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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]

Copyright of Baghdad Science Journal is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A V-shaped sensing surface photonic crystal fiber sensor based on surface plasmon resonance is designed and investigated numerically in the refractive index detection range of 1.32 to 1.41 by applying the finite element method. The Vshaped surface can reduce the distance between the fiber core and the analyte, which enhances the coupling between surface plasmon mode and the fundamental core mode. The effect of the surface angle of the proposed sensor on the mode characteristics and sensing performances is analyzed in detail. The simulation results show that the surface angle of the PCF has a remarkable influence on the sensitivity of the sensor and detection range of the analyte retractive index. This sensor offers maximum sensitivity of 14000 nm/RIU which is approximately 55% larger than the other similar structure for the surface angle of 160o without sacrificing the detection range of the analyte refractive index. The above analysis and results demonstrate that this sensor is feasible and promising in environmental, biological, and chemical sensing. [ABSTRACT FROM AUTHOR]

It is common practice when simulating propagation through an optical fiber to assume that its characteristic parameters are constant and determined solely by the central wavelength of the input pulse. In this paper, we propose a study of the impact that the actual wavelength dependence of these parameters has on the propagation results. To this end, simulations were carried out considering both the constant model and the wavelength-dependent model, applying them to the case of the especially sensitive effect of supercontinuous generation in a photonic crystal fiber. The results showed differences of up to 20% of the spectrum and, hence, the importance of taking into account the wavelength dependence of the dispersion fiber parameters to obtain more-realistic results in the simulations. [ABSTRACT FROM AUTHOR]

Photonic crystal fiber design based on surface plasmon resonance phenomenon (PCF-SPR) is optimized before it is fabricated for a particular application. An artificial intelligence algorithm is evaluated here to increase the ease of the simulation process for common users. COMSOL™ MultiPhysics is used. The algorithm suggests best among eight standard machine learning and one deep learning model to automatically select the desired mode, chosen visually by the experts otherwise. A total seven performance indices: namely, precision, recall, accuracy, F1-score, specificity, and Matthew correlation coefficient, are utilized to make the optimal decision. Robustness toward variations in sensor geometry design is also considered an optimal parameter. Several PCF-SPR-based photonic sensor designs are tested, and a large range optimal (based on phase matching) design is proposed. For this design algorithm has selected support vector machine (SVM) as the best option with an accuracy of 96%, F1-score is 95.83%, and MCC of 92.30%. The average sensitivity of the proposed sensor design with respect to change in refractive index (1.37–1.41) is 5500 nm/RIU. Resolution is 2.0498 × 10 - 5 RIU - 1 . The algorithm can be integrated into commercial software as an add-on or as a module in academic codes. The proposed novel step has saved approximately 75 min in the overall design process. The present work is equally applicable for mode selection of sensor other than PCF-SPR sensing geometries. [ABSTRACT FROM AUTHOR]

Surface plasmon resonance (SPR) sensing methods enable highly sensitive, fast response, and label-free analysis of biomolecular interactions. For SPR sensors, sensitivity and full width at half maximum (FWHM) are two incompatible performance parameters. We propose a refractive index (RI) sensor using a dual-core photonic crystal fiber (PCF) and SPR effects to achieve high sensitivity and a narrow FWHM simultaneously. The air holes of the sensor appear in a hexagonal arrangement, and polishing technology introduces two polishing planes into the cladding. A gold film is deposited on one side of the polished plane to form a highly sensitive RI sensing channel. Five gold nanowires are deposited on the other side of the polished plane to form a RI sensing channel with a narrow FWHM. We analyzed and optimized its structural parameters using the finite element method and determined the optimal structural parameters. The numerical results demonstrate that the maximum sensitivity of the sensor is 21,000 nm/RIU with the narrowest FWHM of 31 nm. Therefore, measuring the refractive index simultaneously with two sensing channels increases the detection accuracy of the measurement. In addition, the findings further indicate that variations in structural parameters do not significantly impact the sensing performance of the sensor, which makes the production of the sensor relatively simple. In conclusion, our work provides a new research method for realizing high sensitivity and a narrow FWHM simultaneously. [ABSTRACT FROM AUTHOR]

