High speed, low loss, low drive power traveling-wave optical switch/modulator for lambda=1.32 micron.

By selection of appropriate waveguide diffusion parameters, we have fabricated a titanium diffused lithium niobate switch/modulator for lambda=1.32 micron that satisfies the three requirements of a practical device: low switch voltage, broad modulation bandwidth and low fiber-coupled insertion loss. We demonstrate a traveling wave directional coupler switch that requires 4. 5 volt to switch, has a -3dB modulation bandwidth of 5.5 GHz, a power per bandwidth figure of merit of 10.9 MW/GHz and fiber- device-fiber insertion loss of only -2.3dB. Such devices may be useful for high-speed signal encoding or time division multiplexing/demultiplexing.