Efficient Optical Modulation with High Data-Rate in Silicon Based Laterally Split Vertical p-n Junction

Abstract

Efficient optical modulation along with high data rate is a prerequisite for the realization of high-performance optical modulator. Optical modulation in silicon with high data-rate and high modulation efficiency is proposed by a laterally separated vertical p-n junction. Two independent but synchronized p-n junctions that supports the common optical mode are created by forming a slot waveguide structure. It provides a prominent way to enhance the light-material interaction necessarily to achieve low \text{V}_{\pi }\text{L} along with the low RC time constant which is crucial for the high-speed operation. The proposed device shows a high modulation efficiency of 0.74 V-cm for 1.2 mm long device. The calculated intrinsic 3-dB bandwidth reaches up to ≈ 58 GHz at a reverse bias of 6 V. We show high speed operation up to 25 Gbit/s for the device length of 600~\mu \text{m} with a simple lumped electrode configuration. The Traveling-wave electrodes as a coplanar waveguide is employed to further improve the speed performance of the device. By taking the advantage of excellent velocity matching between optical group index and RF effective index, high data rate performance up to 100 Gbit/s is obtained with an extinction ratio of 2.4 dB. The proposed device opens new avenues for high speed optical interconnect on an SOI platform. © 1965-2012 IEEE.