Abstract
This paper proposes the combination of multiple shortest-paths routing and particle swarm optimization algorithm to solve the wavelength converters placement problem. Both equal-cost multipath routing and traffic-engineering-aware shortest-path routing are included in the experiments to examine their effectiveness in reducing the overall blocking probability. These routing schemes help to achieve network-wide load balance to ensure higher resource utilization efficiency. Computed results show that our proposed heuristic is highly effective and efficient in reducing the blocking probability in sparse wavelength conversion networks.