Optical gain in Er-Yb doped waveguides fabricated by femtosecond laser pulses

Abstract
Er-Yb doped waveguides at 1.5 µm fabricated by femtosecond laser pulses are reported. Demonstrated is a Gaussian mode-profile, low propagation loss and internal gain in a 25 mm-long waveguide used as the active element in a standard waveguide-amplifier setup.