This research work presents a biomedical application of "photonic crystal fiber (PCF )"–based "surface plasmon resonance (SPR )" biosensors for the earliest possible detection of pregnancy to reduce the risk of miscarriage. The sensor design contains a combination of Au , TiO 2 , and MgF 2 layers of plasmonic materials, which provide better stability to the sensor model. The biosensor parameters are examined for both TM mode and TE mode , following the principle of couple mode light theory. The analyte used in the proposed sensor is women's urine samples, which are investigated based on the variations in their refractive index (RI ) values. The biosensor has obtained the highest wavelength sensitivity (WS ) of 110000 nm / RIU and 130000 nm / RIU for TM mode and TE mode respectively. Peak amplitude sensitivity ( AS) of 24180 RIU - 1 and 31670 RIU - 1 is obtained for TM mode and TE mode , respectively. The biosensor can achieve sensor resolution ( SR) in the order of 10 - 7 for both TM mode and TE mode . The R 2 close to unity is achieved for both TM mode and TE mode . The maximum FOM obtained from the proposed biosensor is 984.84 RIU - 1 and 1078.83 RIU - 1 for RI 1.3420 and 1.3430 RIU , respectively, corresponding to TE mode . [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]

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]

A high-sensitivity refractive index (RI) sensor based on surface plasmon resonance (SPR) effect in D-shape photonic crystal fiber (PCF) is presented and discussed by the finite element method (FEM). The designed PCF is polished to enhance the interaction of the evanescent field with analyte, improving the sensing performance. Simulation results indicate that the sensor has a sensing range from 1.30 to 1.35. The maximum spectral sensitivity of 18,139.37 nm/RIU and a high resolution of 5.5 × 10−6RIU can be obtained at 1.35. The average spectral sensitivity is 10683.3 nm/RIU. For the purpose of optimizing sensing performance, the effects of the structure parameters on the resonant spectra are also studied. The advantage of the sensor is that a simple structure with the same diameter can be used to achieve high refractive index sensitivity and resolution. [ABSTRACT FROM AUTHOR]

The present study reports a design procedure and numerical investigation of a photonic crystal fiber biosensor. The proposed sensor is consisting of irregular arranged rectangular holes. The core area has been arranged of a single rectangle for sensing the cancer cells and normal cells in the frequency range 1.0–2.5 THz. Zeonex has been utilized as a fiber material. The model has been organized and computationally investigated employing software based on the finite element method. The modeling of the designed sensor authenticates its capability in identifying cancer cells. An absorbing layer: perfectly matched layer has been used for calculating optical characteristics. It has been observed that the designed PCF sensor gives a high relative sensitivity of 81.38% for cancer cells and 65.83% for normal cells, respectively. Reduced confinement loss as 5.828 × 10−25 cm−1 has been achieved. Also, the effective area 2.549 × 10−8 µm2, birefringence 4.709 × 10−4, propagation constant 1.01961 × 10−24 and effective refractive index as 1.475 × 10−18 have been investigated. The present manufacturing technique is appropriate for the designing of proposed PCF sensor. [ABSTRACT FROM AUTHOR]

