COUPLING OF STRONGLY AND WEAKLY GUIDING WAVEGUIDES FOR COMPACT INTEGRATED MACH ZEHINDER MODULATORS

摘要

A Mach Zehnder (MZ) modulator with improvedcoupling of input and output fibers is provided. The MZmodulator combines the advantages of weakly guided inputsections with strongly guided sections to optimize thecoupling efficiency and selectivity of the device.Improved coupling between weakly and strongly guidedsections of waveguide is provided by an intermediatetapered waveguide section which provides gradually changingmode confinement, which reduces the mode mismatch loss andtherefore suppresses the relection at the junction betweenthe weakly and strongly guided sections of the waveguide.