JPH0758776A - Optical packet switch device - Google Patents

Abstract

PURPOSE:To provide a device in which an optical packet signal inputted to an exchanging device can be transmitted to a direction indicated by a header part. CONSTITUTION:This device is equipped with an optical demultiplexer 33 which demultiplexes an optical packet signal 31 like a power, and an optical switch element 35 to which one demultiplexed optical packet signal 311 demultiplexed by the optical demultiplexing means 33 and a control light are inputted, and by which the outputting direction of the demultiplexed optical packet signal 311 is switched according to the inputting state of the control light. Moreover, the device is equipped with a non-linear element 37 connected with the control light input terminal of the optical switch element 35, whose input end an other demultiplexed optical packet signal 312 demultiplexed by the optical demultiplexing means 33 is inputted to. The non-linear element 37 has an input and output characteristic that when the light intensity of the input end is larger than a first value, the light intensity of an output end is turned to a first state, and when the light intensity of the input end is less than a second value which is less than the first value, the light intensity of the output end is turned to a second state, and when the light intensity of the input end is between the first value and the second value, the light intensity of the output end is held as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method in which a series of optical signals including a header section and a data section (hereinafter also referred to as an optical packet signal) are indicated by a header section of a plurality of output waveguides. The present invention relates to an optical packet switching device that guides an output waveguide of a path.

[0002]

2. Description of the Related Art As a conventional example of a technique for switching and distributing an optical packet signal based on destination information included in a header portion thereof, for example, a document (IEICE Exchange Research Group SSE88-95 "Space Division Optical Switch") is used. Packet system using ")". FIG. 10 is a block diagram schematically showing the configuration of a 4-input 4-output optical packet switch device according to this system.

In FIG. 10, 11a to 11d are input waveguides, 13 is a header section / data section dividing section, and 15 is O / E.
(Optical / electrical) conversion unit, 17 is a header analysis unit, 19 is a switch control unit, 21 is an optical switch, and 23a to 23d are output waveguides. In this optical packet switch device, an input waveguide has been transmitted. The optical packet signal is divided into a header portion and a data portion by the header portion / data portion dividing portion 13. Next, this header part is the O / E conversion part 1
After being converted into an electric signal in 5, the address is sent to the header analysis unit 17 where the destination is electrically analyzed. Since the switch control unit 19 electrically drives the optical switch 21 based on the analysis result, the data unit outputs the output waveguides 23a to 23a.
It is guided to the target output waveguide of d.

[0004]

However, in the conventional optical packet switch device, an electrical process is required when the header analysis is performed, and the optical switch is also controlled by an electrical signal. Therefore, the limit of the operating speed of this device is determined by the limit of the electrical processing speed and the switching speed of the optical switch. Therefore, there is a problem that there is a limit in improving the throughput of the device. there were. In addition, since the O / E conversion unit is required for the analysis of the header part, there is a problem that the device configuration becomes complicated.

This application has been made in view of the above-mentioned circumstances. Therefore, the object of each invention of this application is that an optical system which can operate at a higher speed than before and can perform header analysis as light without using electrical processing. It is to provide a packet switch device.

[0006]

In order to achieve this object, according to the first invention of this application, an optical packet switch device for distributing an optical packet signal including a data section and a header section to a target route. In, the optical branching means for branching the optical packet signal, the control light, and one of the branched optical packet signals branched by the optical branching means are respectively input, and the one of the branched optical packet signals is input depending on the input state of the control light. An output terminal of the optical switch element is connected to the terminal for inputting the control light of the optical switch element, and the other branched optical packet signal branched by the optical branching means is input to the input terminal. When the light intensity at the input end is input and the light intensity at the input end is equal to or higher than the first value, the light intensity at the output end is in the first state, and the second intensity smaller than the first value In, the light intensity at the output end is in the second state, and at a value between the first value and the second value, the light intensity at the output end is maintained as is or close to the current state. And a non-linear element having an input / output characteristic. Here, maintaining the light intensity as it is means that if the light intensity at the output end is the first (second) state, the first (second) state is maintained, and The state close to that is the same as the output route in the case of the first (second) state when the optical signal of the first (second) state is input to this optical switch element as the control light of the optical switch element. This means that the state of being guided to the path has a light intensity within a range that can be maintained in this optical switch element, and is determined according to the characteristics of the nonlinear element used.

According to the second invention of this application, in the optical packet switch device for distributing the optical packet signal including the data portion and the header portion to the intended route, the data portion and the header portion are divided. The data section / header section dividing means, the control light, and the data section divided by the data section / header section dividing section are respectively inputted,
An optical switch element in which the output path of the data section is switched according to the input state of the control light and a header section divided by the data section / header section dividing means are input, and the following elements (a) to (c) are input. And a control light output section including a.