In this study, a surface plasmon resonance based on Mach–Zehnder interferometer is produced by combining two normal Single mode fibers with a Photonic Crystal Fiber SMF-PCF-SMF for measuring the refractive index (RI) for ion toxic metal lead. In the center of the sensor, a small portion (4 cm) of PCF is created, and after the process of tapering is complete, gold is deposited with a thickness of about (40 nm). A photonic crystal fiber's gold-coated core receives a deposit of toxic lead ions. The computed signal to noise ratio (SNR), sensitivity (S), resolution (R), and figures of merit (FOM): SNR is 0.18, Sensitivity is 11.11 m/RIU, Resolution is 1.7 × 10 - 4 , and FOM is 22.87. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a simple arc shaped Au coated photonic crystal fiber-based refractive index sensor that works on principle of surface plasmon resonance. We analyze the performance of the proposed sensor using the finite element method. Further, we analyze the effect of the arc shaped metal coating on different orientations of air holes in the cladding region. For the sensing range of 1.32–1.37, the proposed PCF sensor structure exhibits a maximum wavelength sensitivity of 14,100 nm/RIU with the resolution of 7.09 × 10–6 RIU. Also, this sensor exhibits a maximum amplitude sensitivity of 109 RIU−1 with a resolution of 9.17 × 10–6 RIU. Further, from the linearity of the proposed sensor, R2, is 0.96181 for the refractive index ranging between 1.32 and 1.37. Furthermore, we carry out perturbation analysis to ensure that the proposed sensor withstands the fabrication tolerance. Therefore, the proposed sensor holds good for a potential contender for sensing in chemical and biological applications. [ABSTRACT FROM AUTHOR]

Hydrogen cyanide gas is a dangerous and fatal gas that is one of the causes of air pollution in the environment. A small percentage of this gas causes poisoning and eventually death. In this paper, a new PCF is designed that offers high sensitivity and low confinement loss in the absorption wavelength of hydrogen cyanide gas. The proposed structure consists of circular layers that are located around the core, which is also composed of circular microstructures. The finite element method (FEM) is used to simulate the results. According to the results, the PCF gives a high relative sensitivity of 65.13% and a low confinement loss of 1.5 × 10−3 dB/m at a wavelength of 1.533 µm. The impact of increasing the concentration of hydrogen cyanide gas on the relative sensitivity and confinement loss is investigated. The high sensitivity and low confinement losses of the designed PCF show that this optical structure could be a good candidate for the detection of this gas in industrial and medical environments. [ABSTRACT FROM AUTHOR]

With the development of laser technology, microstructured optical fibers (MOFs) have become an important part of ultrafast optics, providing excellent platforms for ultrafast laser pulse generation, amplification, and compression, promoting the development of fiber laser systems to generate high power, high pulse energy, and few-cycle duration pulses. MOFs extend the ultrafast laser spectrum to the vacuum ultraviolet (VUV) and even extreme ultraviolet (EUV) regions based on dispersive wave emission and high harmonic generation, as well as to the mid-infrared region based on soliton self-frequency shift (SSFS), contributing compact and low-cost light sources for precision microscopy and spectroscopy. In this paper, first several common types of MOFs are introduced, then the various applications of MOFs in ultrafast optics are discussed, mainly focusing on the aspects of ultrafast laser pulse scaling in pulse energy and spectral bandwidth, and finally the possible prospects of MOFs are given. [ABSTRACT FROM AUTHOR]

A novel ring-core photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) is designed for ultra-low refractive index detection. A gold nanowire is coated on the outer surface of the PCF as a plasma material, greatly facilitating the manufacturing of the sensor. To achieve real-time detection, the analyte is located on the outside of the sensor. The mode coupling effect and main performance parameters are analyzed through finite element method. In addition, by optimizing several important structural parameters, the overall performance of the sensor has been greatly improved. The optimized sensor shows a maximum wavelength sensitivity of 26,000 nm/RIU in the refractive index range of 1.14–1.26, maximum amplitude sensitivity of 300 RIU − 1 , as well as minimum resolution of 3. 8 5 × 1 0 − 6 RIU. The PCF-SPR sensor with outstanding properties has great potential in applications such as oil logging, biosensing, and chemical monitoring. [ABSTRACT FROM AUTHOR]

