LiNbO/sub 3/ integrated optical chip for fiber optical gyroscope fabricated by high temperature proton exchange

The main fiber optical gyroscope's components is a multifunctional integrated optical chip (MIOC). Optolink's MIOC is a solid state waveguide device on X-cut LiNbO/sub 3/ substrate fabricated by high-temperature proton exchange method (HTPE). A very important advantage of proton exchange (PE) waveguides is the following. In such waveguides the extraordinary refraction index is increasing, while refraction index of ordinary ray is decreasing. As a result, proton exchanged waveguides support propagation only extraordinary polarization modes (TE in our case). Therefore, it is not necessary to use in the fiber optical gyroscope a polarizer, which brings additional loss.