Three kinds of polarization controlling waveguide devices made of electro-optic polymers are fabricated, and a novel polarization-independent optical intensity modulator is proposed and analyzed. The poling-induced birefringence in electro-optic polymers is exploited to realize polymeric waveguide polarizers, polarization splitters, and polarization converters. These components will be useful for controlling the polarizations of the light in optical communications, optical signal processings, and optical sensings.
For the simulation and design of the proposed devices, a vectorial beam propagation method for anisotropic media is developed. As a first polarization controlling device, the polymeric waveguide polarizers are fabricated. Their excess losses are less than 0.5 dB, and the extinction ratios of 20.7 dB and 17.1 dB are obtained for TM-pass and TE-pass polarizers, respectively. Next, the polymeric waveguide polarization splitters are fabricated to demonstrate polarization mode splittings with crosstalks of -14.2 dB and -10.1 dB for TM and TE mode splittings, respectively. Finally, the polymeric waveguide polarization converter is fabricated to show successful TE/TM polarization mode conversion with conversion efficiencies of higher than 30 dB. The polarization converter is insensitive to wavelength and easier to fabricate than the other polarization converters containing periodic structures.
As an application of the polymeric polarization converter, a novel polarization independent intensity modulator (PIIM) is proposed by integrating the polarization converter with conventional phase modulators in a Mach-Zehnder interferometer. For the proposed PIIM, it is shown that extinction ratio of better than 30 dB is obtainable regardless of the input polarization states.