An intensity-demodulated fiber-optic magnetometer is proposed and experimentally investigated, which is fabricated via fusion splicing a segment of photonic crystal fiber (PCF) between single-mode fibers (SMFs), with the cladding air holes of PCF filled with magnetic fluid. Using the magneto-optical properties of the magnetic fluid, the transmission spectrum is changed with an external magnetic field. Based on the intensity variations in the transmission spectrum, the magnetic field is detected, and a sensitivity of 0.238 dB/mT is obtained at 1550.03 nm with the length of PCF 5.5 cm. By converting light signals into electrical signals, a sensitivity of 0.003 V/mT is achieved. The fiber-optic magnetometer possesses the advantages of simple fabrication, compact/robust structure, and low cost. [ABSTRACT FROM AUTHOR]

We report a novel kind of antiresonant fiber for flat‐top beam generation with all‐solid configuration. The fiber core introduces a square antiresonance structure with low‐high‐low refractive index distribution, achieving homogenization of the beam profile through its light guidance on the optical field. Attributed to the antiresonant structure, the all‐solid antiresonant fiber transmits the flat‐top beam with very low confinement loss and large mode area. And it generates and transmits flat‐top beam with low loss in wavelength range from 1200 nm to 2200 nm. This would open up the application of antiresonance fiber in beam shaping. [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]

Copyright of Sultan Qaboos University Journal for Science is the property of Sultan Qaboos University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the paper, we propose an elliptical photonic crystal fiber sensor with an open ring channel, which could enhance the sensor performance. Gold is employed as the plasmonic material and coated on open ring channel. Using the finite element method, the wavelength sensitivity, the amplitude sensitivity, and the optical spectrum leakage from the fiber core to the sample channels are examined, and the influence of structural parameters on the sensor performance is investigated. The numerical results show that the proposed sensor exhibits a wide detection range of the refractive index (RI) from 1.20 to 1.40, the maximum wavelength sensitivity is 21,000 nm/RIU, where RIU is the RI unit, and the maximum amplitude sensitivity of 455.45 RIU−1 is obtained for RI of 1.33. Moreover, the feasibility of the multi-function detection to identify fluorine-containing organics, glucose concentration, and pathogens in water is also numerically investigated. [ABSTRACT FROM AUTHOR]

Next-generation optical fibers with diverse operating mechanisms, high functionality, and a porous structure that may be designed are known as photonic crystal fibers, or PCFs. In the meantime, two-dimensional graphene, possessing incredibly unique characteristics, is a perfect material for optoelectronic and optical uses. Recently, many studies have been published based on the integration of graphene with PCFs to create a new graphene PCF (Gr-PCF). There hybrid fibers show outstanding light-mater interaction over a broad spectrum range. This review starts with general introduction about photonic crystal fiber and analysis of optical properties. This is followed by a Plasmonic PCF then Graphene and physicochemical properties of graphene nanomaterials. The review primarily covers the introduction of graphene and PCFs with many Applications including Optics Communications and different physical sensors. [ABSTRACT FROM AUTHOR]

In this manuscript, a sensor is devised employing photonic crystal fiber with localized surface plasmon resonance (PCF-LSPR), emphasizing the manipulation of refractive index (RI) through magnetic fluid (MF). The sensor's air holes adopt a hexagonal arrangement, forming a butterfly core design, and the transmission channels for the effective confinement of optical field energy relies significantly on the regions surrounding the central air hole in both directions. MF serves as the sensing medium, and the top and bottom polished surfaces are coated with gold and titanium dioxide. The sensor undergoes analysis using the finite element method, scrutinizing its model characteristics, structural parameters, and sensing performance. The results indicate a wavelength sensitivity of up to 45,600 nm/RIU and a maximum figure of merit (FOM) of 434 RIU−1. Within the range of magnetic field 30–150 Oe, the highest magnetic field sensitivity records 3350 pm/Oe. Over the temperature range of 27.4–114 °C, the temperature sensitivity measures only 310 pm/°C. A maximum sensor resolution of 2.19×10−6 RIU is achieved for x−pol. The linear relationship between the resonant wavelength and the magnetic field yields R2=0.9945, for degree (2) for x−pol. The proposed sensor exhibits notable advantages, including a structure which is very stable, high sensitivity, ease of integration, and resilience to electromagnetic interference. Additionally, it excels in detecting weak magnetic fields. Its potential applications span from industrial production, military technology, to medical equipment.

