Temperature tuning of microcavity ring and disk resonators at 1.5-μm

We report the temperature-tuning of novel microcavity resonators with wide free spectral range Δλ_fsr, and high finesse. We have fabricated and demonstrated AlGaAs/GaAs ring and disk resonators with diameters of 10.5 and 20.5 μm evanescently coupled to single-mode waveguides. Strong lateral waveguide confinement allows micron-size cavities with negligible bending loss and the resonators can be fabricated with reasonably low loss using nanofabrication techniques, resulting in a high finesse. The 10.5-μm-diameter disk resonator yields a finesse as high as 120 (Q=8600) and Δλ_fsr of 21.6 nm. The temperature tuning is 1.3 nm/10°C, suitable for a thermally-controlled switch or widely tunable filter