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Three distinct configurations of As2S3 chalcogenide photonic crystal fibers (PCFs) were designed to investigate supercontinuum generation (SCG). The optical properties of PCFs with the circular lattice (CL), square lattice (SL), and hexagonal lattice (HL) were comprehensively analyzed to choose the optimal fiber for SCG. This investigation facilitated the identification of three superior structures, specifically designated as #CF, #SF, and #HF, respectively. These structures are unified by operating within an all-normal dispersion regime, each presenting a lattice constant of 1.0 μm and a filling factor of 0.35. These fibers were subjected to a peak power of 4.0 kW and a pulse duration of 270 fs, culminating in an expansive supercontinuum range. Notably, the SC range extended from 2.0 to 6.5 μm for #CF, from 2.0 to 8.3 μm for #SF, and from 1.9 to 6.6 μm for #HF. The SL-PCF exhibited the broadest supercontinuum, attributed to its protracted flat dispersion band. Furthermore, compared to previously reported all-normal dispersion PCFs, the spectral range facilitated by this peak power was significantly augmented. These optical fibers promise to provide supercontinuum spectra with broad bandwidth for practical applications in sensing and gas detection. [ABSTRACT FROM AUTHOR]

This study introduces a Surface Plasmon Resonance (SPR) refractive index sensor based on a D-shaped Polarization Maintaining Photonic Crystal Fiber (PM-PCF). The D-shaped sensor surface is coated with gold nanolayers approximately 40 nm thick. The effect of the structure of the gold nanolayers on the sensor's performance is analyzed. First, a rectangular-shaped layer is introduced. Then, two different shapes (saw-tooth and bow-tie) are selected for further study. The sensor is designed using the Finite Element Method (FEM). The results showed that a single resonant peak in the infrared (IR) region is observed when a rectangular layer shape is used. When the metallic layer shape is changed, two resonant peaks are observed. One is in the visible part of the spectrum, and the second is in the infrared region. The higher sensitivity is achieved from the sensor coated with saw teeth nanolayer structure for the resonant peak located in the IR region equal to 26,000 nm/RIU. While, the spectral resolution for all designs is in the range of 10–5–0–6 RIU for the refractive index range (1.34–1.36). The designed D-shaped SPR sensor, featuring unique gold nanolayer structures, offers a wide range of potential applications across various fields due to its enhanced sensitivity and tunability in visible and IR spectra. Some of these applications are the detection of biomolecules, disease diagnostics, and environmental pollution detection. [ABSTRACT FROM AUTHOR]

In this paper, the supercontinuum generation with all-normal and anomalous dispersion based on Ga8Sb32S60-photonic crystal fibers with an octagonal lattice is investigated in detail. We propose two types of photonic crystal fibers with the same lattice structure but different numbers of air holes in the cladding (O-PCF1 with eight rings of air holes arranged parallel to the axis of the core and O-PCF2 with the air holes in the innermost layer near the core removed) to evaluate the supercontinuum generation performance. By adjusting the structural parameters, the characteristic quantities such as dispersion, effective mode area, nonlinear coefficients, confinement loss can be optimized. The O-PCF2s exhibits flatter and near-zero dispersion, higher nonlinear coefficients with values of 1197.526 W−1 km−1 and 695.739 W−1 km−1, low confinement losses of about 10−6 dB/m at a pump wavelength of 4.5 µm enabling spectra spanning from 1.262 to 9.531 µm and from 1.863 to 18.0 µm corresponding to bandwidths of 6.82 µm and 12.41 µm at 30 dB in the long-wave infrared region with peak powers of 12 kW and 20 kW using all-normal and anomalous dispersions profiles, respectively. Supercontinuum laser sources using the proposed fibers are promising for many potential infrared applications involving optical coherence tomography, fingerprinting, and molecular spectroscopy. [ABSTRACT FROM AUTHOR]

This study introduces a temperature sensor based on solid-core photonic crystal fiber that exhibits insensitivity to polarization. The coupling condition between the core and defect modes is investigated by employing the finite element method. To enhance sensitivity, a thermo-sensitive liquid with a refractive index of 1.65 at 25 °C is injected into the second ring air holes, and a polydimethylsiloxane layer is applied around the filled holes. The impact of the polydimethylsiloxane layer and air hole sizes on the sensing performance is thoroughly analyzed. The proposed sensor's sensing property is evaluated by varying the temperature from 20 to 80 °C, resulting in an average sensitivity of − 3.166 nm/°C. The correlation coefficient is as high as 0.99992 and demonstrates the high linearity of the designed sensor. The full-width at half-maximum and the figure-of-merit are 11 nm and − 0.287/°C, respectively. Furthermore, a resolution of 0.03191 °C and an accuracy of 0.091 /nm show an excellent performance for the proposed device. The sensor's desirable features include high sensitivity, linearity, symmetrical structure, and equal sensitivity for both X and Y polarizations, making it suitable for practical applications. Furthermore, by adjusting some geometrical factors such as the lattice pitch, diameter of holes, number of rings, and thickness and concentration of materials, the sensor can be optimized for favorable operating conditions. [ABSTRACT FROM AUTHOR]

Photonic crystal fiber (PCF) has shown a promising application in various fields of modern optics due to its excellent transmission characteristics. However, conventional numerical solution methods have limitations such as high computational effort and low efficiency in designing PCF structures and characterizing pulse propagation in PCFs. With the advancement of artificial intelligence technology, various types of intelligent computing approaches, especially intelligent algorithm and machine learning algorithm (IML), provide new perspectives to solve the above difficulties. Therefore, an increasing number of researchers are committed to using IML to break through the limitations of conventional methods and accordingly open up a new interdisciplinary research direction. This paper begins with a brief overview of common optical properties and typical algorithms. Subsequently, it reviews specific areas where PCF and IML are combined, including the prediction and optimization of optical properties, the design of polarization devices, fiber lasers and amplifiers, as well as the control and prediction of Supercontinuum generation. Finally, this paper offers insights into the future developments and challenges in this emerging interdisciplinary field. [ABSTRACT FROM AUTHOR]

In this study, a simple air-silica microstructure based on circular-lattice geometry is designed and analyzed to achieve an ultra-large negative dispersion coefficient and high birefringence simultaneously for dispersion compensation. The fiber design has been analyzed numerically by utilizing finite difference mode convergence technique. The influences of varying various geometrical parameters on the dispersion as well as on the birefringence properties have been examined. Through a systematic analysis, the geometrical parameters of the design have been optimized for achieving the desired results. Finally, two photonic crystal fiber designs for narrowband and another design for broadband dispersion compensation have been proposed. The proposed narrowband designs exhibit high negative dispersion of −10,388 and −4,542 ps/nm/km, with birefringence values of 4 × 10−3 and 5.4 × 10−3 at a wavelength of 1.55 μm, respectively. The computed FWHM of the dispersion curves of these designed fibers are found to be 30 and 100 nm, respectively. For the broadband design, dispersion coefficient between −452 and −1,408 ps/nm/km has been achieved over the wide wavelength range of 1.4 to 1.7 μm. Additionally, the compensation ratio and relative dispersion slope of the proposed broadband design have been computed. It is observed that the design provides a negative dispersion coefficient of −932 ps/nm/km and a relative dispersion slope of 0.0036 nm−1 at 1.55 μm wavelength with a birefringence value of 1.23 × 10−2. [ABSTRACT FROM AUTHOR]

