High-speed low-loss Schottky-i-n InP-based optical modulator for RF photonics

An InP-based high-speed optical modulator is presented. The Schottky-i-n waveguide structure on InP-based material was used to reduce the switching voltage V(pi) and the excess loss, while maintaining high-modulation efficiencies. To minimize residual amplitude modulation and to improve power handling capability, the bulk electrooptic effect in InGaAlAs was utilized for phase shifting. As a result, a simple structure InAlAs-InGaAlAs Mach-Zehnder optical modulator with traveling-wave electrodes was fabricated and characterized. This device achieved a switching voltage V(pi) of 3.6 V, extinction ratio (>23 dB) and high-speed operation at 1.55-mu m wavelength.