We propose a single material microstructured optical fiber with more than five octave spanning supercontinuum generation. Due to using single material, compatibility checking between core and cladding material need not required. Moreover, the material is such chosen that optical transmission range is quite high in comparison to others. The fiber is designed in COMSOL platform and according to finite element method (FEM), numerical analysis is accomplished. Dispersion, confinement loss, nonlinearity etc. are investigated and exposed for a wavelength range of 2000–3000 nm. The proposed fiber reveals zero dispersion at 2200 nm, nonlinearity of 14,370 W−1km−1 and confinement loss around 10−9 order in dB/m. Finally, supercontinuum generation has been investigated inside the structure and obtained high coherence that span (from 1500 nm to 34,500 nm) over five octave. The generated spectrum fulfills the requirements for being applicable in frequency metrology, fiber laser and biophotonics. With the best of our knowing, such coherent and widened supercontinuua for single material fiber is yet to be proposed.

This work proposes a design of a porous-core photonic crystal fiber (PC-PCF) made of a cyclic olefin copolymer, Zeonex, with a hybrid cladding for low-loss terahertz (THz) wave transmission. A combination of circular and elliptical air holes is employed, resulting in a very low material absorption loss of 0.045 cm-1 at Dcore = 450 µm and f = 1 THz. A flat dispersion of 0.73 ± 0.13 ps/THz/cm is obtained for a broad frequency range of 0.5–1.4 THz. Core diameter and frequency response of other key features such as normalized frequency (V-parameter), confinement loss, effective area, nonlinearity and the percentage of the power flow through different sections of the proposed PC-PCF are also analyzed. Comparing to state-of-the-art, our design is superior in terms of loss, dispersion and power fraction. Our proposed design can be manufactured using the established extrusion process and be used for long distance low-loss Terahertz (THz) communication.

This paper presents a photonic crystal fiber (PCF) sensor that can be used to measure the temperature and magnetic field simultaneously, and to monitor the changes in them in the environment. When we designed the fiber structure, two circular channels of the same size were added to the fiber to facilitate the subsequent addition of materials. A gold film is added to the upper channel (ch1), and the channel is filled with a magnetic fluid (MF). The sensor can reflect changes in the temperature and magnetic field strength. The two channels containing MF and PDMS in the proposed fiber are called ch1 and ch2. The structure, mode and properties (temperature and magnetic field) were analyzed and discussed using the finite element method. By using the control variable method, the influence of Ta2O5 or no Ta2O5, the Ta2O5 thickness, the diameter of the special air hole, the distance from the fiber core and the distance between them in the displacement of the loss spectrum and the phase-matching condition of the coupling mode were studied. The resulting maximum temperature sensitivity is 6.3 nm/°C (SPR peak 5), and the maximum magnetic field sensitivity is 40 nm/Oe (SPR peak 4). Because the sensor can respond to temperature and magnetic field changes in the environment, it can play an important role in special environmental monitoring, industrial production and other fields.

In order to achieve a high-precision synchronous detection of two different refractive index (RI) analytes, a D-type surface plasmon resonance (SPR) photonic crystal fiber (PCF) RI sensor based on two channels is designed in this paper. The sensor uses a D-shaped planar region of the PCF and a large circular air hole below the core as the sensing channels. Surface plasmon resonance is induced by applying a coating of gold film on the surface. The full-vector finite-element method (FEM) is used to optimize the structural parameters of the optical fiber, and the sensing characteristics are studied, including wavelength sensitivity, RI resolution, full width at half maximum (FWHM), figure of merit (FOM), and signal-to-noise ratio (SNR). The results show that the channel 1 (Ch 1) can achieve RI detection of 1.36–1.39 in the wavelength range of 1500–2600 nm, and the channel 2 (Ch 2) can achieve RI detection of 1.46–1.57 in the wavelength range of 2100–3000 nm. The two sensing channels can detect independently or simultaneously measure two analytes with different RIs. The maximum wavelength sensitivity of the sensor can reach 30,000 nm/RIU in Channel 1 and 9900 nm/RIU in Channel 2. The RI resolutions of the two channels are 3.54 × 10−6 RIU and 10.88 × 10−6 RIU, respectively. Therefore, the sensor realizes dual-channel high- and low-RI synchronous detection in the ultra-long wavelength band from near-infrared to mid-infrared and achieves an ultra-wide RI detection range and ultra-high wavelength sensitivity. The sensor has a wide application prospect in the fields of chemical detection, biomedical sensing, and water environment monitoring.

