Tunable passband flattened 1-from-16 binary-tree structured add-after-dropmultiplexer using SiON waveguide technology

A tunable, flat-passband, 1-from-16 add/drop multiplexer for wavelength-div ision-multiplexing networks is presented. The device is realized in high-in dex-contrast silicon-oxynitride waveguide technology and is based on cascad ed resonant coupler filters in the form of a mirrored binary tree. Tunabili ty is obtained using the thermo-optic effect, The isolation of the transit channels at the drop port is better than 18 dB, and the rejection of the dr op channel at the output port is 26 dB.