Active semiconductor-based grating waveguide structures

Under certain conditions, a high-finesse resonance phenomenon can occur in a grating waveguide structure (GWS). By varying these conditions, a shift i n the resonance wavelength can be achieved. Specifically, utilizing the hig h finesse property of the GWS, small changes in the refractive index can re sult in a tuning range larger than the resonance bandwidth. Here, we consid er different electric-field and charge carrier mechanisms that can affect t he refractive index in semiconductor materials, and exploit them in order t o control the refractive index change and, therefore, the resonance wavelen gth in the GWS. The predicted results are verified experimentally with an a ctive GWS formed with semiconductor materials and operated in a reverse vol tage configuration.