Abstract:
Fabricating of phase-shifted fiber Bragg grating (PSFBG) by a femtosecond (fs) laser
post-processing of standard single mode fiber Bragg grating (FBG) without phase
mask is demonstrated. A central region of grating is irradiated by an fs laser assisted
with a rotating jig, which produces a π phase shift at the central region of the grating
and forms a π phase-shifted FBG. The procedure is simple, fast, and has good
reproductivity. The bandwidth of transmission peak of PSFBG grows with
increasing amount of laser energy or length of irradiation and decreasing translation
speed. Transmission loss decreases with increasing irradiation length. Repeatability
of fs post-processing and temperature stability of PSFBG were investigated.
