Modeling antimonite-based distributed feedback lasers for carbon-dioxide gas sensing

Abstract

This work shows the process of computing coupling coefficients of first-order distributed feedback (DFB) metalsemiconductor quantum-well lasers. For the gas sensing of carbon dioxide (CO₂), the antimonite-based (Sb-based) DFB lasers at the wavelength of 2 μm are discussed. The optical waveguide structure, for each laser, has a built-in grating interface between the metal and semiconductor layers. This work considers the interface with sinusoidal corrugation geometry for preliminary modeling and computation. To compute the coupling coefficient of the metal-grating waveguide, a photonic method, Floquet-Bloch method (FB), is used for the waveguide with such a corrugated semiconductor-metal interface. The optical method, the Ray-optics method (RO), is also used for computation. Both the photonic and the optical methods have close results.