JP5722253B2 - Optical packet switch device and signal processing method - Google Patents

Description

  The present invention relates to an optical packet switching device and a signal processing method for switching a path of an optical packet signal that is a signal obtained by adding information to an optical signal.

  There has been proposed a broadcast & select type optical packet switch in which 2 × 2 switches are connected in multiple stages and multicast control can be realized by ON / OFF of an optical signal by each switch (see Patent Document 1).

  However, since the number of control terminals increases in proportion to the square of N, the broadcast & select type optical packet switch has a problem that the control of the driver that performs the switch control becomes complicated and requires many hardware resources. .

  On the other hand, a wavelength selection type optical switch has been proposed in which a plurality of wavelength variable light sources and wavelength multiplexers / demultiplexers are used to assign wavelengths to each port and perform multiple connection (see Patent Document 2).

  As described above, the wavelength selective optical switch can switch the port from which each optical signal is output by switching the wavelength of each optical signal transmitted by the plurality of wavelength variable light sources. If multicast control is performed using this wavelength switch, it is considered that an N × N large-scale optical packet switch with a small number of control terminals can be realized.

  For example, multicast control using a wavelength switch can be performed by multi-wavelength batch modulation in an external modulator using two N × N wavelength filters. FIG. 9 is a block diagram showing an example of a related optical packet switch device. As shown in FIG. 9, the optical packet switch device includes an N × N wavelength filter 91 that combines optical signals input from N wavelength variable light sources 90 and an optical signal input from the N × N wavelength filter 91. Modulators 95-1 to 95-N that modulate and output optical signals, and N × N wavelength filters that demultiplex optical signals input from the modulators 95-1 to 95-N and output them from N output ports 93.

JP-A-8-36195 JP-A-5-244649

  In the optical packet switching device shown in FIG. 9, since the output power of the light source for the number of multicast ports is concentrated on one modulator, multicast is performed so that the power at the time of wavelength multiplexing is less than the maximum light receiving sensitivity of the modulator. The number is limited. Therefore, there is a problem that the number of multicasts cannot be increased without depending on the maximum light receiving sensitivity in the modulator.

  On the other hand, it is possible to solve the above problem by providing an optical amplifier after the modulator and lowering the output power of the light source, but the signal-to-noise ratio (SNR) deteriorates due to the optical amplifier. The error rate in the light receiver becomes high.

  The present invention has been made in order to solve the above-described problems of the technology, and an optical packet switch device and a signal which can increase the number of multicasts without depending on the maximum light receiving sensitivity of the modulator. An object is to provide a processing method.

In order to achieve the above object, an optical packet switching device of the present invention comprises:
When N and M are natural numbers of 2 or more, MN modulators that are multiplications of M and N;
An optical signal of N wavelengths that is connected to the input side of the MN number of modulators and is input to each of the N or less input ports corresponding to the wavelength is connected to the M number of modulators to which the same modulation signal is input. A first wavelength filter with an N input MN output to output;
A second MN input N output that is connected to the output side of the MN modulators and branches and outputs an optical signal input from the M modulators to N or less output ports corresponding to the wavelength. A wavelength filter of
It is the structure which has.

The signal processing method of the present invention is a signal processing method by an optical packet switch device,
When N and M are natural numbers greater than or equal to 2 , on the input side of MN modulators, which is a multiplication of M and N, N wavelength optical signals input to each of N or less input ports correspond to the wavelengths. Performing first routing of N input MN outputs to be output to the M modulators to which the same modulation signal is input,
On the output side of the MN modulators, the second routing of the MN input N output for branching and outputting the optical signals input from the M modulators to N or less output ports corresponding to the wavelength Is to do .

  According to the present invention, when optical multicast is performed by multi-wavelength batch modulation, the number of multicasts can be increased without depending on the maximum light receiving sensitivity in the modulator.

It is a block diagram which shows the structural example of the optical packet switch apparatus of this embodiment. 1 is a block diagram illustrating a configuration example of an optical packet switch device according to a first embodiment. 3 is a table illustrating an example of a wavelength band of an optical signal generated by a wavelength tunable light source according to the first exemplary embodiment. FIG. 6 is a diagram for explaining the operation of the optical packet switch device according to the first embodiment. 3 is a flowchart illustrating an operation procedure of the optical packet switch device according to the first embodiment. It is a block diagram which shows the structural example of the optical packet switch apparatus of Example 2. FIG. 10 is a table showing an example of a wavelength band of an optical signal generated by a wavelength tunable light source in Example 2. FIG. 10 is a diagram for explaining the operation of the optical packet switch device according to the second embodiment. It is a block diagram which shows an example of a related optical packet switch apparatus.

