Slow-Light Lasing in 1D Photonic crystal InGaAs/GaAs Nano-Ridges Epitaxially Grown on a Si Wafer

Abstract

The integration of lasers on silicon photonics is often considered the "holy grail" of photonics, due to its potential to revolutionize various applications, including sensing, high-speed communication and computing. Silicon-based lasers can facilitate more capable and cost effective photonic integrated circuits (PICs). Aspect ratio trapping (ART) and nano-ridge engineering (NRE) enable the direct growth of high-quality, defect free, direct bandgap III-V semiconductors in the form of nano-ridges on the silicon substrate [1]. These techniques offer an attractive platform for silicon photonics, bringing us closer to realizing the full potential of this technology. Single nano-ridge optically pumped DFB lasers [2], PIN detectors, and more recently, electrically injected continuous-wave lasers have been showcased on this platform [3]. Here, we demonstrate a novel, optically pumped laser, leveraging the slow-light mode arising from the coupling of multiple InGaAs/GaAs nano-ridges in a one-dimensional photonic crystal configuration. This configuration serves to trap light in the form of a high Q-factor slow-light mode while simultaneously coupling it to vertical emission. We experimentally show low-threshold lasing (≤10kW/Cm^2) for a 20 times shorter cavity (~15μm) than previously demonstrated DFB lasers. The laser operates in single mode with a high side-mode suppression ratio (SMSR) (≥10dB). Also, we studied the beam profile in depth, showing highly directional emission. We will present detailed simulation and experimental results.