Narrow Linewidth GaSb/Si₃N₄ Hybrid Integrated 2 μm DBR Laser

Low-power, compact, and narrow-linewidth light sources are crucial for applications such as wavelength- division multiplexing, coherent LIDAR, and high-resolution spectroscopy [1], for which high spectral purity, power efficiency, and small footprint are instrumental. In the 2 μm wavelength range, narrow-linewidth lasers are particularly valuable for gas sensing and remote sensing applications [2]. To this end, hybrid integration of GaSb- based semiconductor optical amplifiers (SOAs) with silicon photonic integrated circuits (PICs) have recently emerged as an attractive solution [3], [4]. Here we present the development of a hybrid distributed Bragg reflector (DBR) laser operating at 2 μm, achieving uncooled continuous wave (CW) operation with a narrow linewidth of 8 kHz at a 0.5 ms timescale and a maximum output power of 17.4 mW [5].