Thermally tunable microring resonator for self-collimated beams in photonic crystals

We demonstrate an ultra-compact thermally tunable microring resonator based on self-collimation effect in photonic crystals. Thermo-optical effect and the index of refraction changes due to temperature in microring resonator are used to manipulate dispersion quantity. Finite-difference time-domain method (FDTD) is used to investigate the characteristics of the microring resonator. The new design exhibits an ON-OFF contrast with an extinction ratio of more than 12 dB, an ultra-compact footprint of 3.3times3.3 mum², and tuning efficiency of 0.08 nm/^degC when it operates at the optical communication wavelength lambda =1.55 mum. The design presented may find applications in areas including ultra-compact optical switch and wavelength filer in integrated optical circuits.