Synthesis of a parallel-coupled ring-resonator filler

An effective and exact synthesis technique for the design of parallel-coupled ring-resonator filters with a maximally flat stop-band characteristic of any order is presented. Simple closed-form formulas determine the Q factor of each resonator and the coupling coefficients. The performances of these filters are discussed for their applications as interleavers and channel-dropping filters in wavelength-division multiplexing systems. (C) 2001 Optical Society of America