LiNbO/sub 3/ modulators: status and advanced concepts for microwave signal processing

The status of the LiNbO/sub 3/ integrated optical circuit technology is reviewed and compared with the alternative solutions for wide bandwidth processing of microwave signals. The advantages of external modulation over direct laser diode modulation of optical radiation in fiber optic systems, mainly in terms of bandwidth and chirping, drove the development of LiNbO/sub 3/ based fabrication technologies of integrated optical modulators at a very high maturity level, which makes LiNbO/sub 3/ advantageous also over other external modulation solutions: semiconductors, electroabsorption, electro-optical polymers. Advanced concepts are presented to face some of the critical issues in the optical signal processing of microwave signals in defence systems (phased array radars, ECM, ESM) and consumer applications.