Thermo-optic tuning of erbium-doped amorphous silicon nitride microdisk resonators

摘要

We demonstrate a technique to yield a direct and sensitive measurement of the thermo-optic coefficient (TOC) for light-emitting materials in optical microdisk resonators. Using photo-luminescence from erbium-doped amorphous silicon nitride (α-SiN_x:Er) as an example, we show how the TOC can be extracted from thermally induced shifts in the resonant microdisk modes. For the highest-performance α-SiN_x:Er material composition, we find a TOC at 1.54 μm of ~3 × 10~(-5) K~(-1) in the 300-500 K range. Additionally, our work demonstrates a convenient all-optical spectroscopic technique for sensitive temperature measurements, with a resolution of ~30 mK in this temperature range.