  The configuration of the optical packet switch device of this embodiment will be described. Hereinafter, N and M are natural numbers of 2 or more, and multiplication of M and N is expressed as “MN”. Further, when X and Y are arbitrary natural numbers of 1 or more, a wavelength filter of X input Y output is expressed as “X × Y wavelength filter”.

  FIG. 1 is a block diagram showing a configuration example of an optical packet switch device according to the present embodiment.

  As shown in FIG. 1, the optical packet switch device includes N input ports, and outputs N types of optical signals input to each input port from MN output ports corresponding to the wavelengths. × MN wavelength filter 1 and modulators 5-1-1 to 5-1-M,..., 5-N-1 to 5-N connected to MN output ports of the N × MN wavelength filter 1 -MN and an MN × N wavelength filter 3 connected to the output side of the MN modulators and for branching and outputting optical signals received from the MN modulators to N or less output ports corresponding to the wavelengths. It is the structure which has. However, M and N are natural numbers of 2 or more.

According to the present embodiment, since M modulators are provided for one input port among the N input ports, the power of the light source concentrated on one modulator is distributed to 1 / M. It becomes possible to make it. Therefore, when performing optical multicasting by multi-wavelength batch modulation using a wavelength switch that performs optical multicasting of N inputs × N outputs, the number of multicasts can be increased without depending on the maximum light receiving sensitivity at the modulator. It becomes possible.
Examples of the optical packet switch device according to this embodiment will be described below.

  The present embodiment is a case where broadcast / multicast is performed by multi-wavelength batch modulation in an N input N output wavelength switch. In this embodiment, the case where the value of M described above is M = 2 will be described.

  The configuration of the optical packet switch device of this embodiment will be described. FIG. 2 is a block diagram showing a configuration example of the optical packet switch device of the present embodiment.

  As shown in FIG. 2, the optical packet switching device includes an N × 2N wavelength filter 11, 2N modulators 15-1 a to 15 -Na, 15-1 b to 15 -Nb, and a 2N × N wavelength filter 13. Have The output ports OUT1 to OUTN of the 2N × N wavelength filter 13 are connected to a wavelength switch system having N-wavelength and wavelength recirculation. In the present embodiment, two modulators are provided for one input port in the N × 2N wavelength filter 11.

  On the input side of the N × 2N wavelength filter 11, N variable wavelength light sources 51-1 to 51-N that output optical signals of N types of wavelengths are connected via separate input ports. . In this embodiment, N is an even number for convenience of explanation. FIG. 3 is a table showing an example of a wavelength band for an optical signal generated by a wavelength tunable light source.

  FIG. 3 shows a necessary wavelength band of the generated optical signal corresponding to the variable wavelength light sources 51-1 to 51-N. If the wavelength tunable light sources 51-1 to 51-N / 2 are defined as the first group and the wavelength tunable light sources 51-N / 2 + 1 to 51-N are defined as the second group, they are generated for each wavelength tunable light source within the same group. Although the wavelength band of the optical signal is different, the wavelength band of the optical signal is common among the groups.

  M is preferably a value obtained by ignoring the decimal part from the value calculated by (the total output power of the wavelength tunable light sources 51-1 to 51-N divided by the maximum light receiving sensitivity of the modulator).

  When k = 1 to N, the coupler 41-k is connected to the modulators 15-ka and 15-kb. A modulation signal is input from the outside to the modulators 15a-ka and 15-kb via the coupler 41-k.

  Each of the modulators 15-ka and 15-kb includes at least one of the intensity and phase of the optical signal input from the N × 2N wavelength filter 11 according to the modulation signal input via the coupler 41-k. Are modulated and output to the 2N × N wavelength filter 13. The modulator 15-ka corresponds to the first group, and the modulator 15-kb corresponds to the second group. The output port of the modulator 15-ka is connected to the input port INka of the 2N × N wavelength filter 13, and the output port of the modulator 15-kb is connected to the input port INkb of the 2N × N wavelength filter 13. Hereinafter, the input ports IN1a to INNa are referred to as upper ports, and the input ports IN1b to INNb are referred to as lower ports.

  The N × 2N wavelength filter 11 and the 2N × N wavelength filter 13 are, for example, N-input 2N-output or 2N-input N-output circular arrayed waveguide gratings (AWG), and input optical signals The route is changed according to the wavelength.

