JP2002164847A - Optical packet route switch, optical transmitter, optical packet route switching method and optical communication system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical packet route switch with high utilization efficiency of wavelength bandwidth without requiring a high-speed digital circuit. SOLUTION: An optical packet multiplexed signal in which of a modulated address signal obtained by multilevel-modulating an address signal and data signal is sub-carrier multiplexed is input. The input optical packet-multiplexing signal is converted into an electric signal in an opto-electric converter 13, and then the modulated address signal is extracted and demodulated in an address demodulator 14. The address signal is maintained on a certain level within a transmission period of one data packet. A route of the input optical packet- multiplexed signal is switched according to the address signal level. Because change speed of the address signal is lower than the clock rate of data, a high speed digital circuit is not necessary. In addition, because an optical signal having only one wavelength is used, sufficient utilization efficiency of wavelength bandwidth can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and an optical transmitting apparatus for switching the path of an optical signal, an optical communication system including the same, and an optical packet path switching system used in the optical communication system.

[0002]

2. Description of the Related Art With the recent spread of the use of the Internet, the amount of data transmitted on a network has been rapidly increasing. Accordingly, the processing speed of a router using a digital electronic circuit (hereinafter referred to as an electric router) is a limiting factor of the speed of a network, and is a problem in further increasing the transmission capacity. As a technique for solving this, optical routing has attracted attention, and wavelength routing has been widely studied.

FIG. 15 is a block diagram showing an example of a conventional optical routing system using wavelength routing. This optical routing system includes a wavelength tunable light source 52 and an optical modulator 53 in a transmitting station 51, and a wavelength separating unit 55 in a relay station.

In a transmitting station 51, a tunable light source 52
Outputs light of a wavelength corresponding to a receiving station that is a destination (address) of data to be transmitted. The optical modulator 53 modulates the light output from the variable wavelength light source 52 according to the input data and outputs the modulated light. The wavelength separating unit 55 of the relay station 54 includes one input port and a plurality of output ports respectively corresponding to the wavelengths assigned to the respective receiving stations, and converts the input optical signal into the output port corresponding to the wavelength. Output from An arrayed waveguide grating optical filter, which is generally a passive optical device, is used for the wavelength separating section 55. The optical signal output from each output port is transmitted to another receiving station (not shown). Here, it is assumed that the number of receiving stations is N.

Next, the flow of an optical signal in the optical routing system will be described with reference to FIG. FIG.
As shown in FIG. 6A, the wavelengths of the optical signals input to the wavelength demultiplexing unit 55 are λ1 (corresponding to the receiving station 1), λ2 (corresponding to the receiving station 2),. ). In this case, during the period when the wavelength is λ1, an optical signal is output only from the output port connected to the receiving station 1,
During the period when the wavelength is λ2, an optical signal is output only from the output port connected to the receiving station 2 (see FIGS. 16B and 16C). Similarly, during a period when an optical signal of a wavelength corresponding to a certain receiving station is input, an optical signal is output only from an output port connected to the receiving station. Therefore, each receiving station receives only the optical signal addressed to itself.

[0006]

The conventional optical routing system described above uses only passive optical devices for signal routing in a relay station and does not require a digital electronic circuit. High-speed routing can be performed. However, despite the fact that the total transmission capacity is the same as when an optical signal of one wavelength is used, there is a problem that the use efficiency of the wavelength band is poor because a plurality of wavelengths are used.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the wavelength band utilization efficiency has been improved while maintaining the advantage of a conventional optical routing system that does not require a high-speed digital electronic circuit. It is an object of the present invention to provide an optical packet path switching device, an optical transmitting device, and an optical packet path switching method, and an optical communication system using these.

[0008]

An optical packet path switching device according to a first aspect of the present invention converts an electric signal including a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations into an optical signal. An optical packet path switching device that receives the converted optical packet multiplexed signal, and outputs a plurality of optical packet signals obtained by separating the optical packet multiplexed signal from a plurality of output terminals respectively corresponding to a plurality of the receiving stations. The optical packet multiplexed signal is a modulated address signal generated by modulating an address signal including information corresponding to each of the receiving stations transmitting the plurality of data packets by a predetermined modulation method using a carrier of a predetermined frequency. An electric signal obtained by frequency-multiplexing the packet multiplexed signal obtained by multiplexing the plurality of data packets in time series The converted optical signal, wherein the address signal is synchronized with a section corresponding to the data packet multiplexed in the optical packet multiplexed signal, and the data packet and the receiving station that receives the data packet are synchronized. Correspondence, and predetermined address information for performing the extraction of the data packet, respectively, for each of the plurality of data packets over the section, the optical packet path switching device, a photoelectric conversion unit, An address demodulation unit, a path control unit, and a path switching unit, wherein the opto-electric conversion unit converts the input optical packet multiplex signal into an electric signal and outputs the electric signal, and the address demodulation unit is Extracting the modulated address signal from the electrical signal output from the photoelectric converter, outputting the address signal obtained by demodulating the modulated address signal, The path control unit generates and outputs a predetermined control signal based on the address information included in the address signal output from the address demodulation unit, and the path switching unit outputs a plurality of control signals corresponding to a plurality of receiving stations. Having an output terminal of the optical packet multiplexed signal and the control signal output by the path control unit are input, the optical packet multiplexed signal is separated, and a plurality of the optical packet multiplexed signals are separated based on the control signal. One of the output terminals is selected, and a plurality of optical packet signals obtained by separating the optical packet multiplexed signal are output from the selected output terminals.