This work suggests a brand-new 1*4 two-dimensional demultiplexer design based on multicore photonic crystal fiber. Numerical models show that the optical signals can be separated in a photonic crystal fiber construction using optical signals with wavelengths of 0.85, 1.1, 1.19, and 1.35 μm injected on the center core and separated into four cores. The innovative design switches different air-hole positions using pure silica layers throughout the length of the fiber to regulate the direction of light transmission between layers. Wavelength demultiplexers are essential parts of optical systemic communications. They serve as a data distributor and can use a single input to produce multiple outputs. The background material is frequently natural silica, and air holes can be found anywhere throughout the length of the fiber as the low-index components. The simulation results showed that after a 6 mm light propagation, the four-channel demux can start to demultiplex.

This study introduces a dual-core photonic crystal fiber incorporating a highly responsive plasmonic refractive index (RI) sensor. The performance of the RI sensor is evaluated based on amplitude sensitivity, wavelength resolution, wavelength sensitivity, and the linearity of the resonance wavelength. Employing the finite element technique (FEM), a numerical analysis of the proposed design is conducted. Results indicate that employing the amplitude interrogation method yields a peak amplitude sensitivity of 605.82 RIU−1 for y-polarization. Furthermore, the wavelength interrogation approach for y-polarized modes demonstrates a maximum wavelength sensitivity of approximately 17,000 nm/RIU and a maximum wavelength resolution of 5.88 × 10−6 RIU. The proposed sensor exhibits a figure of merit of approximately 298 and effectively responds to refractive index variations within the range of 1.28 to 1.40. These promising outcomes, coupled with the broad sensing range, establish the suggested sensor as a promising candidate for the detection of organic chemical solutions.

In this article, Photonic crystal fiber (PCF) based surface plasmon resonance (SPR) sensor is proposed for detecting cancerous cells like Hela for cervical cancer and Basal for skin cancer. The numerical analysis and simulation of the designed biosensor is carried out using the finite element method in conjunction with a layer that is perfectly matched. The PCF sensor based on SPR has a gold layer for the plasmonic effect and a nanolayer of TiO2 to form an adhesion layer in between the gold and silica. The sensor can detect an analyte's refractive index (RI) between 1.360 and 1.392 for two distinct cancerous cell types (Hela and Basal). The proposed biosensor's performance is evaluated using amplitude and wavelength investigation techniques. This study achieves the wavelength sensitivity of 6250 nm/RIU, 5000 nm/RIU, and the amplitude sensitivity of 909.05 RIU−1, 505.53 RIU−1 for Hela and Basal cells, respectively. The results show that the proposed sensor is suitable for real-time biosensing applications.

Modern-day optical systems are evolving towards miniaturization and integration, leading to higher performance demands for polarizing beam splitters (PBSs). A simple-structure and high-performance PBS based on dual-core photonic crystal fiber (DC-PCF) with As2S3 layer is proposed. The finite element method (FEM) and classical coupled-mode theory (CMT) are utilized to investigate the performance of this PBS. Simulation results demonstrate that the proposed PBS can achieve a minimum length of 2.65 mm, a minimum extinction ratio of −64 dB, an operating bandwidth of 420 nm, and a minimum insertion loss of 0.03 dB when the optimal parameters include cladding hole diameter of 1.0 μm, central hole diameter of 2.0 μm, lattice spacing of 2.0 μm, and As2S3 ring layer thickness of 50 nm. Moreover, it also possesses a high birefringence of 3.58 × 10−3 and a negative dispersion of −30 ps/km/nm at 1.55 μm. It is believed that the proposed PBS holds great potential to become a critical device in optical multiplexing technologies.

