CHARACTERISTICS OF MISMATCHED TWIN-CORE FIBER SPECTRAL FILTERS

Both bandstop and bandpass filters can be easily implemented with mism atched twin-core fibers designed to phase-match at a certain wavelengt h. These filters are highly stable with very low temperature and strai n sensitivity. We studied the spectral quality of these filters and th at of cascaded filters designed to achieve improved bandpass response. We have also demonstrated the feasibility of achieving designed loss profile from these filters. This is very useful in gain spectrum flatt ening in Er-doped fiber amplifiers.