Generation of Different Modulation Formats Using Sagnac Fiber Loop With One Electroabsorption Modulator

A simple structure is proposed to generate different modulation formats using a single electroabsorption modulator (EAM). The configuration is based on a Sagnac loop containing two polarization controllers and an EAM which modulates the clockwise and counterclockwise propagating waves inside the Sagnac loop. Measured results demonstrate switchable single-sideband suppression for both reflected and transmitted signals. The second-order harmonic suppression and carrier suppressed modulation are also achieved. A simple analysis explains most of the observed effects.