Single frequency holmium-doped DBR fibre laser at 2.1 μm

We report on the development of a single frequency laser operating at a wavelength of 2.1 μm. This laser uses a holmium-doped distributed Bragg reflector (DBR) structure pumped at 1.15 μm. These lasers have applications in precision measurement, coherent laser radar and beam combination. Initial characterisation of the laser is included.