JP2003005240A - Optical bit string discrimination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert an optical packet signal constituted of a fast serial optical bit string to parallel optical bit strings to read a prescribe optical bit string. SOLUTION: An optical bit string discrimination device is provided with an optical branching device which branches the optical packet signal to an optical path 1 and an optical path 2, a timing generator which takes the optical packet signal branched to the optical path 2 as the input and outputs an electric control signal at the timing corresponding to the input, a sweep wavelength light generation means which takes the electric control signal as the input and generates sweep wavelength light of which the wavelength is changed with time at the bit rate of the optical packet signal, a wavelength conversion means which takes a prescribed optical bit string of the optical packet signal branched to the optical path 1 and the sweep wavelength light as the input at the same timing and converts the wavelength of each optical bit of the prescribed optical bit string to each wavelength of the sweep wavelength light to output it, an optical demultiplexer which demultiplexes the prescribed optical bit string subjected to wavelength conversion by optical bits to respective wavelengths, and optical a receivers which convert optical bits of respective wavelengths demultiplexed by the optical demultiplexer to electric signals and correspond to respective optical bits.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a routing process included in an optical packet signal in each communication node of an optical network system which receives an optical packet signal arriving irregularly from a transmission line and performs a routing process. The present invention relates to an optical bit string identification device for identifying a specific optical bit string for.

[0002]

2. Description of the Related Art Due to the recent rapid spread of the Internet and mobile communication, the rapid increase of data communication, and the speeding up of these communication speeds, there is an urgent need to construct a large capacity communication network. In order to meet such a demand for increasing the transmission capacity, wavelength division multiplexing (WDM) for transmitting a plurality of optical signals having different wavelengths in one optical fiber transmission line.
Transmission systems are being developed. Recently, the number of multiplexes is more than several hundred channels and the transmission capacity exceeds 1 Tbps.
DM transmission systems have been reported.

By the way, the WDM communication technology greatly increases the point-to-point transmission capacity between nodes. However, when constructing a network, the wavelength-multiplexed optical signals in the nodes are separated for each wavelength. It is necessary to route the data packets in the optical signal for each packet. However, it is considered that the routing capacity of a huge amount of signals in electrical processing will reach the limit with the increase in transmission speed and the increase in capacity.

Recently, as a means for solving this problem, a technique of performing routing processing in an optical state (optical layer) without converting an optical packet signal into an electric signal has been attracting attention. Here, the optical packet signal is an optical signal composed of bit strings such as a preamble bit string 51, a destination address bit string 52, a source address bit string 53, and a data bit string 54 as in the frame structure shown in FIG. 9 ( Each bit is written in RZ format). Further, when the transmission source transmits a plurality of optical packet signals, an inter packet gap (inter frame gap) 62 is provided between the optical packet signals 61 as a signal-free time region, as shown in FIG. As a result, each optical packet signal arrives irregularly on the receiving side.

FIG. 11 shows a configuration example of a conventional optical packet routing device. In the figure, an optical packet signal input from each optical transmission line 70 to an input port 71 is partly branched by an optical shunt 72 and input to a destination address discriminator 73, and the rest is input to an optical buffer circuit 75. It is inputted to the optical switch circuit 76 via the. The destination address discriminator 73 reads the destination address after photoelectrically converting the optical packet signal, and the destination address of each optical packet signal is notified to the control circuit 74 as an electric signal. The control circuit 74 controls the optical buffer circuit 75 and the optical switch circuit 76 according to the destination address of each optical packet signal, and transmits each routed optical packet signal from the output port 77 to each optical transmission line 78. But with this configuration,
As the speed of the optical packet signal increases, the destination address discriminator 73 needs to perform high-speed electrical processing, which significantly increases the load on the electric circuit.

Therefore, with the configuration using the optical shunt 81 and the optical delay line 82 shown in FIG. 12, a parallel optical bit string is developed in which the destination address bit string 52 input as the serial optical bit string is expanded spatially in parallel, A method has been proposed in which the optical receiver 83 corresponding to each bit reduces the speed required for reading a destination address bit string. In this method, for example, in the case where a destination address bit string (serial optical bit string) composed of 8 bits is converted into a parallel optical bit string in an optical packet signal composed of a serial optical bit string of a transmission rate of 40 Gbps, the parallel optical bit string The repetition rate becomes 5 Gbps, and the performance required for the optical receiver 83 is relaxed.

