Characteristics of local density of optical states in a tapered grated waveguide at resonant states

Based on Green's function method, we have conducted a systematic numerical investigation on the characteristics of local density of optical states of a tapered grated waveguide and other related parameters such as field profiles, transmission and scattering loss at left and right resonant states. The tapered grated sections are additional corrugated sections at both edges of a regular grated waveguide. We consider two different variations of the corresponding sections namely the uniform and non-uniform corrugation depth configurations. It is found that the characteristics of the local density of optical states for both variations at resonant states are different, especially for the left resonant state. In the mean time, compared to the other cases, a relatively distinct characteristic is also found on the transmission and scattering loss parameters of uniform variations at right resonant case.