Variable optical attenuators based on SOI with 3 μm top silicon layer.

Abstract

In this paper, electro-absorption variable optical attenuators (VOAs) have been designed and fabricated on silicon-on-insulator material with a 3μm thick top silicon layer. We have simulated the impact of doping distance, doping width, doping depth, doping concentration, and doping length on VOA's power consumption at 20dB attenuation. We have found that the power consumption of VOA at 20dB attenuation will decrease as the doping distance and doping width get smaller, while the doping depth and doping concentration get larger. We have further demonstrated that the power consumption can also be reduced by increasing the doping length and by taking a series structure theoretically. In this paper, VOAs with different doping structures, doping distances, doping widths, and doping lengths have been fabricated, and the tested results have verified our theoretical analysis. With doping distance of 8μm, doping width of 15μm, doping length of 1cm, doping concentration of 1×1019 cm-3, and doping depth of 0.9μm, the power consumption of the series VOA at 20dB attenuation is 470mW, and the rising/falling time is 54ns/49.5ns.