Abstract
A highly non-linear solid core photonic crystal fiber (SCPCF) is designed in the present work. Three hexagonal air hole rings in cladding region and four very small air holes are present in a symmetric manner in the core region. By using full vectorial finite element method (FVFEM) with the perfectly matched layer, we study numerically the effective area of modal pattern as well as the nonlinear coefficient of this proposed SCPCF. For this proposed fiber a small modal effective area 5.58 µm2 and a high nonlinear coefficient 21.38 W-1 km-1 are obtained at communication wavelength 1.55 µm for the small air holes in the core with diameter 0.15 µm. This type of SCPCF is useful for different nonlinear applications. © Springer Nature Singapore Pte Ltd. 2017.

Abstract
In this article, a D-shaped photonic crystal fiber based surface plasmon resonance sensor is proposed for refractive index sensing. Surface plasmon resonance effect between surface plasmon polariton modes and fiber core modes of the designed D-shaped photonic crystal fiber is used to measure the refractive index of the analyte. By using finite element method, the sensing properties of the proposed sensor are investigated, and a very high average sensitivity of 7700 nm/RIU with the resolution of 1.30 × 10-5 RIU is obtained for the analyte of different refractive indices varies from 1.43 to 1.46. In the proposed sensor, the analyte and coating of gold are placed on the plane surface of the photonic crystal fiber, hence there is no necessity of the filling of voids, thus it is gentle to apply and easy to use. © 2016, Springer Science+Business Media New York.

Abstract
In this article we propose a decagonal photonic crystal fiber (D-PCF) consisting unique cladding without structural complexity having very high birefringent of the order of 10-2, less effective area of few square microns as well as low confinement loss of the order of 10-2 dB/m at 1.55 µm wavelength. The zero dispersion wavelength is also achieved in the near infrared region. This study clearly attributes to the fact that the zero dispersion wavelength at the near infrared region, very high birefringence and low confinement loss can be adjusted according to the necessity by changing the structural parameters with considerable fabrication tolerance. This fiber can prove itself useful in laser technology, telecommunication, non-linear application, sensor technology and also in making polarization maintaining devices. © 2017 Elsevier B.V.

Abstract
The numerical study of newly designed solid core photonic crystal fiber (SCPCF) having three hexagonal air hole rings in cladding region and one small nano hole at the center are presented. By using full vectorial finite element method (FV-FEM), we analyses the optical properties like effective area, nonlinearity and confinement loss of the proposed PCF. Results show that the change in core diameter controls the effective area, nonlinearity and confinement loss. A low effective area (3.34 µm2), high nonlinearity (36.34 W-1km-1) and low confinement loss (0.00106 dB/km) are achieved at the communication wavelength 1.55 µm for the SCPCF having core air hole diameter 0.10 µm, cladding air holes diameter 1.00 µm and pitch 2.50 µm. This type of PCF is very useful in non-linear applications such as supercontinuum generation, four wave mixing, second harmonic generation etc. © 2015 AIP Publishing LLC.

Abstract
In presented work, the tunable characteristics of magnetic fluid refractive index under the influence of magnetic field with single mode fiber (SMF) with tapered structure are investigated. The sensing fiber probe consists of special down taper joints formed by fusion splicer. Experimental result indicates that the proposed device has excellent magnetic fluid refractive index tunability. The sensitive performances of the sensors are controlled by designing the parameters of the tapered structure and the concentration of Magnetic fluid. Experimental result used to carry out to achieve the magnetic field (intensity and direction) dependent refractive index of the magnetic fluid. © OSA 2016.

Abstract
An intrinsic intensity modulated no core fiber sensor (NCFS) is presented in this paper for rapid detection of adulteration in petrol with kerosene. The sensing principle is based on the phenomenon of absorption of evanescent waves. The sensing head of NCFS is fabricated by stubbing a small section of no core fiber (NCF) between two multi-mode fibers (MMF). A high sensitivity 390 nW/% and 110 nW/% are obtained by the proposed sensor for low and high level of adulteration. The intensity variation and confinement loss with different concentrations of the kerosene in petrol are then verified theoretically by using finite element method. It is found that the theoretical results agree very well with experimental results. The proposed sensor exhibits fast response time and good repeatability in addition to its high sensitivity. The sensor can be useful in industries and automotive companies due to its small size, easy to fabricate, safe with inflammable fuels and required small amount for detection. © 2017 Elsevier GmbH