A lightpath route management system with parallel processing capabilities and a flexible upgradability, allowing new functions to be added to the system without any system program changes, has been designed and implemented for IP-over-CWDM networks with ROADMs. The system can process route management functions composed of some sub applications in parallel in multi machines for high speed performance. In addition, the system was designed to have a flexible upgradability which allows adding new functions to the system, i.e. no changes of the system programs are required when adding the new functions. The system functions are to search possible lightpath routes made by ROADMs with specified switch states, and to output the total optical losses of the routes. The system was implemented and the performance was evaluated. By the system with one management and 3 calculation machines for the parallel processing, the total time to obtain the results for a 5-node IPover-CWDM network was reduced down to 65 % of the total time by the system with a single machine without parallel processing. The system enables the network administrators to manage the lightpath reconfigurations effectively without errors by avoiding making unlinked lightpaths through routes with higher losses to connect nodes, before the reconfiguration.

Lightpath route management system for IP-over-CWDM networks with ROADMs

Stackable reconfigurable optical add-drop multiplexers (S-ROADMs) have been proposed for single-fiber coarse wavelength division multiplexing (CWDM) ring networks so as to perform lightpath reconfiguration remotely. The S-ROADM consists of some modules with different wavelengths required in the node, and with this facility manual ROADM reconfiguration can be performed for low-cost transmission systems. The experimental results clarified that the S-ROADM could multiplex and demultiplex the wavelengths successfully without limiting the wavelengths passing through, making the network's wavelength transparent. The self-healing performance was investigated during a fiber cut in the single-fiber ring networks. Insertion of a new module inside the in-service S-ROADM was also accomplished to increase bandwidth for new users. The experimental results clarify that S-ROADMs provide more flexible CWDM networks in terms of reconfigurability and scalability.

Scalable single-fiber CWDM ring networks with stackable ROADMs

A stackable module with a bidirectional CWDM amplifier has been proposed to introduce the optical amplifier into an S-ROADM for use in an IP-over-CWDM ring network, and the performance was evaluated experimentally. Packet transfer changes were monitored during the lightpath reconfigurations, including 2 lightpaths which needed optical amplifications. The result clarified that the lightpaths were reconfigured successfully, including the remote activation of the amplifiers. As a result, the stackable feature of the amplifier module enables us to provide the cost-effective introduction into the network on an implement-it-when-necessary based service in a fully compatible way with the existing stackable ROADM modules, when constructing the S-ROADM with an amplifier. Therefore, the amplifier module can be used in the same way as the ROADM modules to construct the S-ROADM, providing manually adding capability of the amplifier to in-service networks. Thus, the amplifier module has a big advantage to use it flexibly and economically in the IP-over-CWDM networks.

Stackable ROADM with optical amplifier for use in IP-over-CWDM networks

A bidirectional amplification module has been proposed for use in IP-over-CWDM networks. The module is based on a bidirectional erbium-doped fiber amplifier. The loss compensation characteristics of the module obtained in a bidirectional IP transmission experiment confirmed that the losses of the optical node and the transmission fiber in the network can be compensated for effectively by the module making it possible to increase the number of nodes and the total fiber length of the network.

Bidirectional Amplification Module for IP-over-CWDM Ring Network

A web-based refractive index monitoring system has been designed and implemented for such a biological solution as sucrose solution for bioethanol production, and the system performance was examined. The LPG-FBG hybrid configuration was adopted as the sensor, because both of the refractive index and the temperature should be monitored generally in such a solution. The LPG was fabricated by using a CO 2 laser, and the temperature and refractive index coefficients were measured to be used for the monitoring. The monitoring system was configured such that the monitored data were sent to a computer machine via a web server, and the data were processed by an application in the machine. The application could output the time dependent values of the refractive index or the concentration of a constituent in the solution, and the values are sent to user's web browser to show the monitored values in an on-line graph. Thus, the monitoring system worked over the world-wide-web. The monitoring function of the system was examined by sensing the refractive index changes of a liquid with known physical values, when the liquid temperature changed. The results clarified that the refractive index changes were monitored successfully by the system function.

Web-based refractive index monitoring system for biological solution, employing LPG-FBG hybrid optical sensors

Lightpath route management system has been designed and implemented for IP-over-CWDM networks with ROADMs. The system can search possible lightpath routes made by ROADMs with specified switch states. The function is based on a ROADM graph proposed for representing the ROADMs, and can output lightpath routes usable in the network together with the total optical loss values. The losses can be calculated by only 3 basic values for the ROADM and one value for the fiber link in the network. The experimental results clarified that the difference was within 1 dB between measured and calculated values. The system enables the network administrators to manage the light path reconfigurations effectively without errors by avoiding making unlinked light paths through routes with higher losses to connect nodes, before the reconfiguration.

Lightpath route management system for IP-over-cwdm networks with roadms, based on a roadm graph

Lightpath reconfiguration management system has been designed and implemented for IP-over-CWDM networks with ROADMs. The system can search possible lightpaths made by ROADMs with specified switch states. The function is based on an equivalent graph method proposed for representing the ROADMs, and can output lightpaths in the network together with the total loss values. The system enables the network administrators to manage the lightpath reconfigurations effectively without errors by avoiding making unlinked lightpaths through routes with higher losses to connect nodes, before the reconfiguration.

Lightpath reconfiguration management system for IP-over-CWDM networks with ROADMs, based on equivalent graph method

A lightpath design and management system with parallel processing capabilities and a flexible upgradability has been designed and implemented for IP-over-CWDM networks with ROADMs. The system can process applications composed of some sub applications in parallel in multi machines for high-speed performance. In addition, the system was designed to have a flexible upgradability, i.e. no changes of the system programs are required when adding new functions. The system functions are to design lightpaths and wavelengths allocated to ROADMs for the lightpaths required to groom given traffic. The system can also search possible lightpath routes made by ROADMs with specified switch states, and output the total optical losses of the routes. By the new system implemented for the parallel processing, the total time to obtain the results for a 5-node IP-over-CWDM network was reduced down to 65% of the total time by the system with a single machine without parallel processing.

Lightpath design & management system for IP-over-CWDM networks with ROADMs, employing parallel processing

Stackable reconfigurable optical add/drop multiplexers (S-ROADMs) have been proposed for use in IP over coarse wavelength-division multiplexing (CWDM) networks so as to provide capabilities of remote lightpath reconfiguration and manual ROADM reconfiguration under the best effort transmission specified by the service level agreement. The S-ROADM can be constructed by connecting modules with different wavelengths required in the node. The experimental results clarify that the S-ROADM can add/drop or pass through the wavelengths successfully, providing no limit to the passing-through (PT) wavelengths, that is, ensuring the wavelength transparency in the network. The S-ROADMs could remove congestions by adding a lightpath remotely within a recovery time with degraded SLA. The transmission break time was also within the recovery time when adding a module manually to the in-service S-ROADM to increase bandwidth to be provided to new users. As a result, the S-ROADMs provide more flexible CWDM networks in terms of scalability and reconfigurability. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Nguyen Thi Thanh Thuy

Papers

Lightpath route management system for IP-over-cwdm networks with roadms, based on a roadm graph

Stackable ROADM with optical amplifier for use in IP-over-CWDM networks

Lightpath reconfiguration management system for IP-over-CWDM networks with ROADMs, based on equivalent graph method

Lightpath design & management system for IP-over-CWDM networks with ROADMs, employing parallel processing

Wavelength-transparent IP-over-CWDM network with stackable ROADMs for best effort performance