A novel self-aligned fabrication process for nickel-indiffused lithium niobate ridge optical waveguides

A novel self-aligned fabrication process for Ni:LiNbO3 ridge waveguides has been proposed, By using the self-aligned trilayered structure composed of Ni/Ti/Si, the fabrication process is significantly simplified, and takes ad vantage of suppression of the unwanted planar waveguides and high-coupling efficiency to a single-mode fiber as compared to the conventional processes . Detailed investigations into the characteristics of the ridge waveguides have also proved to be informative under different fabrication parameters. Moreover, the novel self-aligned fabrication process was applied to fabrica te a ridge waveguide Mach-Zehnder modulator. The measured half-wave voltage and extinction ratio were 20.5 V and 12 dB (@ 1.3 mu m), and were 4.2 V an d 8 dB (@0.6328 pound gm).