ABSTRACT
We studied the scaling properties of the metal-clad nanoring laser by examining the laser cavity loss as a function of the laser dimension. Since the laser threshold is determined by the balance between the volume of gain and the total cavity loss, the more slowly the cavity loss increases with a decreasing laser dimension, the better the scaling behaviour will be [6]. The resonant frequencies of the passive laser cavities were calculated using the filter diagonalization method [17]. To reach the lasing threshold, the optical gain must overcome all the losses, including metal absorption loss, optical diffraction loss, and optical scattering loss. In the calculations, the scattering loss was simulated by the grid size in the FDTD model. The grid size was chosen to be 12 nm by observing the edge roughness of the fabricated ring cavity using scanning electron microscope. The epitaxial structure is shown in Fig. 13.2 with all materials lattice matched to InP. Complex refractive index for the metal gold (Au) was taken from Johnson and Christy [18].
