HIGH-SPEED POLARIZATION SCRAMBLER WITH ADJUSTABLE CHIRP

摘要

Two separate electrooptic phase modulators are used in a modified Mach-Zehnder interferometer to vary the absolute and relative optical phases of two orthogonally polarized modes of an input signal independently of each other. A conventional Y-branch splitter on lithium niobate splits the input signal equally into the two waveguide phase modulators and an external polarization splitter recombines the two phase modulated signals in orthogonal polarization states. The polarization in the interferometer is maintained by connecting the outputs of the two phase modulators to polarization maintaining fibers. An alternate embodiment of the present invention uses an additional 3-dB directional coupler to mix the two phase modulated signals before they are combined in orthogonal polarization states.