A high quality-factor(Q) cavity based on a one-dimensional(1D) photonic crystal with gradated elliptical holes was designed using FDTD simulation. Different gradient profiles of the mirror holes were found to correspond to different Qvalues of the cavities. A simple strategy is proposed to construct high-Q cavities by using an S-shaped gradient profile for the elliptical holes' minor axes, such as a cosine function or Gaussian function. Using such a strategy, a Q value exceeding two million is obtained with only ten mirror holes in a cavity.
A magneto-optical(MO)metal-sandwiched multilayered structure composed of metal,MO medium and dielectric buffer layers is presented and investigated by finite-element-method-based-mode solver and perturbation theory.The results show that this structure exhibits large nonreciprocal phase shift,strong mode confinement in the narrow buffer layers as well as very low propagation loss.The propagation length with 1dB loss is much longer than the required length of𝜌π/2 nonreciprocal phase shifts in this structure.The modal area is smaller than half of the conventional MO waveguides.This phenomenon can be used to achieve a compact plasmonic isolator based on the Mach–Zehnder interferometer.
An electrically driven, single-longitudinal-mode GaAs based photonic crystal (PC) ridge waveguide (RWG) laser emitting at around 850 nm is demonstrated. The single-longitudinal-mode lasing characteristic is achieved by introducing the PC to the RWG laser. The triangle PC is etched on both sides of the ridge by photolithography and inductive coupled plasma (ICP) etching. The lasing spectra of the RWG lasers with and without the PC are studied, and the result shows that the PC purifies the longitudinal mode. The power per facet versus current and current-voltage characteristics have also been studied and compared.