[0007]

However, with the parallel optical bit string configuration according to the configuration of FIG. 12, it is possible to reduce the repetition speed required for reading the optical bit string, but the parallel optical bit string is converted with a 1-bit time slot. It is necessary to cut out each optical bit in one time slot time T. That is, the optical receiver 83 is required to have a performance equivalent to a high-speed serial optical bit signal speed in terms of rising and falling, which does not necessarily reduce the load on the electric circuit.

According to the present invention, in an optical bit string discriminating apparatus for converting an optical packet signal composed of a high-speed serial optical bit string into a parallel optical bit string and reading an optical bit, the optical receiver has a performance equivalent to the serial optical bit signal speed. It is an object of the present invention to provide an optical bit string identification device that enables reading of a predetermined optical bit string with a low-speed electric circuit without the need.

[0009]

SUMMARY OF THE INVENTION The present invention relates to an optical bit string discriminating apparatus for discriminating a predetermined optical bit string contained in an input optical packet signal, and an optical shunt for branching the optical packet signal into an optical path 1 and an optical path 2. , A timing generator that inputs an optical packet signal that is shunted to the optical path 2 and outputs an electrical control signal at a timing according to the input, and an electrical control signal from the timing generator is input, and the wavelength is a bit of the optical packet signal. The swept wavelength light generating means for generating swept wavelength light that changes with time according to the rate, the predetermined optical bit string of the optical packet signal shunted to the optical path 1, and the swept wavelength light from the swept wavelength light generating means are provided at the same timing. Wavelength conversion means for inputting and converting the wavelength of a predetermined optical bit string into each wavelength of the swept wavelength light for each optical bit, and for outputting each optical bit output from the wavelength conversion means. An optical demultiplexer that demultiplexes a predetermined optical bit string that has been wavelength-converted into each wavelength, and an optical receiver that supports each optical bit that converts the optical bit of each wavelength demultiplexed by the optical demultiplexer into an electrical signal With.

As a result, the predetermined optical bit string of the optical packet signal is converted into a different wavelength for each optical bit and converted into a parallel optical bit string by the optical demultiplexer. At this time,
There is no subsequent optical bit after each optical bit output to each output port of the optical demultiplexer. Therefore, it becomes unnecessary to gate each optical bit in the conventional parallel optical bit string at a unit bit time corresponding to the transmission speed of the serial optical bit string of the optical packet signal. Therefore, by converting the optical bit string identification device of the present invention into a parallel optical bit string, it is possible to identify a predetermined optical bit string of an optical packet signal using a low-speed electric circuit.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION <First Embodiment> FIG. 1 shows a first embodiment of an optical bit string identifying apparatus of the present invention. Here, a configuration example for inputting the optical packet signal shown in FIG. 9 and identifying the destination address bit string 52 is shown. In addition,
The preamble bit string 51 and the destination address bit string 52 of the optical packet signal are both 8 bits, and the head optical bit of the preamble bit string 51 is "1".

In the figure, an optical bit string identifying device inputs an optical shunt 11 which splits an input optical packet signal into an optical path 1 and an optical path 2, and an optical packet signal which is split into an optical path 2 and outputs an electrical control signal. The timing generator 12 and the swept wavelength light (here, λ1, λ2, ..., λ8) whose wavelength changes temporally at the bit rate of the optical packet signal by inputting the electrical control signal from the timing generator 12 The generated swept wavelength light generator 13, the destination address bit string 52 of the optical packet signal branched to the optical path 1, and the swept wavelength light from the swept wavelength light generator 13 are input at the same timing, and the wavelength of the destination address bit string 52 is optically input. A wavelength converter 14 that converts each wavelength into swept wavelength light and outputs the converted wavelength, and a wavelength-converted destination address block for each optical bit output from the wavelength converter 14. An optical demultiplexer 15 to the door column 52 'for demultiplexing each wavelength, the optical receiver for converting optical bit of each wavelength by the optical demultiplexer 15 is demultiplexed into an electric signal 16-1～16-8
It is composed of

The optical packet signal input to the optical bit string identifying device is split into two optical paths by the optical shunt device 11, and the optical path 1
The optical packet signal shunted to is guided to the wavelength converter 14,
The optical packet signal branched to the optical path 2 is the timing generator 1
Guided to 2. When the optical packet signal of the optical path 2 is input to the timing generator 12, the first optical bit of the preamble bit string 51 of the optical packet signal is received first, and the electrical control signal indicating that the optical packet signal has arrived is swept wavelength optical generator. 13 is sent. Here, the time from the reception of the first optical bit of the preamble bit string 51 of the optical packet signal to the output of the electrical control signal is adjusted to be constant for all the optical packet signals.

