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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]

In this paper, the implementation of an all-optical full adder based on a two-dimensional photonic crystal is proposed. The proposed structure consists of hexagonal lattice of silicon rods embedded in air substrate. To design the proposed optical full adder, three nonlinear ring resonators, some linear waveguides, and some point defects are used. The switching mechanism of the ring resonators is based on nonlinear Kerr effect. The performance of the proposed structure has been analyzed and investigated by using plane wave expansion (PWE) and finite difference time domain (FDTD) methods. The minimum contrast ratio of the structure is 17.02 dB. The response time of the structure is 0.724 ps and can operate at a bit rate of 1.381 Tb/s. The proposed structure is simple, compact, and offers high contrast ratio, fast response time along with high bit rate and therefore can be a promising candidate for high speed data processing, computing, networking, and optical integrated circuits. • In this paper, we have proposed an all-optical full adder using a 2D hexagonal Si-air photonic crystal. • The proposed optical full adder has been designed by using three nonlinear ring resonators along with some linear waveguides. • The switching functionalities of the ring resonators have been achieved by utilizing nonlinear Kerr effect. • The proposed structure is simple, compact, offers high contrast ratio, fast response time and high bit rate respectively. [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]

Milk has almost all essential nutrients which is required for human nutrition. Controlling the quality of milk and milk-based products is imperative for the safety of consumers. In the present paper, an ultra-compact and an ultra-fast photonic crystal based microring resonator is proposed for refractive index sensing applications which can be used for determining the different constituents of milk. The sensitivity of the proposed structure is 1 nm/% of water content and 0.42 nm/% of fat content in the milk. The high value of Q-factor is obtained which is around 16,857 by using the finite difference time domain simulation method. The shift in the resonant wavelength of the output light at the through port of the structure is observed for the different milk samples. [ABSTRACT FROM AUTHOR]

Abstract In the present paper, we study the transmission of the two-dimensional photonic crystal (PC) superellipse ring resonator. The fast growing applications of optomechanical systems lead to strong demands in new sensing mechanism in order to design the sensing elements to nanometer scale. The photonic crystal based resonator has been investigated as promising solutions because the band gap structure and resonator characteristics are extremely sensitive to the deformation and position shift of rod / cavity in PC resonators. This structure opens a single channel filter. The study is extended for tuning of channel filter’s wavelength with a temperature of this structure. The transmission of the channel filter shows a red shift with temperature linearly. This wavelength shift of the channel filter is used for the sensor application. The sensitivity for the proposed structure is found to be 65.3 pm/°C. The outstanding sensing capability renders PC resonators as a promising optomechanical sensing element to be integrated into various transducers for temperature sensing applications.

In this work, the design and the performance of a two dimensional photonic structure with hexagonal geometry is numerically investigated by plane wave expansion (PWE) method. The structure consists in a zinc oxide (ZnO) substrate patterned in a hexagonal configuration with periodic holes with different radius. The photonic crystals exhibited band gaps in the near infrared wavelength range. This kind of photonic structures can be used for a wide range of optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this work, a novel design of a photonic crystal ring resonator with superellipse shape based on a thermo-optic switch is studied. This ring resonator with superellipse shape provides higher flexibility of light manipulation to design a structure with high performance to switch wavelengths. The proposed design composed of two waveguides between them, the photonic crystal ring resonator is placed. Tunability phenomena can change the refractive index of whole structure with an external effect. Based on this phenomena, our proposed design can switch the wavelength 1582 nm after an external effect (thermal effect), in which the refractive index of our proposed design change slightly from 3.19 to 3.25. The results achieved for our proposed switch based on novel ring resonator at 1582 nm where quality factor and footprints are 1977.5 and 277 μm 2 , respectively. The value of lattice constant ‘ a ’ and radius of rods are equal to 546 nm and 0.185* a , respectively. The finite different time domain (FDTD) and plane wave expansion (PWE) methods are used to calculate the outputs spectrum and the band gap, respectively. [ABSTRACT FROM AUTHOR]

In this paper, a channel drop filter based on two-dimensional photonic crystal ring resonator (PCRR) is proposed. The proposed structure consists of bus waveguide, dropping waveguide and a ring resonator. We have focused on improving the dropping efficiency and quality factor of the structure by applying different optimization techniques. Optimized channel drop filter using PCRR is designed, and it is extended to drop three different channels by changing the inner rods radius in each ring resonator that act as a demultiplexer. As designed structure drops three different channels such as 1524, 1544 and 1565 nm, the band gap for the structure is calculated and observed by plane-wave expansion method. The normalized transmission spectra and resonance wavelengths for different radius are obtained using two-dimensional finite-difference time-domain method. The proposed PCRR-based demultiplexer has the channel spacing of about 20 nm which fulfils the requirements of coarse wavelength-division multiplexing systems. The size of the demultiplexer is small; hence, it can be utilized for photonic integrated circuits. [ABSTRACT FROM AUTHOR]

