Energy-efficient variable optical attenuator on SOI with folded waveguides and heaters

We report a variable optical attenuator (VOA) on silicon-on-insulator (SOI) with folded silicon waveguides and TiW heaters to improve the thermal efficiency. The measured extinction ratio of the device is around 20.4 dB with a power consumption of 10.2 mW. The rise and fall times are 17.2 μs and 17.55 μs, respectively.