3C-SiC modulator for high-speed integrated photonics
- PDF / 587,997 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 54 Downloads / 153 Views
Z5.12.1
3C-SiC modulator for high-speed integrated photonics Carlos Angulo Barrios, Christopher Ian Thomas, Michael Spencer, and Michal Lipson School of Electrical and Computer Engineering, Cornell University Ithaca, NY 14853, U.S.A. ABSTRACT We propose a compact 3C-SiC electro-optic modulator for high-speed Si-based integrated optoelectronics operating at 1.55-µm-wavelength. The device is based on an optical microresonator using sub-micron size high-index-contrast SiC waveguides on a SiC-SiO2-Si [SiC-on-Insulator (SICOI)] platform. Three different electrode configurations are analyzed. Switching times on the order of tens of ps are predicted by using low bias voltages. INTRODUCTION Si passive microphotonic devices have been shown to exhibit good performances [1]. However, it is difficult to achieve high-speed optical modulation using Si as active material since it lacks of linear electro-optic (Pockels) effect and has weak Kerr and Franz-Keldysh effects. Cubic (3C or β) SiC has remarkable properties that make it very attractive to be used as an active material in Si-based photonic circuits: 1) 3C-SiC exhibits a significant electro-optic (EO) coefficient of 2.7 pm/V [2]; 2) 3C-SiC is suitable to be grown on a Si substrate and it is compatible with the mature Si technology; 3) 3C-SiC possesses a high bandgap (2.2 eV) which enables it to be used for waveguiding at the visible and near-infrared spectrum range and 4) 3CSiC presents a high breakdown voltage (106 V/cm). In the present work, we propose and analyze a 3C-SiC EO integrated micro-modulator based on high-index-contrast strip waveguides for high-speed applications at 1.55-µm telecommunications wavelength. A SiC-SiO2-Si [SiC-on-Insulator (SICOI)] platform is chosen for optical confinement in the normal direction to the propagation plane. The Pockels effect is used to vary the refractive index (phase). A micro-racetrack resonator converts the phase variation into an intensity modulation. DEVICE STRUCTURE Fig. 1a shows a top-view schematics of the device. It consists of a racetrack resonator defined by a high-index-contrast 3C-SiC square (500 nm x 500 nm) strip waveguide on SiO2. The gap between a bus waveguide and the racetrack is 610 nm and the radius of curvature (Rc) of the curved sections is 10 µm. Lateral and vertical Au electrodes have been defined along the straight sections of the racetrack. Fig. 1b shows cross-section schematics and dimensions of the straight waveguide sections of the resonator for three electrode configurations: horizontal configuration (HC), vertical configuration I (VC-I) and vertical configuration II (VC-II). HC is used for TM (transverse magnetic) mode modulation by producing an in-plane bias electric field through the two electrodes placed on the buried oxide (BOX) layer. VC-I is used for TE (transverse electric) modulation by employing the normal component of the bias electric field produced by three electrodes placed over a SiO2 layer which is assumed to be deposited on the SiC strip waveguide. VC-II is also used for TE modulatio
Data Loading...