The swept wavelength light generator 13 to which the electric control signal is input generates swept wavelength light (λ1 to λ8) whose wavelength changes with time at the bit rate of the optical packet signal. A configuration example of the swept wavelength light generator 13 will be described later.

On the other hand, the optical packet signal shunted to the optical path 1 is input to the wavelength converter 14, so that the destination address bit string 52 and the swept wavelength light from the swept wavelength light generator 13 are input in bit synchronization. , The input timing of both is adjusted. For example, from the first optical bit of the preamble bit string 51 of the optical packet signal to the destination address bit string 5
Since the number of bits is fixed up to 2, the output timing of the electrical control signal output from the timing generator 12 is adjusted, and the swept wavelength light output from the swept wavelength light generator 13 is adjusted according to the electrical control signal. Output timing, or the optical path length of the optical path 1 or the optical path 2 is adjusted. As a result, the destination address bit string 52 becomes a destination address bit string 52 ′ converted into each wavelength λ1, λ2, ..., λ8 of the swept wavelength light for each optical bit. Here, since the fourth bit and the sixth bit are “0”, the optical bits of the wavelengths λ4 and λ6 are not output.

Destination address bit string 5 converted by the wavelength converter 14 into different wavelengths λ1 to λ8 for each optical bit
2'is input to the optical demultiplexer 15 and demultiplexed for each wavelength. However, each optical bit is output to the output port of the optical demultiplexer 15 with a time difference of 1 bit, but there is no subsequent optical bit, and the destination address bit string 52 ′ is separated by 1 bit and parallel optical signals are output. Convert to a bit string. Each optical bit is individually received by the optical receivers 16-1 to 16-8 and converted into an electric signal. This optical receiver has only to perform the receiving process with a time width of 8 bits of the destination address bit string 52 at least every frame period of the optical packet signal, and high-speed processing as in the past is not required.

The optical receivers 16-1 to 16-8 receive the optical bits of the destination address bit string 52 'at a timing shifted by one bit. Therefore, the detection result should be latched. To configure. Alternatively, the optical demultiplexer 15 and the optical receiver 16 as in the second embodiment described below.
An optical delay line may be arranged between -1 to 16-8 so that the demultiplexed optical bits are received at substantially the same timing.

<Second Embodiment> FIG. 2 shows a second embodiment of the optical bit string identifying apparatus of the present invention. Here, the configuration after the optical demultiplexer 15 in the first embodiment will be shown, but the other configurations are the same as those in the first embodiment.
The time interval between the optical bits of the optical packet signal is T. For example, if the signal speed of the optical packet signal is 40 Gbps, T will be 25 ps.

In the figure, an optical demultiplexer 15 and an optical receiver 16 are shown.
Optical delay lines 17-1 to 17-8, which give time delays of 8T to T, are inserted between -1 to 16-8. As a result, the optical bits having the wavelength λ1 to the optical bit having the wavelength λ8 are respectively received by the optical receivers 16-1 to 16-8 at the same time. The delay time set by the optical delay lines 17 to 1 to 17-8 is only required so that the demultiplexed optical bits are received at substantially the same timing.
There is no need for strict time adjustment in bit units such as cutting out a parallel optical bit string at a predetermined timing as in the conventional case.

<Structural Example of Swept Wavelength Light Generator 13> FIGS.
6 shows a configuration example of the swept wavelength light generator 13. The swept wavelength light generator 13 of FIG. 3 is composed of a multi-electrode diffraction grating distributed reflection type semiconductor laser 21 and its control circuit 22. The control circuit 22 controls the multi-electrode diffraction grating distributed reflection type semiconductor laser 21 at a predetermined timing according to the input of the electric control signal from the timing generator 12, and the wavelength is plotted on the time axis as shown in FIG. 7 (a). Output a swept wavelength light that changes continuously. However, the wavelengths λ1, λ2, ..., λ8 are set at the timing corresponding to the bit rate of the optical packet signal.