(A) An output end is connected to a terminal for inputting the control light of the optical switch element, and when the input light intensity is equal to or higher than a first value, the light intensity at the output end is in the first state, A second input light intensity smaller than the first value;
Is less than or equal to the value, the light intensity at the output end is in the second state, and when the input light intensity is between the first value and the second value, the light intensity at the output end remains unchanged. A non-linear element having an input / output characteristic of being maintained.

(B) An output end is connected to an input end of the nonlinear element, the header portion is input to one input end, and light from a light source described later is input to the other input end. An optical amplification element that outputs an optical signal having an intensity corresponding to the intensity of light from a light source from the output end.

(C) A first level (p0) is shown when the header section is not input to the optical amplification element, and a second level (p1) is shown when the header section is input to the optical amplification element. A light source that exhibits a third level (p2) when a particular bit of is input. However, these first to
The third level means the first level <the second level <the third level.
When the level of one of the bits of the header section is expressed as pL and the level of the other is expressed as pH, the following conditions 1 to 4 are satisfied.

PH at one input end of the optical amplification element,
When p2 is input to the other input end, the light intensity at the output end of the optical amplification element becomes equal to or higher than the first value.

PL is provided at one input end of the optical amplification element,
When p0 is input to the other input end, the light intensity at the output end of the optical amplification element becomes less than or equal to the second value.

When the predetermined values other than the above values are input to one input end and the other input end of the optical amplification element, the light intensity at the output end of the optical amplification element is It is a value between the value of 1 and the second value.

When carrying out each of the first and second inventions, it is preferable to connect the optical packet switch devices of the respective inventions in multiple stages. This is because an optical packet switch device having a large number of exchange channels can be configured in this way.

[0015]

According to the configuration of the first invention of this application, a branched optical packet signal obtained by branching the optical packet signal in terms of power is input to the nonlinear element. Here, since this non-linear element changes the output light intensity with the hysteresis characteristic as described above depending on the intensity of the input light, the light intensity of each bit of the optical packet signal should be devised in advance ( (Refer to each embodiment of the first invention) Since the device is reflected in the branched optical packet signal, the optical intensity at the output end of the nonlinear element can be controlled by the branched optical packet signal.
The fact that the light intensity at the output end of the non-linear element can be controlled means that the switching of the optical switching element can be performed as desired, so that the packet signal can be switched to the intended route. Thus, in this first invention,
The optical packet signal itself can be used to switch the packet output route by light without performing any particular analysis of the header section.

According to the configuration of the second invention of this application, (i) when the header section is not input to the optical amplification element of the control light output section, the first section is provided at the light source side input end of this optical amplification element. , And the pL level is input to the input end on the header side, the optical amplifying element outputs light having an intensity equal to or lower than the second value to the nonlinear element. For this reason, the light intensity at the output end of the non-linear element is in the second state, so that the state of the control light of the optical switching element is also in a state corresponding to this second state. Therefore, the output route of the optical switch element is switched to the route to be taken when the control light is in the second state. (Ii) On the other hand, when the header section is input to the optical amplification element of the control light output section, the second level (p1) is basically input from the light source to the optical amplification element. In this state, the header section is input. Since the input end of the optical amplifying element is in the state corresponding to the above regardless of pL and pH, the optical amplifying element outputs the light having the intensity between the first value and the second value to the nonlinear element. Therefore, the light intensity at the output end of the nonlinear element is maintained as it is, and the output path of the optical switch element is not switched. (Iii) However,
When the header section is input to the optical amplification element, and particularly when a specific bit is input, the light of the third level (p2) is input to the light source side input end of the optical amplification element in synchronization with this. It At this time, if the specific bit is at the pH level, the input state of the optical amplifying element is at the third level (p2) and p.
Since the H level is input, this optical amplifying element outputs light having an intensity equal to or higher than the first value to the nonlinear element.
For this reason, the light intensity at the output end of the non-linear element becomes the first state, and the state of the control light of the optical switch element consequently also becomes the state corresponding to this first state. Therefore, the output route of the optical switch element is switched to the route to be taken when the control light is in the first state. The route switched here is maintained until the condition of (i) above is satisfied, that is, until the input of the header part is exhausted, so that this route is not switched until the output of the data part is completed. (Iv) Further, when the specific bit is at the pL level, the input state of this optical amplifying element is the state in which the third level and the pL level are input, and therefore the state corresponding to the above is obtained. Therefore, the optical amplifying element is non-linear. It outputs light having an intensity between the first value and the second value to the element. For this reason, the output state of the non-linear element remains as it is, and the output path of the optical switch element is not switched. As described above, according to the second aspect of the present invention, the output route of the packet can be switched by the light by utilizing the light intensity of the specific bit of the header portion without particularly analyzing the header portion.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the first and second inventions of this application will be described below with reference to the drawings. However, these figures are merely schematic representations so that the present invention can be understood. Further, in each of the drawings used for the description, the same components may be denoted by the same reference numerals, and duplicate description thereof may be omitted.

