Investigation of Ge_20Sb_15Se_65 photonic crystal slab waveguides with slow light at infrared wavelength

The slow light propagation in Ge20Sb15Se65 chalcogenide photonic crystal slab waveguides of air holes have been investigated. The obtained slow-light waveguides can be divided into two categories by perturbing the holes adjacent to the waveguide core: symmetric and asymmetric waveguides. With a bandwidth of 3~30 nm at the center wavelength of 3 μm, it is possible to achieve the group index of 16~43 within 20% in symmetric waveguides, and the group index can be increased up to 130 in asymmetric ones. The result shows perfect slow-light properties in chalcogenide PCSWs and can be used as affordable reference for further research.