The swept wavelength light generator 13 shown in FIG. 4 is a wavelength shifter 27 which is loop-connected with a semiconductor laser 23 that outputs an optical pulse having a single wavelength λ1 and its control circuit 24 via an optical coupler 25 and an optical fiber 26. It is composed of The control circuit 24 controls the semiconductor laser 23 at a predetermined timing according to the input of the electric control signal from the timing generator 12, and outputs an optical pulse of wavelength λ1. This optical pulse is branched and output via the optical coupler 25, and is again input to the optical coupler 25 via the optical fiber 26 and the wavelength shifter 27, and the same branched output is repeated. Here, the wavelength shifter 27 shifts the wavelength each time an optical pulse passes, and sequentially shifts from the wavelength λ1 to λ2 and the wavelength λ2 to λ3 to the wavelength λ8. Furthermore, the loop length of the optical fiber 26 is set to 1 of the optical packet signal.
By making the number equivalent to bits, as shown in FIG. 7 (b), as the swept wavelength light in which the wavelength discretely changes on the time axis, the wavelength λ is generated at the timing corresponding to the bit rate of the optical packet signal
The optical pulses of 1, λ2, ..., λ8 are sequentially output.

The configuration shown in FIG. 4 is a principle one. For example, an optical amplifier inserted in the optical fiber 26 for compensating the branch loss in the optical coupler 25 and a wavelength λ8.
An optical switch for terminating the output of the optical pulse of is provided if necessary.

The swept wavelength light generator 13 shown in FIG.
~ Semiconductor lasers 28-1 and 28-2 for outputting optical pulse of λ8
8-8, a control circuit 29 therefor, and an optical multiplexer 30 that multiplexes and outputs the output light pulses of the semiconductor lasers. The control circuit 29 controls the semiconductor lasers 28-1 to 28-8 at a predetermined timing according to the input of the electrical control signal from the timing generator 12, and outputs the optical pulses of wavelengths λ1 to λ8 to the bit rate of the optical packet signal. Are sequentially generated at a timing according to. Each optical pulse is combined through the optical multiplexer 30, and is output as a swept wavelength light whose wavelength discretely changes on the time axis as shown in FIG. 7B.

Alternatively, the semiconductor lasers 28-1 to 28-
It is also possible to simultaneously generate optical pulses of wavelengths λ1 to λ8 from 8 and delay them by 1 bit using an optical delay line as shown in FIG.

The swept wavelength light generator 13 shown in FIG. 6A has a white pulse light source 31 for outputting a white light pulse including wavelengths λ1 to λ8, a control circuit 32 for the white pulse light source 31, and a white light pulse having a wavelength λ.
Optical demultiplexer 33 for demultiplexing into optical pulses of 1 to λ8, optical delay lines 34-1 to 34-8 for sequentially delaying optical pulses of respective wavelengths by 1 bit, and respective wavelengths adjusted for delay. It is composed of an optical multiplexer 35 which multiplexes and outputs the optical pulse of. The control circuit 32 controls the white pulse light source 31 at a predetermined timing according to the input of the electric control signal from the timing generator 12 to generate a white light pulse. This white light pulse is demultiplexed by the optical demultiplexer 33 into light pulses having wavelengths λ1 to λ8, and each light pulse is converted into an optical delay line 34-1 to 34.
It is sequentially output at a timing corresponding to the bit rate of the optical packet signal via -8 and the optical multiplexer 35.

As the white pulse light source 31, a supercontinuum light source or a super luminescent diode can be used. Further, instead of the optical demultiplexer 33, the optical delay line 34, and the optical multiplexer 35,
As shown in FIG. 6 (b), a grating filter 36 that delays one bit each for optical pulses of wavelengths λ1 to λ8 and sequentially reflects it, and a white light pulse input to the grating filter 36 and each wavelength output The optical circulator 37 that separates the optical pulse may be used.

