Study on optical fiber AM CATV externally modulated transmitter

摘要

Abstract: In this paper two problems associated with optical fiber AM CATV externally modulated transmitter are studied, one is effect of incident polarization on composite second order (CSO) and composite triple beat (CTB), the other is nonlinearity compensation of modulator's transfer function. We conclude that CSO deteriorates and CTB almost keeps unchanged when incident polarization drifting off TE mode and maximum deviation angle should be less than 6$DGR if CSO less than $MIN@70 dBc is demanded. We design predistortion linearity circuit based on Schottky diode and reduce CTB by 15 dB while having no effect on CSO.!7