Optical pulse code modulator

An optical mcdulator has been developed for pulse code modulation transmission systems. This modulator uses the electro-optic effect in lithium tantalate (LiTaO3) and requires less than ten milliwatts drive power to a transistor pulse amplifier which supplies the drive voltage for the lithium tantalate. The LiTaO3crystal is cut to dimensions which allow 100% optical modulation for 30 volts change in potential across electrodes which are plated onto the crystal. This voltage is applied in the form of pulses With a rise time of 2.1 ns and a fall time of 3.3 ns by the transistor pulse amplifier.