For high birefringence photonic crystal fibres (PCF) operating in terahertz (THz) regime, an outstanding model of slotted porous core with triangular lattice-based hexagonal shape cladding has been presented in this study. In this proposed THz-PCF, a five-layer circular air holes arranged in hexagon configuration have been placed in the cladding area, and five rectangular air holes have been positioned in core region for investigating the THz-PCF in polarization maintaining applications. The asymmetrical rectangular slots in core area creates difference between x and y polarized THz waves to offer high birefringence. The compact geometry of hexagonal structure in cladding offers more useful power confinement. The designed PCF offers high birefringence of 0.0866, low effective material loss of 0.0786 cm−1, core power fraction of 42.7%, less confinement loss of 0.02598 cm−1, low dispersion of 0.0963 ps/THz/cm and very less effective area of 0.03 µm2 in a broad frequency range of 0.1–2.3 THz, according to the Finite Element Method based simulation results in COMSOL Multiphysics software. These features enable the proposed PCF to be a better choice for numerous applications like polarization filtering, sensing, short distance communication, etc. in THz photonic integrated circuits. [ABSTRACT FROM AUTHOR]

A numerical investigation of the impact of fourth-order dispersion in the dynamics of Gaussian pulse propagation in photonic crystal fiber is presented. Considering the importance of waveguide dispersion in photonic crystal fiber, higher-order dispersion, especially fourth-order dispersion, is found to be crucial and significantly affects the dynamics. To study the evolution of various pulse parameters during propagation, we adopt the generalized projection operator method to derive the pulse parameter equation. It is observed that the fourth-order dispersion is found to be critical and, hence, remarkably influences the dynamics. A detailed discussion is presented to give further insight into the impact of Fourth order dispersion. Different ansatz-like methods are also considered alongside the Gaussian ansatz. [ABSTRACT FROM AUTHOR]

The ability to transmit data at a high transmission rate is one of the main challenges that has limited the performance of visible light networking systems. In this paper, we present an eight-core photonic crystal fiber designed for multiplexing (MUX) operations at wavelengths of 1.32, 1.3, 1.54, 1.19, 1.4, 0.98, 1.35, and 1.1 µm to overcome this issue. Various MUX parameters, such as transmission rate and normalized power, are examined in this numerical study. A multiplexer is a device that enables multiple messages or signals to be conveyed simultaneously through a single communication channel. A specific type of optical fiber, called photonic crystal fiber (PCF), is used in this context, which has a cladding made of photonic crystals surrounding the fiber core. The fiber features a periodic arrangement of tiny air holes along its length, creating a low-loss periodic dielectric material known as a photonic crystal. In this new design, silica rods are employed instead of multiple air-hole zones along the fiber's length to adjust the coupling length between adjacent channels. The results indicate that after 5.5 mm of light propagation, the operating wavelengths can be effectively multiplexed. [ABSTRACT FROM AUTHOR]

In this work, we propose a novel dual guided PCF design capable of supporting the transmission of 68 OAM modes. The innovative design features a specialized structure with multiple layers composed of pure silica and SF57 material arranged alternately. To enhance physical strength and minimize loss, the fiber is enclosed by a perfectly matched layer (PML). Air holes are strategically added and optimized in the third and fifth layers. Through numerical analysis, we observed that the proposed design yields excellent results across all evaluated parameters. The maximum confinement loss recorded is 10–12 dB/m. The effective refractive index values range from 1.444 to 1.8, with effective refractive index difference values in the order of 10–2. Furthermore, the modal purity and power fraction values exceed 99% for all modes. Dispersion values are maintained below 9.87 ps/THz/cm, and crosstalk values are less than − 12 dB. These results demonstrate the potential of our dual guided PCF design in meeting the increasing demands for high-speed and reliable communicating systems. [ABSTRACT FROM AUTHOR]

Chikungunya virus (CHIKV) poses a significant public health threat due to its capacity to cause widespread and debilitating outbreaks. The virus is responsible for CHIKV fever, a disease characterized by severe joint pain, sudden onset of fever, headache, muscle pain, and rash. The virus has been reported in various regions globally, with outbreaks occurring in parts of Africa, Asia, the Americas, and the Indian subcontinent. Consequently, the scientific community expends substantial efforts in developing dependable, rapid, highly sensitive, and cost-effective techniques in order to identify the CHIKV virus. In this study, an innovative biomedical sensor using photonic crystal fiber technology enables precise detection of the CHIKV virus through uric acid, normal and infected plasma, red blood cells, and platelets in the blood. The introduced sensor identifies those kinds with extremely increased relative sensitivity and minimal losses in contrast to alternative photonic crystal fiber-based biosensors. The introduced sensor showcases a minimal confinement loss of 2.25 × 10− 13 cm− 1, a relative sensitivity of 99.37%, an effective area of 1.36 × 105 µm2, with a minimal effective material loss of 0.001966 cm–1, a numerical aperture of 0.1874, and low dispersion of 0.06. Also, the demonstrated sensor is able to function within the terahertz spectrum, covering a substantial span from 0.8 to 2.6 THz. Furthermore, an extensive comparison analysis is performed between the showcased sensor and related literature on photonic crystal fibers to verify the reliability and effectiveness of the introduced structure. [ABSTRACT FROM AUTHOR]

The exact soliton solutions of perturbed Gerdjikov-Ivanov equation with both constant and variable coefficients are constructed in this work through the application of the modified F-expansion method. This method is used for the very first time on the considered equation. As a result, the traveling wave solutions including soliton solutions are obtained. These soliton solutions enhance understanding of nonlinear phenomena in the fields of photonic crystal fibers, fiber optics and nonlinear fiber optics. The explanation of the obtained results is provided by drawing some 2-dimensional and 3-dimensional graphs using Mathematica. Furthermore, this study discusses the modulation instability for the considered model. The considered method is found to be effective, simple and useful to study the perturbed Gerdjikov-Ivanov equation. [ABSTRACT FROM AUTHOR]

Diabetes is a metabolic disease that seriously endangers human health, and monitoring glucose levels is one of the main diagnostic methods for its prevention and treatment. In this paper, we propose a high-performance glucose sensor based on the Sagnac interferometer (SI) utilizing photonic crystal fiber (PCF) with micro-holes. By setting two columns of micro-holes in the center of the PCF, the high birefringence effect is obtained to improve the detection sensitivity. All air holes are assumed to fill with the glucose solution, and the sensing characteristics of the PCF sensor are theoretically studied by the finite element method (FEM). The results show that the sensitivity and resolution of the PCF glucose sensor can reach 4.14 nm/(g/L) and 0.48 mg/dL within the concentration range of 0–120 g/L, respectively. In addition, the effects of the partial-filling methods and PCF structural parameters on the sensing performance are also analyzed to achieve optimal performance. The proposed glucose sensor possesses high sensitivity and simple structure, which exhibits good application prospects in the field of medical monitoring. [ABSTRACT FROM AUTHOR]

