Electrical and optical response of a Mach-Zehnder electrooptical modulator to pulsed irradiation

Radiation hardness of LiNbO₃:Ti Mach-Zehnder optomodulators under high energy electron pulses at high dose rate is studied for the first time. Both electrical and optical measurements are performed at various dose rates and electrical bias conditions. Electrical and optical perturbations are observed to be synchronous of the irradiation pulse, below a total dose threshold of 1 krad(Si). The optical behavior of the various optomodulators under test is related to their structure. As a matter of fact, optical perturbations are due either to photocurrent which superposes to electrical bias, or to an alteration of couplers characteristics