<Configuration Example of Wavelength Converter 14> FIG. 8 shows a configuration example of the wavelength converter 14. In the figure, wavelengths λ1 to λ
The swept wavelength light (converted light) of 8 is converted to 2 by the optical coupler 41-1.
Two semiconductor optical amplifiers (SOA) 42-1, 4 branched
2-2 is input. The destination address bit string (signal light) 52 of the optical packet signal of wavelength λs is the optical coupler 41-2.
Is input to one of the semiconductor optical amplifiers 42-1 from the opposite direction via. Two semiconductor optical amplifiers 42-1 and 42-2
The output light of is combined by the optical coupler 41-3. A Mach-Zehnder interferometer is configured by the optical coupler 41-1, the semiconductor optical amplifiers 42-1 and 42-2, and the optical coupler 41-3.

When the signal light is input to the semiconductor optical amplifier 42-1, the refractive index changes and the phase of the converted light passing therethrough changes. Therefore, the two semiconductor optical amplifiers 42-
Phases of the respective converted lights extracted to the output ends of 1 and 42-2 are different, and when they are combined by the optical coupler 41-3, the phase change appears as an intensity change, and the output end thereof has a signal light of the wavelength λs. The converted lights of the wavelengths λ1 to λ8 having the same logic (or inversion logic) are output as wavelength converted light.

Although the example using the Mach-Zehnder interferometer type wavelength converter utilizing the cross phase modulation characteristic of the semiconductor optical amplifier is shown here, the wavelength converter utilizing the cross gain modulation characteristic of the semiconductor optical amplifier is also used. can do. However, in that case, since a specific optical bit string whose wavelength has been converted is logically inverted and output, it is necessary to logically invert the bit detection result in the optical receiver.

<Example of Other Configurations of Optical Demultiplexer 15> As the optical demultiplexer 15, an arrayed waveguide diffraction grating type filter (AW) is used.
G) can be used. An optical fiber can be used as the optical delay line 17.

[0031]

As described above, the optical bit string discriminating apparatus of the present invention converts a predetermined optical bit string to be discriminated into a different wavelength for each bit in a high-speed optical packet signal input by a serial optical bit string. Since the optical bit string is configured as a parallel optical bit string, each optical bit does not become a continuous optical pulse string, and a predetermined optical bit string can be received and identified in each optical bit unit by using a low-speed electric circuit.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an optical bit string identification device of the present invention.

FIG. 2 is a diagram showing a second embodiment (main part) of an optical bit string identification device of the present invention.

FIG. 3 is a diagram showing a configuration example of a swept wavelength light generator 13.

FIG. 4 is a diagram showing a configuration example of a swept wavelength light generator 13.

FIG. 5 is a diagram showing a configuration example of a swept wavelength light generator 13.

FIG. 6 is a diagram showing a configuration example of a swept wavelength light generator 13.

FIG. 7 is a diagram showing swept wavelength light output from the swept wavelength light generator 13.

FIG. 8 is a diagram showing a configuration example of a wavelength converter 14.

FIG. 9 is a diagram showing a frame structure of an optical packet signal.

FIG. 10 is a diagram showing a transmission situation of an optical packet signal.

FIG. 11 is a diagram showing a configuration example of a conventional optical packet routing device.

FIG. 12 is a diagram showing a configuration example of a destination address discriminator 73.

[Explanation of symbols]

11 Optical shunt 12 Timing generator 13 Swept wavelength light generator 14 Wavelength converter 15 Optical demultiplexer 16 Optical receiver 17 Optical delay line 21 Multi-electrode diffraction grating distributed reflection type semiconductor laser 22 Control circuit 23 Semiconductor laser 24 Control circuit 25 Optical coupler 26 optical fiber 27 wavelength shifter 28 Semiconductor laser 29 Control circuit 30 Optical multiplexer 31 White pulse light source 32 control circuit 33 Optical demultiplexer 34 Optical delay line 35 Optical multiplexer 36 Grating filter 37 Optical circulator 41 Optical coupler 42 Semiconductor optical amplifier 51 preamble bit string 52 Destination address bit string 53 Source address bit string 54 data bit strings

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Sakamoto             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Yoshihisa KAI             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Noguchi alone             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation (72) Inventor Shigeto Matsuoka             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 2K002 AA02 AB01 AB12 AB18 BA01                       CA13 DA08 DA10 DA11 EA28                       EA30                 5K002 AA03 BA02 BA06 BA13 CA05                       DA01                 5K069 BA09 CB10 DB33 DB41 EA20                       EA22 EA24 EA25 EA26

