Mach-Zehnder optical modulator integrated with tunable multimode interference coupler of Ti:LiNbO_3 waveguides for controlling modulation extinction ratio

摘要

A Mach-Zehnder optical modulator with the tunable multimodeinterference coupler was fabricated using Ti-diffused LiNbO_3. Themodulation extinction ratio could be voltage controlled to maximize up to50 dB by tuning the coupler. Optical single-sideband modulation was alsoachieved with a sideband suppression ratio of more than 30 dB.