An optical packet path switching device according to a second aspect of the present invention comprises:
A plurality of optical packets into which an optical packet multiplex signal obtained by converting an electric signal including a packet multiplex signal obtained by multiplexing a plurality of data packets transmitted to each of a plurality of receiving stations into an optical signal is inputted, and the optical packet multiplex signal is separated. An optical packet path switching device that outputs a signal from a plurality of output terminals respectively corresponding to a plurality of receiving stations, wherein the optical packet multiplexed signal corresponds to each of the receiving stations respectively transmitting a plurality of the data packets. A plurality of modulated address signals generated by respectively modulating a plurality of address signals using a carrier having a predetermined frequency by a predetermined modulation method, and the packet multiplexed signal obtained by multiplexing a plurality of the data packets in a time series. An optical signal obtained by converting an electric signal obtained by multiplexing, wherein each of the plurality of address signals is Predetermined address information corresponding to the receiving station that receives the data packet in the optical packet multiplexed signal and synchronized with a section corresponding to the data packet multiplexed in the optical packet multiplexed signal is provided over the section. The optical packet path switching device,
A photoelectric conversion unit, a plurality of address demodulation units, and a path switching unit, wherein the photoelectric conversion unit converts the input optical packet multiplexed signal into an electric signal, Output, each of the plurality of address demodulators extracts one predetermined modulation address signal from the electric signal output from the photoelectric converter, and converts the address signal obtained by demodulating the modulation address signal. Output, the path switching unit has a plurality of output terminals corresponding to a plurality of receiving stations, respectively, the input optical packet multiplexed signal and the plurality of address signals output from the plurality of address demodulation units, respectively. One of the plurality of output terminals is selected based on the address information, and a plurality of optical packet signals obtained by separating the optical packet multiplex signal are selected. And outputting from each of the serial output terminal.

An optical packet path switching device according to a third aspect of the present invention comprises:
In the first or second aspect, the modulation address signal is an amplitude modulation signal based on the address signal,
The address demodulation unit includes an electric filter that extracts the modulation address signal from the electric signal output from the photoelectric conversion unit, and an amplitude demodulation unit that demodulates the modulation address signal.

An optical packet path switching device according to a fourth aspect of the present invention comprises:
In the first or second aspect, the modulation address signal is a phase modulation signal based on the address signal,
The address demodulation unit includes an electric filter for extracting the modulation address signal from the electric signal output from the photoelectric conversion unit, and a phase demodulation unit for demodulating the modulation address signal.

An optical packet path switching device according to a fifth invention comprises:
The invention according to any one of the first to fourth inventions, further comprising an optical delay unit that is inserted and connected before the path switching device and that delays the optical packet multiplexed signal.

According to a sixth aspect of the present invention, there is provided an optical transmission apparatus comprising: a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations in a time series; A plurality of address information indicating respective correspondence with the receiving station, and an optical packet obtained by converting an electrical signal including an address signal generated based on the plurality of address information and the packet multiplexed signal into an optical signal. An optical transmitter for outputting a multiplexed signal, based on a plurality of input address information, for each of a plurality of data packets, synchronized with a section corresponding to the data packet multiplexed in the packet multiplexed signal. The predetermined information for performing the extraction of the data packet and the correspondence of the receiving station that receives the data packet, respectively, An address converter that generates an address signal having the same, and a modulated address signal obtained by converting the address signal output from the address converter using a predetermined modulation method using a carrier having a predetermined frequency. An address modulation unit, a frequency multiplexing unit that frequency-multiplexes the modulated address signal output from the address modulation unit together with the input packet multiplexed signal, and converts an electric signal output from the frequency multiplexing unit into an optical signal. And an electro-optical conversion unit.

According to a seventh aspect of the present invention, there is provided an optical transmitting apparatus comprising: a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations in a time series; A plurality of address information indicating respective correspondences with the receiving stations, and converting an electric signal including a plurality of address signals generated based on the plurality of address information and the packet multiplexed signal into an optical signal. An optical transmitter for outputting an optical packet multiplexed signal, based on the plurality of input address information, the predetermined information synchronized with the section corresponding to the data packet multiplexed in the packet multiplexed signal, A plurality of address signals having an interval are generated for each of the plurality of data packets multiplexed in the packet multiplexed signal. A dress conversion unit, provided in correspondence with the plurality of address signals output from the address conversion unit, and using a carrier having a predetermined frequency different from each other, outputting a modulation address signal obtained by conversion according to a predetermined modulation method. A plurality of address modulating units, a frequency multiplexing unit that frequency-multiplexes the plurality of modulated address signals output from the address modulating unit together with the packet multiplexed signal, and an optical signal output from the frequency multiplexing unit. And an electro-optical converter for converting the light into an electric light.

An optical transmission apparatus according to an eighth aspect of the present invention is the optical transmission apparatus according to the sixth or seventh aspect, further comprising a connection inserted before the frequency multiplexing unit for inputting the packet multiplexed signal, for delaying the packet multiplexed signal. It is characterized by having a part.

A ninth aspect of the present invention provides an optical packet path switching system,
An optical packet to which an optical packet multiplexed signal obtained by converting an electric signal including a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations into an optical signal is inputted, and the transmission path is appropriately switched and outputted. A path switching method, wherein the optical packet multiplexed signal is obtained by modulating an address signal including information corresponding to each of the receiving stations transmitting a plurality of the data packets by a predetermined modulation method using a carrier having a predetermined frequency. An optical signal obtained by converting an electrical signal obtained by frequency-multiplexing the generated modulated address signal and the packet multiplexed signal obtained by multiplexing the plurality of data packets in time series, wherein the address signal is the optical signal. The data packet and the data are synchronized with a section corresponding to the data packet multiplexed in the packet multiplex signal. The plurality of data packets for each of the plurality of data packets over the interval, corresponding to the reception station that receives the packet and extracting the data packets. The packet multiplex signal is converted to an electric signal, a modulated address signal is extracted from the electric signal, the modulated address signal is demodulated, and the optical packet is demodulated based on the address information included in the demodulated address signal. A path of the optical packet signal from which a multiplex signal is separated is switched.

According to a tenth aspect of the present invention, in the optical packet path switching system according to the ninth aspect, the timing of starting the transmission of the address signal is compared with the timing of starting the transmission of the data packet. It is characterized in that it is set earlier by a time corresponding to a delay time generated at the time of switching.

An optical packet path switching system according to an eleventh invention is the optical packet switching system according to the ninth invention, wherein a plurality of the modulated address signals are provided and frequency-multiplexed.

An optical communication system according to a twelfth aspect is characterized in that
The optical packet path switching device according to any of the fifth aspect and the sixth aspect,
To an optical transmission device according to any one of the eighth to eighth aspects.

