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In this paper, with dispersion engineering, two waveguides with silicon core and SiO2 cladding are proposed to generation the supercontinuum spectrum and optical frequency combs. By injecting a pulse with a peak power of 800 (W) and a pulse duration of 50 (fs), the output supercontinuum spectrum is obtained from a wavelength of 1100 (nm) to 4000 (nm). Also, by applying a maximum power of 1 KW and a pulse width of 100 (fs), optical frequency combs based on a supercontinuum with a broadband frequency combs have been obtained. Our proposed structure has good potential for engineering and achieving flatness dispersion which there are two zero dispersion wavelengths at 1890 (nm) and 2850 (nm). This flat dispersion can be very useful to achieve the desired output spectrum. Due to the materials used and the flat structure of the proposed waveguides, these waveguides can be used for integrated optical circuits as well as applications in optical communications, spectroscopy, and sensors.

Due to the importance of all-optical demultiplexers (DEMUXs) in optical communication networks, this study aims to design and simulate a novel type of DEMUX using 2D photonic crystals (2D-PhCs). The proposed structure consists of one input waveguide and eight output channels considering linear and point defects. To design this DEMUX, silicon dielectric rods with the refractive index of 3.45 are employed in the air background, the radius of which is equal to R = 0.21Ʌ (Ʌ = 0.522µm) where Ʌ is the lattice constant. The photonic band gap (PBG) and output spectrum of the structure are analyzed by the plane wave expansion (PWE) and finite-difference time-domain (FDTD) methods, respectively. The simulation results indicate the average quality factor and transmission efficiency are 3,602 and 98%, respectively, and inter-channel crosstalk ranges from − 60.5 to -25.5 dB.

In this paper, the design and simulation of an ultra-fast 4 × 2 encoder have been optimized in a new and unique way using the wave interference technique based on two-dimensional photonic crystal structures. To create the given structure, nano-resonators (NR) were used in combination with curved 2-branch waveguides to take advantage of wave interference as well as reduce losses and light scattering in the structure to achieve the desired results. Due to its special design, the proposed structure has been symmetrical with a structural size of about 149 µm2. This symmetry caused the same results to be obtained in different states of the used encoder. The results from the structure simulation indicated a contrast ratio of 7.88 dB, a delay time of 0.21 ps, and a bit rate of 4.761 Tbit/s. All simulations were performed with a central wavelength of 1550 nm and an input power intensity of about 1 mW/µm2. To optimize the structure and evaluate the results obtained from it, the changes were made in the structural parameters such as the size of the radius of dielectric rods, the size of NRs, and the value of lattice constant, and the effects of wavelength, operating frequency, and input power intensity on the simulation results were investigated. The analysis of the results of simulations and optimizations indicated the design of a completely principled and logical structure with very suitable results in comparison with other structures proposed in this field so that it can be used appropriately in integrated optical circuits and can be considered as the basic structure for other designs. In the present research, the plane-wave expansion method was used to extract and analyze the photonic bandgap and the finite-difference time-domain method to obtain the results of the output spectrum of the proposed structure.

The split of the sunlight spectrum by the bandgap energy of multi-junction solar cells is a highly effective way to increase solar cell efficiency. The reason is that the energy of photons is effectively absorbed, and there is a reduction in solar cell loss. In this contribution, we report on the performance of a double-junction copper gallium diselenide/copper indium gallium diselenide (CGS/CIGS) solar cell with a cadmium sulfide (CdS) buffer layer simulator. The J–V characteristics and the external quantum efficiency were simulated under AM1.5 illumination. Increased efficiency was seen as a result of the change in the thickness of layers and different molar ratio amounts of gallium, and the optimal amount of each factor was obtained. In this study, a single CGS solar cell was used as the top cell and a single CIGS solar cell as the bottom cell in the tandem configuration, which showed conversion efficiencies of 16.175% and 15.696%, respectively. Finally, solar cell efficiency of 32.3% was obtained in the double-junction state, an increase of 6% compared with the reference cell.

