Integrated Midinfrared Laser Based on an Er-Doped Chalcogenide Microresonator

On-chip midinfrared (mid-IR) optical sources play an increasingly important role in building a fully integrated photonic system for sensing, imaging, communications, and signal processing applications. In this paper, we present a practical room-temperature planar design for an Er-doped chalcogenide-based mid-IR laser, which features a multimode microresonator. The cavity is carefully designed to have a high Q-factor at both pump (0.66 μm) and lasing (3.6 μm) wavelengths, which are separated by more than two octaves. This is achieved by using a novel idea of operating the cavity as a microdisk at the pump wavelength and as a microring at the lasing wavelength. Detailed numerical analysis shows that the high-Q feature of the cavity greatly reduces the lasing threshold to 7.6 μW, with a laser slope efficiency of 10%.