Femtosecond written phase-shifted-gratings and fiber Bragg gratings arrays using defocusing and phase-mask movement

Phase-shifted-gratings and arrays of fiber-Bragg-gratings are inscribed with a uniform phase-mask. These gratings are inscribed with 800 nm femtosecond pulses and a uniform phase-mask where the wavelength tube-ability is achieved by defocusing and phase-mask movement.