PCF Based Sensor with High Sensitivity, High Birefringence and Low Confinement Losses for Liquid Analyte Sensing Applications

In this paper, we report a design of high sensitivity Photonic Crystal Fiber (PCF) sensor with high birefringence and low confinement losses for liquid analyte sensing applications. The proposed PCF structures are designed with supplementary elliptical air holes in the core region vertically-shaped V-PCF and horizontally-shaped H-PCF. The full vectorial Finite Element Method (FEM) simulations performed to examine the sensitivity, the confinement losses, the effective refractive index and the modal birefringence features of the proposed elliptical air hole PCF structures. We show that the proposed PCF structures exhibit high relative sensitivity, high birefringence and low confinement losses simultaneously for various analytes

Multi-channel SPR biosensor based on PCF for multi-analyte sensing applications

This paper presents a theoretical investigation of a novel holey fiber (Photonic Crystal Fiber (PCF)) multi-channel biosensor based on surface plasmon resonance (SPR). The large gold coated micro fluidic channels and elliptical air hole design of our proposed biosensor aided by a high refractive index over layer in two channels enables operation in two modes; multi analyte sensing and self-referencing mode. Loss spectra, dispersion and detection capability of our proposed biosensor for the two fundamental modes (HE x 11 and HE y 11 ) have been elucidated using a Finite Element Method (FEM) and Perfectly Matching Layers (PML)

Design and numerical analysis of dual-core photonic crystal fiber-based biosensor

In this study, the coupling and the relative sensitivity characteristics of a Dual-Core Photonic Crystal Fiber (DC-PCF)-based liquid sensor are evaluated by employing the full-vectorial Finite element Method (FV-FEM). The simulation results demonstrate that coupling length of the proposed sensor varies between 2mm and 0.2mm length at wide wavelength range (800–1600 nm) for low index analytes (1.33–1.36). Besides, birefringence of order ≈ 10-4 is reported. It is found that analyte with 1.36 index reaches higher sensitivity levels. On the other hand, the coupling length of the proposed sensor can be optimized with the ellipticity ratio of the central core hole. Bending analysis on coupling length and optical power fluctuations is also reported. It is found that the power °ow in one core is increasing almost 90% towards the bending direction. The proposed structure with simple design parameters has a great potential in various biomedical applications including DNA detection and can also be employed as fibre-based refractometer in various sensing applications

A theoretical investigation of a photonic crystal fibre with ultra-flattened chromatic dispersion with three zero crossing dispersion wavelengths

This paper presents a novel non-defective core photonic crystal fiber (PCF) which was found to produce three zero dispersion wavelength (ZDW), which may lead to a very powerful spectral densities compared to that of single or double ZDW PCFs. More so, the presented PCF design not only has the three ZDW achieved for the PCF, but also, been able to achieve a high negative chromatic dispersion (−220.39 ps/km.nm), and ultra-flatted chromatic dispersion of ± 0.9 ps/km·nm within operating wavelength range of 1.53–1.8 μm. These characteristics may be helpful for applications in the fields of supercontinuum generation (SCG), soliton pulse transmission, and detecting or sensing and optical communication systems. The propagation properties of the proposed PCFs: effective index, confinement loss and chromatic dispersion, are well researched making use of full vectorial finite element method (FEM)

Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

Effect of the elliptic rods orientations on the asymmetric light transmission in photonic crystals

In this work, we report a novel design of a photonic crystal utilizing elliptic rods. The two-dimensional (2D) photonic crystal consists of an asymmetric distribution of unit cells to ensure the one-way transmission of light. Analysis performed indicated that the orientation of the ellipse along the major and minor axis has an influence on the shift of the transmission. In particular, this results in shift of the transmission towards high frequencies and subsequent oscillation of its magnitude. The peak of the transmission band was also found to be strongly influenced by the orientation angle, θ. It has been demonstrated that the strong asymmetric propagation properties of the proposed photonic crystal structure enables the switching of incident light from one direction to another. The proposed structure may be applied as a building block to integrated photonics applications

Highly Nonlinear Bending-Insensitive Birefringent Photonic Crystal Fibres

Highly nonlinear birefringent Photonic Crystal Fibre (PCF) that exhibits low losses and small effective mode area across a wide wavelength range has been presented. The effects of angular orientation on bending losses of the proposed PCFs have been thoroughly investigated by employing a full vectorial finite element method(FEM). It has been demonstrated that it is possible to design a bending-insensitive nonlinear PCF with a birefringence in the order of 10-2 and a nonlinear coefficient of 49 W-1km-1 at the wavelength of 1.55 ?m. Also,significant improvements on key propagation characteristics of the proposed PCFs have been demonstrated by carefully altering the desired air hole diameters and the hole-to-hole spacing. It is demonstrated that two zero dispersion wavelengths can be achieved by the proposed design

Highly birefringent nonlinear PCF for optical sensing of analytes in aqueous solutions

This paper presents a design of a nonlinear Photonic Crystal Fiber (PCF) based sensor exhibiting simultaneously high sensitivity, high birefringence and low confinement losses for liquid analyte sensing applications. We investigate the PCF sensor performance for the following analytes; Water, Ethanol and Benzyne. The impact of various design parameters of the highly nonlinear PCF on the relative sensitivity, the confinement losses and the birefringence features of the proposed PCF structure is numerically investigated by employing the full vectorial Finite Element Method (FEM). According to our FEM numerical results, a three ring nonlinear PCF based sensor is designed that simultaneously offers high birefringence of order 10?3 and high relative sensitivity at wide wavelength range