Realistic photonic bandgap structures for TM-polarized light for all-optical switching

We investigate manufacturable photonic crystal (PhC) structures with a large photonic bandgap for TM-polarized light. Although such PhC structures have been the object of only a limited number of studies to date, they are of central importance for ultra fast all-optical switches relying on intersubband transitions in AlAsSb/InGaAs quantum wells, which support only TM polarization. In this paper, we numerically study substrate-type PhCs for which the two-dimensional approximation holds and three-dimensional photonic-crystal slabs, both with honeycomb lattice geometry. Large TM PBGs are obtained and optimized for both cases. Two types of PhC waveguides are proposed which are able to guide TM modes. Their unique properties show the potential to apply as waveguiding structures in all-optical switches.