TW344037B - Lithium niobate TE/TM polarization splitter using nickel and zinc diffusions - Google Patents

Abstract

A process for producing a polarization splitter by double nickel diffusion, which comprises the following steps: (1) using a mask etching technique to etch out longitudinal grooves on a Z-cut lithium niobate chip 10; (2) plating a nickel layer 20; (3) masking one half of the chip in the perpendicular longitudinal direction, and plating a nickel layer 30, followed by plating a zirconium oxide layer 40; (4) removing the photoresist by washing with an organic solvent; (5) simultaneously diffusing the two at a high temperature for a short period of time during which nickel 20 and nickel 30 will diffuse into the lithium niobate chip, such that the region where the thickness of nickel is thinner will form a single-ordinary waveguide, and the region where the thickness of nickel is thicker will form a random polarization waveguide; in which the zirconium oxide 40 will remain on the surface as a mark of the random polarization waveguide; (6) finally using the mask etching technique to etch out a longitudinal groove connected with the zirconium oxide 40 at a slant angle; (7) plating a nickel layer 50; (8) washing off the photoresist; and (9) carrying out diffusion at a lower temperature to form a single-extraordinary waveguide.