Long period gratings for wavelength specific loss in a fibre laser

We introduce a method that alters the operating wavelength of a laser transition by using long period fibre gratings which couple from the core into an effective continuum of cladding modes. We shift the operating wavelength of an Nd³⁺- doped aluminosilicate fibre laser from 1057 nm to 1088 nm which represents dominant lasing from Nd³⁺ ions in Al³⁺ deficient sites.