A widely tunable THz wave has been parametrically generated and reported recently by us utilizing a LiNbO3 crystal with a monolithic grating coupler under a noncollinear phase matching condition. However, the output direction of the THz wave is strongly dependent on the generated frequency due to the nature of noncollinear phase matching, as well as the grating coupler. In this letter, a novel ...

Thermo-optical silicon-on-insulator (SOI) waveguide switch has been fabricated and characterized. The switch is based on a 2x2 Mach-Zehnder interferometer and 9 microns thick ridge waveguides. The extinction ratio of the switch is 17 dB with ultra-slow modulation and it is limited by the unoptimized directional coupler lengths. Thermo-optical switching with conventional on/off modulation was de...

Recent experience with X-band accelerator structure development has shown the rf input coupler to be the region most prone to rf breakdown and degradation, effectively limiting the operating gradient. A major factor in this appears to be high magnetic fields at the sharp edges of the coupling irises. As a first response to this problem, couplers with rounded and thickened iris horns have been e...