A DC to multigigabit/s polarization-independent modulator based on a Sagnac interferometer

A broadband, electrically controlled polarization-independent intensity modulator (PLM) based on a Sagnac interferometer is presented. Influences from asymmetric modulation and traveling wave effects are analyzed and methods to eliminate these effects are proposed. Compared to Mach-Zehnder interferometer-based modulators, this modulator is independent of the input polarization state and less sensitive to ambient perturbations due to its reciprocity property. A prototype modulator operating at 1 and 2.488 Gb/s modulation rates is demonstrated.