.
Held at a high level voltage at each corresponding time position
Then, the optical signal is decompressed to a lower intermediate voltage.
Data for longer than the data length
The optical gate is periodically repeated
The electric pulse in n optical gate elements of each element group;
Within the time position where the high level voltage of the signal is applied
First to the optical gate element where the header of the optical signal is incident
The electric pulse is generated at the time when the medium level voltage is held.
A current is injected from the raw circuit through the resistor,
Is first injected into the optical gate element and the data of the optical signal
And the current generated by the current and the resistance
Other optical gates in the n number of cells due to a high level voltage drop
The device is characterized in that it suppresses the passage of the data.
Sign.

[0010]

According to the optical self-routing circuit of the present invention, when the header part optical signals of a plurality of optical packet signals are present at the same time and a collision of the optical packet signals occurs, the same self-routing circuit follows the priority according to a slight time difference. When one of the optical gates connected to the output terminal allows the optical packet signal to pass through, the other optical gate does not pass the optical packet signal, so that a plurality of packet optical signals are not simultaneously output to the same output terminal. Can be self-routing.

[0011]

FIG. 1 is a diagram showing a first embodiment of the present invention. The optical packet signals A to D input to the optical waveguides 1700 to 1703 are divided into two by optical splitters 1710 to 1713, respectively, and optical gates 1720, 1724 and 172 are provided.
1, 1725 and 1722, 1726 and 1723,
It is incident on 1727. The optical signals output from the optical gates 1720 to 1723 are transmitted to the optical waveguide 1704 via the optical coupler 1730.
Output from Output optical signals from the optical gates 1724 to 1727 are output from the optical waveguide 1705 via the optical coupler 1731. Electric pulse generation circuit 1740 and optical gate 17
20 is connected via a resistor 1750 and the optical gate 1
Delay elements 1751, 1752, and 1753 are connected between 720, 1721, 1722, and 1723. The electric pulse generation circuit 1740 and the optical gate 1724 are connected by a resistor 1
760 and optical gates 1724, 1724
25, 1726, and 1727, a delay element 1761,
1762 and 1763 are connected.

FIG. 2 is a timing chart for explaining the operation of FIG. 201 indicates a voltage pulse applied to the resistor 1750, the time t ₁ V _HO next between ~t _2, t
Kept between V _LO of ₂ ~t _12. 202 denotes a voltage pulse applied to the optical gate 1720, and the time t
₁ ~t smaller V _H than during V _{HO 2,} between t ₂ ~t ₁₂ V
Keep V _L less than _LO . 203 to 205, shows a voltage pulse applied to the optical gates 1721-1723, by the action of the delay element 1,751-1,753, V _H from 202
Are waveforms delayed from t ₂ to t ₄ .

[0013] 206 shows a voltage pulse applied to the resistor 1760, next between V _HO time t ₅ ~t _6, kept between V _LO of t ₆ ~t _12. 207 indicates a voltage pulse applied to the optical gates 1724, a small V _H than during V _HO time t ₅ ~t ₆ by resistors 1760, keeping the small V _L from between V _LO of t ₆ ~t _12. 208 to 210 are optical gates 1725 to 1
727 shows the voltage pulse applied to the delay elements 1761-
Due to the operation of 1763, the time at which V _H becomes longer than 207 becomes a waveform delayed from t ₆ to t ₈ .

The optical packet signals A and C input to the optical gates 1720 and 1724 and 1722 and 1726 respectively are 21
Time t ₁ ~t ₅ and the light amount as shown and 1,213 exists header portion of P _1, time t ₁₀ ~t ₁₁ and the data portion is present. Also, optical gates 1721 and 1725, 1723 and 17
The optical packet signals B and D respectively incident on 27
There is a header portion of the P ₁ of the light amount at time t ₅ ~t ₉ as shown and 2,214, data portion is present at time t ₁₀ ~t _11.

The optical packet signals A and C are signals that are desired to be output from the optical waveguide 1704, and they may collide with each other.
The applied voltage at 22 becomes _VH . But light gate 1720
Since the applied voltage becomes _VH first, the optical gate 1720
Is quickly switched to a state in which it passes through the subsequent data section.
When the optical gate 1720 moves to this operating state, the optical gate 17
20 is increased, and this injected current and the resistance 175
Since the voltage applied to the optical gate 1722 decreases due to the voltage drop due to 0, the optical gate 1722 can no longer pass the data portion subsequent to the optical packet C. As a result, only the data portion of the optical packet signal A is
20 and an optical waveguide 170 via an optical combiner 1730.
4 is self-routed.

