Hardware-Efficient WDM/SDM Network

Master's thesis presentation

Time: Thu 2019-09-26 13.00

Lecturer: Lida Liu

Location: Seminar room Grimeton at COM, Electrum, elevator B, 4th floor, Isafjordsgatan 22, Kista

Optical networking has been developing for decades and wavelength-division multiplexing (WDM) is the main technology used to carry signals in fiber-optical communication systems. However, its development has slowed because it is approaching the Shannon limit of nonlinear fiber transmission. Researchers are looking for multi dimensional multiplexing. Space-division multiplexing (SDM) is an ideal way to scale network capacities. The capacity of WDM/SDM network could be expanded to several times the capacity of WDM network but the active hardware devices may also increase by several times.

This project aims to answer a practical question: How to construct a WDM/SDM network with less hardware resource? There is no mature research about WDM/SDM network yet. Therefore, the problem can be divided into two parts: (1) how to build a WDM/SDM network and (2) how to allocate resource and compute routes in such a network to minimize hardware resources.

First, this thesis proposes a WDM/SDM node which has bypass connections between different fibers and architecture on demand (AoD) to effectively decrease the number of active hardware devices within the node. Then, two types of networks were constructed: one with bypass connections in each node and another one without any bypass connections. These networks were under the control of a software defined network (SDN) controller. The controller knew the wavelength resources within the networks. Several algorithms were applied to these networks to evaluate the effect of a bypass network and to identify the desired characteristics (to find short length path and decrease the probability of spectrum fragmentation) of an algorithm suitable for a network with bypass connections. The results of applying the proposed algorithms in two networks proved that the bypass connections increased the blocking probability in small topology but did not affect the results in large topology. The results in a large-scale network with bypass network were almost the same as the results in a network without bypass connections. Thus, bypass connections are suitable for large-scale network.

Keywords: WDM, SDM, SDN, routing and wavelength assignment, large-scale network, hardware resource