Low-loss optical switch using Brewster angle

Fabrication and actuation errors of submicron silicon waveguide optical switches are reported to remain within sub-100 nm ranges. These errors cause high loss ruining the optical performance of the switches at the on-state. Elliptical tips with tip angles about the Brewster angle are studied in an attempt to reduce the high-loss of such optical switches. Numerical computations are conducted in 3D Finite Difference Time Domain analysis. Optical performances at various distances both along and perpendicular to the light propagation directions are studied for tips with angles above and below the Brewster angle. Effect of fabrication and actuation errors on the performance of optical switch is reduced using tips with angles greater than Brewster angle. Transmittance of optical switch is calculated to be 94.69% when 1.5 μm-wide and 74°-angled waveguide tip geometry after two cascaded waveguide pairs is utilized.