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In this paper, the implementation of an integrated system of half adder and half subtractor based on 2D Si-air photonic crystal is proposed. The structure includes two input ports, one control port, and two output ports. When light is absent in the control port, the structure operates as a half adder and when light is present in the control port, it functions as a half subtractor. The operation of the structure is based on the phenomenon of constructive and destructive interference of light waves. The novelty of the proposed structure is that using a single control signal, both half adder and half subtractor operations can be realized. Since no nonlinear material has been used to design the structure, the power consumption of the structure is very low. Another advantage of the structure is that same materials have been used for all the rods which makes the fabrication process easier. The structure has been simulated by utilizing PWE and FDTD methods. Different performance parameters such as contrast ratio, rise time, delay time, fall time, response time, and bit rate for the designed structure have been obtained as 14.78 dB, 0.25 ps, 0.3 ps, 0.11 ps, 0.44 ps, and 2.27 Tb/s respectively. Due to its high contrast ratio, fast response time, high bit rate, and smaller dimension, the designed structure can be a promising candidate for realizing high speed optical integrated circuits. [ABSTRACT FROM AUTHOR]

2D photonic crystal ring resonator (2DPCRR)-based highly sensitive chemical/biochemical sensor is designed and simulated. It consists of triangular lattice air holes on a silicon slab of refractive index 3.46 . The sensitivity is determined by shifts in the resonance wavelength as a function of the refractive index of sensing holes. Simulations are performed using the two-dimension finite-difference time-domain method, and the band diagram is calculated using the plane wave expansion method. The 2DPCRR has ultra-compact footprint of 75 μ m 2 , high-quality factor of 3105.58 , with a spectral width of 0.5 nm at the resonant wavelength of 1552.79 nm . Sensor shows a high figure of merit (862 RIU - 1) , a low detection limit (1.2 ∗ 10 - 4 RIU) , and a maximum sensitivity of 431 nm / RIU . The proposed sensor exhibits considerable performance enhancements in comparison with previously published results. [ABSTRACT FROM AUTHOR]

Quantum Controlled NOT (CNOT) gate is a well known logic gate in the world of quantum computing and data processing from application point of view. Recently, photonic crystal based logic gates have attracted increasing attention from researchers due to their compact size, low power requirement, high speed, simplified design, better confinement and ability for integration in optical network. In this paper, we have designed and simulated all-optical CNOT gate based on two-dimensional photonic crystal composed of hexagonal lattice of silicon (Si) rods arranged in air background. The operation of the proposed structure is based on the phenomenon of interference of light waves. Finite difference time domain and plane wave expansion methods have been used to simulate the proposed structure. We have found the contrast ratios at the output ports are 16.66 dB and 16.02 dB respectively. The response time of the proposed structure is 0.612 ps and can operate at a bit rate of 1.63 Tbps. The proposed structure offers fast response time and high contrast ratios that ensure efficient performance and make it suitable for high speed optical integrated circuits. [ABSTRACT FROM AUTHOR]

In this paper, we propose a nanocavity photonic crystal slab (NCPCS) sensor for simultaneous detection of ambient temperature (T) and refractive index (RI) of the surrounding media. 2D-finite difference time-domain (2D-FDTD) approach is employed to run simulations, while the plane wave expansion (PWE) method is used to investigate the band diagram. Transverse magnetic (TM) modes are considered for the band gap calculations. The sensitivity of the proposed structure has been tested by varying background air hole refractive index from 1 to 1.05 in the step of 0.01 and the temperature sensitivity is determined in the range 305 K–330 K. The structure parameters are optimized yielding quality factor (Q) of 3872 , transmission of 97 %, and low detection limit of 9.3 * 10 - 5 RIU . For dual-parameter sensing, RI sensitivity of 431 nm / RIU and T sensitivity of 138 pm / K is obtained. The proposed NCPCS sensor exhibits considerable performance enhancements of sensitivity, Q-factor, and detection accuracy in comparison to previously published results. [ABSTRACT FROM AUTHOR]

In this study, we investigate a new design of a high-sensitivity photonic-crystal pressure sensor (PCPS). The basic structure consists of a triangular array of silicon rods suspended in air. The designed sensor comprises two quasilinear waveguides that are coupled through a resonant cavity. The detection principle is based on the change in the refractive index of the Si material as a function of the pressure variation within the range of 0 to 3 GPa, resulting in a significant shift in the wavelength of the proposed sensor. The sensor offers high sensitivity of approximately 18.2 nm/ GPa, along with very fast response, high-quality factor, and ultra-compact size. The proposed design is reliable and simple to be integrated into various detection applications. [ABSTRACT FROM AUTHOR]