  The N × 2N wavelength filter 11 sends optical signals input from the wavelength tunable light sources 51-1 to 51-N / 2 to the upper ports IN1a to INNa via the modulators 15-1a to 15-Na corresponding to the wavelengths. The optical signals input from the wavelength tunable light sources 51-N / 2 + 1 to 51-N are routed to the lower ports IN1b to INNb via the modulators 15-1b to 15-Nb corresponding to the wavelengths.

  The 2N × N wavelength filter 13 routes optical signals input from the modulators 15-1a to 15-Na via the upper ports IN1a to INNa to the output ports OUT1 to OUTN / 2 corresponding to the wavelengths, Optical signals input from 15-1b to 15-Nb via lower ports IN1b to INNb are routed to output ports OUTN / 2 + 1 to OUTN corresponding to the wavelength. The input ports IN1a to INNa and the output ports OUT1 to OUTN / 2 correspond to the first group, and the input ports IN1b to INNb and the output ports OUTN / 2 + 1 to OUTN correspond to the second group.

  Next, the operation of the optical packet switch device of this embodiment will be described. FIG. 4 is a diagram for explaining the operation of the optical packet switching device of this embodiment, and FIG. 5 is a flowchart showing the operation procedure. Here, it is assumed that a modulated signal is input from the outside to the coupler 41-1, and an optical signal modulated in accordance with the modulated signal is branched into four output ports OUT1, OUTN / 2, OUTN / 2 + 1, and OUTN for output. .

  Each of the wavelength tunable light sources 51-1, 51-N / 2, 51-N / 2 + 1, 51-N outputs optical signals of N types of wavelengths as shown in FIG. The N × 2N wavelength filter 11 routes and outputs optical signals of N types of wavelengths input from these wavelength variable light sources to two output ports corresponding to the wavelengths (step 101). Specifically, the N × 2N wavelength filter 11 routes the optical signal input from the wavelength tunable light sources 51-1 and 51 -N / 2 to the modulator 15-1 a, and the wavelength tunable light sources 51 -N / 2 + 1, The optical signal input from 51-N is routed to the modulator 15-1b. It is classified into two by the two-dot chain line shown in FIG. 4, the upper side corresponds to the first group, and the lower side corresponds to the second group.

  Each of the modulators 15-1 a and 15-1 b modulates the optical signal input from the N × 2N wavelength filter 11 according to the modulation signal input via the coupler 41-1, and 2N × N wavelength filter 13. Are output to the input ports IN1a and IN1b (step 102).

  When the modulated optical signal is input from the modulator 15-1a via the input port IN1a, the 2N × N wavelength filter 13 routes these optical signals to the output port OUT1 and the output port OUTN / 2 and outputs them. To do. Further, when the modulated optical signal is input from the modulator 15-1b via the input port IN1b, the 2N × N wavelength filter 13 routes these optical signals to the output port OUTN / 2 + 1 and the output port OUTN. (Step 103).

  In FIG. 4, a path through which an optical signal input from the wavelength tunable light source 51-1 to the N × 2N wavelength filter 11 is output from the output port OUT1 of the 2N × N wavelength filter 13 via the modulator 15-1a, A broken line indicates a path through which an optical signal input from the wavelength tunable light source 51-N / 2 to the N × 2N wavelength filter 11 is output from the output port OUTN / 2 of the 2N × N wavelength filter 13 via the modulator 15-1a. Is shown.

  In FIG. 4, an optical signal input from the wavelength tunable light source 51-N / 2 + 1 to the N × 2N wavelength filter 11 is output from the output port OUTN / 2 + 1 of the 2N × N wavelength filter 13 via the modulator 15-1b. A path through which an optical signal input from the wavelength variable light source 51-N to the N × 2N wavelength filter 11 is output from the output port OUTN of the 2N × N wavelength filter 13 via the modulator 15-1b. Is indicated by a one-dot chain line.

  Multiple wavelength tunable light sources share the same optical signal wavelength band, and the same modulated signal distributed by the coupler 41-1 is input to the modulators 15-1a and 15-1b. The optical signal modulated by the modulator 15-1a is branched and output to the output port OUT1 and the output port OUTN / 2, and the corresponding optical signal modulated by the modulator 15-1a is output to the output port OUT1 and The output is branched to the output port OUTN / 2.

