Properties of a novel noncascaded type, easy-to-design, ripple-free optical bandpass filter

The chief principle and properties of a novel noncascaded type optical band pass filter with three unique general characteristics are presented, This d evice is based on a combination of a Michelson interferometer and a Gires-T ournois resonator (GTR). First, the filter has square-like frequency respon se with zero ripple, wide flat-top (0.74 x bandwidth), unity contrast, shar p steepness, and infinite rejection ratio when GTR front surface mirror ref lectance rho is equal to one-third. Second, this filter possesses variable bandwidth and center-wavelength tunability features with simple control mec hanism and nanosecond temporal response potential. Third, the desired featu res of the filter can be synthesized easily by mere inspection since only t hree parameters are required, and their expressions are given in simple ana lytic forms. Numerical results showing these features are presented and oth er characteristics are briefly discussed.