We have developed a new type of hybrid-structured Photonic Crystal Fiber (H-PCF) that includes a sectored core-cladding configuration. It's composed of a cladding with a regular circular sectored lattice structure and a core with a hexagonal sectored lattice structure. To extensively design, analyze, and calculate the fiber's properties, the finite element method has been used. The results provide validation for the superior performance of this novel fiber design. It simultaneously achieves extremely low effective material loss and confinement loss equal to 0.0145 cm⁻1 and 1 × 10⁻14 cm⁻1, respectively, at the 1 THz frequency. Furthermore, the fiber demonstrates nearly zero flattened dispersion (− 0.45 ± 0.55 ps/THz/cm) across the 0.9–1.3 THz frequency range, along with important attributes such as a large core power fraction (50%) and an effective area of 5 × 105 µm2. The suggested PCF design is practical for manufacturing utilizing currently available technologies. Moreover, the proposed PCF design, employing common structured regions in the circular and hexagonal patterns for the sectored cladding and core regions, respectively, is feasible for fabrication using existing technologies. Overall, this H-PCF shows significant potential for various THz applications, especially in THz wave guidance. [ABSTRACT FROM AUTHOR]

This study proposed photonic crystal fiber sensors with two distinct plasmonic layers were proposed and compared in order to identify skin cancer cells in comparison to normal blood cells. In order to attain high sensitivity for the detection of this surface plasmon resonance (SPR)-based sensor, a comparison is made between several layers of Silver-Titanium dioxide and Gold-Titanium dioxide. In addition, the presence of a TiO2 layer helps to lessen the chemical instability of silver and improves the SPR effect. For the purpose of this work, a numerical analysis of the sensor was performed using the finite element technique. It is possible to quantify the confinement loss of two sensors, as well as their sensitivity to changes in amplitude and wavelength, by modifying some influential factors such as the diameter of the airhole and the thickness of the plasmonic layer (Ag, Au). This allows for the evaluation of the effectiveness of the sensors in detecting a target analyte. For the purpose of identifying skin cancer cells, the highest amplitude sensitivity of silver as a plasmonic layer is 610 RIU-1, and the maximum spectral sensitivity is 7500 nm/RIU. The greatest spectral sensitivity of gold as a plasmonic layer for the detection of skin cancer cells is 7000 nm/RIU, while the maximum amplitude sensitivity of gold is 800 RIU-1. In-depth discussion has been held regarding the manufacturing procedure for the sensor that has been proposed. When it comes to the detection of organic and biological compounds, this biosensor that is now under investigation demonstrates promising characteristics due to its stability and good sensitivity. [ABSTRACT FROM AUTHOR]

In this paper, a novel D-shaped photonic crystal fiber (PCF) refractive index (RI) sensor based on surface plasmon resonance (SPR) effect is proposed. By introducing a smiley-faced hole and Ag-TiO2 composite micro-grating, the high RI sensing performances can be realized. With finite element method, the propagation characteristics of the proposed D-shaped SPR-PCF RI sensor are numerically investigated. The simulation results show that the average wavelength sensitivity (WS) is 5400 nm/RIU, and the maximum WS can reach 15,500 nm/RIU in the RI range from 1.30 to 1.39. Besides, the proposed D-shaped SPR-PCF RI sensor can obtain the maximum resolution (R) of 4.95 × 10−5RIU and the maximum figure of merit (FOM) of 423.78 RIU−1, respectively. It is believed that the proposed SPR-PCF RI sensor has potential applications in the fields of environmental monitoring, biomedical analysis, and food safety management. [ABSTRACT FROM AUTHOR]

A novel Segmented Clad-Graded Index (SC-GI) photonic crystal fiber with a circular core composed of As38Se62 is proposed to realize the supercontinuum spectrum in the entire transparency range of As38Se62 (2–10 μm). SC-GI PCF conveys dual Zero Dispersion Wavelengths at around 2.4 μm and 6.4 μm. The devised PCF also offers a very small effective mode area of 2.46 μm2 and a very high nonlinear coefficient of 12,005 W−1 km−1 at the pump wavelength of 2.4 μm. Detailed numerical simulations reveal that a short length of SC-GI PCF (~ 28 mm) is capable of showing a broad SC spectrum ranging from 3 to 9.5 μm (− 30 dB level of power) using an input source of moderate peak power (1.8 kW) pumping at 3.4 μm. To the best of the author's knowledge, this is the first time report of SCG in Segmented Cladding Fiber design. The evaluated SC covers the transparency window of the background material and also covers the mid-IR region. This type of high broadening opens the gateway for applications like optical metrology, optical coherence tomography (OCT), food quality control, telecommunications and future applications covering the Mid-IR region.Please confirm the corresponding author is correctly identified and amend if necessary.Yes, Corresponding author is correctly mentioned. [ABSTRACT FROM AUTHOR]

In this article, a surface plasmon resonance (SPR) sensor based on photonic crystal fiber (PCF) is simulated and analyzed by finite element method (FEM). Gold and titanium oxide (TiO2) are used as plasmonic layers. The TiO2 layer is placed under the gold layer to increase the sensitivity of this sensor. The sensor's top and bottom surfaces are polished, and the plasmonic layer is placed on both these surfaces. Unlike sensors with typical external circular coating, less plasmonic material is used. Additionally, unlike internal coating sensors, there is no issue of partial air holes coating and achieving a uniform thickness of the plasmonic layer. Also using two plasmonic levels can expand the range of refractive index (RI) detection. The sensor's structure creates birefringence, allowing complete coupling between the core mode and both plasmonic layers. This results in more reliable detection ability. By optimizing the dimensions and arrangement of air holes and the sensor's structure, the ability to detect unknown analytes in the ultra-wide range of refractive index of 1.21–1.41 with the maximum wavelength sensitivity (WS) of 61,000 nm / RIU , the maximum amplitude sensitivity (AS) of 1294.29 RIU - 1 , the maximum figure of merit (FOM) of 657.14 RIU - 1 and the sensor resolution (SR) of 4.35 × 10–6 RIU have been obtained. This sensor operates in the visible to near-infrared wavelength range. During its design, feasibility in construction was taken into consideration, along with reducing the complexity and multiplicity of structural parameters. As a result, the sensor delivers excellent performance in detection parameters and is a suitable option for RI detection applications like organic chemicals and biosensing. [ABSTRACT FROM AUTHOR]

