All-optical logic gates based on two-dimensional low-refractive-index nonlinear photonic crystal slabs
ABSTRACT This article demonstrates theoretical design of ultracompact all-optical AND, NAND, OR, and NOR gates with two-dimensional nonlinear photonic crystal slabs. Compound Ag-polymer film with a low refractive index and large third-order nonlinearity is adopted as our nonlinear material and photonic crystal cavities with a relatively high quality factor of about 2000 is designed on this polymer slab. Numerical simulations show that all-optical logic gates with low pump-power in the order of tens of MW/cm2 can be achieved. These design results may provide very useful schemes and approaches for the realization of all-optical logic gates with low-cost, low-pump-power, high-contrast and ultrafast response-time.
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ABSTRACT: In this work, we present a heterostructure All Optical Flip-Flop configuration based on all optical switching with Kerr nonlinear photonic crystal. In this Square-Hexagonal structure, we propose three different schemes for the cavities in order to show the tradeoff between switching time and triggering power. Loss in the system is reasonably low because of the perfect band gap matching at bending points where two lattices join. The proposed RS-Flip Flop has exceptional features which make it one of the well optimized and most practical structures to be used in the all optical integrated circuits. The novel design has a fast switching action (in the order of a few ps), and low input power (in the order of 100 mW/0m2). Also high contrast of the output signals for ON and OFF states, can help the easy detection or coupling to the other devices. The structure is fascinatingly uncomplicated which results in the ultra small dimensions of that in order to be placed in an all optical integrated circuit. Furthermore, we provide profound analytical view on functioning of system, as analyzed by the finite difference time domain (FDTD) method.Optics Communications 01/2011; 285(24). DOI:10.1016/j.optcom.2012.06.095 · 1.54 Impact Factor
Conference Paper: Design of silicon photonic crystal integrated optical devices[Show abstract] [Hide abstract]
ABSTRACT: Photonic crystal has attracted extensive interest in the past 25 years due to its great power to mold the flow of light in micrometer/nanometer scale and promising aspects in building all-optical integrated devices and circuits. In this talk we present our recent efforts of design, fabrication, and characterization of integrated optical elements and devices in infrared silicon two-dimensional photonic crystal slabs. These devices operate either on band gap confinement or on band dispersion control. We focus on topics such as the broad-band wide-angle self-collimation effect, on-chip optical diodes and isolators, new cavities without apparent confinement barriers, and polymer-silicon hybrid nonlinear photonic crystal.Numerical Simulation of Optoelectronic Devices (NUSOD), 2012 12th International Conference on; 01/2012
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ABSTRACT: An optical logic NOT gate (OLNG) is presented based on photonic crystal (PhC) waveguides without nonlinear materials and optical amplifiers. Also, a way of determining the operating parameters is presented. It is demonstrated through finite-difference time-domain simulations that the structure presented can operate as an OLNG. The optimized contrast ratio, defined as the logic-"1" output power divided by the logic-"0" output power, is found to be 297.07 or 24.73 dB. The size of the OLNG can be as small as 7a×7a, where a is the lattice constant of the PhC. Further, the OLNG presented in this paper can operate at a bit rate as high as 2.155 Tbit/s, which is much higher than that of electronic or optical logic gates developed until now. Moreover, as it is not based on the nonlinear effect, the OLNG can operate at very low powers and a relatively large operating bandwidth. This is favorable for large-scale optical integration and for developing multiwavelength parallel-processing optical logic systems.Applied Optics 02/2012; 51(5):680-5. DOI:10.1364/AO.51.000680 · 1.78 Impact Factor