Third order lateral grating distributed feedback quantum cascade laser emitting around 4.7 μm

Abstract Lateral grating is an effective and concise method for realizing single-mode laser sources, and it exhibits significant research value due to its regrowth-free characteristic and ideal wavelength reliability. In this study, by combining a third-order lateral grating design with an advanced fabrication process, we demonstrate a lateral grating distributed feedback quantum cascade laser emitting around 4.7 μm with high-ideal single-mode performance and emission wavelength stability. A single-longitudinal-mode output power of 13 mW is achieved, with a side mode suppression ratio of 20 dB, and the wavelength shift ratio is as low as 0.04 nm/mA, indicating exceptional wavelength stability. Benefiting from the improvements in high-order lateral grating design and the high-quality deep etching grating production, this research on lateral grating distributed feedback quantum cascade lasers simplifies the manufacturing process and controls the cost of mid-infrared light sources. This is of great significance for promoting the commercialization of mid-infrared quantum cascade lasers.