An interleaver with tunable bandwidth ratio based on microring resonator coupled Mach–Zehnder interferometer

A fundamental structure of a passive interleaver based on microring resonator coupled Mach–Zehnder interferometer is proposed in this paper. The most conspicuous advantage is the simplicity, compactness of the structure and the flatness of the passband top. Then we propose two methods of realizing a bandwidth tunability in this structure. A further analysis shows that both methods have their own strengths. We expect the compact and flexible interleaver can provide some potential and important implications for upgrading a hybrid Dense Wavelength Division Multiplexing (DWDM) system.