An optical communication system according to a thirteenth aspect of the present invention provides the optical transmission apparatus according to any one of the sixth to eighth aspects, wherein the optical transmission apparatus transmits the plurality of optical packet multiplexed signals having different wavelengths from each other. The same number of first to fifth optical transmitters
An optical packet path switching device according to any one of the above aspects of the invention.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a block diagram of an optical packet path switching device according to Embodiment 1 of the present invention. 1, the optical packet path switching device includes an optical branching unit 11, a path switching unit 12, an optical-electrical conversion unit 13, an address demodulation unit 14, and a path control unit 15.
The path switching unit 12 includes an optical input terminal 16 and an optical output terminal 17.
1 to 17N. Hereinafter, an operation of the optical packet path switching device according to the present embodiment will be described with reference to FIG.

The signal input to the optical packet path switching device is obtained by modulating an address signal including information corresponding to each of the receiving stations transmitting a plurality of data packets by using a carrier having a predetermined frequency by a predetermined modulation method. An optical packet multiplexed signal obtained by converting an electric signal obtained by frequency-multiplexing the generated modulated address signal and a packet multiplexed signal obtained by multiplexing the plurality of data packets in time series into an optical signal.

The optical branching unit 11 branches the input optical packet multiplex signal. The path switching unit 12 includes a path control unit 15
Output terminal 1 according to a predetermined control signal output from
One of the signals 71 to 17N is selected to output an optical packet multiplexed signal input to the optical input terminal 16. The opto-electric converter 13 converts the optical packet multiplex signal into an electric signal. The address demodulation unit 14 extracts a modulated address signal indicating the destination of the data signal from the electric signal output from the photoelectric conversion unit 13 and reproduces and outputs the address signal by demodulation. The path control unit 15 generates the control signal based on the address signal output from the address demodulation unit 14 and inputs the control signal to the path switching unit 12. Each light output terminal 171-17N
Are connected to a plurality of corresponding receiving stations (not shown) via optical transmission lines (not shown).

Next, in this embodiment, the format of the transmission signal and the path switching operation of the optical signal will be described in detail with reference to FIGS. As shown in FIG. 2, the input optical packet multiplex signal is a signal obtained by converting a signal obtained by frequency-multiplexing a data signal and a modulation address signal into an optical signal. Here, as shown in FIG. 3A, the address signal is a signal having address information uniquely corresponding to each of the plurality of receiving stations as a level value as shown in FIG. On the other hand, the level “1” is assigned to the receiving station 2 and the level “2” is assigned to the receiving station 2. Next, as shown in FIG. 3 (b), the modulated address signal is a signal obtained by multi-level modulation of a carrier having a predetermined frequency uniquely corresponding to the level of the address signal.

On the other hand, the data signal is a signal composed of a packet transmitted to each receiving station. Here, the data packet transmitted to the k-th (k = 1, 2,..., N) receiving station among the N receiving stations is Dk. The data packet is transmitted in the order of D1, D2,..., DN, for example, as shown in FIG. A signal transmitted by arranging data packets in time series in this manner is a packet multiplexed signal.

In the transmission period of each data signal, the modulated address signal and the address signal hold the level corresponding to the receiving station to which the data packet is to be transmitted. For example, during the transmission period of the data packet addressed to the receiving station 1, the level of the address signal (modulation information of the modulated address signal) holds "1", and during the transmission period of the data packet addressed to the receiving station 2, the address signal is maintained. (Modulation information of the modulation address signal) always holds “2”. A partial optical signal corresponding to each data packet in an optical packet multiplexed signal obtained by frequency-multiplexing the modulated address signal and the data signal and converting the signal into an optical signal is referred to as an optical packet.

The path control unit 15 switches the path by a predetermined control signal so that the optical packet is output from the optical output terminal connected to the receiving station to the receiving station corresponding to the level of the address signal. The unit 12 is controlled. For example, when the level of the address signal is "1", the light output terminal 1
71, the optical packet is output from the optical output terminal 172 when the level is "2". By matching the timings during the period in which the optical packet and the address signal are sent in the path switching unit 12, each optical packet can be output without the processing of controlling the propagation delay time, etc. Output spontaneously only from the terminal (Fig. 3
(See (d) to (f)). By the procedure described above, the path of the optical packet can be switched.

In the present embodiment, the optical packet transmitted to the receiving station is switched once without converting the optical packet into an electrical signal, and only the address signal is electrically processed. In addition, the same period as the length of each optical packet,
By adopting a configuration in which the address signal keeps a constant level, compared with the conventional route switching method using an electric router that performs the address extraction processing at the same speed as the clock rate of the data signal, the same processing can be performed with lower speed and easier processing. The effect of can be obtained. Also, despite using only one wavelength optical signal, it realizes the same function as the conventional optical routing system using routing of a plurality of wavelengths, and greatly improves the wavelength utilization efficiency.

Next, another signal format of the present embodiment will be described. In this signal format, the number of levels of an address signal (modulated address signal) is determined by the optical output terminal 171.
The signal format is the same as the signal format described with reference to FIGS. In the signal format of FIG. 3, the number of optical output terminals 171 to 17N and the number of address signal levels are set to be equal, and an optical packet is set to be output from any one of the optical output terminals 171 to 17N. Is not compatible with so-called multicast, which transmits all broadcasts to a plurality of receiving stations simultaneously and simultaneously. In this signal format, as shown in FIG. 4, in the level setting of the address signal, a level indicating multicast (N + 1 in the figure) is added in addition to the level corresponding to each receiving station. Then, when an address signal of a level indicating multicast is input to the path control unit 15, control is performed such that the optical packet is output from the optical output terminal to all or a plurality of predetermined receiving stations. As a result, multicasting of optical packets can be realized.

Although FIGS. 3 and 4 show an example in which the transmission order of the optical packets is D1, D2,..., DN,
The transmission order of the optical packets is not limited to this, and may be any order, and the length of the optical packet may not be constant. Further, in the above description, the address signal sent from the address demodulation unit 14 to the path control unit 15 has been described as one level information having multiple values. However, the digital information representing the level may be transferred in a parallel form. Further, each of the optical output terminals 171 to 17N may be connected to a facility such as a relay station as well as a receiving station.