Claims (10)

[Claims] 1. An optical bit string identifying device for identifying a predetermined optical bit string included in an input optical packet signal, comprising: an optical shunt that splits the optical packet signal into an optical path 1 and an optical path 2; A timing generator that inputs an optical packet signal and outputs an electrical control signal at a timing according to the input, and an electrical control signal from the timing generator is input, and the wavelength is determined according to the bit rate of the optical packet signal. A swept wavelength light generating means for generating a swept wavelength light that changes with time, a predetermined optical bit string of the optical packet signal shunted to the optical path 1 and the swept wavelength light from the swept wavelength light generating means are input at the same timing. , A wavelength conversion unit for converting the wavelength of a predetermined optical bit string into each wavelength of the swept wavelength light for each optical bit and outputting the wavelength, and each optical converter output from the wavelength conversion unit. Optical demultiplexer that demultiplexes a predetermined optical bit string wavelength-converted for each wavelength into each wavelength, and an optical demultiplexer that converts the optical bit of each wavelength demultiplexed by the optical demultiplexer into an electrical signal An optical bit string identification device comprising an optical receiver. 2. The optical bit string identification device according to claim 1, wherein the swept wavelength light generation means includes a multi-electrode diffraction grating distributed reflection type semiconductor laser and a control circuit thereof, and the control circuit is the timing generator. The multi-electrode diffraction grating distributed reflection type semiconductor laser is controlled so that the output wavelength is sequentially shifted according to the bit rate of the optical packet signal by the input of the electric control signal from, and the wavelength is continuously changed on the time axis. An optical bit string discriminating device having a configuration for outputting a swept wavelength light. 3. The optical bit string identification device according to claim 1, wherein the swept wavelength light generation means outputs a light pulse of a single wavelength and its control circuit, and outputs the output light pulse to the optical packet signal. And a wavelength shift means for sequentially wavelength-shifting and outputting at a bit rate of, the control circuit controls the light source at a predetermined timing according to the input of the electrical control signal from the timing generator, and an optical pulse to be output. An optical bit string identifying device having a configuration for outputting swept wavelength light whose wavelength discretely changes on the time axis via the wavelength shift means. 4. The optical bit string identification device according to claim 1, wherein the swept wavelength light generation means multiplexes an optical pulse output from each light source with a light source and a control circuit for outputting an optical pulse having a different wavelength. And an optical multiplexer to output, the control circuit controls each light source at a predetermined timing according to the input of the electrical control signal from the timing generator,
An optical bit string identification device having a configuration in which an output optical pulse is configured to output a swept wavelength light whose wavelength discretely changes on a time axis through an optical multiplexer. 5. The optical bitstream identification device according to claim 1, wherein the swept wavelength light generation means includes a white pulse light source that outputs a white light pulse and its control circuit, and an optical pulse having a different wavelength for the white light pulse. An optical demultiplexer for demultiplexing the optical packet, and output means for sequentially outputting optical pulses of each wavelength according to the bit rate of the optical packet signal, wherein the control circuit inputs an electrical control signal from the timing generator. The white pulse light source is controlled at a predetermined timing according to the above, and the output white light pulse is output through the optical demultiplexer and the output means to the swept wavelength light whose wavelength changes continuously or discretely on the time axis. An optical bit string identification device having a configuration for outputting. 6. The optical bit string identifying device according to claim 5, wherein the white pulse light source is a supercontinuum light source. 7. The optical bit string identifying device according to claim 5, wherein the white pulse light source is a super luminescent diode. 8. The optical bit string identification device according to claim 1, wherein the wavelength conversion means is a configuration using a Mach-Zehnder interferometer type wavelength converter that utilizes the mutual phase modulation characteristic of a semiconductor optical amplifier. Optical bit string identification device. 9. The optical bit string identifying apparatus according to claim 1, wherein the wavelength converting means is a structure using a wavelength converter utilizing the mutual gain modulation characteristic of a semiconductor optical amplifier. Identification device. 10. The optical bit string identification device according to claim 1, wherein the optical demultiplexer is an arrayed waveguide diffraction grating type filter.