In this work, we report our recent progress on monolithic integration of magneto-optical oxide thin films and nonreciprocal photonic devices on silicon. We demonstrate strong Faraday rotation of − 6000 deg/cm at 1550 nm wavelength in silicon integrated Ce1.5Y1.5Fe5O12 films, which exceeds the Faraday rotation of epitaxial CeiY2Fe5Oi2 thin films on garnet substrates. We also present the design of a broadband optical isolator using silicon/CeYIG/silicon MMI structure. The device shows 20 dB isolation bandwidth of 1.6 nm, and insertion of 0.817 dB at 1550 nm wavelength, with a very compact device footprint of 310.42 μm. The fabrication tolerance and influence of a YIG seed layer on the device performance are also discussed.