A highly sensitive and simple structure side-polished micro-structured fiber (MOF) refractive index (RI) sensor based on surface plasmon resonance is proposed and studied by the finite element method. The gold nanofilm used to stimulate plasmons is directly deposited on the inner wall of the open-loop channel of a MOF consisting of an arrangement of six cladding air-holes. The sample analyte is arranged on the outer surface of the optical fiber to improve the utilization rate of the sensor and reduce the tediousness of operation. Meanwhile, in order to increase the leakage intensity of evanescent field, three large air-holes were introduced near the fiber core. Research has shown that the proposed sensor can achieve sensing detection in the range of 1.19–1.37 RI. The maximum sensitivity in the x-polarized direction can reach 12,500 nm/RIU, and its corresponding resolution is 3.64 × 10–5 RIU. Moreover, it has a high linear response of 0.9944 within the RI detection range of 1.19–1.33. Obviously, the proposed sensor has a simple structure, wide RI detection range, and high sensitivity, which can make it widely used in biomedical and analytical chemistry. [ABSTRACT FROM AUTHOR]

A hollow-core photonic crystal fiber based Refractive Index sensor in the terahertz frequency regime for bio-sensing application is proposed in this paper. Refractive index variation is used for the identification of different analytes with refractive indices ranging from n = 1.35 to 1.39. Zeonex is chosen as the fiber material. The proposed photonic crystal fiber (PCF) sensor features a solitary rectangular core enclosed by an arrangement of 16 rectangular air holes within the cladding area with different heights and widths. Simulation and numerical analysis are conducted using Finite Element Method-based based Comsol Multiphysics Software. The proposed PCF sensor exhibits relative sensitivity of 98.8%, an Effective Mode Area of 1.06 × 10−7 m2 with a very low confinement loss of 7.751 × 10–14 dB/cm are achieved at a frequency of 1.4 THz for an analyte of refractive index 1.39 in X Polarization direction of electric field. Moreover, birefringence, non-linearity, effective refractive index and power fraction are also analyzed. Further simple PCF structure based on rectangle ensures that fabrication is feasible with current fabrication techniques.Please check and confirm that the authors and their respective affiliations have been correctly identified and amend if necessary.I have checked the authors name and affiliations and found its correct.Kindly check and confirm whether the corresponding author and corresponding mail ID is correctly identified.I have checked about corresponding authors name and email id. I found it correct. [ABSTRACT FROM AUTHOR]

This article proposes a novel Si3N4-based five-ring hexa-circular photonic crystal fiber (PCF) that shows a remarkably high nonlinear coefficient (NLC) and birefringence (Br). Several distinctive optical features, including birefringence, nonlinearity, effective area, numerical aperture, confinement loss, dispersion, etc., are investigated utilizing the COMSOL Software. The simulation analysis demonstrates that a zero-crossing dispersion for Y- polarization and an extremely high Br and NLC of 0.22 and 2687.51 W - 1 Km - 1 are reached at the wavelength of 1.55 μ m . The proposed PCF, having extremely high Br and NLC properties, can be useful for prospective future applications in the areas of supercontinuum generation, nonlinear optics, polarization-maintaining, and so on. [ABSTRACT FROM AUTHOR]

In this paper, a surface plasmon resonance (SPR) sensor based on photonic crystal fiber (PCF) which can be filled with multiple analytes is proposed. The sensor has two elliptical groove microchannels. By changing the depth of the groove, the distance between the analyte to be measured and the sensor core can be reduced, thereby enhancing the energy coupling between the core mode and the plasma mode. The sensor can achieve both single-channel operation and dual-channel simultaneous measurement, which can effectively improve the detection efficiency. When the two channels work simultaneously, the maximum wavelength sensitivity of 1900 nm/RIU and 18,000 nm/RIU can be achieved by channel 1 and channel 2, respectively. The refractive index detection range of the sensor is 1.17 to 1.30. As far as we know, this is the first PCF-SPR sensor that dual channels are introduced into low refractive index detection. [ABSTRACT FROM AUTHOR]

This article presents a highly sensitive plasmonic sensor with a focus on enhancing its capabilities through innovative design and simple geometric structure. A hexagonal-shaped photonic crystal fiber (PCF) based surface plasmon resonance sensor is designed and proposed for external sensing applications. The plasmonic material is made of gold and positioned on the outer side of the designed PCF. For detection purposes, the flow of the testing analyte is introduced on the exterior section of the PCF. The sensing capability of this innovative sensor is meticulously examined using the finite element technique facilitated by the COMSOL Multiphysics software. The suggested sensor, with a refractive index of 1.38, has a maximum amplitude sensitivity and wavelength sensitivity of 765.86 RIU−1 and 8,000 nm/RIU respectively. At the same refractive index, the sensing resolution of the sensor is 1.31 × 10–5 for amplitude sensitivity and 1.25 × 10–5 for wavelength sensitivity. Additionally, the sensing capability of the sensor lies in the range of the analyte refractive indices from 1.33 to 1.39. Furthermore, the sensing performance of the designed sensor is analyzed by optimizing the values of several design parameters including air-hole diameter, pitch, and gold layer thickness. The suggested sensor can recognize biological analytes with high sensitivity, improved sensing resolution, and appropriate linearity. [ABSTRACT FROM AUTHOR]

We propose three hollow-core anti-resonant fibers with different nested tube structures and numerically analyse their confinement loss, single-mode performance and bending loss by using the finite element method. The results show that the nested semi-elliptical structure FD#2 and the hybrid nested FD#3 structure have excellent transmission performance. The confinement loss of FD#2 and FD#3 at 1.55 µm is 0.00037 dB/km and 0.0004 dB/km respectively, and the high order mode extinction ratio is around 1700 for both FD#2 and FD#3. The bandwidths of FD#2 and FD#3 with losses less than 0.01 dB/km are within 1.36–1.73 μm and 1.42–1.8 μm, respectively. In addition, the bending resistance of FD#2 and FD#3 is excellent, with bending losses of 0.003 dB/km and 0.001 dB/km at a bending radius of 8 cm. We also evaluated the manufacturing tolerance range of these two structures in the actual manufacturing process. The structure proposed in this paper is expected to provide new ideas for the design of nested elements, and provide more possibilities for optical fiber design suitable for large-capacity data transmission and gas sensing applications. [ABSTRACT FROM AUTHOR]

In this paper, a new and simple structure of a photonic crystal fiber (PCF) surface plasmon resonance biosensor is designed for detecting aqueous solutions. The graphene and magnesium fluoride (MgF2) materials are used externally around the PCF to increase the sensitivity of the sensor. The performance of the sensor is analyzed using the finite element method. The numerical results show that the proposed PCF provides an average wavelength sensitivity (Sw) and amplitude sensitivity (SA) as high as 4000 nm/RIU−1 and 16,905.15 RIU−1, respectively, for analytes with refractive indices (RIs) ranging from 1.33 to 1.342. When the MgF2 layer is eliminated from the structure, the values of Sw and SA are decreased to 2500 nm/RIU−1 and 12,155.2 RIU−1, respectively. Therefore, it is concluded that adding an MgF2 layer externally on the graphene layer of the proposed PCF increases the Sw and SA parameters. It is also exhibited that by increasing the thickness of graphene layers, the confinement loss is enhanced, and the SA is decreased. In addition, by adding the thickness of the MgF2, both SA and confinement loss parameters are increased. The results also show a linear relationship between the parameters with a very high figure of merit (FOM) of 17,416.66RIU−1 and a resolution of 2.5 × 10–5. [ABSTRACT FROM AUTHOR]