As described above, in the present embodiment, the address information is frequency-multiplexed together with the data packet as a carrier modulation signal, and a constant level is maintained for the same period and at the same timing as the length of the data packet. Does not require high-speed digital signal processing, and can achieve optical packet path switching with a simpler configuration. In addition, although the configuration uses only one wavelength of light, the same function as the conventional optical routing system is realized, and the wavelength use efficiency can be improved.

(Embodiment 2) FIG. 5 is a block diagram of an optical packet path switching device according to Embodiment 2 of the present invention. In the configuration described in Embodiment 1, an optical delay unit 18 is provided. Hereinafter, an operation of the optical packet path switching device according to the present embodiment will be described with reference to FIG. The description of the same components as those in the first embodiment is omitted.

In the first embodiment having the configuration shown in FIG. 1, it is assumed that there is no delay time generated at the time of the route switching operation in the route switching unit. However, if the delay time cannot be ignored, it is shown in FIG. Thus, the configuration including the optical delay unit 18 is adopted. Here, the optical delay unit 18 is provided with the photoelectric conversion unit 13.
The delay time equivalent to the sum of the delay times required for the photoelectric conversion of the optical packet multiplexed signal, the extraction and demodulation of the modulated address signal by the address demodulation unit 14 and the path switching by the path control unit 15 and the path switching unit 12 is calculated by the optical packet multiplexing. Give to the signal. Thus, the timing at which the optical packet and the address signal in the optical packet multiplexed signal are input to the path switching unit 12 can be matched, and the same effect as that of the first embodiment having the configuration of FIG. 1 can be obtained.

(Embodiment 3) FIG. 6 is a block diagram of an optical packet path switching device according to Embodiment 3 of the present invention. 6, the optical packet path switching device includes an optical branching unit 11, a path switching unit 12, a photoelectric conversion unit 13
, An address demodulation unit 14 and a path control unit 15. Further, the address demodulation unit includes an electric filter 22,
And an amplitude demodulation circuit 23. The path switching unit 12
Has an optical input terminal 16 and optical output terminals 171 to 17N. Hereinafter, the operation of the optical packet path switching device according to the present embodiment will be described with reference to FIG.

In this embodiment, the configuration of the address demodulation unit 14 in the configuration of FIG. 1 described in the first embodiment is further embodied. Optical branching unit 11 and path switching unit 12
The functions of the photoelectric conversion unit 13 and the path control unit 15 are the same as those described in the first embodiment. In the address demodulation unit 14, the electric filter 22 includes the photoelectric conversion unit 13.
A modulation address signal is extracted from the electric signal output from the controller. The amplitude demodulation circuit 23 demodulates the modulated address signal output from the electric filter 22.

The optical packet multiplexed signal in this embodiment is almost the same as the optical packet multiplexed signal in Embodiment 1 shown in FIG. 2, and the modulation method of the modulation address signal is multi-level amplitude modulation (multi-level ASK modulation). ). In the present embodiment, this can be realized with a simple configuration by using an envelope detection circuit as the amplitude demodulation circuit 23. Note that the configuration of the amplitude demodulation circuit 23 is not limited to the envelope detection circuit, and any configuration may be used as long as the circuit can demodulate an amplitude-modulated signal. As described above, this embodiment has an advantage that the address signal can be demodulated with a simpler circuit, in addition to the same advantages as the first embodiment.

(Embodiment 4) FIG. 7 is a block diagram of an optical packet path switching device according to Embodiment 4 of the present invention. In FIG. 7, the optical packet path switching device includes an optical branching unit 11, a path switching unit 12, a photoelectric conversion unit 13
, An address demodulation unit 14 and a path control unit 15. Further, the address demodulation unit includes an electric filter 22,
And a phase demodulation circuit 24. The path switching unit 12
Has an optical input terminal 16 and optical output terminals 171 to 17N. The operation of the optical packet path switching device according to the present embodiment will be described below with reference to FIG.

The functions of the optical branching unit 11, the path switching unit 12, the photoelectric conversion unit 13, and the path control unit 15 are the same as those of the first embodiment.
This is the same as that described above. In the address demodulation unit 14, the electric filter 22 extracts a modulated address signal from the electric signal output from the photoelectric conversion unit 13. The phase demodulation circuit 24 demodulates the modulated address signal output from the electric filter 22.

The optical packet multiplexed signal in the present embodiment is almost the same as the optical packet multiplexed signal in the first embodiment shown in FIG. 2, and the modulation scheme of the modulation address signal is multi-level phase modulation (multi-level PSK modulation). Or multi-level FSK modulation). The phase demodulation circuit 24 may have any configuration as long as the circuit can demodulate the phase-modulated signal. The phase-modulated signal has high resistance to amplitude fluctuation, and can demodulate the address signal even if the amplitude of the modulation address signal input to the phase demodulation circuit 24 fluctuates due to the fluctuation of the intensity of the optical packet multiplexed signal. As described above, this embodiment has an advantage that the demodulation of the address signal is possible even if the intensity of the optical packet multiplex signal fluctuates, in addition to the same advantages as in the first embodiment.

(Embodiment 5) FIG. 8 is a block diagram of an optical packet path switching device according to Embodiment 5 of the present invention. 8, the optical packet path switching device includes an optical branching unit 11, a path switching unit 12, a photoelectric conversion unit 13,
, An electrical branching unit 25, and the first to Nth address demodulating units 1
41 to 14N. The path switching unit 12 has an optical input terminal 16 and optical output terminals 171 to 17N. The k-th address demodulator 14k includes an electric filter 22k and a demodulator 26k. Hereinafter, the operation of switching the signal format and the path of the optical signal in the present embodiment will be described with reference to FIGS. 9 and 10.

In this embodiment, a plurality of binary-modulated address signals are used instead of one multi-level modulated address signal used in the first embodiment. As shown in FIG. 9, an optical packet multiplex signal is a signal obtained by converting a signal obtained by frequency-multiplexing a data signal and a plurality of modulation address signals into an optical signal. Each modulation address signal corresponds to one reception station, and the first to Nth reception stations are provided with the first to Nth modulation address signals from the low frequency side.