Both of the optical packet signals B and D may collide with the output of the optical waveguide 1705 with a desired signal, and the optical gates 1725 and 1725, 1
The applied voltage of 727 becomes _VH . However, the light gate 172
Since the applied voltage of 5 becomes _VH first, the optical gate 172
5 is quickly switched to a state in which the subsequent data section is passed. When the optical gate 1725 moves to this state, the optical gate 17
25, the injected current and the resistance 1760 increase.
Since the voltage applied to the optical gate 1727 decreases due to the voltage drop caused by the above, the optical gate 1727 can no longer pass the data portion following the optical packet signal D. As a result, only the data portion of the optical packet signal B passes through the optical gate 1725 and passes through the optical coupler 1731 to the optical waveguide 1.
Self-routed to 705.

As described above, in the present embodiment, the header portion of the optical packet signal is at time t ₁ t ₅ , but not only is self-routing depending on which of t ₅ to t ₉ , but also the applied voltage of the optical gate is faster. Priority control is performed in the order of _VH . FIG. 3 is a diagram showing a second embodiment of the present invention. The optical packet signals A to D input to the optical waveguides 1700 to 1703 are divided into two by optical waveguides 1710 to 1713, respectively, and are divided into two optical gates 1720, 1724 and 1721, 1
725, 1722, 1726 and 1723, 172
7 is incident. Output optical signals from the optical gates 1720 to 1723 are output from the optical waveguide 1704 via the optical coupler 1730. Output optical signals from the optical gates 1724 to 1727 are output from the optical waveguide 1705 via the optical coupler 1731. Electric pulse generation circuit 1740 and optical gate 1720-
Reference numeral 1723 denotes an optical gate 1724 through a resistor 1900.
1727 is connected via a resistor 1910.

FIG. 4 is a timing chart for explaining the operation of FIG. 401 indicates a voltage pulse applied to the resistor 1900, next between V _HO time t ₁ ~t _4, t ₄
Keep the V _LO time of ~t _10. 402 is an optical gate 1720-1
Shows the voltage pulse applied to the 723, while the resistance 1900 at time t ₁ ~t ₄ V _HO smaller V _H, t ₄ ~t ₁₀
During this time, V _L that is smaller than V _LO is maintained. 403 is a resistor 1910
Shows the voltage pulse applied to, next between V _HO time t ₄ ~t _7, kept between V _LO of t ₇ ~t _10. 404 is an optical gate 1
724 to 1727 indicate applied voltage pulses,
During V _HO smaller V _H at time t ₄ ~t ₇ by 10,
kept between V _LO is smaller than V _L of t ₇ ~t _10.

The optical packet signal A incident on the optical gates 1720 and 1724 is at a time t ₁ to t _{2 as} shown at 405.
Quantity header portion of P ₁ is, data portion is present in the t ₈ ~t ₉ in. As the optical packet signal B which is incident to the optical gate 1721,1725 indicates to 406, the light amount at time t ₄ ~t ₅ a header portion of the P ₁ is, data portion is present in the t ₈ ~t _9. Optical packet signal C enters the optical gate 1722,1726 header portion of the light amount P ₁ at time t ₂ ~t ₃ as shown in 407, the data unit is present in the t ₈ ~t _9. Optical packet signal D which is incident to the optical gate 1723,1727 light amount at time t ₅ ~t ₆ as shown in 408 is the header portion of P _1, the data unit is present in the t ₈ ~t _9.

Both the optical packet signals A and C are signals which are desired to be output from the optical waveguide 1704 and may collide with each other, and the header portion may be generated during the time when the voltage applied to the optical gates 1720 and 1722 is V _H. Exists. However, since the optical packet signal A has the light amount P1 in the header portion _first , the optical gate 1720 is quickly switched to a state in which the subsequent data portion is passed. When the optical gate 1720 shifts to this operation state, the injection current to the optical gate 1720 increases, and the voltage drop due to this current and the resistance 1900 causes the optical gate 1722 to drop.
, The applied voltage of the optical gate 1722 can no longer pass through the data portion of the optical packet signal C. As a result, only the data portion of the optical packet signal A passes through the optical gate 1720 and is self-routed to the optical waveguide 1704 via the optical coupler 1730.

The optical packet signals B, Both D, may conflict with the desired signal and outputs the optical waveguide 1705, a header section in the time the applied voltage of the light gates 1725,1727 is a V _H Exists. But optical gate 1725 is switched quickly to a state for passing the data portion of the subsequent because towards optical packet signal B is the header portion is the light amount P ₁ above. When the optical gate 1725 shifts to this state, the injection current to the optical gate 1725 increases, and the voltage applied to the optical gate 1727 decreases due to the voltage drop due to this current and the resistor 1910. The data portion following the signal D cannot be passed. As a result, only the data portion of the optical packet signal B passes through the optical gate 1725 and is self-routed to the optical waveguide 1705 via the optical coupler 1731.

As described above, in this embodiment, not only the self-routing is performed depending on whether the header portion of the optical packet signal is at the time t _{1 to} t ₄ or t _{4 to} t ₇ , but also the header is early within the time. Priority control is performed in the order in which the units exist.

