session EuMC20 " Microwave Photonics " [EuMC20-4], http://www.eumweek.com/2008/A technique is described to implement a microwave filtering approach based on optical resonators. This technique involves the laser stabilization onto a resonator mode, and the use of the two lateral sidemodes for RF or microwave filtering. The Q enhancement compared to the classical non-coherent optical delay line technique is high, and the equivalent microwave Q overcome the best microwave resonators, at least in the upper microwave range