Highly Efficient Broadband Waveguide Adiabatic Polarization Converter With Apodization

In this letter, we report the design of an electro-optic polarization converter based on Ti-indiffused lithium niobate waveguide under the rapid adiabatic passage mechanism, a technique borrowed from a parallel scheme of robust and nearly complete population transfer in two level atomic systems and nuclear magnetic resonance. We show that this scheme enables very high efficiency of conversion between two orthogonally polarized modes of the waveguide for a wide range of wavelengths. We also introduce a novel design for the apodization of electrode pattern to get a ripple-free bandwidth spectrum.