As2S3/Sr(Ti0.7Co0.3)O3 and As2S3/Sr(Ti0.6Fe0.4)O3 strip-loaded waveguides for integrated magneto-optical isolator applications

Sr(Ti0.6Fe0.4)O3 (STF) and Sr(Ti0.7Co0.3)O3 (STC) room-temperature ferromagnetic oxides were grown epitaxially on LaAlO3(001), (LaSr)(AlTa)O3 (001) and Si (001) substrates. Both materials were demonstrated to be magneto-optically active, and more optically transparent at 1550nm wavelength compared with other non-garnet ferromagnetic materials. As2S3/STF and As2S3/STC strip-loaded waveguides were fabricated on epitaxial STF or STC films grown on LSAT (001) substrates using thermal evaporation and lift-off processing. The absorption of STF at 1550 nm was measured by ellipsometry and by optical transmission spectrum measurements of the As2S3/STF waveguides, which gave similar results. A novel design for a Non-Reciprocal Phase Shift (NRPS) strip-loaded waveguide using chalcogenide glass (ChG) as the guiding layer is proposed. The NRPS and figure of merit of these waveguides are simulated. The ChG strip-loaded waveguide structure shows advantages both in fabrication and device performance according to the simulation results. Our study suggests the possibility of magneto-optical magneto-optical isolators monolithically integrated on a silicon platform.