PROTON-EXCHANGED PERIODICALLY SEGMENTED CHANNEL WAVE-GUIDES IN LITHIUM-NIOBATE

Annealed proton-exchanged periodically segmented channel waveguides were fabricated in Z-cut lithium niobate. The propagation losses as a function of the duty cycle and the segmentation period are reported. Waveguiding was observed at large segmentation periods, up to 100 mu m. For duty cycles > 0.5, the propagation losses are nearly the same as measured for a continuous waveguide with the same width, namely similar to-1.45 dB/cm. With decreasing duty cycle, the mode expands in the transverse directions.