1. Description of first invention 1-1. First Embodiment of First Invention FIGS. 1A and 1B are diagrams for explaining a first embodiment of the first invention. In particular, FIG. 7A is a diagram showing the configuration of the optical packet switching device 30 of this embodiment, and FIG. 7B is a diagram showing the optical packet signal 31 in which the bits in the header portion are at the low level (p.
It is explanatory drawing in the case of (L level).

The optical packet switch device 30 of this embodiment
Is an optical branching means 33 for branching the optical packet signal 31 in power in this example, control light, and the optical branching means 33.
One of the branched optical packet signals 31 _{1 that} has been branched by is input respectively, and the output route of the _one branched optical packet signal 31 ₁ is output according to the input state of the control light.
5a or 35b and an optical switch element 35. Further, the output terminal is connected to the terminal for inputting the control light of the optical switch element 35, and the other branched optical packet signal 3 branched by the optical branching means 33.
When 1 ₂ is input to the input end and the light intensity of the input end is equal to or higher than the first value, the light intensity at the output end is in the first state, and when the light intensity is equal to or lower than the second value which is smaller than the first value. The light intensity at the output end is in the second state, and the first
And a value between the second value and the second value, the nonlinear element 37 has an input / output characteristic that the light intensity at the output end is maintained as it is or close to it.

Here, the light branching means 33 can be constituted by a known means. The power ratio at which the optical branching unit 33 branches the optical packet signal 31 may be determined according to the design. In FIG. 1, the optical packet signal 31 is 1: 1.
The example shown in FIG.

Further, in this case, the optical switch element 35 is composed of a 1 × 2 type known optical control type optical switch whose output path is switched to either of the output ends 35a and 35b by control light. In FIG. 1, reference numeral 35c indicates a control light input end. Such an optical switch element is disclosed in, for example, the reference (199).
2nd IEICE Spring Conference, C-194pp4-2
36 or 1992.5.25 IEICE Technical Committee on Integrated Photonics (IP92-11IEICE), pp23
-28). Of course, another device such as an OEIC type device may be used as long as the same operation is performed.

Further, the non-linear element 37 is constituted by an element having a hysteresis characteristic between the input light intensity and the output light intensity as described with reference to FIG. 2 in this case. Specifically, when the input light intensity becomes equal to or higher than the first value (value indicated by pH2 in FIG. 2), the output light intensity is in the first state (p in FIG. 2).
-In), and when the input light intensity falls below a second value smaller than the first value (value indicated by pL0 in FIG. 2) or less, the output light intensity is in the second state (p in FIG. 2). -OFF), and when the input light intensity reaches a value between the first value and the second value (such as the value indicated by pL1, pL2, and pH1 in FIG. 2), the output light intensity changes. It is an element having a characteristic of being maintained as it is or in a state close to this. Such an element is disclosed in, for example, the literature (Journal of the Institute of Electronics, Information and Communication Engineers, Vol. 75C-No. 6, pp555-56).
0, Aug. 1992).

