Hybrid filters with chirped gratings for DWDM applications
The Characteristic Matrix Sample Simulation developed to simulate hybrid filters (made of thin film multilayer filters deposited or glued onto the clived faces of Bragg gratings (Bg) in waveguides) is adapted for the case of chirped gratings and gaussian gratings. The principle of three new kinds of hybrid filters is demonstrated. Hybrid filters with long chirped Bg are useful as multiple bandpass filters giving new possibilities in term of separation of the peaks and spectral rejection. This points out again the considerable interest of hybrid filters in order to have a single passband with simultaneously a broad rejection.