- In this work, we study the problem of maximizing lightpath reliability in optical mesh networks against simultaneous failures of multiple fiber links without using protection schemes. The fiber links belong to shared risk link groups (SRLGs) that have arbitrary failure probabilities. This problem is NP-hard and we propose heuristic algorithms for networks with large numbers of SRLGs as well as optimal solutions for networks with smaller numbers of SRLGs. The solutions are evaluated through simulations. Keywords – lightpath reliability; multiple failures; Shared Risk Link Group (SRLG)