In this case, the packet signal 31 is assumed to be composed of a data section 31a and a header section 31b. However, the data portion 31a is represented by a binary value indicating that each bit shines strongly or weakly. 1 in FIG.
1 ax indicates a weakly shining bit, and 31 ay indicates a strongly shining bit. In the data section 31a, the nonlinear element 3 after being branched by the optical branching means 33 is used.
In the branch optical packet signal 31 ₂ on the 7 side, the light intensity of the bit in the data portion in the weakly shining state becomes larger than the second value described in the explanation of the nonlinear element 37, and the light intensity in the bit in the strongly shining state becomes Each intensity before branching is set so that the intensity is smaller than the first value described in the description of the non-linear element 37. By doing this,
The output of the non-linear element 37 is not changed due to the influence of the data portion of the branched optical packet signal 31 ₂ . Further, in this case, the header section is a 1-bit signal section expressed by light of either high level or low level. However, in the case where the header portion is at a high level, the first value (pH in FIG. 2) described in the description of the non-linear element 37 in the state after the header portion is branched by the optical branching means 33.
2) In order to have a larger value, and when the header part is at a low level, this header part is used by the optical branching means 33.
Each of these high and low levels is set to a value (including a non-shining state) smaller than the second value (pL0 in FIG. 2) described in the description of the non-linear element 37 in the state after being branched by the. Has been set. By doing so, when the header portion 31b becomes high level, the light intensity at the output end 37a of the nonlinear element is in the first state (see FIG. 2 above).
PH 2) of the non-linear element and the light intensity at the output end 37a of the non-linear element becomes the second state (pH of FIG. 2 above).
2), the optical switch element 35 can be switched accordingly. In this example, when the header section 31b is at a high level, the two output terminals 35 of the optical switch element are
The output end 35a of a and 35b becomes effective, while
It is assumed that the output end 35b becomes valid when the header portion 31b is at the low level. Here, an example has been described in which the low level of the header section is set to a value smaller than (pL0 in FIG. 2) (including the non-shining state), but the low level of the header section is in a range not exceeding pH2. (Eg pL
1, pL2, pH1, etc.). This is because when there is no optical packet signal, the light intensity at the output end of the non-linear element 37 causes the optical switch element to be in a state in which its output end 35b side is effective, so that the low level of the header part, for example, pL1,
This is because this output state is maintained even with pL2 and pH1.

In the optical packet device according to the first aspect of the present invention, when the header section 31b is at the high level (in the case of FIG. 1A), the output signal of the nonlinear element 31b is output by the header section 31b of the branched optical packet signal 31 _2. Since the intensity becomes pH2, the optical switch element switches to enable the output end 35a accordingly. This switched state is switched because the level at the input end of the nonlinear element 37 becomes 0 (the input light intensity becomes pL0 or less in FIG. 2) after the branched optical packet signal 31 ₂ is input to the nonlinear element. In the meantime, the optical packet signal 31 ₁ branched to the optical switch element 35
Is output to the output terminal 35a side. In this processing, adjustment of the input timing of the branched optical packet signal 31 ₂ and the branched optical packet signal 31 ₁ to the nonlinear element or the optical switch element may be performed by a known technique. Further, a technique of adding an appropriate guard time as necessary may be used. On the other hand, in this embodiment, since the non-linear element 37 is in the output light state of pL0 when there is no input, the optical switch element 35 is normally in the state of enabling the output end 35b. Therefore, when the header section 31b is at a low level (in the case of FIG. 1 (B)), the optical switching element 35 does not particularly switch the output route, and the branched optical packet signal 31
₁ is output to the output terminal 35b side of the optical switch element 35 without any problem. In this way, the optical packet signal is switched to the output end 35a or 35b of the optical switch element 35.

1-2. Second Embodiment of First Invention Next, by connecting the optical packet switch devices of the first invention in multiple stages, an optical packet device with one input and multiple outputs is constructed.
Further, an example in which a large-scale optical packet device having a plurality of inputs and a plurality of outputs is configured by arranging the one-input and multi-output devices configured as described above in multiple stages in parallel and making predetermined connections (second invention of the first invention) Example) will be described. 3 is a diagram provided for the description. Here, in the first invention, two optical packet devices according to the first embodiment are connected in multiple stages to form a device 30x having one input and three outputs.
And an optical packet switching device 40 with three inputs and three outputs is configured by using three of them. Specifically, first, the two output terminals 35a, 35 of the optical switch element 35 of the optical packet switch device 30 of the first embodiment are first.
In either one of b (in this example, the output end 35b on the side where the header section is effective when the header is at a low level), the other optical branching means 3 in the optical packet switch device 30 of the first embodiment is used.
Three input terminals are connected to form a one-input / three-output device 30x. Three sets of such devices 30x are prepared, and among these, between the output ends of the optical switch elements of each optical packet switch device 30, which are not used for connection with another optical packet switch device 30, The output terminals in the same state are connected to each other by the optical multiplexing means 41, 42 or 4
Enter in 3.

