JP2010124280A - Optical burst signal accommodation light inserting/separating apparatus and optical burst signal accommodation light inserting/separating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accomplish a node configuration optically amplifying an optical burst signal without causing any characteristic deterioration, amplifying an existing optical wavelength multiplexed signal conventionally, and accommodating an optical burst signal even when a low speed optical switching device is used for an optical signal inserting portion. <P>SOLUTION: In an existing light inserting/separating apparatus, there are newly inserted an optical amplifier capable of optically amplifying an optical burst signal; a photocoupler for superimposing an optical burst signal to be passed through and an optical burst signal to be inserted; and an optical filter for dropping only a specified wavelength of the optical burst signal and passing through other wavelengths. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical wavelength add / drop device and an optical add / drop method for accommodating an optical burst switching signal in an existing optical path switching ring network.

FIG. 1 shows an optical add / drop device (ROADM, Reconfigurable) used in an existing optical path switching ring network.
Optical Add / Drop Multiplexer). ROADM is an apparatus that can be used in a ring-type optical network and can extract an optical signal of an arbitrary wavelength from wavelength-multiplexed optical signals and insert an optical signal of an arbitrary wavelength. Therefore, it is possible to take out and insert a wavelength path frame without converting it into an electrical signal.

  FIG. 1 a shows a configuration of a ROADM including wavelength selective switches 11 and 12 (WSS, Wavelength selective switch) and an optical amplifier 13. WSSs 11 and 12 are devices that switch light by wavelength. The optical amplifier 13 is a device that can directly amplify light without converting the light into electricity. The wavelength paths are taken out (Drop) and inserted (Add) by the WSSs 11 and 12. FIG. 1b shows the configuration of the ROADM further including an optical amplifier 14, a wavelength blocker 15 (WB), and optical couplers 16 and 17 (CPL). The wavelength blocker 15 is a device that passes through or blocks any selected wavelength or all wavelengths in the optical fiber. The optical couplers 16 and 17 are devices for branching by copying light and for inserting a wavelength into an optical fiber. In this configuration, the light is branched by the optical coupler 17, the wavelength dropped by the wavelength blocker 15 is blocked, the wavelength dropped by the WSS 11 is extracted, and the wavelength inserted by the WSS 12 and the optical coupler 16 is inserted into the optical fiber. FIG. 1c shows a configuration of the ROADM in which an optical coupler 16 is added to the configuration of FIG. 1a. In this configuration, the wavelength inserted by the optical coupler 16 is inserted into the optical fiber.

  An existing optical path switching ring network provides an optical fiber, uses a signal obtained by multiplexing light wavelengths (optical wavelength multiplexed signal), has a fixed bandwidth, and has only a large granularity. On the other hand, an optical burst switching signal (hereinafter referred to as an optical burst signal) is a signal that can change the service granularity at a light level from a fine band (50 Mbps) to a large band (for example, 10 Gbps). Furthermore, it is possible to share a wavelength between ground by multiplexing using TDM.

  FIG. 2 shows an outline of an optical wavelength multiplexed signal and an optical burst signal. In this figure, the vertical axis represents wavelength and the horizontal axis represents time. FIG. 2a shows an optical wavelength division multiplexed signal, where there are a plurality of wavelengths in one optical fiber, and a continuous signal is transmitted with respect to time. FIG. 2b shows an optical burst signal, in which a plurality of wavelengths flow intermittently in one optical fiber so as not to collide with each other. The optical burst signals are scheduled so as not to overlap on the time axis, and are switched at high speed (several hundred microseconds). In the case of an optical burst signal, only one optical signal transmission / reception device is required, and there is an advantage that a band between grounds can be dynamically changed.

  Due to the difference in the characteristics of the optical wavelength multiplexing signal and the optical burst signal of the existing optical network, the following method has been used to accommodate the optical burst switching signal in the existing optical path switching ring network. .

  The first method is to replace the optical amplifier in the ROADM. In order to accommodate an optical burst signal in an optical amplifier, the requirements for a transient response to light ON-OFF are severe. For this reason, in the optical amplifier included in the existing ROADM, sufficient rise time and fall time for maintaining signal characteristics cannot be obtained with respect to ON / OFF of the optical burst signal. For this reason, when an optical burst signal is amplified by an existing optical amplifier, the characteristics deteriorate. In order to solve this problem, it has been considered to replace an existing optical amplifier with a built-in ROADM with an amplifier corresponding to an optical burst signal (Non-Patent Document 1).

  The second method is to replace the optical switching device in the ROADM. In the conventional ROADM configuration, since a low-speed optical switching device is mounted on the insertion side, it is practically difficult to insert an optical burst signal of the same wavelength in the free time of the optical burst signal passing through the optical node. there were. In order to solve this problem, it has been considered to replace it with a high-speed switching device compatible with burst switching (Non-patent Document 2).

