Comparison of guided-wave approaches to optical bistability (A)

P. Vincent, Nicole A. Paraire, M. Nevière +2 more

A new use of gratings in nonlinear optics is presented, i.e., the realization of bistable components. The device studied here consist of grating couplers ruled on a Kerr nonlinear medium, which use the guided-wave resonance to increase the local field and thus the nonlinearities. The result is that they are intrinsic bistable optical systems with high-speed, low pumping thresholds, and geometry well adapted to optical integration. First, a linear electromagnetic study of the devices is presented. It follows optimizing the grating parameters in order to get the best coupling between the incident beam and the guided mode inside the corrugated waveguide. Then a graphical construction is given that demonstrates the bistable character of the system in nonlinear optics. Next a nonlinear analysis of the devices is rigorously derived from Maxwell equations. It states precisely the predictions of the graphical construction and allows comparison of the effectiveness of the guided-wave resonance with the surface plasmon resonance in order to reduce the threshold of bistability.

Y. Ron Shen

G. I. Stegeman

The minimum power required for a nonlinear phase shift of π/2, and the maximum propagation distance are evaluated for the semiconductors GaAs and InSb in four guided wave geometries: surface plasmons at the interface between two semi-infinite media and guided by a thin metal film, and single and multilayer thin-film optical waveguides. Optimum configurations compatible with guided wave technology are identified.

Guy Vitrant, P. Arlot, R. Reinisch

A guided wave is launched through a nonlinear prism coupler whose prism-waveguide gap is filled with a liquid crystal. We observe that the intensity of the guided wave may exhibit optical bistability. Tests are realized which proove that the loops are true bistable cycles and not only hysteresis. The experimental results are in good agreement with plane-wave calculations. The disagreement with finite-width incident beam calculations is explained by a thermal averaging process within the liquid crystal.

Sergei N Bagaev, V. A. Nikulin, Е. А. Титов