Effects of the inclined femto laser incidence at the phase mask on FBG carving
The inclined incidence of the femto laser on the phase mask in fiber Bragg grating (FBG) carving has a significant effect on the quality of FBG fabrication. Based on that the infrared femto laser has highly spatial coherence and the order walk-off will happen behind the phase mask, the interferogram generated at the fiber core by the inclined femto laser beam has been analyzed using the multi-beam interference principle. The influence of beam inclination on the coherence of the 0th and [Formula: see text] orders diffraction with different exposure distance, the visibility of interferogram and the frequency component of the transverse interferogram intensity has also been analyzed. It is meaningful for the FBG fabricating with the femto laser.
IR femtosecond pulsed laser-based fiber Bragg grating inscription in a photonic crystal fiber using a phase mask and a short focal length lens
