Design of silicon waveguides integrated with 2D graphene oxide films for
Kerr nonlinear optics
Abstract
The Kerr nonlinear optical performance of silicon nanowire waveguides
integrated with 2D layered graphene oxide (GO) films is theoretically
studied and optimized based on experimentally measured linear and
nonlinear optical parameters of the GO films. The strong mode overlap
between the silicon nanowires and highly nonlinear GO films yields a
significantly enhanced Kerr nonlinearity for the hybrid waveguides. A
detailed analysis for the influence of waveguide geometry and GO film
thickness on the propagation loss, nonlinear parameter, and nonlinear
figure of merit (FOM) is performed. The results show that the effective
nonlinear parameter and nonlinear FOM can be increased by up to ≈52 and
≈79 times relative to bare silicon nanowires, respectively. Self-phase
modulation (SPM)-induced spectral broadening of optical pulses is used
as a benchmark to evaluate the nonlinear performance, examining the
trade-off between enhancing Kerr nonlinearity and minimizing loss. By
optimizing the device parameters to balance this, a high spectral
broadening factor of 27.6 can be achieved ‒ more than 6 times that
achieved in previous experiments. Finally, the influence of pulse chirp,
material anisotropy, and the interplay between saturable absorption and
SPM is also discussed. These results provide useful guidance for
optimizing the Kerr nonlinear optical performance of silicon waveguides
integrated with 2D layered GO films.