Very large bandwidth noncollinear coplanar magneto-optic interaction with magnetostatic forward volume waves in an yttrium iron garnet-gadolinium gallium garnet (YIG-GGG) waveguide is reported for the first time. Bandwidths of 0.78 and 1.03 GHz centered, respectively, at the carrier frequencies of 2.5 and 6.0 GHz, and TM0 -TE0 mode-conversion efficiencies of 0.54 and 0.50% have been achieved at the optical wavelength of 1.317 μm using a single microstrip transducer and homogeneous dc magnetic fields of 2200 and 3500 Oe. A summary of related coupled-mode analysis is also presented.