  In the present embodiment, the N wavelength variable light sources 51-1 to 51-N are classified into two groups, and optical signals input from the wavelength variable light sources 51-1 to 51-N / 2 as the first group. Are modulated by the modulators 15-1a to 15-Na, and optical signals input from the variable wavelength light sources 51-N / 2 + 1 to 51-N as the second group are modulated by the modulators 15-1b to 15-Nb. By doing so, it becomes possible to disperse the power of the light source concentrated on one modulator. In a wavelength switch using an N × N wavelength filter and a modulator, the number of multicasts can be increased without depending on the maximum light receiving sensitivity of the modulator by using the target of the wavelength switch and multi-wavelength batch modulation. it can.

  This embodiment is also a case where broadcast / multicast is performed by multi-wavelength collective modulation in an N-input / N-output wavelength switch, but this is a different method from the first embodiment. Also in this embodiment, the case where M = 2 is described.

  The configuration of the optical packet switch device of this embodiment will be described. FIG. 6 is a block diagram showing a configuration example of the optical packet switch device of the present embodiment.

  As shown in FIG. 6, the optical packet switch device includes an N × 2N wavelength filter 21, 2N modulators 15-1 a to 15 -Na, 15-1 b to 15 -Nb, and a 2N × N wavelength filter 23. Have The output ports OUT1 to OUTN of the 2N × N wavelength filter 23 are connected to a wavelength switch system having N-wavelength and cyclicity. Also in this embodiment, two modulators are provided for one input port in the N × 2N wavelength filter 21, but the optical signal routing method is different from that in the first embodiment.

  On the input side of the N × 2N wavelength filter 21, N variable wavelength light sources 51-1 to 51-N that output optical signals of N types of wavelengths are connected via separate input ports. . Also in this embodiment, N is an even number. FIG. 7 is a table showing an example of a wavelength band for an optical signal generated by a wavelength tunable light source.

  FIG. 7 shows a necessary wavelength band of the generated optical signal corresponding to the wavelength variable light sources 51-1 to 51-N. If the wavelength tunable light sources 51-1 to 51-N / 2 are defined as the first group and the wavelength tunable light sources 51-N / 2 + 1 to 51-N are defined as the second group, they are generated for each wavelength tunable light source within the same group. Although the types of wavelengths of optical signals are common, the types of wavelengths of optical signals are different when compared between groups.

  M is preferably a value obtained by ignoring the decimal part from the value calculated by (the total output power of the wavelength tunable light sources 51-1 to 51-N divided by the maximum light receiving sensitivity of the modulator).

  When k = 1 to N, the coupler 41-k is connected to the modulators 15-ka and 15-kb as in the first embodiment. A modulation signal is input from the outside to the modulators 15a-ka and 15-kb via the coupler 41-k.

  Each of the modulators 15-ka and 15-kb includes at least one of the intensity and phase of the optical signal input from the N × 2N wavelength filter 21 according to the modulation signal input via the coupler 41-k. Are modulated and output to the 2N × N wavelength filter 23. The output ports of the modulators 15 -ka and 15 -kb are connected to the input port INk of the 2N × N wavelength filter 23. In this embodiment, the modulators 15-ka and 15-kb are provided adjacent to each other. However, the modulator 15-ka corresponds to the first group, and the modulator 15-kb corresponds to the second group. It corresponds to.

  The N × 2N wavelength filter 21 and the 2N × N wavelength filter 23 are, for example, N-input 2N-output or 2N-input N-output circular arrayed waveguide gratings (AWG), and input optical signals The route is changed according to the wavelength.

  The N × 2N wavelength filter 21 sends optical signals input from the wavelength tunable light sources 51-1 to 51-N / 2 to the input ports IN1 to INN via the modulators 15-1a to 15-Na corresponding to the wavelengths. The optical signals input from the wavelength tunable light sources 51-N / 2 + 1 to 51-N are routed to the input ports IN1 to INN via the modulators 15-1b to 15-Nb corresponding to the wavelengths.

  The 2N × N wavelength filter 23 routes optical signals input from the modulators 15-1a to 15-Na via the input ports IN1 to INN to output ports OUT1 to OUTN / 2 (not shown) corresponding to the wavelength. Then, the optical signals input from the modulators 15-1b to 15-Nb via the input ports IN1 to INN are routed to the output ports OUTN / 2 + 1 (not shown) to OUTN corresponding to the wavelengths.

  Next, the operation of the optical packet switch device of this embodiment will be described. FIG. 8 is a diagram for explaining the operation of the optical packet switch device according to the present embodiment. Here, it is assumed that a modulated signal is input from the outside to the coupler 41-N, and an optical signal modulated according to the modulated signal is branched into an output port OUT1 and an output port OUTN and output.

