Gigacycle-bandwidth coherent-light traveling-wave amplitude modulator

We have constructed an optical amplitude modulator having a bandwidth of approximately one Gc/s and requiring about a fifty volts drive to produce a 100 per cent amplitude modulation. The wide-bandwidth low drive power performance is obtained by using the traveling-wave approach previously used in the gigacycle bandwidth phase modulator. The electro-optic material is KDP cut in the same orientation used in the phase modulator and combined with other optical elements to produce retardation-amplitude modulation. Temperature variations through the KDP produce a deflection and decollimation of the output beam. Experiments have been conducted to determine the magnitude of these effects. Corrective measures have been devised. Comparatively good agreement between the computed and the measured bandwidth has been obtained.