Er³⁺ Active Yb³⁺Ce³⁺ Co-Doped Fluorozirconate Guided-Wave Chip Lasers

We report efficient 1.55-μm laser operation in a waveguide chip laser femtosecond-laser inscribed in bulk fluorozirconate glass. The ternary doped glass is composed of erbium as the active laser ion, ytterbium sensitizer, and cerium to enhance the branching ratio from the pump to the erbium upper laser state. We have achieved slope efficiencies up to 25%, with a low 100-mW threshold. To meet diverse application requirements, we also report the wide tunability of 1507-1593 nm, and large single-transverse-mode Gaussian beam-output from the 55 μm diameter waveguides.