OPTICAL MODULATION METHOD AND DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical modulation method and device by which the number of components of optical members which are needed to be disposed so as to be spatially distributed can be reduced.

SOLUTION: The optical modulation device 1 modulates signal light having the transmittance higher than a prescribed threshold in a prescribed first frequency and is provided with an electrooptical crystal 3 in which the signal light is made incident, a signal electrode 4 and a ground electrode 5 controlling a voltage signal for modulation having a second frequency lower than the first frequency so that the voltage signal can be applied to the electrooptical crystal 3 and the application of the voltage signal can be suspended, and a modulation signal outputting part 6. The electrooptical crystal 3 has a function for lowering the transmittance in the first frequency of the incident signal light to the transmittance lower than the threshold by an electrooptical effect of the electrooptical crystal 3 in the state that the voltage signal for modulation is applied.

COPYRIGHT: (C)2004,JPO