[0023]

As described above, according to the present invention, it is possible to obtain an optical self-routing circuit for self-routing one of the optical packet signals preferentially when a plurality of optical packet signals collide.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical self-routing circuit according to a first embodiment of the present invention;

FIG. 2 is a timing chart showing the operation of the optical self-routing circuit of FIG. 1;

FIG. 3 is a configuration diagram of an optical self-routing circuit according to a second embodiment of the present invention;

FIG. 4 is a timing chart showing the operation of the optical self-routing circuit of FIG. 3;

FIG. 5 is a configuration diagram of a conventional optical self-routing circuit.

FIG. 6 is a diagram for explaining a structure of an optical gate;

FIG. 7 is a timing chart illustrating the operation of the optical self-routing circuit of FIG. 5;

[Explanation of symbols]

 1700 optical waveguide 1701 optical waveguide 1702 optical waveguide 1703 optical waveguide 1704 optical waveguide 1705 optical waveguide 1710 optical splitter 1711 optical splitter 1712 optical splitter 1713 optical splitter 1720 optical gate 1721 optical gate 1722 optical gate 1723 optical gate 1724 optical gate 1725 Optical gate 1726 Optical gate 1727 Optical gate 1730 Optical combiner 1731 Optical combiner 1740 Electric pulse generator 1750 Resistance 1760 Resistance 1900 Resistance 1910 Resistance

Claims (2)

(57) [Claims] An optical signal from each of n input terminals is converted into m optical signals.
N m optical splitters for splitting into signals and connected to the output terminals of the n m optical splitters,
And an electric pulse is applied.
m optical gate element groups each including n optical gate elements
And n × m optical gate elements constituting each of the m optical gate element groups.
M outputs that merge the outputs of the G element and output them to each of the m output terminals
And supplying an electric pulse to each of the m optical gate element groups.
And an electric pulse generating circuit.
An optical cell for exchanging optical signals between an input terminal and m output terminals
Routing circuit, wherein the optical signal includes a header indicating a destination and data following the header.
And the header is previously provided at the m output terminals.
The electricity is set corresponding to the assigned time position.
The pulse generation circuit includes a resistor and each of the m optical gate element groups.
N optical gates connected to each other through the
The delay element is electrically connected vertically through a delay element having the same delay amount.
Column-connected, and each of the n optical gate elements has the electric
The electric pulse signal from the pulse generation circuit is applied to the delay element.
The electric pulse signal is applied after being delayed in time, and the electric pulse signal
Is held at a high level voltage within
Keep at a small medium level voltage for more than the data length of the optical signal.
And then dropped to a lower low level voltage
Is periodically repeated, and the n optical gate elements of each of the m optical gate element groups are
Within the time position of the header of the optical signal incident in the
First, a high level voltage of the electric pulse signal is applied.
Medium level voltage of the electric pulse signal to the optical gate element
Is held from the electric pulse generation circuit at the time when
A current is injected through a resistor, and the optical gate element into which the current is first injected is the optical signal.
At the same time as the current and the resistance
This high level voltage drop causes the other of the n
Inhibiting the optical gate element from passing the data
An optical self-routing circuit, characterized in that: 2. An optical signal from each of n input terminals is converted into m optical signals.
N m optical splitters for splitting into signals and connected to the output terminals of the n m optical splitters,
And an electric pulse is applied.
m optical gate element groups each including n optical gate elements
And n × m optical gate elements constituting each of the m optical gate element groups.
M outputs that merge the outputs of the G element and output them to each of the m output terminals
And supplying an electric pulse to each of the m optical gate element groups.
And an electric pulse generating circuit.
An optical cell for exchanging optical signals between an input terminal and m output terminals
Routing circuit, wherein the optical signal includes a header indicating a destination and data following the header.
And the header is previously provided at the m output terminals.
The electric pulse generation circuit is set corresponding to the assigned time position, and the electric pulse generation circuit
N optical gates connected to each other via a resistor and constituting each of the m optical gate element groups.
Are electrically connected in cascade, and the n optical gates are
Each element has an electric pulse from the electric pulse generation circuit.
Signals are applied at the same time, and the electric pulse signal
Held at a high level voltage and then smaller
At a medium level voltage for at least the data length of the optical signal.
And then drop to a smaller low level voltage.
The optical gate element group is repeated periodically, and the n
Time position where the high level voltage of the electric pulse signal is applied
Within which the header of the optical signal is first incident
At the time when the medium-level voltage is held in the gate element,
A current is injected from the electric pulse generation circuit through the resistor.
The optical gate element into which the current is first injected is the optical signal
At the same time as the current and the resistance
This high level voltage drop causes the other of the n
Inhibiting the optical gate element from passing the data
An optical self-routing circuit, characterized in that: