Thulium-doped tellurium oxide laser for optical communication at 2-µm window

We demonstrate compact thulium-doped tellurium oxide microring lasers integrated on a low-loss silicon nitride platform with the output powers of up to 4.1 mW. We observe lasing in the wavelength range of 1.84-1.88 μm under 1.6 μm resonant pumping at 1.3 μm waveguide-microring gap size.