Multimode optical fibers with a large core diameter and high numerical aperture are disclosed herein. Multimode optical fibers disclosed herein comprise a core region having a radius greater than 30 microns and a cladding region surrounding and directly adjacent to the core region, the cladding region comprising a depressed-index annular portion comprising a depressed relative refractive index. The depressed cladding region is surrounded by a titania doped cladding region. The fiber has a total outer diameter of less than 120 microns, and exhibits an overfilled bandwidth at 850 nm greater than 200 MHz-km.