Investigation On Nonlinear Photonic Crystal Bistable Devices

Photonic crystals (PCs) have received intensive and extensive studies in the last decade due to their potential applications. People have started to explore the applications of PC-based devices in optical communication and signal processing on the basis of theoretical studies. So far, most of the research works focus on the linear properties of PCs and the investigations of nonlinear PCs in both theoretical and experimental aspects are on the horizon.We have investigated the bistability of PC defects with Kerr nonlinearity based on theoretical analysis and numerical simulation. First, we predict the bistable transmission behavior of nonlinear PC defects by using the coupled mode theory (CMT). Then, the bistable behaviors of nonlinear PC defects are simulated by use of the finite-difference time-domain technique. It is demonstrated that the CMT is an effective method for analyzing the bistability of nonlinear PC defects. In addition, it is found that the transition contrast at the down-transition point is much larger than that at the up-transition one. Therefore, the operation point for all-optical switching is preferably chosen to be close to the down-transition point. Our theoretical analysis issupported by the simulation results.Finally, we have studied the applications of nonlinear PC bistable switches in all-optical signal processing and telecommunication. It is shown that devices with superior properties can be successfully designed and fabricated.