Attack protection is an important issue for optical networks.In this paper

an attack propagation model for high-power inter-channel crosstalk attacks in optical networks and optical amplifier gain competition attacks is constructed and a Routing and Wavelength Assignment（RWA）algorithm for limiting the scope of the physical layer attack influences proposed.In the routing assignment stage

this algorithm assigns the routing with smaller maximum light-path attack scope to the light-path request so as to reduce the scope of attack influences.Simulation results show that compared with commonly used algorithms

this algorithm can effectively limit the scope of physical layer attack influences and improve the security of optical networks.