Mode converters and sorters for quasiphase matching waveguide devices

We have demonstrated efficient second-harmonic generation of higher-order modes in periodically poled lithium niobate waveguides using a TM/sub 00/ to TM/sub 10/ mode converter based on an asymmetric Y-junction. Higher-order mode converters, combiners, and separators will expand the functionality of quasiphase matched waveguide devices.