High-efficiency ultra-fast all-optical photonic crystal diode based on the lateral-coupled nonlinear elliptical defect

An all-optical Fano-like diode featuring a nonlinear lateral elliptical micro-cavity and a reflecting column in the photonic crystal waveguide is proposed. The asymmetric micro-cavity is constructed by removing one rod and changing the shape of the lateral rod from a circle to an ellipse. A reflecting pillar is also introduced into the waveguide to construct an F–P cavity with the elliptical defect and enhance the asymmetric transmission for the incident light wave transmitting rightwards and leftwards, respectively. By designing the size of the ellipse and optimizing a reflecting rod at a suitable position, a maximum forward light transmittance of −1.14 dB and a minimum backward transmittance of −57.66 dB are achieved at the working wavelength of 1550.47 nm. The corresponding response time is about 10 ps when the intensity of the pump light beam resonant at 637 nm is 3.97 W/μm 2 .