Numerical Modeling of a Rectangular Hollow-Core Waveguide for the Detection of Fuel Adulteration in Terahertz Region

Abstract

A petrol adulteration sensor based on a rectangular shaped hollow-core photonic crystal fiber is proposed and numerically analyzed in the terahertz regime. The performance of the proposed sensor was evaluated when it is employed to characterize different kerosene mixtures. In this research, the adulterated fuel sample is filled in the rectangular hollow channel and the electromagnetic signal of the terahertz band is also driven through the same channel. The received signal after the interaction of fuel with the terahertz signal will advise the refractive index of the fuel oil inside the core, which will also bear the information of how much extrinsic component is present in the fuel. The finite element method based simulation shows that the proposed sensor can reach a high relative sensitivity of 89% and presents low confinement losses at 2.8 THz. The reported sensing structure is easily realizable with the conventional manufacturing techniques. Consequently, this proposed fiber may be treated as an essential part of real-life applications of petrol adulteration measurements.

Design of a Highly Sensitive Photonic Crystal Fiber Sensor for Sulfuric Acid Detection

“…The single-mode propagation parameter, which is also termed as V parameter or V eff is also calculated. This parameter of any PCF informs whether the fiber will experience multimodal distortion or not when guiding an EM signal of a particular wavelength/frequency [ 24 , 25 ]. The fundamental equation of extracting V eff of an optical fiber is as follows [ 24 ]: where R is the core radius, and the refractive index of core and cladding are indicated by n co and n cl , respectively.…”

“…This parameter of any PCF informs whether the fiber will experience multimodal distortion or not when guiding an EM signal of a particular wavelength/frequency [ 24 , 25 ]. The fundamental equation of extracting V eff of an optical fiber is as follows [ 24 ]: where R is the core radius, and the refractive index of core and cladding are indicated by n co and n cl , respectively. The only condition to be a single-mode fiber is that the numerical value of this parameter must be less than or equal to 2.405.…”

Terahertz Sensing Based on Photonic Crystal Fibers

“…In addition to wave communication functions, PCFs can also be used for optical sensing. To apply a PCF in sensing applications, the sample under test is filled in the core and after that, the electromagnetic wave is injected through the core [26]. The light interacts with the sample, and after analyzing the received signal, the unknown sample can be identified [26].…”

“…To apply a PCF in sensing applications, the sample under test is filled in the core and after that, the electromagnetic wave is injected through the core [26]. The light interacts with the sample, and after analyzing the received signal, the unknown sample can be identified [26]. However, solid core PCF cannot be used in sensing applications as it is not possible to inject analyte inside of the solid core.…”

“…Now, the loss characteristics of different types of terahertz PCF sensors are discussed below. To reduce the confinement loss and the effective material loss, numerous types of core and cladding structured PCFs were presented [26,[32][33][34][35]. However, the light confinement inside the core is largely dependent on the geometric structure of PCF.…”