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Layered 2D graphene oxide (GO) films are integrated with micro-ringresonators (MRRs) to experimentally demonstrate enhanced nonlinear optics.Both uniformly coated (1−5 layers) and patterned (10−50 layers) GO films areintegrated on complementary-metal-oxide-semiconductor (CMOS)-compatibledoped silica MRRs using a large-area, transfer-free, layer-by-layer GO coatingmethod with precise control of the film thickness. The patterned devices furtheremploy photolithography and lift-off processes to enable precise control of thefilm placement and coating length. Four-wave-mixing (FWM) measurementsfor different pump powers and resonant wavelengths show a significantimprovement in efficiency of 7.6 dB for a uniformly coated device with 1 GOlayer and 10.3 dB for a patterned device with 50 GO layers. The measurementsagree well with theory, with the enhancement in FWM efficiency resultingfrom the high Kerr nonlinearity and low loss of the GO films combined withthe strong light–matter interaction within the MRRs. The dependence of GO’sthird-order nonlinearity on layer number and pump power is also extractedfrom the FWM measurements, revealing interesting physical insights aboutthe evolution of the GO films from 2D monolayers to quasi bulk-like behavior.These results confirm the high nonlinear optical performance of integratedphotonic resonators incorporated with 2D layered GO films.