High data rate and ultra-compact optical encoder based on 2D linear photonic crystal ring resonator

In the present work, a high-speed optical encoder is proposed based on two-dimensional photonic crystal ring resonator (2D-PCRR) using coupled mode theory and resonance effect. Square shaped ring resonator, couplings rods and several waveguides have been utilized in the proposed structure. Silicon rods in air structure has been designed with rod radius of 0.1a and lattice constant 0.540 nm. The photonic band gap is being calculated using plane wave expansion method and finite-difference-time-domain method to analyze the performance characteristics of optical encoder like: transmission spectra, electric field view, contrast ratio, delay time, response time etc. The operating wavelength of structure is 1550 nm, to perform encoder operation where only one input port is activated at a time while other input ports are inactivated and accordingly equivalent binary encoded signal is produced at output ports. The proposed encoder is designed with fast response time 222.76 fs, high data rate of 4.48 Tbps and ultra-compact size of 140.84µm2. Hence the proposed device is suitable for high-speed optical computation, photonic integrated devices and high speed optical integrated circuits.

All optical NAND/NOR and majority gates using nonlinear photonic crystal ring resonator

All optical logic gates are building blocks for all optical data processors. One way of designing optical logic gates is using threshold switching which can be realized by combining an optical resonator with nonlinear Kerr effect. In this paper we showed that a novel structure consisting of nonlinear photonic crystal ring resonator which can be used for realizing optical NAND/NOR and majority gates. The delay time of the proposed NAND/NOR and majority gates are 2.5 ps and 1.5 ps respectively. Finite difference time domain and plane wave expansion methods were used for simulating the proposed optical logic gates. The total footprint of the proposed structure is about 988 μm2.