In this paper, plane wave expansion and stiffness matrix methods are adopted to analyze the dispersion relation of Rayleigh surface acoustic waves in a piezoelectric phononic composite composed of two homogeneous layers (ZnO and AlN) deposited on a one-dimensional piezoelectric (111) Si/AlN phononic substrate. The effect of crystallographic orientation of silicon on the dispersion relation is discussed. We found that the width of the gap became larger when the middle layer was introduced. The influence of filling fraction, thicknesses of the film and the middle layer on the band gap width is discussed. In addition, the phase velocity and the electromechanical coupling coefficient for Rayleigh surface modes are calculated versus the filling fraction. A comparison of phononic composite with ZnO/AlN/(111)Si layered structure is presented to deduce the interest of introduction of the phononic substrate. [ABSTRACT FROM AUTHOR]

In the present paper, we study the transmission of the two-dimensional photonic crystal (PC) superellipse ring resonator. The fast growing applications of optomechanical systems lead to strong demands in new sensing mechanism in order to design the sensing elements to nanometer scale. The photonic crystal based resonator has been investigated as promising solutions because the band gap structure and resonator characteristics are extremely sensitive to the deformation and position shift of rod / cavity in PC resonators. This structure opens a single channel filter. The study is extended for tuning of channel filter's wavelength with a temperature of this structure. The transmission of the channel filter shows a red shift with temperature linearly. This wavelength shift of the channel filter is used for the sensor application. The sensitivity for the proposed structure is found to be 65.3 pm/°C. The outstanding sensing capability renders PC resonators as a promising optomechanical sensing element to be integrated into various transducers for temperature sensing applications. [ABSTRACT FROM AUTHOR]

In this paper, we described a versatile two steps approach for the realization of silica inverse opals functionalized with DNA-aptamers labelled with Cy3 fluorophore. The co-assembly method was successfully employed for the realization of high quality inverse silica opal, whilst the inverse network was functionalized via epoxy chemistry. Morphological and optical assessment revealed the presence of large ordered domains with a transmission band gap depth of 32%, after the functionalization procedure. Finite Difference Time-Domain (FDTD) simulations confirmed the high optical quality of the inverse opal realized. Photoluminescence measurements evidenced the effective immobilization of DNA-aptamer molecules labelled with Cy3 throughout the entire sample thickness. This assumption was verified by the inhibition of the fluorescence of Cy3 fluorophore tailoring the position of the photonic band gap of the inverse opal. The modification of the fluorescence could be justified by a variation in the density of states (DOS) calculated by the Plane Wave Expansion (PWE) method. Finally, the development of the aforementioned approach could be seen as proof of the concept experiment, suggesting that this type of system may act as a suitable platform for the realization of fluorescence-based bio-sensors.

A two-dimensional photonic crystal (PC) composed of textile fiber and air is initially discussed in this paper. Textile materials are so called soft materials, which are different from the previous PCs composed of rigid materials. The plain wave expansion method is used to calculate band structure of different PCs by altering component properties or structural parameters. Results show that the dielectric constant of textile fibers, fiber filling ratio and lattice arrangement are effective factors which influence PCs' band gap. Yet lattice constant and fiber diameter make inconspicuous influence on the band gap feature. [ABSTRACT FROM AUTHOR]

The plane-wave expansion (PWE) method is employed to calculate the photonic band structures of metal/dielectric (M/D) periodic systems. We consider a one-dimensional (1D)M/D superlattice with ametal layer characterized by a frequency-dependent dielectric function. To calculate the photonic band of such a system, we propose a new method and thus avoid solving the nonlinear eigenvalue equations. We obtained the frequency dispersions and the energy distributions of eigen-modes of 1D superlattices. This general method is applicable to calculate the photonic band of a broad class of physical systems, e.g. 2D and 3D M/D photonic crystals. For comparison, we present a simple introduction of the finite-difference (FD) method to calculate the same system, and the agreement turns out to be good. But the FD method cannot be applied to the TM modes of the M/D superlattice. [ABSTRACT FROM AUTHOR]

Wideband slow light in an ellipse-shaped-hole slotted photonic crystal waveguide (ESPCW) has been theoretically demonstrated. By adjusting the length of major and minor axes of air holes and tuning the holes position of the second row adjacent to the slot, the group index and bandwidth of slow light can be engineered effectively at the same time. Through the optimization of ESPCW structures by the plane wave expansion (PWE) method, the nearly constant group indices at 46, 80.7, and 215.5 are obtained, and we accordingly attain the flat bandwidths of 4.81, 2.66, and 1.02 nm around the operating frequency of 1550 nm, while the variation of each group index is restricted within ±10% range. Meanwhile, the normalized delay-bandwidth product stays around 0.14, with minimal dispersion on the order of 10 6ps 2/km for all the cases. [ABSTRACT FROM PUBLISHER]

