In this letter, we report on the inscription of a fourth-order fiber Bragg grating made line-by-line in the optical fiber using a femtosecond laser. Strong Bragg resonance (
$sim$ 17 dB) and low insertion loss (
$sim$0.5 dB) were obtained with only 2000 periods. Measured refractive index change of these inscribed lines reaches up to
$7times 10^{-3}$ . The grating was fully characterized and the low insertion loss together with low polarization-dependent loss were realized compared to gratings made by the point-by-point method. The high temperature annealing experiment shows the grating can survive up to at least 800
$^{circ}hbox{C}$.
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