  We report enhanced nonlinear optics in complementary metal oxide
semiconductor compatible photonic platforms through the use of layered two
dimensional (2D) graphene oxide (GO) films. We integrate GO films with silicon
on insulator nanowires (SOI), high index doped silica glass (Hydex) and silicon
nitride (SiN) waveguides and ring resonators, to demonstrate an enhanced
optical nonlinearity including Kerr nonlinearity and four wave mixing (FWM).
The GO films are integrated using a large area, transfer free, layer by layer
method while the film placement and size are controlled by photolithography. In
SOI nanowires we observe a dramatic enhancement in both the Kerr nonlinearity
and nonlinear figure of merit (FOM) due to the highly nonlinear GO films. Self
phase modulation (SPM) measurements show significant spectral broadening
enhancement for SOI nanowires coated with patterned films of GO. The dependence
of GO Kerr nonlinearity on layer number and pulse energy shows trends of the
layered GO films from 2D to quasi bulk like behavior. The nonlinear parameter
of GO coated SOI nanowires is increased 16 fold, with the nonlinear FOM
increasing over 20 times to a FOM greater than 5. We also observe an improved
FWM efficiency in SiN waveguides integrated with 2D layered GO films. FWM
measurements for samples with different numbers of GO layers and at different
pump powers are performed, achieving up to 7.3 dB conversion efficiency (CE)
enhancement for a uniformly coated device with 1 layer of GO and 9.1 dB for a
patterned device with 5 layers of GO. These results reveal the strong potential
of GO films to improve the nonlinear optics of silicon, Hydex and SiN photonic
devices.