The functions of the optical branching unit 11, the path switching unit 12, and the photoelectric conversion unit 13 are the same as those described in the first embodiment. The electric branching unit 24 branches the electric signal output from the photoelectric conversion unit 13 into N signals. The first to Nth address demodulators 141 to 14N extract and demodulate the corresponding modulated address signals, and input the demodulated address signals to the path switching unit 12, respectively.

First to Nth electric filters 221 to 22N
Extracts the first to Nth modulated address signals corresponding to each other and removes other modulated address signals and data signals. For example, the first electric filter 221 extracts the first modulated address signal, and the second electric filter 222 outputs the second modulated address signal.
Is extracted. The first to N-th demodulation circuits 261 to 26N demodulate the modulated address signals output from the corresponding first to N-th electric filters 221 to 22N, and transmit the demodulated address signals to the path switching unit 12, respectively. input.

Next, the optical signal path switching operation in the present embodiment will be described in detail with reference to FIG. N
The optical packet transmitted to the k-th receiving station among the three receiving stations is Dk. The optical packet is transmitted in the order of D1, D2,..., DN, for example, as shown in FIG. Here, during the transmission period of each optical packet, the level of the address signal corresponding to the receiving station to which the packet is to be transmitted is transmitted as "1". For example, the level of the first address signal is maintained at "1" only during the period when the optical packet D1 addressed to the receiving station 1 is transmitted, and is set at "φ" otherwise. Also, the level of the second address signal is maintained at "1" only during the period when D2 is transmitted, and otherwise at "φ" (see FIGS. 10A and 10C).

In the path switching section 12, the first to N-th address signals are made to correspond to the first to N-th optical output terminals, respectively.
Switch the output destination of the optical packet. That is, when the level of the first address signal is “1”, the light output terminal 171
Therefore, when the level of the second address signal is "1", the optical packet is output from the optical output terminal 172. The path switching unit 12 matches the period during which an optical packet is input with the period during which the corresponding address signal is “1”, so that each optical packet is processed without performing processing such as propagation delay time control. The signal is spontaneously output only from the optical output terminal corresponding to the destination (see FIGS. 12F and 12G). By the procedure described above, the path of the optical packet can be switched.

In this embodiment, since each address signal corresponds to one optical output terminal, if the levels of the plurality of address signals are simultaneously set to "1", the optical signals are simultaneously output from the plurality of optical output terminals. It is possible to output.
That is, multicasting to a plurality of receiving stations can be easily realized.

As a modulation method of the modulation address signal in the present embodiment, amplitude modulation (binary ASK), phase modulation (binary PSK or binary FSK), or the like can be used. When amplitude modulation is used, the address signal can be demodulated by a simple circuit as in the third embodiment. On the other hand, when the phase modulation is used, the demodulation of the address signal is possible even if the intensity of the optical packet multiplex signal fluctuates as in the fourth embodiment.

The above description has been made on the assumption that there is no delay time in the path switching operation in the path switching unit 12. However, if the delay time cannot be ignored, the configuration shown in FIG. Similarly, it can be dealt with by providing an optical delay unit. As described above, the present embodiment has an advantage that multicast can be easily realized in addition to the same advantages as in the first embodiment.

(Embodiment 6) FIG.11 is a block diagram of an optical transmission apparatus according to Embodiment 6 of the present invention. In FIG. 11, the optical transmission device includes an address conversion unit 30, an address modulation unit 31, a frequency multiplexing unit 32, and an electro-optical conversion unit 33. The optical transmitting apparatus according to the present embodiment is an apparatus for transmitting an optical signal whose path can be switched in the optical packet path switching apparatus according to the first embodiment. Hereinafter, the operation of the optical transmission device according to the present embodiment will be described with reference to FIG.

Based on the input address information, the address conversion unit 30 inputs an address signal that maintains a constant level corresponding to the address information to the address modulation unit 31 during the data transmission period. The address modulator 31 outputs a modulated address signal obtained by modulating a carrier having a predetermined frequency with the input address signal. Frequency multiplexing unit 3
2 frequency-multiplexes the data signal and the modulation address signal. The electro-optical converter 33 converts the signal frequency-multiplexed by the frequency multiplexer 32 into an optical signal. The format of the optical signal (including the address signal and the data signal) output by the optical transmitting apparatus according to the present embodiment is the same as that described in Embodiment 1 with reference to FIGS. 2 and 3A to 3C. The description is omitted because it is the same.

The data signal may be a modulated signal as well as a baseband signal. As described above, by using this embodiment, the optical packet path switching device according to the first embodiment can transmit an optical signal whose path can be switched.

(Embodiment 7) FIG.12 is a block diagram of an optical transmission apparatus according to Embodiment 7 of the present invention. 12, the optical transmission device includes first to N-th address modulation units 311 to 31N, a frequency multiplexing unit 32, an electro-optic conversion unit 33, and an address conversion unit 34. The optical transmitting apparatus according to the present embodiment is an apparatus for transmitting an optical signal whose path can be switched in the optical packet path switching apparatus according to the fifth embodiment. Hereinafter, an operation of the optical transmission device according to the present embodiment will be described with reference to FIG.

The address conversion unit 34 includes the address modulation unit 3
Binary first to Nth address signals are sent to 11 to 31N. When the address information indicating the destination of the data is input, the address conversion unit 34 transmits the address signal holding the level “1” to the address modulation unit corresponding to the address information during a period in which the corresponding data is transmitted. And an address signal having a level of “φ” to other address modulation units. For example, the level of the first address signal is set to “1” during the period in which the data addressed to the receiving station 1 is being sent to the address modulator 311, and the second level is sent to the address modulator 311 during the period when the data addressed to the receiving station 2 is being sent. The address signal level is sent to the address modulation unit 312 as “1”. When performing multicasting, a plurality of pieces of address information are input to the address conversion unit 34 at the same time, and the address conversion unit 34 simultaneously sends an address signal of level “1” to the address modulation unit corresponding to each address. .

