Tuning the resonant wavelength of long period fiber gratings by etching the fiber's cladding

In this paper the resonant wavelength of a long period fiber grating (LPG) is tuned toward longer wavelength by etching the fiber. For LP04 and LP05 cladding modes, the tuning ranges of 23 and 81 nm are achieved, respectively. Also the dependence of the resonant wavelength on the cladding radius of LPG is theoretically simulated.