Abstract: In this paper, two-dimensional circular Photonic Crystal Ring Resonator (2D PCRR) based Add Drop Filter (ADF) using circular rods is designed for ITU-T G.694.2 eight channel Coarse Wavelength Division Multiplexing (CWDM) systems to add/drop a channel centered at a resonant wavelength of 1491nm. The Plane Wave Expansion (PWE) method and 2D Finite Difference Time Domain (FDTD) method are employed to obtain the Photonic Band Gap (PBG) range and output spectra of the ADF. Close to 100% of coupling and dropping efficiencies, 13nm of passband width and 114.69 of quality factor are observed for the designed filter at 1491nm which is highly sufficient and fulfill the requirement of ITU-T G.694.2 CWDM system. Further, the resonant wavelength tuning possibilities of ADF are theoretically studied to cover the lower channels of CWDM systems. The structural parameters such as refractive index, lattice constant and radius of the rod in the structure are considered for resonant wavelength tuning. [Copyright &y& Elsevier]

A two dimensional Photonic Crystal based Bandpass Filter is designed by exploiting coupling between the quasi waveguides and the circular Photonic Crystal Ring Resonator (PCRR). The output efficiency, resonant wavelength and bandwidth of PCBPF are investigated by varying the dielectric constant of the structure. The normalized transmission spectra of circular PCRR are taken using 2D Finite Difference Time Domain method. The Photonic Band Gap is calculated by Plane Wave Expansion method. Close to 100% (Band II) output efficiency is observed over the wavelength range from 1,504 to 1,521 nm and 85% (Band I) is obtained at 1,420 nm through simulation. The full width half maximum bandwidth of these bands is 35 and 20 nm, respectively. Further, the parameters that affect the resonant wavelength, output efficiency and bandwidth of the filter such as size of the reflector, radius of the coupling rods, lattice constant, rod radius and number of rods in the structure are analyzed. The overall size of the proposed filter is 11.4 μm × 10.2 μm, which is smaller than the filters already reported in the literature and highly desirable for Photonic Integrated Circuits. [ABSTRACT FROM AUTHOR]

Abstract: We propose a novel photonic crystal slab waveguide that provides a single-mode band with large bandwidth. The proposed waveguide is obtained by introducing a line defect in a triangular lattice of air holes in a dielectric slab. This line defect consists of holes which are not located in the original lattice points. The plane wave expansion (PWE) method is used to extract the band diagram of guiding modes and based on the results, photonic crystal holes in the defect row and its adjacent rows are modified to maximize the waveguide bandwidth. We show that using the proposed structure, a single-mode bandwidth of 17% can be achieved. [Copyright &y& Elsevier]

In this paper, a 2-D photonic crystal double ring resonator based biosensor has been designed for the detection of chikunguniya virus through normal and infected plasma, platelets, red blood cell & uric acid in blood. The refractive index of whole blood is a function of wavelength, it constitutes such as plasma, platelets, RBC and uric acid for sensed transmittance, quality factor and power efficiency. The resonant peak of the structure shifting from high to low refractive index of blood component shows the sensitivity of the material. In case of chikungunya, It's also observed that it has a low quality factor (60.12), high transmission efficiency (98 %) and good sensitivity (3.43 × 103nm/RIU). In case of chikungunya, FDTD software is more suitable to evaluate the results. [ABSTRACT FROM AUTHOR]

Abstract: Photonic crystal channel drop filters (CDFs) with a ring resonator have been reported and have shown good optical properties to drop the light. Photonic crystal ring resonators (PCRRs) offer scalability in size and flexibility in mode design due to their multi-mode nature [1] compared to point-defect or line-defect photonic crystal (PhC) cavities. It is far smaller in size than other corresponding devices. In this paper, we proposed several channel drop filters combination of ring resonators and point defect micro-cavities. These ring resonators work as energy couplers. They capture the electromagnetic energy propagated in the input waveguide and send it to the output waveguide at its resonant frequencies. But ring resonators have too many resonant frequencies because of their multi-mode nature. So, point defect micro-cavities are used to further filter the original light wave. In our designed CDFs, close to 100% drop efficiency has been achieved at their center normalized frequencies, respectively. [Copyright &y& Elsevier]

In this paper, we described a versatile two steps approach for the realization of silica inverse opals functionalized with DNA-aptamers labelled with Cy3 fluorophore. The co-assembly method was successfully employed for the realization of high quality inverse silica opal, whilst the inverse network was functionalized via epoxy chemistry. Morphological and optical assessment revealed the presence of large ordered domains with a transmission band gap depth of 32%, after the functionalization procedure. Finite Difference Time-Domain (FDTD) simulations confirmed the high optical quality of the inverse opal realized. Photoluminescence measurements evidenced the effective immobilization of DNA-aptamer molecules labelled with Cy3 throughout the entire sample thickness. This assumption was verified by the inhibition of the fluorescence of Cy3 fluorophore tailoring the position of the photonic band gap of the inverse opal. The modification of the fluorescence could be justified by a variation in the density of states (DOS) calculated by the Plane Wave Expansion (PWE) method. Finally, the development of the aforementioned approach could be seen as proof of the concept experiment, suggesting that this type of system may act as a suitable platform for the realization of fluorescence-based bio-sensors. [ABSTRACT FROM AUTHOR]