Measurement for polarization mode dispersion of LiNbO3integrated waveguide modulator used white light interferometry

Abstract

ABSTRACT We present a method to measure the polarization mode dispersion (PMD) of the LiNbO 3 multifunctional integrated waveguide modulator (MFIWM) which is consist of a Y-waveguide, two extended polarization maintaining (PM) fibers, lead-in PM pigtail and lead-out PM pigtail. This method is based on an all-fiber time-domain scanning white light interferometer and utilizes fast Fourier transform (FFT) technology to obtain interferometric phase. The PMD of each part of MFIWM was measured and distinguished accurately . ,W¶V demonstrated that , the PMD of Y-waveguide is SVQPNP#QPZKLFKL s approximately 40~1 60 times of the PMD of PM fiber s LQWKH0),:0XQGHUWHVW . Keywords: LiNbO 3 modulator, polarization maintaining fiber, polarization mode dispersion, white light interferometry , time-domain scanning 1. INTRODUCTION Polarization mode dispersion (PMD) is a significant characteristic parameter of LiNbO 3 multifunctional integrated waveguide modulator (MFIWM) which consists of polarization maintaining (PM) fiber and Y-waveguide . On the one hand, PMD leads to distortion of result when we measure the polarization extinction ratio (PER) of LiNbO3 Y-waveguide whose PER is a vital parameter for fiber optic gyroscope design [1]. On the other hand, the Y-waveguide whose PMD is known can be used to compensate for the PMD caused by the anisotropy of optical fib ers in the high capacity, long-haul optical communication systems [ 2] .