In this paper, we first present the design of a nano-ring resonator-based filter, in which scattering rods are used at the corners of the structure. By choosing a suitable radius for the dielectric rods in the nano-ring resonator, low channel spacing and high-quality factor parameters have been achieved at 1586.8 nm wavelength. Then, using this filter, a 2-channel demultiplexer is developed. In the proposed demultiplexer, two lattice constants are used: a1 for the main structure and a2 for the structure in the nano-ring resonator. The difference in the lattice constants results in an increase in the quality factor. Some of the advantages of this 2-channel demultiplexer include an average quality factor of 5443, average channel spacing of 0.35 nm, and central wavelengths of 1554.5 nm and 1557.1 nm, respectively, for the first and second channels. Moreover, the minimum and maximum inter-channel cross talks are − 17.63 dB and − 12.1 dB, respectively. Due to the 2.6 nm inter-channels spacing, this structure can be exploited in optical integrated circuits, WDM and DWDM systems.

Using a two-dimensional photonic crystal lattice, a compact and simple structure has been introduced in the present study to construct an all-optical half adder. The designed structure operates under the interference effect. The phase difference has been created in different states by putting the point defects and the difference in the length of the input waveguides. To do analyses, the finite-difference time-domain method and the plane wave expansion have been used. The advantages of this design include the small dimensions, high possibility of construction, compatibility with the silicon-based technology, and equality of the output power in the logic states 0 and 1. The contrast ratio calculated for the port Sum and the port Carry has been equal to 9.3 and 8.22 dB. The response time has been equal to 0.22 ps, generating the data transfer rate of 4.55 Tbps.

In the present paper, a four-channel optical demultiplexer (DMUX) based on two-dimensional photonic crystal has been presented. In this optical demultiplexer, filtering and wavelength separation were performed using point defects between the output and input waveguides. To design the optical demultiplexer, a 31 × 21 resonance filter with a lattice constant (Λ) of 0.54 μm and the radius of the dielectric rods of 0.2Λ was first designed, and then it was expanded to obtain a four-channel 31 × 41 demultiplexer. The output wave spectrum was measured for four channels in the range of 1541.5 nm to 1557.6 nm. The average quality factor of 2567, the average crosstalk of − 25 dB, and the transmission coefficient of higher than 97% were obtained.

The present paper examines a photonic crystal-based ring resonator created using a triangular lattice to design a biosensor with a sensing cavity based on an optical filter. Using this structure, the central wavelength of 1547 nm can be filtered with a transmission coefficient of 95%. Additionally, the maximum value of ultra-high-quality factor (Q) in the proposed structure is about 3740 at 1496 nm wavelengths. Moreover, the minimum detection limit and maximum sensitivity for the proposed structure are calculated to be 7.15 × 10–8 RIU (refractive index unit) and 561 nm/RIU, respectively. In this paper, the effects of structural parameters, including refractive index, lattice constant, and the radius of the rods in the resonator core on the central wavelength of the filter, transmission coefficient, and quality factor have been investigated. The plane wave expansion (PWE) method has been used to extract the photonic bandgap and the finite-difference time-domain (FDTD) method has been used to study the optical behavior of the photonic crystal structure.

Supercontinuum spectrum generation is a process in which laser beam in femtoseconds and high power (kilowatts) is converted into a broad-spectrum beam of light after passing through a specific environment. Of course, achieving this range comes with many limitations. In this paper, photonic crystal fibers are used as a substrate for input pulse due to the ability to control dispersion and loss, and creating single-mode operating conditions. One of the main factors for the formation of supercontinuum spectra of injection pulses is maintaining the nonlinear performance of this type of fiber by controlling the effective mode area and also using chalcogenides (nonlinear coefficients about 100 times higher than silica) in their structure. In the proposed structure, a photonic crystal fiber with silica base element and air cavities with hexagonal structure with the center of Ge11.5As24Se64.5 chalcogenide element have been used to provide the nonlinear property of the structure. Also, in this structure, a ring of Ge20Sb15Se65 chalcogenide elements has been used to reduce the effective mode region and create a flat dispersion curve at a wavelength of 1300 nm (second telecommunication window). The input pulse power is 10 kW and its width is 50 femtoseconds, which has caused the range of the supercontinuum from 800 nm to 1900 nm. This structure can be used to provide the required wavelengths as a carrier in a wavelength division multiplexing (WDM).

