Post-fabrication resonance trimming of Si 3 N 4 photonic circuits via localized thermal annealing of a sputter-deposited SiO 2 cladding

We report a resonance trimming technique, applicable to waveguides employing an SiO 2 cladding. The SiO 2 is deposited by a room temperature sputtering process. Resonance shifts of micro-ring resonators of 4.4 nm were achieved with furnace annealing, whereas a resonance shift of 1.4 nm was achieved using integrated micro-heaters. For our device layout, with 30 μ m ring separation, the thermal cross-talk is negligible, and isolated trimming of …