The dependence of magnetostatic wave (MSW) modes and its bandwidth on the external DC bias magnetic fields in the magneto-optic film was illustrated.Three kinds of magnetostatic modes

those of the magnetostatic backward volume wave (MSBVW)

the magnetostatic forward volume wave (MSFVW) and the magnetostatic surface wave (MSSW)

was taken into account together by studying the generation of the magnetostatic waves under arbitrarily tilted bias magnetic field

and then the diffraction performance of the MSW-based magneto-optic Bragg cells may easily be calculated.Our calculation shows that

(1) for the same magnitude of external bias magnetic fields

in the conventional magnetization directions there is the largest MSW bandwidth and the operating frequency of the MSBVW-based Bragg cell is higher than that of the MSFVW-based Bragg cell

(2) under an appropriately inclined bias magnetic field

all three magnetostatic modes can respectively be excited at higher and higher frequencies

and (3) the MSFVW bandwidth may move to higher frequencies by tilting the external bias magnetic field.