The proposed work presents design and simulation of a new reconfigurable optical logic AND, NOT and NOR gate constructed in a two dimensional (2D) photonic crystals (PhCs). Due to many advantages like high speed, fast response, high bit rate and compact size these optical gates find applications in optical devices, communications and optical sensors for next generation optical systems. The proposed gate structures can be used in realization of all optical devices used in photonic integrated optical circuits. These optical logic gates are constructed in 6 µm * 6 µm in 2D PhCs square lattice structure with a lattice constant a = 0.648 µm. All the gates are realized by creating structural disorders in the cross-waveguide geometries of 2D PhCs. The plane wave expansion (PWE) is utilised to get the complete band gap and required band of the waveguide. Finite difference time domain (FDTD) technique is utilised to investigate the performance of these gates. The several performance parameters are examined using this structure and observed that proposed structure has reduced size, fast response time, better contrast ratio against the existing designs and high bit rates of 1.88 Tbit/s and 1.55 Tbit/s for NOT and NOR gates respectively. The amplitude of the optical signal larger than 0.5 arbitrary units (a.u.) and less than 0.1 (a.u.) at output are considered as logic '1' and '0' respectively. The gates are implemented in third optical window at the wavelength of 1.55 µm. RSoft FullWAVE simulator is used to perform simulation. [ABSTRACT FROM AUTHOR]

The author of this article illustrates a new design and simulation of a twodimensional photonic crystal (PhC) based hydrostatic pressure sensor with a wide dynamic range that ranges from 0 to 4 Gpa and is conducted at a high resolution using the Finite Elements Method (F.E.M) under COMSOL software. In order to analyze the detection principle and its characteristics, the sensor is based on a triangular array PhC-2D of air-immersed silicon rods with a refractive index of 3.6 is used. The sensor consists of a hexagonal shaped ring resonator, which sits between two obtuse angle shaped waveguides. The two waveguides are configured by removing a row of B rods (line faults) and the ring resonator by removing a few rods. This ring resonator reduces the effect of external parameters such as humidity, temperature, etc. The band diagram is presented as well as analyzed using the plane wave expansion (PWE) under the Mat lab software on the one hand and on the other hand, on the other hand, results are obtained and illustrated such as: the distribution of the refractive index 'n' within the structure with the mesh, the distribution of the electric field (TE) at resonance in 2 and 3D, the total energy density (TED), the power flow norm (PFN) and transmission. The sensor is designed for wavelengths between 1520nm and 1640nm. The simulation results show that due to the applied pressure, the refractive index of a sensor is changed and thus the resonant wavelength is shifted linearly to longer wavelengths. The designed sensor behaves linearly between 0GPa and 4GPa of applied pressure and 4.6 nm/GPa of pressure sensitivity. [ABSTRACT FROM AUTHOR]

The optimized representation of an effective all-optical 3-input XOR/XNOR gate is designed with T-shaped 2-D photonic crystals (PhC) composed of silicon (Si) material embedded in an air background. Both XOR/XNOR logic gates are implemented in a single layout, with a phase change between the input signals applied. The beam interference concept is used to design the layout and simulation results are evaluated using finite-difference-time-domain (FDTD) method. This layout has a contrast ratio (CR) of 13.37 dB and 11.81 dB for XOR and XNOR gates respectively. Several other parameters such as response time, transmission efficiency, insertion loss etc., are calculated resulting in good outputs by optimizing the radius and refractive index that can be employed in photonic integrated circuits.

In the present work, a high-speed optical encoder is proposed based on two-dimensional photonic crystal ring resonator 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 have been designed with rod radius of 0.1a and lattice constant 'a' as 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, 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 140.84 µm2. Hence the proposed device is suitable for high-speed optical computation as photonic integrated circuit. [ABSTRACT FROM AUTHOR]

The implementation of an optimized three-input OR gate has been accomplished through the use of T-shaped two-dimensional photonic crystals, which are made of silicon material submerged in an air background. Several parameters, such as refractive indices and radius, have been varied and the ON-to-OFF contrast ratios for the various parameters have been compared in order to reduce the probability of an error in the designed structure being produced. The simulation has been carried out for various combinations of OR gate and electric field intensities have been calculated at a specific wavelength of 1550 nm using the Finite-difference-time-domain method. Furthermore, the designed structure has achieved a contrast ratio of approximately 8.66 dB, a response time of 12 fs, transmission efficiency for the minimum and maximum values of 23% and 169%, insertion loss of 2.27 dB, and an operating speed of 83.3 Tbps, making it suitable for use in optical signal processing. [ABSTRACT FROM AUTHOR]