Performance prediction for silicon photonics integrated circuits with layout-dependent correlated manufacturing variability.

This work develops an enhanced Monte Carlo (MC) simulation methodology to predict the impacts of layout-dependent correlated manufacturing variations on the performance of photonics integrated circuits (PICs). First, to enable such performance prediction, we demonstrate a simple method with sub-nanometer accuracy to characterize photonics manufacturing variations, where the width and height for a fabricated waveguide can be extracted from the spectral response of a racetrack resonator. By measuring the spectral responses for a large number of identical resonators spread over a wafer, statistical results for the variations of waveguide width and height can be obtained.

Sub-wavelength grating for enhanced ring resonator biosensor.

While silicon photonic resonant cavities have been widely investigated for biosensing applications, enhancing their sensitivity and detection limit continues to be an area of active research. Here, we describe how to engineer the effective refractive index and mode profile of a silicon-on-insulator (SOI) waveguide using sub-wavelength gratings (SWG) and report on its observed performance as a biosensor. We designed a 30 μm diameter SWG ring resonator and fabricated it using Ebeam lithography.

Spiral Bragg grating waveguides for TM mode silicon photonics.

We demonstrate spiral Bragg grating waveguides (BGWs) on the silicon-on-insulator (SOI) platform for the fundamental transverse magnetic (TM) mode. We also compare TM spiral waveguides to equivalent transverse electric (TE) spiral waveguides and show that the TM spiral waveguides have lower propagation losses. Our spiral waveguides are space-efficient, requiring only areas of 131×131 µm(2) to accommodate 4 mm long BGWs, and, thus, are less susceptible to fabrication non-uniformities.

Design and fabrication of SOI micro-ring resonators based on sub-wavelength grating waveguides.

Standard silicon photonic strip waveguides offer a high intrinsic refractive index contrast; this permits strong light confinement, leading to compact bends, which in turn facilitates the fabrication of devices with small footprints. Sub-wavelength grating (SWG) based waveguides can allow the fabrication of low loss devices with specific, engineered optical properties. The combination of SWG waveguides with optical micro-resonators can offer the possibility of achieving resonators with properties different from the traditional SOI rings.

Silicon-on-insulator sensors using integrated resonance-enhanced defect-mediated photodetectors.

A resonance-enhanced, defect-mediated, ring resonator photodetector has been implemented as a single unit biosensor on a silicon-on-insulator platform, providing a cost effective means of integrating ring resonator sensors with photodetectors for lab-on-chip applications. This method overcomes the challenge of integrating hybrid photodetectors on the chip. The demonstrated responsivity of the photodetector-sensor was 90 mA/W.