Most research works in routing and design of optical networks assume that the optical medium can carry signals without any bit error. However, the physical impairments on the optical signal quality introduced by optical components, such as erbium-doped fiber amplifiers (EDFA) and optical cross connects (OXCs), must be considered in the routing and design problems of WDM networks in practice. In this paper, we studied the dynamic connection provisioning problem in WDM networks under multiple signal quality constraints. We present a polynomial time optimal algorithm that finds an active path for an incoming connection request with minimum network resource consumption. Simulation results show that our solution outperforms the previously best solution to the problem.