Power efficiency and ability to high-speed modulation enables LEDs to transmit data in optical wireless communications. Optical camera communication (OCC) is a special type of VLC in which imaging sensor is using as a receiver instead of photodetector. Some challenges of such systems are the low data transmission rate and the light flickering. Recently under-sampled modulations are developed. In this paper to overcome flickering issue, we used one of undersampled modulation named UPSOOK which enable us to modulate data with a frequency many times higher than the frame rate. Due to the presence of color filters in these sensors, the data transmission rate in OCC systems can be increased by using RGB LED and WDM. On the other hand, using windowing method to find optimum region for data detection, bit error rate (BER) decreased.

In this paper, we investigate the effect of the number of quantum-dot (QD) layers on the performance of the 1.3um QD-vertical-cavity surface-emitting lasers (QD- VeSELs). QD rate equations and thermal conduction equation is solved self-consistently to consider the effect of self-heating on the characteristics of the QD- VeSEL. Results demonstrate that a further increase in the number of QD layers leads to a decrease in self-heating of the laser which enhances the maximum achievable output power and 3-dB modulation bandwidth of the laser. It is also shown that with an increase in the number of QD layers, the roll-over of the optical power occurs at higher injection currents which leads to improve in the dynamic and static behavior of the laser.

In this study, we have designed and simulated a photonic crystal (PhC) nonlinear AND logic gate. First, a suitable photonic crystal ring resonator (PhCRR) structure is designed and simulated that can be used for obtaining the switching power intensity after applying the nonlinear Kerr effect. In this structure, GaAs dielectric rods have been used in the air. The plane wave expansion (PWE) method is used to obtain the guided modes in the proposed structure and the two-dimensional finite-difference time-domain (2D-FDTD) method is also employed to simulate the structure. According to the results obtained from the numerical calculations, the minimum switching power intensity for the structure is equal to 800 W/μm2. Using the designed PhCRR and the obtained switching power intensity, an optimal compact photonic crystal AND logic gate based on the Kerr effect is designed and simulated which exhibits a good performance. The minimum contrast ratio, the response time, and the total area of the structure are 11.04 dB, 1.8 ps, and 194.56 μm2, respectively.

Despite a significant growth in their efficiency in the last decade, perovskite solar cells suffer from low absorption power in the infrared range which forms a wide range of the solar spectrum. To find solutions to improve the performance of solar panels and the efficiency of their absorption, this research examined the effects of using nanostructures and plasmonic nanoparticles for modification of perovskite solar cells' active layer to create a wider absorption spectrum. For this purpose, the effects of different factors, such as the composition, radius and location of plasmonic nanoparticles on light absorption, open-circuit voltage, short-circuit current density and power conversion efficiency (PCE), were considered. Silver spherical nanoparticles were selected to be placed in the absorbent layer because of their low loss and high absorption power. By selection of optimum size, radius and position of nanoparticles and the location of metallic nanoparticles inside the transporting layers of the carrier, an improvement in the absorption and a 43% increase in the PCE of the perovskite solar cell were achieved.

Chalcogenide-based photonic crystal fibers (PCFs), due to their nonlinear properties, are capable of producing supercontinuum spectra, which can be used in the wavelength division multiplexing (WDM). These types of fibers highly absorb telecommunication wavelengths and hence cannot be used to transmit information over the corresponding wavelengths. We have studied the dispersion engineered chalcogenide PCF numerically, which is important to produce ultra-flat broadband supercontinuum (SC) spectra in all-normal dispersion areas. A 1 mm long, hexagonal chalcogenide PCF made from As2S3/Ge20Sb15Se65 and silica glass pumped at 1550 nm provided a SC bandwidth of 5000 nm with pump power of 1 kW. Here, we have reached zero-dispersion wavelength (ZDW) at third telecommunication window, which in turn has given us a broad spectrum at this window with reasonable efficiency.

