Integrated all-Si traveling-wave optical modulators and photodetectors operating beyond 40 GHz

We present high-speed, traveling-wave (TW) Si Mach-Zehnder modulators and Si sub-bandgap photodetectors (SBPD) monolithically integrated on an Si-only photonics platform without incorporation of Ge epitaxial growth process. Through constructing a detailed equivalent circuit model on the components, we design the device structure and TWelectrodes for operating the device with bandwidth beyond 40 GHz. The experimental results show the 3-dB bandwidths of the Si modulator and photodetectors are 35 and 44 GHz, respectively, generally agreeing well with our design. The measured photoresponsivity of the SBPD varies from 0.1 A/W to nearly 1 A/W, depending on the bias voltage. These two components potentially can be utilized for an integrated optical transceiver operating for 50 Gbit/s data transmission. (C) The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License.