In this paper, we have proposed an all-optical logic gate structure based on line and point defects created in the two dimensional square lattice of silicon rods in air photonic crystals (PhCs). Line defects are embedded in the ГX and ГZ directions of the momentum space. The device has two input and two output ports. It has been shown analytically whether the initial phase difference between the two input beams is π /2, they interfere together constructively or destructively to realize the logical functions. The simulation results show that the device can acts as a XOR and an OR logic gate. It is applicable in the frequency range of 0–0.45 ( a / λ ), however we set it at ( a / λ =) 0.419 for low dispersion condition, correspondingly the lambda is equal to 1.55 µm. The maximum delay time to response to the input signals is about 0.4 ps, hence the speed of the device is about 2.5 THz. Also 6.767 dB is the maximum contrast ratio of the device.

All-optical XOR and OR logic gates based on line and point defects in 2-D photonic crystal

All-optical NOR and NAND gates based on photonic crystal ring resonator

We propose a new configuration of interference based OR, XOR, NOT and AND optical logic gates on a two dimensional square lattice photonic crystal (PhC) platform. The working of these devices was analyzed by the FDTD method and the operating frequency range was explored using the plane wave expansion method. The XOR and NOT gates have high contrast ratio which is more than 35 dB between high and low logic states, for a particular wavelength. All these devices are operating with multiple wavelengths. The impact of structural parameter like radius on the operating wavelength and Contrast Ratio (CR) was analyzed. It is found that the optimization of structural parameters makes it possible to obtain the operating wavelength allowed by band structure. These proposed devices were made up of linear waveguides and square ring resonator waveguides, without using nonlinear materials, optical amplifiers and external phase shifters.

Interference based square lattice photonic crystal logic gates working with different wavelengths

In this paper, a nonlinear photonic crystal structure is proposed in order to implement all-optical NOT and OR logic gates. The proposed structure includes combiners and limiters. The limiters are designed using ring resonator. Also, the combiners are optimized with changing the radius of rods near the crosspoint of waveguides in order to enhance the performance of structure. Nonlinear rods of proposed structure are made of silicon nanocrystal which has been used in order to create the frequency shift for different values of input power. Plane wave expansion and finite difference time domain methods have been utilized to simulate the performance of proposed logic gate. Simulation results show that the ON–OFF logic-level extinction ratio and bit rate are −18.7 dB and 333 Gbit/s, respectively.

All-optical photonic crystal NOT and OR logic gates using nonlinear Kerr effect and ring resonators

Realization of all optical half-adder based on self-collimated beams by two-dimensional photonic crystals

All-optical photonic crystal AND gate with multiple operating wavelengths

All-optical photonic-crystal encoder capable of operating at multiple wavelengths

We proposed a binary numbers operating NOT/NOR gates with cylindrical silicon structure in all-optical logic system. Operating principle, as revealed by both theoretical calculation and two dimensional finite-difference time-domain simulation. Proposed logic system can show their capabilities. This device is potentially applicable for photonic integrated circuits.

Binary Operating in All-Optical Logic Gates Based on Photonic Crystals

For stimulates great developments in high-speed and high-capacity Cloud Computing Technologies (CCT) systems in the future. The all-optical logic gate based on planar photonic crystal (PPC) waveguide is a promising technology. We design an all-optical AND gate in PPC, as an ultracompact component for planar lightwave circuit integration with suitable choice of parameters, perform this task. The PPC waveguides are composed of circular dielectric rods set in two-dimensional triangular lattice. To realize the AND logic function, as predicted using 2D finite-difference time-domain simulations. The combination of the ring and line defect coupler waveguides forms the device. On the basis of our simulations, we found that the optimized scheme maximizes the power transmission above 80% at a wavelength of 1.55 um. Besides, this device can apply to all-optical Arithmetic Logic Unit (ALU) in all-optical computing and potentially applicable for photonic integrated circuits (PICs) in the future.

Optical logic operation for AND Gate based on planar photonic crystal circuit

We propose a AND logic gate based on photonic crystal with cylindrical silicon structure. It takes advantages of the device sizes are drastically reduced to a scale of a few tens of micrometers and the easy-to-implement logic function. Furthermore, the multi-input AND gate can apply to all-optical Arithmetic Logic Unit (ALU) devices of photon computer in the future.

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Yi-Pin Yang

Papers

All-optical photonic crystal AND gate with multiple operating wavelengths

All-optical photonic-crystal encoder capable of operating at multiple wavelengths

Binary Operating in All-Optical Logic Gates Based on Photonic Crystals

Optical logic operation for AND Gate based on planar photonic crystal circuit

AND logic gate for optical processing