Influence of titania cladding on SOI grating coupler and 5 μm-radius ring resonator

Titania cladding is deposited on a 5 μm-radius silicon-on-insulator ring resonator and grating couplers which are patterned by deep-ultraviolet lithography. The influence of titania cladding is studied by measuring the transmission spectra of the ring resonator coupled to a pair of single-mode fibers through the grating couplers. Temperature dependent wavelength shift of TE-like mode through the ring resonator is reduced to −20 to +20 pm/K from 74 pm/K without a noticeable degradation of insertion loss through the ring and the transmission peak of grating coupler is shifted at about 50 nm by the addition of titania cladding.