Each of the address modulators 311 to 31N outputs a modulated address signal obtained by binary-modulating a carrier having a unique frequency with an input address signal. The frequency multiplexing unit 32 frequency-multiplexes the data signal and the modulation address signal. The electro-optical converter 33 converts the signal frequency-multiplexed by the frequency multiplexer 32 into an optical signal. The format of the optical signal (including the address signal and the data signal) output from the optical transmitting apparatus according to the present embodiment is the same as that described in the fifth embodiment with reference to FIGS. 9 and 10A to 10D. The description is omitted because it is the same.

The data signal is not limited to the baseband signal, but may be a modulation signal. As described above, by using this embodiment, the optical packet path switching device according to Embodiment 5 can transmit an optical signal whose path can be switched.

Embodiment 8 FIG. 13 is a block diagram of an optical transmission apparatus according to Embodiment 8 of the present invention. In FIG. 13, the optical transmission device includes an address modulation unit 31, a frequency multiplexing unit 32, an electro-optical conversion unit 33, and a delay unit 35. Hereinafter, the operation of the optical transmission device according to the present embodiment will be described with reference to FIG.

The address modulation unit 31, the frequency multiplexing unit 32,
The function of the electro-optical converter 33 is the same as that described in the sixth embodiment. The delay unit 35 is provided on the input side of the frequency multiplexing unit 32, and gives the data signal a delay time equivalent to the delay time generated when the optical packet path switching device performs an optical signal path switching operation. Therefore, the optical transmission device according to the present embodiment compares the address signal with the data signal,
The transmission is performed at an earlier timing by a time corresponding to the delay time. This is a difference from the sixth embodiment, and the format of the optical signal output by the optical transmitter according to the present embodiment is the same as that of the sixth embodiment in other respects.

In this embodiment, it is also possible to adopt a configuration in which a delay unit is added to the input side of the frequency multiplexing unit 32 in the same configuration as in FIG. As described above, in the present embodiment, in the optical packet path switching device described in the first to fifth embodiments, the address signal is earlier than the data signal by the time corresponding to the delay time generated when the path of the optical signal is switched. Send at the timing. Therefore, even when the delay time at the time of path switching cannot be ignored, it is possible to perform path switching at accurate timing without taking special measures for the optical packet path switching apparatus.

(Embodiment 9) FIG.14 is a block diagram of an optical communication system according to Embodiment 9 of the present invention. FIG.
In 4, the optical communication system includes a transmitting station 41, a primary relay station 44, and secondary relay stations 461 to 46N.
The transmitting station 41 includes optical transmitting devices 421 to 42N and a multiplexing unit 43. The primary relay station 44 includes a wavelength separating unit 45, and the secondary relay stations 461 to 46N include optical packet path switching devices 471 to 47N, respectively. Have. Hereinafter, the operation of the optical communication system according to the present embodiment will be described with reference to FIG.

Each of the optical transmitters 421 to 42N has the same configuration and function as any of the optical transmitters described in the sixth to eighth embodiments, and outputs optical signals having different wavelengths. The multiplexer 43 wavelength-multiplexes the optical signals output from the optical transmitters 421 to 42N. The wavelength-multiplexed optical signal is transmitted from the transmitting station 41 to the primary relay station 44. The wavelength separation unit 45 separates the wavelength-multiplexed optical signal for each wavelength. The optical signals separated for each wavelength are transmitted from the primary relay station 44 to the secondary relay stations 461 to 46N. Optical packet path switching devices 471 to 47N are the same as those in the first embodiment.
It has the same configuration and function as any of the optical packet path switching devices described in the above.

In this embodiment, Embodiments 1 to 5
The optical signal path switching method described above and wavelength routing are used together. Therefore, each optical packet path switching device 47
Assuming that the number of optical output terminals of 1 to 47N is M, N × M receiving stations can be accommodated, and only the wavelength routing described in the section of the related art is performed (the number of accommodable receiving stations). Compared with N), the number of receiving stations that can be accommodated can be greatly increased.

Note that the form of the network in the present embodiment is not limited to that shown in FIG.
If the optical packet path switching device described in any one of the above-described embodiments 5 and 5 and the optical transmission device described in any one of the sixth to eighth embodiments are used and wavelength routing is used in combination,
It may take any form. Although the number of optical output terminals of the optical packet path switching devices 471 to 47N has been described as M in the above description, the number of optical output terminals does not need to be the same, and may be different from each other. As described above, in the present embodiment, since the optical signal path switching method described in Embodiments 1 to 5 and wavelength routing are used in combination, the number of reception stations that can be accommodated is smaller than in the case where only wavelength routing is performed. It can be increased significantly.

[0064]

According to the first aspect of the invention, the address information is processed by maintaining a constant level as the address information to be multiplexed with the data packet for the same period and the same timing as the length of the data packet. In doing so, high-speed digital signal processing is not required, and optical packet path switching can be realized with a simpler configuration. In addition, although the configuration uses only one wavelength of light, it realizes the same function as the conventional optical routing system,
The wavelength use efficiency can be improved.

According to the second invention, in addition to the same effect as the first invention, multicast can be easily realized. According to the third aspect, in addition to the same effect as the first or second aspect, even if the intensity of the input optical packet multiplex signal fluctuates, the address signal can be demodulated. According to the fourth aspect, in addition to the same effect as the first or second aspect, even if the intensity of the input optical packet multiplex signal fluctuates, the address signal can be demodulated. According to the fifth aspect, in addition to the same effect as any one of the first to fourth aspects, by giving a delay to the optical signal, extraction and demodulation of the address signal and switching of the optical signal path can be performed. Even when the generated delay time cannot be ignored, the path can be switched at an accurate timing.

According to the sixth aspect, the optical packet path switching device of the first aspect can transmit an optical signal whose path can be switched. According to the seventh aspect, the optical packet path switching device according to the second aspect can transmit an optical signal whose path can be switched. According to the eighth invention, in addition to the same effect as the sixth or seventh invention, even when the delay time at the time of performing the path switching at the relay station cannot be ignored,
The route can be switched at an accurate timing without taking any special measures for the relay station.

