High-extinction ratio TE-pass polarizer fabricated in LiNbO3 by proton exchange and titanium indiffusion

TE-pass integrated optical waveguide polarizers have been made in Z-cut, T-propagating LiNbO3 using titanium indiffusion in conjunction with proton exchange. The two exchanged regions are adjacent to the Ti-indiffused waveguide on both sides and at the output end of the sample. In the proton-exchanged regions, (Delta) ne > 0, (Delta) no < 0. Thus, the TM mode is radiated into the substrate. The polarizer operating at (lambda) equals 1.3 micrometers exhibits an extinction ratio > 53 dB and fiber-waveguide- fiber excess loss is 4 dB.