We demonstrated and fabricated a 20μm-long ultra-compact variable optical attenuator based on thermo-optical effect with slow light photonic crystal waveguide (PCWG). In simulation, we optimize the line-defect width and radius/period ratio (r/a) of the PCWG for deep photonic band gap and large slope photonic band edge. An r/a=140nm/410nm W1 PCWG is selected for its -60dB depth and 36dB variable attenuation range when the tunable refractive index change is 0.01. We also study different shapes of micro-heaters for low power consumption and high heat transfer efficiency. A 24.6mW and 75.9% heat transfer efficiency are achieved in a 2μm-wide right-angle-shaped micro-heater. In experiment, A 4.6nm red shift at the cutoff wavelength of the fundamental mode and a 10dB tunable attenuation range are achieved through tuning the temperature of the W1 PCWG by an 4.7μm-wide aluminum micro-heater with a maximum power consumption as low as 30.7mW.

Date Published: 28 November 2011
PDF: 6 pages
Proc. SPIE 8308, Optoelectronic Materials and Devices VI, 83080B (28 November 2011); doi: 10.1117/12.904382

Published in SPIE Proceedings Vol. 8308:
Optoelectronic Materials and Devices VI
Guang-Hua Duan, Editor(s)