Abstract

External modulators are used in optical communication systems as directly modulating the light source leads to sprectral broadening, and hence limiting the capacity of the system. Currently, Mach-Zehnder interferometric optical modulators built in lithium niobate substrate are widely used, but these modulators, as well as some other types of optical modulators, have a linear intensity response, and so only a small modulation index of about 2%-5% may be used for analog systems. Several techniques^1-5 are used to improve the linearity of the response function of these optical modulators, so that the dynamic range can be maximally utilized.

© 2002 Optical Society of America