In this study, we propose a new design based on photonic crystal fibers (PCFs) for broadband dispersion compensation in telecommunication networks. The proposed design has a hexagonal structure arrangement of air-holes rings of different diameters between the silica core and the cladding. The PCF properties like effective area, nonlinearity, dispersion slope, confinement loss, and birefringence are reported and discussed. For the best performance we present three designs A, B and C. Simulation results show that the three designs cover the six-telecommunication optical bands O-, E-, S-, C-, L- and U- bands (wavelengths ranging from 1260 to 1675 nm). Design A achieves a large negative dispersion value of about − 1716 ps/(nm.km) with relative dispersion slope equals to that of conventional single-mode optical fibers (SMFs) of about 0.0036 nm−1, which makes it very suitable for long-haul DWDM transmission systems. With a little modification in the core, designs B and C achieve much higher confinement ability and achieve a very large birefringence value for polarization mode dispersion and sensing applications. Design C is engineered to have exact opposite dispersion of SMF with zero dispersion at the wavelength 1310 nm, which makes it a promising design in CWDM transmission system. The numerical values have been investigated using the full vector finite element method. [ABSTRACT FROM AUTHOR]

The present investigation examines a novel dual-core photonic crystal fiber (PCF) for early cancer cell detection that is based on a surface plasmon resonance (SPR) biosensor. The PCF is coated with Au/TiO2 layers to boost sensor effectiveness by enhancing the adhesion between the fiber and gold layers. The sensor was simulated and analyzed using the COMSOL Multiphysics software, which is based on the finite element method (FEM). Spectral and amplitude interrogations were used to explore the RI fluctuations of various cancer cells. The observed RI values varied within the range of 1.36–1.401. The biosensor's highest sensitivity was found to be 11,429 nm/RIU for MCF-7 cells using spectral interrogation and 1251.18 RIU−1 for MDA-MB231 cells utilizing amplitude interrogation techniques. Additionally, the sensor shows the maximum resolution for basal cells, which is 8.75 × 10−6 RIU. [ABSTRACT FROM AUTHOR]

Selectively thickening core wall is an effective approach to improve the birefringence of hollow core photonic bandgap fiber (HC-PBGF). However, the variation of core wall thickness has a significant influence on the transmission loss and transmission bandwidth. In this paper, the effects of selectively thickening core wall on birefringence and loss performance of the HC-PBGF are systematically investigated. Numerical analysis results indicate that when the core wall thickness in the y-direction is 2.4 to 3.3 times as that in the x-direction, the birefringence of a 19-cell HC-PBGF can be improved to 10− 4, meanwhile the transmission loss can be controlled below 10 dB/km. The high birefringence (≥ 10− 4), low transmission loss (< 10 dB/km) performance can be maintained in a wide waveband from 1460 to 1610 nm, even under a tight bending radius of 6 mm. The applicability of selectively thickening core wall on improving birefringence is also confirmed in the 7-cell HC-PBGF and 37-cell HC-PBGF, where the birefringence of 7-cell HC-PBGF and 37-cell HC-PBGF can be enhanced to 5.5 × 10− 4 and 5.0 × 10− 5, respectively. Moreover, to further reduce the transmission loss, two modified structures (adding nodes or anti-resonant layer) are discussed. The numerical analysis results demonstrate that the structure by adding nodes on the thickened core wall is more advantageous in terms of reducing transmission loss and expanding transmission bandwidth. [ABSTRACT FROM AUTHOR]

The photonic crystal fiber (PCF) based plasmonic sensors have drawn incredible attention from researchers in many research disciplines due to their versatility, quick response, label-free detection, design freedom, and low weight. Here, a gold-coated hexagonal lattice PCF sensor having an external analyte detection facility is proposed using the surface plasmon resonance (SPR) technology. The design and performance optimization of the proposed sensor has been completed using commercially available COMSOL Multiphysics 5.5. Firstly, design parameters were optimized by varying one parameter at a time then the sensor performance was calculated using well-known intensity and wavelength interrogation techniques in the analyte refractive index (RI) ranging from 1.33–1.405. Excellent amplitude sensitivity (AS), (609.023 RIU - 1 ), and wavelength sensitivity (WS), (18,000 nm/RIU), along with an outstanding resolution ( 5.56 × 10 - 6 RIU), are attained with optimum design parameters. Secondly, the sensor performance is carried out with four bacteria (common pathogens in water) such as Enterococcus faecalis, Escherichia Coli (E. coli), Vibrio Cholera, and Bacillus Anthracis, and the sensor exhibits tremendous WS (nm/RIU) and AS ( RIU - 1 ) of 7317.07 and 918.77, respectively. Owing to its straightforward design and high sensitivity, the proposed sensor can be effectively applied in any healthcare system to ensure safe drinking water. [ABSTRACT FROM AUTHOR]

For accurate bio-sample identification, we present a unique optimized surface plasmon resonance sensor based on an X-shaped exposed-core photonic crystal fiber. Applications are made easier by the placement of the target analyte and plasmonic material on the fiber's exterior surface. The sensor has four separate silica channels that reach from the core to the metallic outer surface creating X-shape. These channels were intentionally placed to provide the highest sensitivity while maintaining the sensor's ability to be manufactured. Within a refractive index range of 1.33 to 1.40, our optimized sensor demonstrates improved detecting abilities, including a wavelength sensitivity of 8000 nm/RIU and amplitude sensitivity of - 1175.12 R I U - 1 . The suggested sensor also exhibits exceptional performance parameters, such as a resolution of 1.25 × 10 - 5 , a maximum signal-to-noise ratio (SNR) of 2.041 dB, a figure of merit (FOM) of 160.0 R I U - 1 , a detection accuracy (DA) of 0.02 nm−1, and minimum full width half maxima (FWHM) of 50 nm. When examining variations in the optical properties of the PCF due to different RIs of normal and cancer cells using finite element analysis, we achieve amplitude sensitivities of - 844.91, - 418 and - 1221.8 R I U - 1 for HeLa, Basal and MDA-MB-231 cell lines, respectively. [ABSTRACT FROM AUTHOR]

This study proposed a new PCF design to extend the SC generation beyond the long wavelength edge of the MIR molecular fingerprint region. The proposed design was made of AsSe2 glass as a background material whose has a significant nonlinear refractive index at 11 × 10−18 m2 W−1. The proposed PCF design was consist of five layers of circular air holes arranged in a triangular lattice of pitch size (Λ = 2 µm). The air hole diameters of the first layer were different in size with other layers to give more flexibility in the control of the chromatic dispersion. The geometrical parameters of the PCF design are modified to achieve the anomalous dispersion regime. We applied the Finite Difference Method to compute the linear and nonlinear parameters of the proposed PCF structure including dispersion, loss, effective mode area and the Kerr nonlinearity. The Nonlinear Schrödinger Equation is numerically solved by using Split-Step Fourier method to evaluate MIR SC generation. The simulated results showed that by using only 4 cm of the suggested PCF design pumped with 3 kW peak power and 330 fs pulses at 8 μm wavelength in the anomalous dispersion regime is enough to generate coherent MIR SC covering from 5 to 21 μm. This is to the authors' knowledge longer MIR SC wavelength can be generated from PCF design under abnormal dispersion profile. [ABSTRACT FROM AUTHOR]

This paper presents a 4-channel demultiplexer totally based on a two-dimensional photonic crystal with silicon air holes and defects with the advent of a graphene sheet, in multiplexing systems that use Dense Wavelength Division Multiplexing. Methods that incorporate Plane Wave Expansion and finite difference time domain are used, as they have significant efficiency to generate the photonic hollow modes of the demultiplexer and analyze the global distribution and transmission, respectively. Parameters of transmission overall performance, maximum quality factor, spectral width, crosstalk, and channel spacing of the demultiplexer are very important statistics to confirm the overall performance of the device, whose values are about 92%, 1944.3, 0.9 nm, − 60 dB and 0.1 nm, respectively, whose consequences are problem to the validation of the requirements of the Dense Wavelength Division Multiplexing device (ITU.G.694.1). The proposed demultiplexer includes a bus or linear waveguide with graphene to guide the slight wave and 4 resonant cavities wherein graphene is placed withinside the center to select out the wavelength in a hexagonal lattice form of dielectric air holes in air. The bus waveguide transmits slight into the resonant hole area and exits through the respective falling waveguide. [ABSTRACT FROM AUTHOR]

Methods for solving the generalized nonlinear Schrödinger equation (GNLSE) with adaptive step-size methods including the local error method (LEM) and conservation quantity error method (CQEM) are described. Supercontinuum generation (SCG) in liquid-core photonic crystal fibers (PCF) is numerically simulated by using LEM and CQEM in the time domain and frequency domain (FD) respectively. According to the numerical simulation results, the advantages and disadvantages of different adaptive step-size methods are compared, and the influence of different adaptive step-size methods on the coherence of SC is analyzed. A supercontinuum (SC) spectrum spanning from approximately 1300–2800 nm with high-coherence properties is numerically generated in the 5 cm fiber with 50 fs and 1000 W pump pulses at 1.55 μm. The numerical results demonstrate that the performance of the SC generated in FD is also better because the nonlinear operator is more effective in FD. In addition, the pulse evolution process based on LEM is smoother and the coherence is better due to its higher number of iterations and accuracy, so it is adapted to accurately modeling the SCG in PCF. However, the CQEM is more computationally efficient and can minimize the computational effort, so it is suitable for the fast modeling of SCG in PCF. This numerical study helps to optimize the numerical process of SCG and find a new way for the generation of highly coherent SC. [ABSTRACT FROM AUTHOR]

We present a numerical study on efficient mid-infrared Raman soliton generation in a tellurite microstructured optical fiber with femtosecond Tm-doped fiber laser pulses as the pump source. A tunable soliton exhibits a wavelength shift of up to 3.54 µm and a power conversion efficiency of up to 74.2% while consuming a pump peak power of no more than 1 kW at 1.96 µm, owing to the proper design of the dispersion and nonlinearity of the tellurite fiber. We investigated the effects of pump parameters on soliton properties and found that adjusting the pump pulse duration allows for a broader tuning range of up to 3.63 µm or a higher conversion efficiency of 94.5%. The study describes an effective means of constructing compact and efficient femtosecond tunable mid-infrared laser sources with low operation power, which will boost potential applications in the important region of above 2 µm. [ABSTRACT FROM AUTHOR]

Highly sensitive biosensor based on D-shaped photonic crystal fiber (PCF) with plasmonic grating is introduced and analyzed. The suggested structure is tested using four different grating structures (rectangular, triangular, circular, or elliptical) on the polished surface of the D-shaped PCF. The sensing operation depends on surface plasmon resonance mechanism where the analyte refractive index (RI) is utilized to control the coupling between the core mode and surface plasmon mode via phase matching phenomenon. Rhodium is employed as a plasmonic material to induce the SPMs. The resonance (i.e., phase matching) wavelength is a function of the analyte RI. The geometrical parameters of the proposed structure are optimized using full vectorial finite element method to enhance the sensor sensitivity. The proposed biosensor can be utilized in the detection of different cancerous Basel, Breast and Cervical cells. The performance of the reported biosensor is investigated in terms of sensitivity, linear response, and fabrication tolerance. The reported biosensor has high sensitivities of 19,750 nm/RIU, 20,428 nm/RIU and 20,041 nm/RIU for the detection of Basel, Breast and Cervical cancer cells, respectively. The presented biosensor is a good candidate for biological sample detection and organic chemical sensing. [ABSTRACT FROM AUTHOR]

Multimode polymer optical fibers (POFs) are considered to be the best choice for short-distance communication lines due to their advantageous properties. One must pay close attention to POFs' most crucial transmission property, bandwidth (BW), which affects the fibers' transmission capacity. The improvement of POF transmission qualities, particularly BW, which is its most crucial property, has been the subject of many researches during the past few decades. Both experimental and theoretical approaches have been used to address this issue. Up to now, there were no commercial simulation tools available for studying the transmission characteristics of multimode optical fibers. To overcome this problem, the modal continuum approach is employed to characterize light transmission in various kinds of multimode optical fibers. This modal continuum approach, which uses the time-dependent power flow equation (TD PFE), plays the most important role in the theoretical approaches. The PFE is the most comprehensive because it takes into account attenuation, mode coupling and modal dispersion, which significantly affects the BW. It can also be modified to accommodate various refractive index profiles, including step-index (SI), W-type index and graded index (GI) profiles. This review analyzes the pertinent literature related to the use of modal continuum-based models for BW modeling in conventional and microstructured multimode POFs. An overview of methodologies for optical fiber analysis with a focus on modal continuum approximation, and solutions to the TD PFE for various multimode fiber types, is provided. [ABSTRACT FROM AUTHOR]

To solve the problem of the narrow detection range of D-type photonic crystal fiber (PCF) sensor, a novel refractive index (RI) sensor with an ultra-wide detection range is proposed and analyzed by finite element method. The polishing design provides a flat coating platform for the metal film, ensuring the uniformity of the coating, thereby improving the performance of the sensor. The sensor mainly works in the visible and infrared bands with a detection range of 1.04–1.42, the detection range width can reach 0.38 RIU. To the best of our knowledge, the detection range of this sensor exceeds that of all D-type PCF sensors currently known. The parameters of the sensor are analyzed by numerical calculation and the result shows that the maximum wavelength sensitivity of the sensor is 12,100 nm/RIU, the maximum amplitude sensitivity is −846.4824 RIU−1, resolution can reach 8.2645 × 10−6 RIU, and the maximum figure of merit is 295.1807. In addition, the sensor also has extremely high fabrication stability, which greatly improves the practical application value of the PCF sensor, which is suitable for biomedical research, water quality monitoring, cancer detection and other fields. [ABSTRACT FROM AUTHOR]

In this research, we proposed a Terahertz (THz) refractive index-based Hollow-Core Photonic Crystal Fiber (HC-PCF) biosensor for examining various brain cancerous tissues. Six design variants with cladding segments ranging from 4 to 16 are analyzed using the finite element method (FEM). The biosensor demonstrates high sensitivity (94.9 to 97.46%), minimal Effective Mode Loss (EML) of 0.00246 cm−1with an effective mode area of 2.84 × 10−8 m2 and a power core ranges from 93% to 95.9% for the 16-segment cladding. The second contribution involves applying machine learning (ML), utilizing Autoencoder Augmentation Network (AEAN) for data augmentation and Bayesian Ridge Regression Multioutput Regressor (BRRMOR) for rapid prediction of biosensing parameters. The effectiveness of the ML model is demonstrated with a high r2 score of 0.992 for unknown HC-PCF structures, showcasing computational efficiency compared to Finite Element Method simulations. [ABSTRACT FROM AUTHOR]

This paper introduces a new design based on As2Se3 photonic crystal fibers, with the first layer of air holes near the core being removed. Dispersion properties were investigated for fibers with various types of lattice, including circular, square, and hexagonal lattice. Three fibers with a flat, all-normal dispersion, and a low dispersion value are proposed for supercontinuum generation at the same pump wavelength of 5.5 µm. The input pulse has a duration of 180 fs and a low peak power of 2.778 kW propagating in 10 cm fibers length, generating supercontinuum spectrums at 30 dB levels of 5.725 µm, 5.348 µm, and 5.936 µm, respectively, for circular, square, and hexagonal lattices. In addition, the fiber with the hexagonal lattice has the highest nonlinear coefficient of 862.654 W−1.km−1 and the lowest confinement loss of 0.137 dB/m, causing the largest bandwidth. The supercontinuum generation with low peak power using optimized PCFs with high nonlinearity and low confinement loss, makes them suitable for many application areas, e.g., the polarization-maintaining, coherent optical communications, nonlinear optics, etc. [ABSTRACT FROM AUTHOR]

In this study, we present a multi-surface plasmon resonance biosensor for detecting refractive index in the near-infrared range that is both straightforward and extremely effective. Titanium dioxide is used to create a thin adhesive coating that is used to firmly bond the gold (Au) layer to the photonic crystal fibers (PCF's) silica surface. A wavelength interrogation maximum sensitivity of 29,162 nm/RIU in the detection region of (1.36954, 1.37639, 1.38324, and 1.39057) and a standard sensitivity of 10,949 nm/RIU are just a few of the amazing performance attributes of the suggested sensor. Additionally, it uses both wavelength interrogation and amplitude techniques to show the highest amplitude sensitivity of 20,134.19 RIU−1 and a theoretical maximum resolution of 9.804 × 10 - 6 RIU. These findings appeal that the Multi-PCF surface plasmon resonance sensor has the best sensitivity and resolution yet observed, making it a prime candidate for the detection of organic compounds, biomolecules, chemical analytes, and other substances. The successful results achieved for each tested analyte show our sensor's reliability and robustness. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel polymer circular photonic crystal fiber (C-PCF) with a composite cladding structure that can support 92 terahertz (THz) orbital angular momentum (OAM) modes in the 1.5–3.5 THz frequency range. The difference in effective refractive index between the corresponding HE and EH modes is more than 10 - 3 . At 2.5 THz, the confinement losses of most vector modes are less than 10 - 10 dB/cm, and the smallest dispersion variation is 0.0487 ps/THz/cm. All vector modes have effective mode areas greater than 4 × 10 - 7 m 2 . Furthermore, the fiber's mode purity is greater than 96% over 2.3–3.5 THz. All of these properties indicate that this fiber has a larger potential for application in the next generation of terahertz multimode communication. [ABSTRACT FROM AUTHOR]

In this study, we describe the doping effect of nano-sized bimetallic core-shell structures on the optical responses of one-dimensional ternary photonic crystals (1DTPC). The varying radius of the metallic core and metallic shell tune the localized surface plasmon resonances (LSPRs) and the near field coupling with an incident wave, which tailors the dielectric responses of nanocomposite (NC) and optical properties of 1DTPC. Also, the tunable reflectance and absorption are studied with the distinct filling fraction signifying the high number of nanoparticles leads to an enhanced electromagnetic field near nanoparticles and near field coupling. The design of the NC is based on Maxwell-Garnett model with core shell of silver (Ag) and gold (Au) incorporated in the Si host. The near-field coupling and tunability of LSPRs exhibits tunable resonant reflectance dips, PBG edge deformations, and the optical properties are discussed with the transfer matrix method (TMM). The optical response, reflectance/absorptions of 1DTPC configuration as (MgF2|NC|SiO2)20 vary with the filling fractions of Ag@Au and angle of incident waves. The studied 1DTPC can be used to design numerous optical devices such as sensors, optical filters, solar cells, optical imaging and absorption-based instruments as well as biomedical applications. [ABSTRACT FROM AUTHOR]

Multiwavelength nanophotonic devices are essential components in photonic integrated circuits for on-chip all-optical signal processing applications with enhanced data-storage capacity and increased bandwidth. Wavelength demultiplexing is a widely used photonic processing function, required for photonic signal processing on compact silicon chip designs. In this paper, we study optical rainbow trapping in a line defect photonic waveguide, and propose to use that effect for demultiplexing the light at visible spectrum. A defect waveguide is created in graded-index photonic crystal (GRIN PC) structure (the structure is composed of Si- PC cylinders having gradually varying radii along one dimension) as main channel, which allows the rainbow-trapping along the waveguiding channel. Vertical (side) channels are introduced to the system for efficient wavelength demultiplexing with low crosstalks and high coupling efficiencies thanks to the fact that incident light is localized at different positions along the main channel for certain operating visible wavelengths of The corresponding inter-channel cross-talks of is obtained at these incident wavelengths, which strengthens the idea of using such a GRIN PC structure for efficient wavelength demultiplexing applications. The studied multichannel demultiplexing device is relatively compact with a footprint of , which could be fabricated via simple lithography processes on a single Si- wafer. As far as authors' knowledge, this is the first time in literature that GRIN PC waveguide is implemented for multichannel wavelength demultiplexing function. The proposed GRIN PC design could be implemented for color sensitive photo-detection, absorption enhancement and optical spectroscopy. [ABSTRACT FROM AUTHOR]

This paper presents the review of recent progress in photonic crystal fiber (PCF) and its applications. PCF possesses prominent potential for demonstrating various optical devices such as logic gates, combinational circuits, sensors, absorbers, etc. Recent development in PCFs incorporates the deep learning algorithms which deploy new functionalities and enhance the performance capacity in term of accuracy and optimization in comparison to conventional techniques based on Maxwell solver like finite element method (FEM), and plane wave expansion and finite difference time domain (FDTD) method. Thus, this review paper describes the overview of recent development along with historical background of PCFs and rigorous study on deep learning which incorporates neural network and machine learning algorithms like polynomial expansion method, gradient boost, and random forest. [ABSTRACT FROM AUTHOR]

In this paper, a large mode area photonic crystal fiber (PCF) based on chalcogenide glass A s 2 S 3 with excellent bending resistance and single-mode operation characteristics is proposed.The guiding properties of the PCF are investigated using the full vector finite element method with perfectly matched layers. Numerical results indicate a single-mode bandwidth of 170 nm, covering the wavelength range from 1.1 to 2.8 μ m. The effective mode area exceeds 720 μ m 2 for a wavelength of 2.0 μ m and a bending radius of 10 cm. The bending radius ranges from 7 to 40 cm, 5 to 30 cm, and 3 to 19 cm at the three commonly used operating wavelengths of 1.31 μ m, 1.55 μ m, and 2.0 μ m, respectively. As a result, the designed chalcogenide PCF is bend insensitive and can maintain stable single-mode operation even at different working wavelengths. Moreover, the proposed PCF is easy to fabricate and has potential for application in high power fiber lasers. [ABSTRACT FROM AUTHOR]

A photonic crystal fiber (PCF) sensor for detecting harmful chemicals such as di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), and bisphenol S (BPS) in polycarbonate plastics has been proposed using fused silica as the substrate, consisting of a decagonal core hole and 2 layers of circular cladding air holes arranged in a hexagonal pattern, and numerically analysed using COMSOL Multiphysics with the Finite Element Method. The PCF sensor was evaluated for the effective area, nonlinear coefficient, chromatic dispersion, V-parameter, power fraction, relative sensitivity, and confinement loss from the visible to infrared wavelength range. The results show relative sensitivities of 99.14%, 99.93%, and 99.95% for DEHP, BPA, and BPS, respectively, at an optimum wavelength of 0.4 µm, with confinement losses ranging from 10−21 to 10−17 dB/m for all the test analytes. The design was also shown to be robust against variations in cladding air hole layers and global dimensions, making it a promising candidate for practical sensing applications in the plastic production industry. Furthermore, the sensor's ability to achieve low confinement losses, low chromatic dispersion, and a high nonlinear coefficient demonstrates its suitability for a range of other applications including optical communication, supercontinuum generation, and light illumination. [ABSTRACT FROM AUTHOR]

In this paper, mixed integer nonlinear programming (MINLP) optimization algorithm integrated with kriging surrogate-model is newly formulated to optimize the dispersion characteristics of photonic crystal fibers (PCFs). The MINLP is linked with full vectorial finite difference method (FVFDM) to optimize the modal properties of the PCFs. Through the optimization process, the design parameters can take real and/or integer values. The integer values can be used to selectively fill the PCF air holes to control its dispersion characteristics. However, the other optimization techniques deal with real design parameters where the PCF can be optimized using none or predefined infiltrated air holes. The MINLP algorithm is used to obtain an ultra-flat zero dispersion over a broadband of wavelength range from 1.25 to 1.6 μm using silica PCF selectively infiltrated with Ethanol material. To show the superiority of the proposed algorithm, nematic liquid crystal selectively infiltrated PCFs are also designed with high negative flat dispersion over wide range of wavelengths from 1.25 to 1.6 μm for the quasi transverse magnetic (TM) and the quasi transverse electric (TE) modes. Such designs have negative flat dispersions of − 163 ± 0.9 and − 170 ± 1.2 ps/Km nm, respectively over the studied wavelength range. Therefore, the MINLP algorithms could be used efficiently for the design and optimization of selectively filled photonic devices. [ABSTRACT FROM AUTHOR]

A surface plasmon resonance (SPR)-based photonic crystal fiber (PCF) magnetic field sensor with hexagonal lattice is proposed. Magnetic fluid is injected into two air holes for magnetic field sensing. In order to obtain the optimal structure of magnetic field sensor, four types of hexagonal PCF models are discussed and compared. The influence of structure parameters d, d 1 , d 2 , t, D, and Λ on sensing characteristics is analyzed when the PCF-3 is determined. The maximum sensitivity and corresponding resolution can reach 1150 pm/Oe and 0.087 Oe, and figure of merit (FOM) is up to 0.0556/Oe in the magnetic range of 30–150 Oe. The maximum wavelength sensitivity is 25000 nm/RIU, when the range of refractive index (RI) is from 1.420 to 1.450. In addition, the temperature sensitivity is only 65 pm/K, indicating small temperature crosstalk. The proposed sensor has the advantages of large FOM, good linearity and simple structure, enabling accurate measurement of magnetic field, especially suitable for weak magnetic field detection. Good performance makes it applicable to industrial production, military affairs, health and environmental monitoring. [ABSTRACT FROM AUTHOR]

We present a specialty photonic bandgap fiber (PBG) with multiple concentric cores based on the one-dimensional (1D) photonic crystal geometry in an all-solid form. It comprises three sets of tailored bilayer thickness in which each set of bilayer forms an effective core region that allows confinement of specific range of wavelengths. Thus, the successive overlap of the wavelength ranges supported by each of these concentric cores effectively enhances the overall transmission bandwidth of the designed 1D PBG fiber. Moreover, the concept can be extended to form a large number of concentric cores that allows further enhancement of the fiber bandwidth. As a proof-of-concept, an ultra-wide low-loss bandwidth covering a wavelength range of ∼ 1600 nm for the fundamental mode are achieved. Going beyond, an advanced level customization of the proposed fiber geometry enables further minimization of loss and enhancement in structural robustness. The propagation dynamics of an ultrashort pulse ∼ 300 fs are investigated numerically in both the normal and the anomalous dispersion regime of the proposed specialty fiber in the presence of nonlinearity and loss. Eventually, such all-solid multicore large-bandwidth fiber is proposed as a promising candidate for the delivery of ultrashort optical pulses over long distance with minimum amount of distortion and wave-breaking possible. [ABSTRACT FROM AUTHOR]

The main goal of the article is to present the optical soliton solutions of the nonlinear Schrodinger equation, comprising Kudryashov's quintuple power-law with dual form nonlinearity which has very important applications in domination soliton pulse propagation through optical fibers and photonic crystal fibers. To achieve our goal, two potent analytical techniques are employed: the Sardar-Subequation method and the new method G ′ k G ′ + G + r -expansion method, which represent a novel approach not found in existing literature. Furthermore, our approach offers distinctive solutions characterized by a rich variety of trigonometric and hyperbolic functions. The majority of our results are depicted graphically to highlight our achievements. [ABSTRACT FROM AUTHOR]