In this report, four different metallic grid connectivity models, namely graphene, aluminum, gold, and silver for the copper gallium diselenide/copper indium gallium diselenide (CGS/CIGS) dual-junction solar cell, are discussed. In this structure, it is assumed that the metal contact with the aluminum-doped zinc oxide (ZnO:Al) layer forms an ohmic contact. This assumption is true since the metal grids are sandwiched. The sandwich metal grid is such that at first a metal layer having an ohmic contact with ZnO:Al is deposited, then the desired metal layer is placed on the metal layer as contact. In fact, this metal grid replaces the transparent conductor oxide (TCO) in the structure. Using a metal grid instead of a TCO will increase the transparency and thus be more absorbent, because the TCO also has some absorption and does not allow much light to enter the absorber layer. Based on the results of the simulation and comparison of the performance of the metal patterns, we conclude that by choosing the graphene ohmic contact, we will achieve higher efficiency and absorption. The CIGS dual-junction solar cell features were obtained by graphene metal grid, short circuit current of 14.7403 mA/cm2, open circuit voltage of 1.99054 V, fill factor of 38.78%, and efficiency of 11.38%.

In this paper, an ultracompact all-optical encoder based on a photonic crystal nanoresonator was designed. The proposed structure consists of several waveguides and two nanoresonators. The nanoresonators were designed by reducing the radius of the dielectric rods. To analyze the all-optical encoder, plane-wave expansion and finite-difference time-domain methods were, respectively, applied to calculate the bandgap diagram and to obtain the transmission and propagation of optical field. The contrast ratio, delay time, data transfer speed, and total footprint of the logic gate equaled 9.51 dB, 0.24 ps, 4.16 Tb/s, and 148 µ m 2 , respectively. In addition to these parameters, two new parameters were investigated: the range of optical power required, and the frequency range for better logic gate efficiency. Due to the ultracompacted size, low power consumption, low delay time, and simplicity of structure, this all-optical encoder is suitable for use in low-power optical integrated circuits.

In this paper, we investigated the concept of the Sagnac effect in passive integrated optical gyroscope base photonic crystal ring resonator for angular velocity sensing. This configuration utilizes one 3 dB coupler, two Bus waveguides, and five ring resonators for rotation sensing. The structure has been designed using dielectric silicon rods which are embedded in air. The transmission efficiency of the photonic crystal ring resonator at 1551 nm is about 96% with quality factor and bandwidth values equal to 4326 and 0.35 nm, respectively. By measuring the power of the output port, it is possible to estimate the phase shift and then to measure the rotation rate. The central wavelength of structure is assumed to be equal to 1569.9 nm. The structure characteristics have been investigated by using the two-dimensional finite-difference time-domain method. The footprint of the structure is approximately 279 μm2.

In visible light communications with the optical orthogonal-frequency-division multiplexing (O-OFDM) technique, the high peak-to-average-power-ratio (PAPR) is an important issue due to the limited dynamic range of light emitting diode (LED)-based light sources. To address this problem, we propose a hybrid OFDM-pulse time modulation (PTM) scheme where bipolar O-OFDM samples are converted into the digital PTM formats of pulse width modulation (PWM) and pulse position modulation (PPM) for the intensity modulation of LEDs. We convert the DC biased optical OFDM (DCO-OFDM) and asymmetrically clipped optical OFDM (ACO-OFDM) samples to PTM and show that DCO-OFDM-PTM offers improved bit error rate (BER) performance. For example, for 16-quadrature amplitude modulation (QAM) at the BER of 10−3, the signal-to-noise ratio (SNR) gains are ∼ 1.35 dB and ∼ 1 dB for DCO-OFDM-PPM and DCO-OFDM-PWM compared to ACO-OFDM-PPM and ACO-OFDM-PWM, respectively. Simulation results show that DCO-OFDM-PPM displays an improved BER performance compared with DCO-OFDM-PWM for both lines of sight (LOS) and diffuse configurations. For instance, for an ideal LOS channel and for 16-QAM at the BER of 10−3, the required SNR values are ∼ 4.5 and ∼ 10.2 dB for DCO-OFDM-PPM and DCO-OFDM-PWM, respectively.

We propose a metal-insulator-metal (MIM) structure consisting of a resonator and surface plasmon polariton (SPP) waveguides. By increasing the pressure, the resonator further deforms. Applying a maximum pressure of 6.2 MPa on the proposed device, a blue shift of 150 nm in the resonant wavelength is computed. Under the above mentioned pressure, the corresponding shift is linearly proportional to the pressure variation in a wide range of wavelength. This optical pressure sensor has a high sensitivity of 24 nm/MPa which makes it very suitable candidate for mechanical, electrical, biological, and biomedical engineering applications. The proposed device is simulated using finite-difference time-domain (FDTD) method.

A new design for perovskite solar cell using kesterite mesostructure is introduced and simulated to enhance the performance of perovskite solar cells. The NiO and ZnO used as inorganic p-type and n-type carriers transporting layers, respectively. Plasmonic network is employed to improve the absorbance of kesterite mesoscopic perovskite solar cell. Plasmonic network which induces near field into the absorber layer and the kesterite mesostructure which enhances light absorption and hole transportation, lead to higher light confinement inside the perovskite absorber layer. They are able to broaden the absorbance spectrum and enhance the external quantum efficiency of the bare planar perovskite solar cell without any light-trapping structure by 29%.

We theoretically analyze the detection of a cancer cell in the one-dimensional photonic crystal by infiltrating different sample cells in the cavity layer. The defect modes appear in their transmission spectra only if the nanocomposite layers are included on either side of the cavity layer. This analysis is carried out by a dielectric constant and the transmittance peak of the cancer cell is compared with the normal cell. The transmittance peak shifts are analyzed with various filling factors for optimization purposes. Through the shifting spectrum, the sensitivity of cancer cell from the normal cell is obtained from a minimum of 42 nm/RIU to a maximum of 43 nm/RIU.

Photonic crystals are nanoscale structures that affect the motion of photons. The strong light limitation in photonic crystals and the adjustment of its structural parameters have led to the emergence of photonic crystal biosensors. Moreover, the use of holes as a feature of photonic crystals has resulted in sensors that are very sensitive to low refractive index changes with a small sensing area, which offers flexibility and integration on single-chip systems. Using emerging optofluidic technology, label-free biosensors are on the rise. In this review, we examine various types of photonic crystal sensors, such as waveguides, nanoresonators, LX resonators, holes, multi-channel resonators, nano RINGS resonators, and fibers. These sensors are based on the measurement of biomolecules and the refractive index properties that have been identified. Finally, a variety of challenges and guidelines for the construction of label-free diagnostic biosensors are examined.

In the field of optical technologies, modern optical scenarios such as integrated multi-operand optical gates are considered as very useful and effective substrates. In this paper, a new and unique design and three-dimensional simulation of a graphene-based integrated half adder by the use of ring resonators and central waveguides have been presented. The proposed structure includes two separate AND and XOR gates, and the presence of graphene in this design allows to tune the wavelength and to turn on or off the structure at the desired wavelength without changing the design parameters and only by changing the Fermi voltage of graphene. The half adder logic is controlled based on the output power of the CARRY and SUM ports at a central wavelength of 1550 nm. Additionally, the extinction ratio obtained for each of the CARRY and SUM ports has been equal to 21.76 dB and 18.73 dB, respectively. The average quality factor of the output of resonators for XOR and AND gates has been 873.75 and 1116.96, respectively. In the proposed structure, single-layer graphene was used because the graphene plasmonic effect was considered. The Extinction ratio in our work is better than the other works. Finite-difference-time-domain (FDTD) and coupled mode theory (CMT) have been the two methods used to extract and analyze the results of the output spectrum of the proposed structure, and the results of the output spectrum have been exactly the same in the two methods.

In this paper, photonic crystal ring resonators with hexagonal lattice structure are used to design a four-channel optical demultiplexer. The structure size, the average transfer coefficient, the quality factor, and the channel spacing are equal to 424.5 µm2, 95.8%, 1943, and 2 nm, respectively. The average crosstalk is also computed to be −18.11 dB. In this study, the plane wave expansion (PWE) and finite-difference time-domain (FDTD) methods are used, respectively, to characterize the photonic bandgap and to investigate the optical behavior of the structure. The proposed design can be used in dense wavelength division multiplexing (DWDM) systems.

In this paper, a new hybrid microstructured optical fiber (H-MOF) based upon photonic bandgap (PBG) light guiding mechanism which can be used for dispersion compensation in optical transmission systems is designed and simulated. The H-MOF core is made up of silica glass and the holes in the cladding network are filled with As2Se3 chalcogenide glass. By selecting an appropriate geometrical parameters for the structure, the dispersion and confinement losses of the proposed H-MOF at 1.55 µm are calculated to be −6700 ps/nm/km and 6 × 10−4 dB/m, respectively. Relative dispersion slope (RDS) of the H-MOF at 1.55 µm is about 0.00347 nm−1. The proposed H-MOF is suitable for use in wavelength division multiplexing and dispersion compensating systems in optical fiber transmission networks.

In this paper, we considered a silicon solar cell with some ribbon nanoparticles including silver (Ag), aluminum (Al), gold (Au), and platinum (Pt) ribbon nanoparticles. The dimensions of nanoparticles affect the absorption and efficiency of solar cells. Here, various dimensions were examined, and the width, height, and period of the ribbon nanoparticle were taken into account. In this paper, we investigated the effect of height, width, period, and materials of ribbon nanoparticles by finite-difference time-domain method. The simulation results show that the maximum absorption was obtained equal to 12.90% by using the silver ribbon nanoparticles having width (x) of 25 nm, height (h) of 50 nm, and period (p) of 50 nm. In this case, the fill factor was obtained as 81.31%.

We have investigated the numerical method on optical properties of vertical InP nanowires with three types of random structures, i.e. random diameter, height, and position. It is found that light absorption in random structures is improved compared to their periodic structures. Also, enhancement of absorption in random position structure is slight while random diameter shows significant absorption enhancement, which achieves 10.4% improvement compared to the periodic structure. This is due to additional resonances, broadening of existing resonance, and lower optical reflection.

This manuscript presents a simple nano-resonator for using in an all-optical AND logic gate based on the photonic crystals. This nano-resonator is formed by changing the size of a dielectric rod in the photonic crystal structure. In this structure, the mechanism of interference effect is used which requires less power. The results reveal that the contrast ratio is 6 dB. The output optical power at logical level “one” is enough to be able to set up the next gate. In addition to simplicity, the use of nano-resonator also increases the speed of logic gate performance. Due to the features considered for the all-optical AND logic gate, it can be used in optical integrated circuits and optical communication systems.

In the present paper, a new 2-bit analog-to-digital converter (ADC) was designed and simulated by using 2D photonic crystal (PC) structures to create a relatively faster and smaller structure. For this purpose, a PC structure with a square lattice and silicon rods in the air bed was used. In the proposed structure, a combination of an optical filter with a linear waveguide, optical nanoresonators, and interference effects was used to create a 2-bit ADC. To create a structure in optimal conditions with maximum output optical power, the size of nanoresonators was scanned to reach the best size. The proposed structure operated at the operating wavelength of 1550 nm with a response time of about 1.63 ps, a sampling rate of about 613 GS/s, and a resolution sampling rate product (RSRP) value of about 2453 ks. Additionally, the size of the structure was about 194 µ m 2 , which is small compared with other structures proposed in this field; it also enjoys high simplicity and flexibility like structures with other functions, including 4-bit converters. The amount of power used to create different logic states was at the rate of m W / µ m 2 , which is much lower than the amount used in similar structures and is achieved using nonlinear effects and materials. Therefore, due to the excellent results obtained, this structure is recommended to be used in optical integrated circuits. The plane wave expansion method was used to extract the photonic bandgap, and the finite-difference time-domain method was used to obtain the results related to the output spectrum of the designed structures.

