The principles of the common methods to measurement the propagation loss of the NLO polymer film optical waveguide are summarized, and the typical experimental arrangements are presented.

The parameters of the optical slab glass waveguide (refractive index and thickness of thin film) were measured by a new technique for using the prism coupler, i. e., leaky mode method.

At the present time, the mainstream optical filter techniques including dielectric thin-film filter, array waveguide (AWG), Fabry-Perot (F-P) filter, fiber Bragg grating (FBG).