“Mitigation of Transient Response of Erbium-Doped Fiber Amplifier for Burst Traffic of High Speed Optical Packets”, Lasers and Electro-Optics, 2007. CLEO 2007, JTuA133. "Development of ultra-high-speed switch using PLZT thin-film optical waveguide (Device technology for photonic network and its application, etc.)", Vol.104, No.372 (20041015) pp. 19-24, PN2004-52

  However, the first method has a problem that the amplification band of the optical amplifier corresponding to the optical burst signal is narrow and the band of the conventional optical wavelength multiplexed signal cannot be amplified, and it is difficult to maintain the conventional service. Also, there is a problem that the service must be stopped to replace the optical amplifier. Further, in the second method, a high-speed switching device that supports burst switching is expensive, and it is difficult to solve the problem because there is no device that operates stably. Moreover, since the optical switching device is replaced in the same manner as in the first method, there is a problem that the service must be stopped.

  Therefore, the present invention makes it possible to amplify an optical burst signal without degrading the characteristics of the optical burst signal, and a node configuration capable of amplifying an existing optical wavelength division multiplexed signal as usual, and a low-speed optical switching device is used for the optical signal insertion portion Even so, an object of the present invention is to provide an optical burst signal accommodation optical insertion / separation device and an optical burst signal accommodation optical insertion / separation method that realize a node configuration capable of accommodating an optical burst signal.

  To achieve the above object, an optical burst signal accommodation optical insertion / separation device according to the present invention is an optical burst signal accommodation optical insertion / separation device that inserts and separates an optical wavelength division multiplexed signal and an optical burst signal into an optical network, Separating means for separating the optical burst signal from the optical network; first amplifying means for optically amplifying the optical wavelength multiplexed signal; means for extracting a first wavelength from the optical wavelength multiplexed signal; Means for inserting a second wavelength into the signal, second amplification means for optically amplifying the separated optical burst signal, means for extracting a third wavelength from the separated optical burst signal, and the third wavelength Means for superimposing the wavelength of the extracted optical burst signal and the fourth wavelength of the optical burst signal, and the superimposed optical burst signal to the optical network. And means for entering.

  The separating means blocks the optical wavelength multiplexed signal and optical burst signal of the optical network, blocks the branched optical wavelength multiplexed signal, and blocks the other branched optical burst signal. It is also preferable to include a means for

  In order to achieve the above object, an optical burst signal accommodation optical insertion / separation method according to the present invention is an optical burst signal accommodation optical insertion / separation method for inserting and separating an optical wavelength division multiplexed signal and an optical burst signal from an optical network, A separation step of separating the optical burst signal from the optical network; a first amplification step of optically amplifying the optical wavelength multiplexed signal; a step of extracting a first wavelength from the optical wavelength multiplexed signal; and the optical wavelength multiplexing Inserting a second wavelength into the signal; a second amplification step for optically amplifying the separated optical burst signal; a step of extracting a third wavelength from the separated optical burst signal; and the third wavelength. Superimposing the wavelength of the extracted optical burst signal and the fourth wavelength of the optical burst signal, and the superposed optical burst Comprising the steps of: inserting a signal into the optical network.

  The separating step includes branching the optical wavelength multiplexed signal and the optical burst signal of the optical network, blocking the branched one optical wavelength multiplexed signal, and blocking the other branched optical burst signal. It is also preferable to include the step of carrying out.

  According to the present invention, it is possible to accommodate an optical burst switching signal in an existing optical path switching ring network with a minimum node configuration change, and it is possible to accommodate a user who uses the optical burst signal. .

  The best mode for carrying out the present invention will be described in detail below with reference to the drawings.

  FIG. 3 shows a configuration of the optical insertion / separation device in the present embodiment. Corresponding to the conventional three-system configuration, this embodiment also has a three-system configuration.

  In the present embodiment, an optical amplifier 31 capable of optically amplifying an optical burst signal, an optical coupler 33 for superposing an optical burst signal to be inserted and an optical burst signal to be inserted, and an optical burst in an existing optical add / drop device. The optical burst signal is accommodated in the existing optical path switching ring network by newly inserting an optical filter 32 that drops only a specific wavelength of the signal and passes through other wavelengths.

  The configuration in which the above-described device is inserted into the configuration in FIG. 1a is FIG. 3a, the configuration in which the above-described device is inserted into the configuration in FIG. 1b is FIG. 3b, and the configuration in which the above-described device is inserted into the configuration in FIG. 3c.

  In the optical add / drop device according to the present embodiment, first, an optical signal is separated into an optical wavelength multiplexed signal and an optical burst signal. In the configurations of FIGS. 3 a and 3 c, separation is performed by the WSS 11. In the configuration of FIG. 3B, after the optical signal is copied and branched by the optical coupler 17, the optical burst signal is blocked by the wavelength blocker 15, and the optical wavelength multiplexed signal is dropped and blocked by the WSS 11. In FIG. 3, the optical wavelength multiplexed signal is drawn with a solid line, and the optical burst signal is drawn with a dotted line. Thereby, only the optical wavelength multiplexed signal flows through the optical amplifier 13 of FIG.

  By separating the optical burst signal, the optical burst signal can be amplified by the optical burst signal corresponding optical amplifier 31, and it is not necessary to amplify the optical wavelength multiplexed signal by the optical burst signal corresponding optical amplifier 31.