Photonic crystal fibers (PCFs) have emerged as promising candidates for enabling high-performance 5G communication systems, attributed to their low loss and wide bandwidth characteristics. In this research, we leverage the capabilities of COMSOL Multiphysics v5.6 software to meticulously design a novel photonic crystal fiber (PCF) design based on Topas, featuring a rectangular air gap core with integrated slots, surrounded by a cladding composed of circular and octagon air holes. The circular air holes are arranged in square and octagon lattice structures, while the octagon air holes form a rhombic lattice. The proposed structure exhibits a high birefringence of 0.05 and low effective material loss (EML) of 0.059 cm−1 and 0.057 cm−1 at 2 THz for x and y polarization mode, respectively. Moreover, the proposed waveguide also has a low confinement loss of 10−10 and 10−11 cm−1 for x and y polarization mode. Thus, the proposed PCF structure exhibits significant potential for facilitating 5G requirements. [ABSTRACT FROM AUTHOR]

The problem of generating ultrashort Raman solitons with a wavelength in the range of 1600–1700 nm, which are formed in a nonlinear fiber when splitting a high-power pump pulse with a wavelength of ~1550 nm, is considered numerically and experimentally. The specificity of the problem is the use of a photonic crystal fiber with a large mode area and close to zero birefringence as a nonlinear light guide. The results obtained show the possibility of controlling the central wavelength of a Raman soliton in the range of 1625–1700 nm by controlling the polarization state of the pump pulse at the input to the photonic crystal fiber. The proposed method for controlling the wavelength is notable in that the energy of the Raman soliton remains approximately the same throughout the entire tuning range, which is very attractive for a number of applications. [ABSTRACT FROM AUTHOR]

Liquid infiltration into photonic crystal fibers (PCFs) opens new horizons in optical fiber design. This innovation allows precise control of the refractive index, dispersion, and nonlinear effects within the PCF core, expanding its adaptability for various applications. Through numerical simulations, we explore the impact of different liquids on chromatic dispersion in PCFs, emphasizing the role of filling ratios. Our findings unveil shifts in zero dispersion wavelengths, with chloroform causing significant changes. Lower filling ratios reduce dispersion sensitivity, while higher ratios enable dispersion compensation. This study advances our understanding of liquid-filled PCFs, vital for cutting-edge photonics research and practical applications. [ABSTRACT FROM AUTHOR]

The present work has been performed with an intent of designing a robust, profound, and highly sensitive sensor for numerous explosive detections. The main objective of the present study is to design a simplified structure with fabrication feasibilities. The proposed structure of an explosive detector includes a hollow core surrounded with four sectored-type air holes in the cladding area and silica as background of the fiber which operates for 1–2 THz frequency band. Furthermore, the optical guiding property of the detector is examined, and numerical study has been performed. The modelling has been performed with the help of COMSOL Multiphysics 5.6a software based on finite element method, and Origin 2023 software is used for plotting and analyzing the characteristic curves. The suggested sensor structure has been analyzed for various explosives such as TNT, RDX, HMX, and PETN. Optical parameters such as effective refractive index, confinement loss, effective area, nonlinearity, propagation constant, and relative sensitivity have been evaluated. The proposed structure offers relative sensitivity of 84.02%, 69.42%, 71%, and 79.31% for TNT, RDX, HMX, and PETN samples, respectively. The proposed detector structure offers better sensing proficiency for explosive detection. The simplified design favors the fabrication possibilities and makes it economically effective. The proposed study will add up to the developments in the field of photonics and chemical detection and, moreover, will open new doors for better application for security and explosive sensing. [ABSTRACT FROM AUTHOR]