mid-ir quantum cascade Laser Integrated on Ge-based pHoTonics circuits – LIGHTUP

Silicon photonics is expected to have a major impact for the development of mid-infrared photonics by leveraging the reliable and high-volume fabrication technologies already developed for microelectronic integrated circuits. A key point for the development of real applications for mid-IR photonics is the coupling of the photonic circuits with the mid-IR light source. In this context, LIGHT UP project addresses the integration of an an InAs/AlSb – based Quantum Cascade Laser (QCL) on a mid-InfraRed Germanium (Ge)-based photonics integrated circuit. The groundbreaking concept of the project is the epitaxial growth of QCL devices on the Ge-based photonics circuit, to offer large-volume, wafer-level complete mid-IR photonic platform. Both the QCL active region and the Ge-based photonics circuit will be specifically designed to optimize both the coupling strategy and the material properties, i.e., to preserve low optical losses and large optical gain. As a final demonstrator, the demonstration of a Ge-based PIC with a monolithically integrated QCL working at 7.4 µm is targeted. The choice of this wavelength is related to potential application to alkane sensing, that can be easily tested and can show rapidly the impact of the proposed work. The results achieved within the LIGHT UP project will give answers on the possibilities and opportunity of a new and ambitious monolithically integrated III-Sb on Ge-based mid-IR platform. In a long term vision, a large number of unique and innovative devices such as an ultra-compact, wideband and tunable light source coupled with on-chip optical modulator, photodetectors, or with integrated spectrometers will then be envisioned. Such a platform is expected to be have a major impact for many applications, including real-time environmental monitoring of pollutants, early medical diagnostic, or free space telecommunications, among others.