HIGH-SPEED OPTICAL MODULATOR FOR APPLICATION IN INSTRUMENTATION

The design and characterization of the first integrated optic modulator for commercial instrument application are described. Alternative forms of modulation including direct laser current modulation and optical heterodyne techniques are reviewed for the application which requires modulation to 20 GHz. The advantages of an integrated optic modulator fabricated using titanium in-diffused lithium niobate are overviewed. Performance tradeoffs between x-cut and z-cut LiNbO3 including bandwidth, modulation efficiency, bias point stability, and acoustic resonances are detailed. The x-cut device is found to give the best overall performance for this instrument application. Device reliability and testing, including temperature cycling, humidity, electrostatic discharge, mechanical shock, and vibration are described for complete packaged and pigtailed devices. Measurement and calibration of the modulation frequency response are important for instrument applications. Several techniques are discussed and calibrations are compared. © 1990 IEEE