According to the perturbation theory, the coupled-mode equations for guided optical waves in the magneto-optical fiber

Bragg gratings (MFBGs) under non-uniform magnetic field are derived. The equivalent relation between the magnetically-

induced non-uniform fiber Bragg grating (MnFBG) and the corresponding non-magnetic chirped grating is expressed and

verified by the piecewise-uniform MFBG model under linear magnetic field. On the basis of the equivalent relation, the

MnFBGs can be effectively investigated by means of simulations. The characteristics of the MnFBGs under three typical

magnetic field distributions with application to optical pulse compression are simulated, and the minimal pulse width can

be achieved for the same magneto-optical coupling parameter of 2.2 × 10

3m-1.