Broadband 2-μm emission on silicon chips: monolithically integrated Holmium lasers

Laser sources in the mid-infrared are of great interest due to their wide applications in detection, sensing, communication and medicine. Silicon photonics is a promising technology which enables these laser devices to be fabricated in a standard CMOS foundry, with the advantages of reliability, compactness, low cost and large-scale production. In this paper, we demonstrate a holmium-doped distributed feedback laser monolithically integrated on a silicon photonics platform. The Al2O3:Ho3+ glass is used as gain medium, which provides broadband emission around 2 mu m. By varying the distributed feedback grating period and Al2O3:Ho3+ gain layer thickness, we show single mode laser emission at wavelengths ranging from 2.02 to 2.10 mu m. Using a 1950 nm pump, we measure a maximum output power of 15 mW, a slope efficiency of 2.3% and a side-mode suppression ratio in excess of 50 dB. The introduction of a scalable monolithic light source emitting at > 2 mu m is a significant step for silicon photonic microsystems operating in this highly promising wavelength region. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement