LiNbO3 Light Modulator

Abstract

Up to this time, LiNbO3 has not been considered to be a desirable material for a light modulator because of its susceptibility to ``optical damage.'' We ascertained that the LiNbO3 light modulator could be constructed practically without optical damage when the crystal was heated to ∼170–180 °C. A pair of polished LiNbO3 single crystals were soldered on a piezoelectric resonance damper of copper with pure tin, and were encapsulated in a glass vacuum vessel which prevented turbulence by heated air. It was demonstrated that the performance of the modulator was fine, especially with regard to extinction ratio, temperature characteristics, frequency response, and so on. In this report, we describe the optical-damage-free LiNbO3 modulator generally, from the growth condition of a high optical quality crystal to the construction and the performances of the modulator.