Abstract
This paper presents the performance analysis of two new sensing configurations of refractive index based on surface plasmon resonance (SPR) in microstructured D-type optical fiber with a thin gold layer using simulations obtained with COMSOL Multiphysics. The configurations are analyzed in terms of the intensity of the electric field. The results are compared with a conventional SPR D-type optical fiber sensor for refractive index measurement.

Abstract
The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of certain gases allows for the possibility of planning corrective actions to minimize their negative impact on the surroundings. Optical fiber technology is well suited to this purpose and here we describe the main attributes and results obtained from a fiber optic sensing system projected to gather data on distributed temperature and gas emissions in these harsh environments.

Abstract

Abstract
This paper presents the performance analysis of a sensing configuration of refractive index, based on surface plasmon resonance (SPR) in microstructured D-type optical fiber with a thin gold layer, using the finite-element method. The configuration is analyzed in terms of the loss and distribution Poynting vector. The results are compared with a conventional SPR D-type optical fiber sensor for refractive index measurement. The simulation results show an improvement of the sensitivity and resolution (10 x 10(3) nm/RIU and 9.8 x 10(-6) RIU, respectively, when considering an accurately spectral variation detection of 0.1 nm).

Abstract
This paper presents an optical fiber sensor, that uses surface plasmon resonance on metallic wires to directly and simultaneously measure both the refractive index and the temperature. The sensor is constituted by gold wires on a D-type fiber engineered, using numerical simulations based on the finite-element method to support plasmon modes with strong dependencies to either one of the measured parameters. In particular, the influence of the temperature on the structure of the plasmon modes results from contributions from the thermooptic effect in the fiber core and sensing layer, and phononelectron scattering along with electron-electron scattering in the metal wire. The performance of the sensor is evaluated in terms of its sensitivity and resolution.

Abstract
This article presents a review of the numerical techniques employed in simulating plasmonic optical sensors based on metal-dielectric nanostructures, including examples, ranging from conventional D-type fiber sensors, to those based on photonic crystal D-type fibers and incorporating metamaterials, nanowires, among other new materials and components, results and applications. We start from the fundamental physical processes, such as optical and plasmonic mode coupling, and discuss the implementation of the numerical model, optical response customization and their impact in sensor performance. Finally, we examine future perspectives.