Photonic Crystal Fiber Based Optical Fiber Core Design For Sensing and Transmission in Terahertz Spectrum

Abstract

Terahertz radiation occupies a middle ground between microwaves and infrared light waves known as the terahertz gap, where technology for its generation and manipulation is in its infancy. The frequency band of 0.1-10 THz, known as THz band has brought potential applications in many important fields. For wave propagation THz systems use free space as medium. But in free space waves face many difficulties which is very big issue for wave propagation. So we have to use guided transmission instead of unguided transmission. In the meantime many guided transmission line has many kinds of deprivation such as effective material loss, confinement loss, bending loss, dispersion loss, power fraction issue etc. So we had decided to make a hollow core porous core fiber which has less losses than other PCF. Mainly we have been inspired from previous papers in which these losses was too much high for THz wave guidance. Then we have designed a novel hollow core photonic crystal fiber (PCF) which consists of symmetrical hexagonal rings in its cladding distributed in three rows. The prime objective of this work is to increase the sensitivity but other significant features like effective material loss, confinement loss, effective area, numerical aperture and dispersion have been thoroughly investigated over a wide bandwidth using the finite element method-based commercially available software, COMSOL version 5.3. Numerical simulation shows that, a maximum chemical sensitivity of 99.39%, 99.76% and 99.44% can be obtained for methanol, benzene and water respectively at optimum operating conditions. The symmetry in design makes the proposed structure easily feasible to be fabricated using the existing fabrication technologies. Thus it is believed that the proposed PCF has the potential to uplift the standard of photonic crystal fiber sensors and open a new window in this field of research.