A new integrated all-optical switch based on a micro-cavity

Abstract

Integrated all-optical switches [1] can be of great importance for optical transparent telecommunication network. All-optical switching is based on the phase change of the light due to the intensity in nonlinear optical (NLO) materials. The materials investigated up to now exhibit NLO coefficients which are still too low for realistic high speed devices performance at low optical power. A possible way to improve the NLO is enhancement of the electric field inside the material using micro-cavities. Recently, rotationally symmetric dielectric micro-cavities with radii larger than the wavelength are modelled theoretically for linear and NLO materials. These micro-cavities can confine large electromagnetic fields in small volumes and act as optical cavities with high quality factors (Q’s >104 [2]). Examples of these micro-cavities are semiconductor microdisk lasers and Nd:YAG spherical lasers. All kind of NLO processes, such as stimulated Raman scattering and sum-frequency generation, have already been reported for liquid droplets, however, in integrated optic devices micro-cavities have not yet been used. The spatial distribution of the internal field in the cavity is in general dominated by the near resonance-mode, the whispering gallery mode, when the incident frequency is near one of the high-Q modes, ω0.