Electroabsorption modulators on waveguide micro-ring cavity resonators with self-aligned total internal reflectors

Abstract

The switching characteristics of an electroabsorption modulator fabricated on a waveguide-coupled micro-ring-cavity resonator were investigated. The ring cavity resonator consists of ridge waveguide regions, total internal reflector mirrors, and a coupling region. The coupling region is implemented with a multi-mode interferometer (MMI) waveguide to enhance the coupling coefficient. The total internal reflection mirrors were fabricated by self-aligned RIBE process resulting in minimal insertion losses of around 0.7 dB/mirror. The gain medium was a 1.55 μm InGaAsP MQW ridge waveguide, and the passive waveguide was a re-grown 1.4 μm InGaAsP ridge structure. The sharp variation of the optical transmission through the micro-ring-cavity resonator near the resonance wavelength was utilized to realize efficient semiconductor optical modulators with a high extinction ratio. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.