Er:Yb multimode double-clad fibres are intended for high-power applications at a wavelength of 1.5 μm, where the high slope efficiency results in negligible amplified spontaneous emission at 1 μm.

The fiber femtosecond oscillator, which emits red light at 635 nm, employs a figure-nine cavity configuration. It applies a double-clad Pr 3+-doped fluoride fiber as the visible gain medium ...