When operating the optical packet switching device 40 of the second embodiment of the first invention, it is assumed that the data portion and the header portion of the optical packet signal are constructed under the conditions of the first embodiment. The optical packet signal satisfies the conditions. This will be described with reference to FIGS. First, the data portion 51a of the optical packet signal 51 used here may be the same as that of the first embodiment. on the other hand,
First, the header section 51b is composed of at least the same number of bits (2 bits in the illustrated example) as the number of stages (2 in the example of FIG. 3) of the optical packet device 30 of the first embodiment. This is because the first bit of the header portion 51b is used for the non-linear element 37 of the first-stage optical packet switch device 30, and the second bit of the non-linear element 37 of the first-stage optical packet switch device 30. This is because it is used.
Further, the light intensity at the low level of the header portion 51b is set to a range (value larger than pLo) that does not bring the nonlinear element 37 into the p-OFF state (see FIG. 2). This is because the output state of the non-linear element set by setting the first bit of the header section 51b at the high level indicates that the light intensity indicating the low level of the second bit of the header section is pL.
This is because if it is 0 or less, it changes depending on this level, and as a result, the output route of the optical switch element may be switched to an undesired direction even during signal transmission. Further, in the header portion 51b, the light intensity indicating the higher level state is set lower for the later bits (see FIG. 4A). However, in order to obtain the p-PN state of each non-linear element of the multistage optical packet device according to the first embodiment, the optical intensity indicating the state at the higher level is lowered for the bit after the header portion 51b. The first value of pH2 is set to be lower in strength in the latter stage. If the high level value of each bit in the header section is the same and the pH2 of the non-linear element in each stage is the same, the output terminal 35 of the optical packet switch device 30 in the subsequent stage is
This is because the signal to be output from a is also output from the output end 35a of the optical packet switch 30 at the preceding stage, and desired exchange cannot be performed.

In order to deepen the understanding of the second embodiment of the first invention, the respective optical packet signals of FIGS. 4A to 4C are shown in FIG.
Will be described below. However, the signal input / output timing and the like can be adjusted as desired by a known technique, and the description thereof will be omitted.

First, the two types of optical packet signals shown in FIG. 4A are treated in the same manner because the first bits of the header section 50b are both at high level (higher level).
That is, all the optical packet signals shown in FIG. 4A are processed by the first-stage optical packet switch device 30 according to the principle described in the first embodiment, and the first-stage optical packet switch device is processed. It is output from the output end 35a of 30 and sent to the optical multiplexing means 45.

Next, in the optical packet signal of FIG. 4B, the first bit of the header portion 50b is at the low level, so the first
First, the output end 35b of the optical packet switch device 30 of the second stage is sent to the optical packet switch device 30a of the second stage. Although the second bit of the header section 50b is at a high level, this level is not so high as to change the state of the non-linear element of the optical packet switch device 30 at the first stage. It will be sent. However, the high level of the second bit of the header section 50b in the case of FIG.
This optical packet signal is processed by the second-stage optical packet switching device 30 according to the principle described in the section of the first embodiment because the level is sufficient to change the state of the non-linear element of 0. It is output from the output end 35a of the optical packet switch device 30 of the stage and sent to the optical multiplexing means 41.

Next, in the optical packet signal of FIG. 4C, since the first and second bits of the header section 50b are both at the low level, the optical packet switch devices of the first and second stages are shown. 30 is processed according to the principle described in the section of the first embodiment, and the second-stage optical packet switching device 3
It is output from the output terminal 35a of 0 and sent to the optical multiplexing means 43.

2. Description of the second invention In the above-mentioned first invention, the optical packet signal is branched in power and one of the branched optical packet signals obtained by this is input to the input end of the optical control type optical switch element, and the other is input. All-optical switching was performed by using it to generate control light for the optical switch element. In the following second invention, all-optical switching is performed by utilizing the header portion of the optical packet signal for generating control light of the optical control type optical switch element. The second invention will be described below with reference to some embodiments.

2-1. First Embodiment of Second Invention FIG. 5 is a diagram for explaining the first embodiment of the second invention.
In addition, in FIG. 5, FIG. 1 used in the description of the first invention is used.
Constituent components similar to those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and the description thereof will be omitted.

The optical packet switching device 60 of the first embodiment of the second invention comprises a data section / header section dividing means 63 for dividing the data section 61a and the header section 61b of the optical packet signal 61, and the control light and An optical switch in which the data part 61a divided by the data part / header part dividing means 63 is input, and the output route of the data part 61a is switched to either of the output ends 35a and 35b depending on the input state of the control light. And element 35. Further, the header section 61b divided by the data section / header section dividing means 61 is input, and the control light output section 69 including the nonlinear element 37 similar to the first invention, an optical amplification element 65 described below, and a light source 67. Equipped with. Further, in this example, a monitoring device 71 is provided. The monitoring device 71 monitors whether or not the optical packet signal is sent to the device 60, and with respect to the light source 67, whether or not the timing at which the optical packet signal 61 is input to the optical amplifying element 65, and the header. This is to inform about the timing when a specific bit (described later) in the set arrives. However,
If the timing of arrival of the optical packet signal and the timing of arrival of the specific bit are known in advance, the monitoring device 71 is not essential.