According to the ninth aspect, the address information to be multiplexed and transmitted together with the data packet is maintained at a constant level for the same period and at the same timing as the length of the data packet. The optical packet path switching can be realized with a simpler configuration without the need for digital signal processing. Also, while using only one wavelength of light, it realizes the same function as the conventional optical routing system,
The wavelength use efficiency can be improved. According to the tenth aspect, in addition to the same effect as that of the ninth aspect, even when the delay time at the time of performing the route switching at the relay station cannot be ignored, accurate information can be obtained without taking any special measures for the relay station. It is possible to switch the path at the timing. According to the eleventh aspect, in addition to the same effect as the ninth aspect, multicast can be easily realized.

According to the twelfth aspect, the address information to be multiplexed with the data packet is maintained at a constant level for the same period and at the same timing as the length of the data packet. The optical packet path switching can be realized with a simpler configuration without the need for digital signal processing. In addition, although the configuration uses only one wavelength of light, it realizes the same function as the conventional optical routing system,
The wavelength use efficiency can be improved. According to the thirteenth aspect, in addition to the same effect as the twelfth aspect, it is possible to greatly increase the number of receiving stations that can be accommodated as compared with the case where only wavelength routing is performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical packet path switching device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of modulation information of an optical packet multiplexed signal according to Embodiment 1 of the present invention.

FIG. 3 is an explanatory diagram of a non-multicast format of an optical signal according to the first embodiment of the present invention;

FIG. 4 is an explanatory diagram of a multicast compatible format of an optical signal according to the first embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of an optical packet path switching device according to a second embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of an optical packet path switching device according to Embodiment 3 of the present invention.

FIG. 7 is a block diagram illustrating a configuration of an optical packet path switching device according to a fourth embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of an optical packet path switching device according to Embodiment 5 of the present invention.

FIG. 9 is an explanatory diagram of modulation information of an optical packet multiplexed signal according to Embodiment 5 of the present invention.

FIG. 10 is an explanatory diagram of a format of an optical signal according to a fifth embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of an optical transmission device according to Embodiment 6 of the present invention.

FIG. 12 is a block diagram showing a configuration of an optical transmission device according to Embodiment 7 of the present invention.

FIG. 13 is a block diagram showing a configuration of an optical transmitting apparatus according to Embodiment 8 of the present invention.

FIG. 14 is a block diagram showing a configuration of an optical communication system according to Embodiment 9 of the present invention.

FIG. 15 is a block diagram showing a configuration of a conventional optical routing system.

FIG. 16 is an explanatory diagram of a wavelength routing method in a conventional optical routing system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Optical branching part 12 Path switching part 13 Opto-electric conversion part 14, 141-14N Address demodulation part 15 Path control part 16 Optical input terminal 171-17N Optical output terminal 18 Optical delay part 22, 221-22N Electric filter 23 Amplitude demodulation circuit Reference Signs List 24 phase demodulation circuit 25 electric branching unit 261 to 26N demodulation circuit 30, 34 address conversion unit 31, 311 to 31N address modulation unit 32 frequency multiplexing unit 33 electro-optic conversion unit 35 delay unit 41, 51 transmission station 421 to 42N optical transmission device 43 Multiplexing unit 44 Primary relay station 45, 55 Wavelength separating unit 461-46N Secondary relay station 471-47N Optical packet path switching device 52 Wavelength variable light source 53 Optical modulator 54 Relay station

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04L 12/56 (72) Inventor Yu Fuji 1006 Oojidoma, Kadoma, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (Reference) 5K002 BA06 CA14 DA01 DA09 DA32 5K028 AA06 BB08 KK01 KK05 KK32 5K030 HA08 HB28 HB29 JA01 JL03 KX20 LB08

Claims (13)

