The performance of high-speed lithium niobate modulators and switches make them attractive for high bit-rate communication systems. Significant process has been made to improve the speed and lower the drive voltage of these devices using both broad-band and narrow-band velocity matching techniques. Here I describe our results toward realizing broad-band, low- voltage, adjustable chirp modulators. These modulators are intended to replace directly modulated laser diodes in the transmitters of dispersion limited optically amplified systems. Also, presented is our work on high-speed switches for use as multiplexers and demultiplexers in optical-time-division multiplexed systems. These techniques are important because they offer the potential of very high bit-rate (> 10 Giga-bit-per-second) transmission systems utilizing relatively low bandwidth electronic components.