Here, the data part / header part dividing part 63 can be constructed by a known technique. If the data part and the header part are respectively composed of light having different wavelengths, the data part / header part dividing part 63 can be composed of a wavelength filter.

Further, the optical amplification element 65 of the control light output section 69.
Has its output connected to the input of the non-linear element 37,
The header section is input to one input end, the light from the light source 67 is input to the other input end, and an optical signal having an intensity corresponding to the intensity of light from the header section and the light source (described later).
Is output from the output end to the nonlinear element.

Further, the light source 67 of the control light output section 69 shows the first level (p0) when the header section is not input to the optical amplification element 65, and the second level when it is input. (P1), and shows the third level (p2) when a particular bit of the header section is input.

Further, the optical packet signal 61 is constructed by setting each bit thereof in a lit state or a non-lit state (may be weakly lit). In this case, the light intensity in the shining state is represented by pH, and the light intensity in the non-shining state is represented by pL. Therefore, the header portion 61b is also composed of a combination of pH intensity bits and pL intensity bits. Further, a certain bit in the header portion 61b (this is called a specific bit) is a bit indicating the route switching information of the packet signal. Of course, this particular bit also has either pH or pL intensity.

Here, the optical amplifying element 65 includes the header portion 61.
b, an optical signal having an intensity corresponding to the intensity of light from the light source 67 is output. Therefore, in the case of this example in which each level is set as described above, there are six types shown in Table 1 below. A combination of optical signals is conceivable. However, the light source 60
When the input from P0 is p0, the input end on the header side of the optical amplification element does not become pH, so the combination of p0pH in Table 1 is excluded, so after all, there are five combinations of light shown in Table 1. The signal is considered.

[0039]

[Table 1]

Then, the first to third levels of the light source 67 are set so as to satisfy the condition of first level <second level <third level and the following conditions.

PH is applied to one input end of the optical amplification element 65,
When p2 is input to the other input end, the light intensity pH2 at the output end of the optical amplification element 65 becomes equal to or higher than the first value described in the description of the nonlinear element 37.

PL is provided at one input end of the optical amplification element 65,
When p0 is input to the other input end, the light intensity at the output end of the optical amplification element becomes equal to or less than the second value.

When the predetermined value other than the above values is input to one input end and the other input end of the optical amplification element, the light intensity at the output end of the optical amplification element is It is a value between the value of 1 and the second value.

To summarize Table 1 and the above explanations, the relationship between the intensities of the input light and the output light in Table 1 is shown in FIG. And each of these outputs (p
L0 to pH2) corresponds to the input light intensity in the graph of FIG.

Next, in order to deepen the understanding of the optical packet device of the first embodiment of the second invention, the operation of this device will be described. 7 and 8 are time charts used for the explanation. In particular, FIG. 7 is a time chart used for explaining the operation when the specific bit 61x in the header section 61b is at a high level, and FIG. 8 is a specific bit 61x in the header section 61b.
6 is a time chart used for explaining the operation when is at a low level.