[Claims] 1. An optical packet multiplexed signal obtained by converting an electric signal including a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations into an optical signal, and inputting the optical packet multiplexed signal. An optical packet path switching device that outputs a plurality of separated optical packet signals from a plurality of output terminals respectively corresponding to a plurality of the receiving stations, wherein the optical packet multiplexed signal transmits a plurality of the data packets. A modulated address signal generated by modulating an address signal containing information corresponding to each of the receiving stations using a carrier having a predetermined frequency by a predetermined modulation method,
An optical signal obtained by converting an electric signal obtained by frequency-multiplexing the packet multiplexed signal obtained by multiplexing the plurality of data packets in time series, wherein the address signal is multiplexed in the optical packet multiplexed signal. In synchronization with the section corresponding to the data packet
Correspondence between the data packet and the receiving station that receives the data packet, and predetermined address information for performing each of the extraction of the data packet, over the interval, for each of the plurality of data packets, The optical packet path switching device has an optical-electrical conversion unit, an address demodulation unit, a path control unit, and a path switching unit, and the optical-electrical conversion unit converts the input optical packet multiplexed signal into electrical signals. The address demodulation unit extracts the modulation address signal from the electric signal output from the photoelectric conversion unit, and outputs the address signal obtained by demodulating the modulation address signal. The path control unit generates and outputs a predetermined control signal based on the address information included in the address signal output from the address demodulation unit. The path switching unit has a plurality of output terminals respectively corresponding to a plurality of receiving stations, and inputs the input optical packet multiplexed signal and the control signal output by the path control unit, The output terminal that separates the optical packet multiplex signal, selects one of the output terminals based on the control signal, and selects a plurality of optical packet signals from which the optical packet multiplex signal is separated. An optical packet path switching device, wherein each of the signals is outputted. 2. An optical packet multiplexed signal obtained by converting an electric signal including a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations into an optical signal, and separating the optical packet multiplexed signal. An optical packet path switching device that outputs the plurality of optical packet signals from a plurality of output terminals respectively corresponding to a plurality of receiving stations, wherein the optical packet multiplexed signal transmits a plurality of the data packets, respectively. A plurality of modulated address signals generated by modulating a plurality of address signals corresponding to the respective receiving stations by a predetermined modulation method using a carrier of a predetermined frequency, and the packet multiplexing in which a plurality of the data packets are multiplexed in a time-series manner And an optical signal obtained by converting an electric signal obtained by frequency-multiplexing a signal and a plurality of the address signals. Each corresponding to the receiving station receiving the data packet in the optical packet multiplexed signal, and the predetermined address information synchronized with the section corresponding to the data packet multiplexed in the optical multiplexed packet signal, The optical packet path switching device has an optical packet conversion unit, a plurality of address demodulation units, and a path switching unit, and the optical packet conversion unit receives the input optical packet multiplexed signal. Is converted to an electric signal and output to the plurality of address demodulation units, respectively. The plurality of address demodulation units respectively extract one predetermined modulation address signal from the electric signal output from the photoelectric conversion unit. Outputting the address signal obtained by demodulating the modulated address signal, wherein the path switching unit includes a plurality of output terminals respectively corresponding to a plurality of receiving stations. And selecting one of the output terminals from among a plurality of output terminals based on the input packet optical multiplex signal and the address information in the plurality of address signals respectively output from the plurality of address demodulators. ,
An optical packet path switching device, wherein a plurality of optical packet signals obtained by separating the optical packet multiplex signal are output from the selected output terminals. 3. The modulation address signal is an amplitude modulation signal based on the address signal. The address demodulation unit extracts the modulation address signal from the electric signal output from the photoelectric conversion unit. The optical packet path switching device according to claim 1, further comprising: a filter; and an amplitude demodulation unit that demodulates the modulated address signal. 4. The modulation address signal is a phase modulation signal based on the address signal, and the address demodulation unit extracts the modulation address signal from the electric signal output from the photoelectric conversion unit. The optical packet path switching device according to claim 1, further comprising: a filter; and a phase demodulation unit that demodulates the modulated address signal. 5. The optical packet path switching device according to claim 1, further comprising an optical delay unit inserted and connected in front of said path switching device to delay said optical packet multiplexed signal. The optical packet path switching device according to any one of the above. 6. A correspondence between a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations in a time series and a plurality of receiving stations respectively receiving the plurality of data packets. Transmitting a plurality of address information indicating a plurality of address information and outputting an optical packet multiplexed signal obtained by converting an electrical signal including an address signal generated based on the plurality of address information and the packet multiplexed signal into an optical signal. Based on the input plurality of address information, for each of the plurality of data packets, in synchronization with a section corresponding to the data packet multiplexed in the packet multiplexed signal,
An address conversion unit that generates an address signal having predetermined information for performing the extraction of the data packet and the correspondence of the reception station that receives the data packet, respectively, over the section; output from the address conversion unit; An address modulator that outputs a modulated address signal obtained by converting the address signal, using a carrier wave of a predetermined frequency, by a predetermined modulation method; and inputting the modulated address signal output from the address modulator. An optical transmission device, comprising: a frequency multiplexing unit that frequency-multiplexes the packet multiplexed signal together with the packet multiplexed signal; and an electro-optical conversion unit that converts an electric signal output from the frequency multiplexing unit into an optical signal. 7. A correspondence between a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to a plurality of receiving stations in time series and a plurality of receiving stations respectively receiving the plurality of data packets. And outputting an optical packet multiplexed signal obtained by converting an electric signal including a plurality of address signals generated based on the plurality of address information and the packet multiplexed signal into an optical signal. An optical transmitter, based on the input plurality of address information, based on the address signal having predetermined information synchronized with a section corresponding to the data packet multiplexed in the packet multiplexed signal over the section, An address conversion unit for generating a plurality of data packets for each of the plurality of data packets multiplexed in the packet multiplexed signal; A plurality of address modulation units provided in correspondence with the plurality of address signals output from the address conversion unit and outputting modulated address signals obtained by conversion by a predetermined modulation method using carrier waves having different predetermined frequencies. A frequency multiplexing unit that frequency-multiplexes the plurality of modulated address signals output from the address modulation unit together with the packet multiplexed signal; and an electro-optical converter that converts an electric signal output from the frequency multiplexing unit into an optical signal. And an optical transmission device. 8. The optical transmission apparatus according to claim 6, further comprising a delay unit that is inserted and connected before the frequency multiplexing unit that inputs the packet multiplexed signal and delays the packet multiplexed signal. 8. The optical transmission device according to 7. 9. An optical packet multiplexed signal obtained by converting an electric signal including a packet multiplexed signal obtained by multiplexing a plurality of data packets transmitted to each of a plurality of receiving stations into an optical signal, and appropriately switching a transmission path. An optical packet path switching system, wherein the optical packet multiplexed signal is an address signal including information corresponding to each of the receiving stations transmitting the plurality of data packets, respectively, using a carrier having a predetermined frequency. A modulation address signal generated by modulation by a modulation method,
An optical signal obtained by converting an electric signal obtained by frequency-multiplexing the packet multiplexed signal obtained by multiplexing the plurality of data packets in time series, wherein the address signal is multiplexed in the optical packet multiplexed signal. In synchronization with the section corresponding to the data packet
Correspondence between the data packet and the receiving station that receives the data packet, and predetermined address information for performing each of the extraction of the data packet, over the interval, for each of the plurality of data packets, Converting the input optical packet multiplexed signal into an electric signal, extracting a modulated address signal from the electric signal, demodulating the modulated address signal, and converting the demodulated address signal into the address information of the obtained address signal. An optical packet path switching method for switching a path of the optical packet signal obtained by separating the optical packet multiplexed signal based on the optical packet multiplexed signal. 10. A timing for starting transmission of said address signal is set earlier than a timing for starting transmission of said data packet by a time corresponding to a delay time occurring when a path of said optical packet signal is switched. 10. The optical packet path switching method according to claim 9, wherein: 11. The optical packet path switching system according to claim 9, wherein a plurality of said modulated address signals are provided and frequency-multiplexed. 12. An optical communication system comprising: the optical packet path switching device according to any one of claims 1 to 5; and the optical transmission device according to any one of claims 6 to 8. 13. A plurality of optical packet multiplexed signals each having a different wavelength from each other are transmitted.
An optical communication system comprising: the optical transmission device according to any one of Claims 8 to 8; and the same number of optical packet path switching devices according to any one of Claims 1 to 5 as the optical transmission devices.