External cavity lasers based on SiN platform for biomedical applications

In this article, we present experimental and simulation results of a novel dual-wavelength laser source that emits in the regime of 764nm and 820nm. These wavelength regimes are chosen to match the absorption lines of oxygen gas and water vapour. The dual-wavelength laser source is realised by combining two External Cavity (EC) lasers on a SiN platform. In particular, each of these EC lasers is formed by butt-coupling a SiN resonant mirror to a reflecting semiconductor gain chip that results in highly monochromatic source (10MHz) to match the narrow absorption lines of the gases. Ultimately, this SiN based dual-wavelength source will have applications in the field of biomedical for continuous monitoring of oxygen in body cavities.