Layered two-dimensional
(2D) graphene oxide (GO) films are integrated with micro-ring resonators (MRRs)
to experimentally demonstrate enhanced nonlinear optics in the form of
four-wave mixing (FWM). Both uniformly coated and patterned GO films are integrated
on CMOS-compatible doped silica MRRs using a large-area, transfer-free,
layer-by-layer GO coating method together with photolithography and lift-off
processes, yielding precise control of the film thickness, placement, and
coating length. The high Kerr nonlinearity and low loss of the GO films combined
with the strong light-matter interaction within the MRRs results in a
significant improvement in the FWM efficiency in the hybrid MRRs. Detailed FWM
measurements are performed at different pump powers and resonant wavelengths for
the uniformly coated MRRs with 1−5 layers of GO as well as the patterned devices
with 10−50 layers of GO. The experimental results show good agreement with
theory, achieving up to ~7.6-dB enhancement in the FWM conversion efficiency (CE)
for an MRR uniformly coated with 1 layer of GO and ~10.3-dB for a patterned
device with 50 layers of GO. By fitting the measured CE as a function of pump
power for devices with different numbers of GO layers, we also extract the dependence
of GO’s third-order nonlinearity on layer number and pump power, revealing interesting physical insights about the evolution
of the layered GO films from 2D monolayers to quasi bulk-like behavior. These
results confirm the high nonlinear optical performance of integrated photonic resonators incorporated with 2D
layered GO films.
Two dimensional graphene oxide films for enhanced optical nonlinear performance in CMOS compatible integrated devices