  Each of the wavelength tunable light sources 51-1 and 51-N outputs optical signals having N wavelengths as shown in FIG. The N × 2N wavelength filter 21 routes the optical signal input from the wavelength tunable light source 51-1 to the modulator 15-1a, and routes the optical signal input from the wavelength tunable light source 51-N to the modulator 15-1b. To do.

  Each of the modulators 15-1a and 15-1b modulates the optical signal input from the N × 2N wavelength filter 21 in accordance with the modulation signal input via the coupler 41-1, and 2N × N wavelength filter 23. Output to the input port IN1.

  When the modulated optical signal is input from the modulator 15-1a via the input port IN1, the 2N × N wavelength filter 23 routes and outputs the optical signal to the output port OUT1. Further, when the modulated optical signal is input from the modulator 15-1b via the input port IN1, the 2N × N wavelength filter 23 routes and outputs the optical signal to the output port OUTN.

  FIG. 8 shows a path through which an optical signal input from the wavelength tunable light source 51-1 to the N × 2N wavelength filter 21 is output from the output port OUT1 of the 2N × N wavelength filter 23 via the modulator 15-1a. It is indicated by a broken line. Further, a path through which an optical signal input from the wavelength tunable light source 51-N to the N × 2N wavelength filter 21 is output from the output port OUTN of the 2N × N wavelength filter 23 via the modulator 15-1b is indicated by a one-dot chain line. Show.

  Multiple wavelength tunable light sources have different types of wavelengths of optical signals between groups, and the same modulation signal distributed by the coupler 41-1 is input to each of the modulators 15-1a and 15-1b. Thus, although the types of wavelengths are different, the optical signals modulated in the same way by the modulators 15-1a and 15-1b are branched and output to the output port OUT1 and the output port OUTN.

  In the present embodiment, the N wavelength variable light sources 51-1 to 51-N are classified into two groups, and optical signals input from the wavelength variable light sources 51-1 to 51-N / 2 as the first group. Are modulated by the modulators 15-1a to 15-Na, and optical signals input from the variable wavelength light sources 51-N / 2 + 1 to 51-N as the second group are modulated by the modulators 15-1b to 15-Nb. By doing so, it becomes possible to disperse the power of the light source concentrated on one modulator. In a wavelength switch using an N × N wavelength filter and a modulator, the number of multicasts can be increased without depending on the maximum light receiving sensitivity of the modulator by using the target of the wavelength switch and multi-wavelength batch modulation. it can.

1 N × MN wavelength filter 3 MN × N wavelength filter 5-1-1 to 5-NM modulator 11, 21 N × 2N wavelength filter 13, 23 2N × N wavelength filter 15-1a to 15-Na, 15 -1b to 15-Nb modulator

Claims (4)

When N and M are natural numbers of 2 or more, MN modulators that are multiplications of M and N;
An optical signal of N wavelengths that is connected to the input side of the MN number of modulators and is input to each of the N or less input ports corresponding to the wavelength is connected to the M number of modulators to which the same modulation signal is input. A first wavelength filter with an N input MN output to output;
A second MN input N output that is connected to the output side of the MN modulators and branches and outputs an optical signal input from the M modulators to N or less output ports corresponding to the wavelength. A wavelength filter of
An optical packet switching device. The optical packet switch device according to claim 1,
The first wavelength filter includes:
N tunable light sources connected to the input side are classified into M groups, MN modulators are classified corresponding to the M groups, and optical signals input from the tunable light sources are classified. Output to a modulator corresponding to the same group as the wavelength tunable light source,
The second wavelength filter is:
The N output ports are classified corresponding to the M groups, and an optical signal input from the modulator is branched to N / M or less output ports corresponding to the same group as the modulator. Output optical packet switch device. The optical packet switch device according to claim 1 or 2,
The M is a value obtained by ignoring the decimal part from a value calculated by (total output power of wavelength variable light sources connected to the input side of the first wavelength filter / maximum light receiving sensitivity of the modulator). Optical packet switch device. A signal processing method by an optical packet switch device,
When N and M are natural numbers greater than or equal to 2 , on the input side of MN modulators, which is a multiplication of M and N, N wavelength optical signals input to each of N or less input ports correspond to the wavelengths. Performing first routing of N input MN outputs to be output to the M modulators to which the same modulation signal is input,
On the output side of the MN modulators, the second routing of the MN input N output for branching and outputting the optical signals input from the M modulators to N or less output ports corresponding to the wavelength A signal processing method.

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