First, the optical packet switching device 60
The initial state (see FIG. 5) will be described. The light intensity of each part until the optical packet signal 61 is input is the light source 67.
In the output of the first level p0, the optical amplification element 65
It is assumed that the output of the above is pL0 and the output of the non-linear element 37 is p-OFF. Now, the optical packet signal 61 is divided into a data portion 61a and a header portion 61b by the optical dividing means 63, the data portion 61a is an input end of the optical switch element 35, and the header portion 61b is an optical amplifying element 65.
It is assumed that the data is input to one of the input terminals. The monitoring device 71 informs the light source 67 that the header section 61b has been input to the optical amplification element 65. At the same time that the header portion of the light source 67 is input to one input end of the optical amplification element 65 (see FIG. 7,
At time t _{1 in} FIG. 8, light emission is started at the intensity of the second level p1 and when the optical packet signal is output to either of the output terminals 35a and 35b of the optical switch element 35 according to the principle described later (FIG. 7). , Time t _{5 in} FIG. 8) Light emission is stopped and the level returns to the first level p0 again. The light source 67 outputs light of intensity p1 in principle while it is emitting light, except that the header portion 6
When the specific bit 61x in 1b is input to one input end of the optical amplification element 65, in synchronization with this (time t _{2 in} FIGS. 7 and 8), the light having the third level p2 of intensity is output. Here, when the specific bit 61x is at a high level (in the case of FIG. 7), p2 and pH are input to the input end of the optical amplification element, and as can be understood from Table 1, the optical amplification element 6
5 outputs the light having the intensity of pH 2 to the non-linear element 37. p
Since the level of H2 is a level that can change the output state of the non-linear element 37, as a result, the output state of the non-linear element 37 becomes the p-ON state (see FIG. 2), and the optical switch element 35 accordingly responds to the data section. 61 is led to the output end 35a. On the other hand, when the specific bit 61x is low level (in the case of FIG. 8), p2 and pL are provided at the input end of the optical amplification element.
Is input, and the optical amplifying element 65 outputs light having an intensity of pL2 to the nonlinear element 37. When the input intensity of the nonlinear element is pL2, the output state of the nonlinear element 37 remains as it is, that is, p-OFF. As a result, the optical switch element 35 guides the data section 61 to the output end 35b. It should be noted that the time other than the time when the specific bit 61x is input to the optical amplification element 65 (time t _{1 to} t ₂ , t in FIGS. 7 and 8)
_{3 to} t ₅ ), since the intensity of the light from the light source 67 is p1, the output intensity of the optical amplifying element 65 can be only pL1 or pH1, and these values are values that can change the output state of the nonlinear element 37. Therefore, the output path of the optical switch element 35 is fixed and does not switch until the data part is output from the desired output end.

After the data portion 61a has finished passing through the inside of the optical switch element 35, the output light intensity of the light source 67 becomes p0,
In addition, since the input on the header side of the optical amplification element 65 is in the no signal state, that is, the pL level, p0 and pL are input to the input end of the optical amplification element 65. As a result, the output state of the non-linear element 37 becomes the p-OFF state, and the device 6
0 becomes a standby state in preparation for the arrival of the next optical packet signal.

In the second invention, the optical switch element 3 is used.
It is possible to provide a header section non-addition means for adding a new header section in the subsequent stage of 5.

2-2. Second Embodiment of Second Invention Next, the optical packet switch device 60 of the first embodiment of the second invention is connected in multiple stages to form a device with one input and multiple outputs, and further, this is arranged in parallel in multiple stages. An example of configuring an optical packet switch device with multiple inputs and outputs will be described. FIG. 9 is a diagram used for the explanation. Here, first, the first aspect of the second invention
By connecting three devices 60 of the embodiment in multiple stages (however, the state in which the data section / header section dividing means 33 is shared is shown), an optical packet switch apparatus 60x with 1 input and 4 outputs.
And further four of them are provided, and between these, output terminals in the same state are connected to each other by the optical multiplexing means 8.
Input to 1, 83, 85 or 87.

When the apparatus of the second embodiment of the second invention is used, the specific bit used in the control light output section of each stage is assigned from the plurality of bits of the header section 61b without duplication. And a bit of. The timing of inputting a specific bit may be adjusted by a known technique.

The first and second inventions described above can be applied to various packet switching systems (for example, ATM switching system and X25 packet formation). Further, although an example of a large-scaled device has been described in each of the above-mentioned first and second inventions, the scale (3 × 3 or 4 × 4) shown there is merely an example.

Further, in the above-mentioned first embodiment of the invention, the optical branching means is used for branching the packet signal in power, but instead of this, means for branching the optical signal according to the optical wavelength and optical branching are used. A means for branching the optical signal depending on the state of the plane of polarization may be used. As an input method of the optical packet signal at this time, there is a method of inputting the same signal to the optical branching means in different wavelengths or polarization states, or a method of inputting the header part and the data part in different wavelengths or polarization states. Conceivable. Here, in the latter case, the nonlinear element 3
The sending of the header portion to the 7 side can be realized by performing the timing at the output state of the light source 63 in FIG. 8 used in the description of the second invention.

[0053]

As is apparent from the above description, according to the first and second inventions of this application, an optical control type optical switch capable of high-speed operation is used as a switch, and the control light thereof is In the first invention, the optical packet signal is generated by using a branched signal and a predetermined non-linear element, and in the second invention, a header portion in the optical packet signal, a predetermined optical amplification element, and a light source. And the non-linear element are used to generate the packet, so that packet switching can be performed by light. Therefore, it is possible to provide an optical packet switch device that can operate at a higher speed than before and can perform header analysis in the optical state without using electrical processing.

Further, since it is possible to omit an O / E conversion unit for analyzing the electric circuit portion for routing processing, which is conventionally required, for example, the header portion, simplification of the apparatus can be expected.