In this paper, a new design of all-optical NOT logic gate is proposed. In this structure, a photonic crystal nano-resonator and three waveguides are used. The nano-resonator is formed by removing two dielectric rods. The contrast ratio for the proposed NOT logic gate is 20.75 dB. The maximum response time and the rate of sending information equal to 0.466 ps and 2.145 Tbit/s, respectively. In addition, very low power consumption, small size, and simple design are the main features of this logic gate. These features allow the designed structure to be used in all-optical switches. To accomplish this, two types of logic gates placement alongside each other in the optical integrated circuits are proposed and investigated. In both types, the logic gates are tested for single use and simultaneous use, and the accuracy of the performance and effect of each on the other is measured. The results clearly show that the two logic gates, along with each other, have acceptable performance and can easily be used in the optical integrated circuit.

In this paper, an ultra-compact structure is presented for realization of all-optical NOT and XOR logic gates which can be compatible with silicon technology. Logic gates are based on two-dimensional photonic crystals, and the lattice constant and the radius of the rods are selected in such a way in order to operate the logic gates at 1550 nm. The proposed structure consists of three waveguides which are connected to each other using a T-shaped junction. This structure is optimized by two nano-resonators and has also two input ports and one output port. For our numerical studies, the plane-wave expansion and finite-difference time-domain methods have been used. The contrast ratios for the proposed all optical NOT and XOR logic gates are respectively 43.40 and 43.38 dB. The response time of the logic gates is 0.37 ps, which in turn creates a data transmission rate of 3.15 Tb/s. Our studies have shown that the NOT-designed logic gate is suitable for the use in optical integrated circuits.

In this paper, a two-dimensional photonic crystal biosensor for medical applications based on two waveguides and a nanocavity is presented. The waveguides and nanocavity are created by introducing line and point defects into a photonic crystal, respectively. It could be shown that by injecting an analyte into a sensing hole, and thus changing its refractive index, may shift the resonant wavelength. The proposed structure is designed for the wavelength range of 1.5259–1.6934 μm. Sensitivity, the most important biosensor parameter, was studied and found to be approximately equal to 83.75 nm/refractive index units (RIU). An important specification of this structure is its very small dimensions. Two-dimensional finite-difference time domain and plane-wave expansion methods were used for both to simulate the proposed structure and to obtain the band diagrams.

In this paper, a new circular microstructured optical fiber (C-MOF) based upon photonic band gap (PBG) light guiding mechanism is proposed which can be used for dispersion compensation in optical transmission systems. The C-MOF core is made up of silica glass and the holes in the cladding network are filled with As 2 Se 3 chalcogenide glass. By selecting an appropriate geometrical parameters for the structure, the dispersion and confinement losses of the proposed C-MOF at 1.55 μm are respectively calculated to be −2450 ps/nm/km and 0.013 dB/m. Relative dispersion slope (RDS) of the C-MOF at 1.55 μm is about 0.00332 nm −1 . The proposed C-MOF is suitable for use in wavelength division multiplexing and dispersion compensating systems in optical fiber transmission networks.

In this paper, we present a diamond-shaped biosensor based on the nano-ring resonator using two-dimensional photonic crystal (2D-PhC). The biosensor is consisted of a ring resonator and two waveguides. The ring resonator with two end waveguides on both sides, are placed in the middle of structure. Due to the analyte binding to the sensing hole, the refractive index of hole is changed and consequently the resonant wavelength is shifted. According to the results, the resonant wavelength shift in the range of 1.33–1.54 is linearly proportional to the refractive index variations. The quality factor and the sensitivity of biosensor are respectively obtained about 3700 and 3.4 nm/fg. The minimum detectable biomolecule weight in a sensing hole for a diamond-shaped nano-ring resonator is derived as 0.029 fg.

The propagation loss of a fiber can be increased by coupling core mode and surface mode which will deteriorate the performance of photonic bandgap fiber (PBGF). In this paper, we presented an aircore PBGF for gas sensing applications. By designing Λ = 2.63 µm, d = 0.95 Λ, and Rcore= 1.13 Λ, where Λ is the distance between the adjacent air holes, the fiber was single-mode, no surface mode was supported with fiber, and more than 90% of the optical power was confined in the core. Furthermore, with optimizing the fiber structural parameters, at wavelength of λ = 1.55 µm that is in acetylene gas absorption line, significant relative sensitivity of 92.5%, and acceptable confinement loss of 0.09 dB/m, were simultaneously achieved.