  The optical burst signal is dropped by using the optical filter 32 as shown in FIG. Further, the optical wavelength division multiplexed signal is dropped by the WSS 11 as usual, as shown in FIG.

  In the configuration of the conventional optical add / drop device, it is not possible to superimpose the inserted wavelength and the inserted wavelength. In other words, it was only an add-or-continue function of passing through a wavelength or inserting a wavelength. In the case of an optical burst signal, since it is necessary to superimpose the inserted wavelength and the inserted wavelength, an Add-and-continue function of inserting a wavelength further through the wavelength is required. Therefore, in this embodiment, the add-and-continue function is realized by using the optical coupler 33. The wavelength passed through by the optical coupler 33 and the inserted wavelength are mixed so that the optical burst signal can be inserted into the optical network.

  In the present embodiment, the wavelength that passes through the optical filter 32 and the wavelength (C) of the optical burst signal to be inserted are overlapped by the optical coupler 33. Thereafter, it is inserted into the optical network together with the optical wavelength multiplexed signal (D) inserted by the WSS 12. In FIGS. 3b and 3c, both the optical burst signal and the optical wavelength division multiplexed signal are inserted into the optical network via the optical coupler 16 that can be inserted into the optical network.

  In general, optical burst signals are used in OBS networks. The OBS network is a network in which when there is data to be transmitted, a certain wavelength is allocated for a time necessary for this data transmission, and the data to be transmitted is transmitted as an optical burst signal of the allocated wavelength.

  FIG. 4 shows a network model realized by the optical add / drop device of this embodiment. The optical burst signal compatible optical amplifier 31, optical filter 32, and optical coupler 33 are added to the ROADM of the existing all optical network as shown in FIG. The optical network is a network that supports optical burst signals.

  With the optical burst signal accommodating optical add / drop device of this embodiment, a wavelength resource sharing type optical burst switch network (OBS network) can be virtually constructed on an existing all-optical network, and services of the existing network are performed. It becomes possible to implement a new wavelength resource sharing type service.

  As described above, the optical burst signal accommodating optical add / drop device of the present embodiment is configured to insert an optical amplifier, an optical coupler, and an optical filter into an existing ROADM, so that existing services are not stopped. It is possible to construct an OBS network that can be updated and has the above-mentioned advantages over an existing optical network.

  Moreover, all the embodiments described above are illustrative of the present invention and are not intended to limit the present invention, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

1 shows an optical add / drop device used in an existing optical path switching ring network. An outline of an optical wavelength multiplexed signal and an optical burst signal is shown. The structure of the optical insertion / separation apparatus in this embodiment is shown. It is a network model implement | achieved by the optical insertion / separation apparatus of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11, 12 Wavelength selection switch 13, 14 Optical amplifier 15 Wavelength blocker 16, 17 Optical coupler 31 Optical amplifier corresponding to optical burst signal 32 Optical filter 33 Optical coupler

Claims (4)

An optical burst signal accommodating optical insertion / separation device that performs insertion and separation of an optical wavelength multiplexed signal and an optical burst signal with respect to an optical network,
Separating means for separating the optical burst signal from the optical network;
First amplification means for optically amplifying the optical wavelength division multiplexed signal;
Means for extracting a first wavelength from the optical wavelength multiplexed signal;
Means for inserting a second wavelength into the optical wavelength multiplexed signal;
Second amplification means for optically amplifying the separated optical burst signal;
Means for extracting a third wavelength from the separated optical burst signal;
Means for superimposing the wavelength of the optical burst signal from which the third wavelength has been extracted and the fourth wavelength of the optical burst signal;
Means for inserting the superimposed optical burst signal into the optical network;
An optical burst signal accommodating optical insertion / separation device comprising: The separating means includes
Means for branching the optical wavelength multiplexed signal and the optical burst signal of the optical network;
Means for blocking one of the branched optical wavelength multiplexed signals and blocking the other branched optical burst signal;
The optical burst signal accommodating optical insertion / separation device according to claim 1, comprising: An optical burst signal accommodating optical insertion / separation method for inserting and separating an optical wavelength division multiplexed signal and an optical burst signal from an optical network,
Separating the optical burst signal from the optical network;
A first amplification step for optically amplifying the optical wavelength division multiplexed signal;
Extracting a first wavelength from the optical wavelength multiplexed signal;
Inserting a second wavelength into the optical wavelength multiplexed signal;
A second amplification step for optically amplifying the separated optical burst signal;
Extracting a third wavelength from the separated optical burst signal;
Superposing the wavelength of the optical burst signal from which the third wavelength has been extracted and the fourth wavelength of the optical burst signal;
Inserting the superimposed optical burst signal into the optical network;
An optical burst signal accommodating optical insertion / separation method comprising: The separation step includes
Branching the optical wavelength multiplexed signal and the optical burst signal of the optical network;
Blocking one of the branched optical wavelength division multiplexed signals and blocking the other branched optical burst signal;
The optical burst signal accommodating optical insertion / separation method according to claim 3, further comprising:

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