[Brief description of drawings]

1A and 1B are explanatory views of a first embodiment of the first invention.

FIG. 2 is an explanatory diagram of a nonlinear element used in the first and second inventions.

FIG. 3 is a diagram for explaining a second embodiment of the first invention.

4A to 4C are explanatory diagrams of an optical packet signal used in the second embodiment of the first invention.

FIG. 5 is an explanatory diagram of the first embodiment of the second invention.

FIG. 6 is a diagram for explaining an optical amplification element.

FIG. 7 is an operation explanatory view (1) of the device of the second invention.

FIG. 8 is an operation explanatory view (No. 2) of the device of the second invention.

FIG. 9 is an explanatory diagram of a second embodiment of the second invention.

FIG. 10 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

30: Optical packet device of the first embodiment of the first invention 31: Optical packet signal 31 ₁ : One branch optical packet signal 31 ₂ : Other branch optical packet signal 31a: Data part 31ax: Weakly shining bit 31ay: Strongly shining bit 31b: Header part (example of high level) 31bx: Header part (example of low level) 33: Optical branching means 35: Switch element (1 × 2 optical control type optical switch) 35a, 35b: Optical switch Output end 37 of element: Non-linear element 37a: Output end of non-linear element pH2: First value pL0: Second value pL1, pL2, pH1: Value between first value and second value p-ON: 1st state p-OFF: 2nd
State 61: optical packet signal 61a: data part 61b: header part 63: data part /
Header section dividing means 65: Optical amplification element 67: Light source 69: Control light output section 71: Monitoring device

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Hiroshi Ishida 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (4)

[Claims] 1. An optical packet switch device for distributing an optical packet signal including a data section and a header section to a target route, an optical branching unit for branching the optical packet signal, a control light, and the optical branching unit. One of the branched optical packet signals that has been branched is input respectively, and an optical switch element that switches the output route of the one branched optical packet signal depending on the input state of the control light, and the control light of the optical switch element is input. An output end is connected to a terminal for inputting the other branched optical packet signal branched by the optical branching means to the input end, and at the output end when the optical intensity of the input end is equal to or higher than a first value. Light intensity of the first state, the light intensity at the output end becomes the second state when the second value is smaller than the first value, and the first value and And a non-linear element having an input / output characteristic that the light intensity at the output end is maintained at or near the current value at a value between the second value and the second value. . 2. An optical packet switch device comprising the optical packet switch device according to claim 1 connected in multiple stages. 3. An optical packet switch device for allocating an optical packet signal including a data part and a header part to a target route, wherein a data part / header part for dividing the data part and the header part of the optical packet signal. A splitting means, an optical switch element to which the control light and the data portion split by the data portion / header splitting means are respectively inputted, and an output route of the data portion is switched depending on an input state of the control light; An optical packet switch device comprising a control light output unit to which a header part divided by a unit / header part dividing means is input and which includes the following elements (a) to (c). (A) An output end is connected to a terminal for inputting the control light of the optical switch element, and when the input light intensity is equal to or higher than a first value, the light intensity at the output end is in the first state, and the input light is When the intensity is equal to or less than the second value smaller than the first value, the light intensity at the output end is in the second state, and the input light intensity is at a value between the first value and the second value. A non-linear element having an input / output characteristic that the light intensity at the output end is maintained as it is or close to the current state. (B) The output end is connected to the input end of the non-linear element, the header part is input to one input end, and light from a light source described later is input to the other input end. An optical amplification element that outputs an optical signal having an intensity corresponding to the intensity of light from the output end to the nonlinear element. (C) The first level (p0) is shown when the header section is not input to the optical amplification element, and the second level (p1) is shown when the header section is input, and the header section is particularly specified. The light source that indicates the third level (p2) when the bits of are input. However, the first to third levels satisfy the condition of first level <second level <third level, and one level of each bit of the header section is pL and the other level is Is expressed as pH (pL <pH), the following conditions 1 to 4 are satisfied. When pH is input to one input end of the light amplification element and p2 is input to the other input end, the light intensity at the output end of the light amplification element becomes equal to or higher than the first value. When pL is input to one input end of the optical amplification element and p0 is input to the other input end, the light intensity at the output end of the optical amplification element becomes equal to or less than the second value. When the predetermined value other than the above values is input to one input end and the other input end of the optical amplification element, the light intensity at the output end of the optical amplification element is the first value. And a second value. 4. The optical packet switch device according to claim 3 is connected in multiple stages, and the specific bit used in the control optical output section of each stage is allocated from a plurality of bits of the header section without duplication. An optical packet switch device characterized in that it has only one bit.