Hollow Core Antiresonant Fiber Based Polarizer and Refractive Index Sensor
Kumary Sumi Rani Shaha, Abdul Khaleque
Abstract
We propose a new single polarization guided antiresonant fiber design made of nested and double ring cladding tubes with a high index material layer coating that can function as a polarizer and sensor. The diverse cladding tube combinations along with a high index content layer enhance the fiber's ability to block one polarized ray through coupling effect and also provide minimal loss for other polarized ray by inhibited coupling mechanism. Besides, the development of two modes for the proposed structure are investigated where the cladding mode crosses with the core mode at desired wavelength, results light blocking for one polarization. Hence, the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</i> -polarized ray's confinement loss founds 576 dB/m, where 0.0018 dB/m loss is experienced in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</i> -polarization, allowing the maximal polarization extinction ratio of 320000 at 1.55 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m along with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$>$</tex-math></inline-formula> 100 value for 40 nm bandwidth with a high birefringence of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.55\times 10^{-4}$</tex-math></inline-formula> . Moreover, the polarizing operation is successfully performed, where a crosstalk of larger than 20 dB for a compact length of 20 cm, is found from 1.538 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m to 1.568 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula> m of wavelength. Furthermore, the sensing performance is achieved as an example, such as the maximal wavelength sensitivity is found about 1293 nm/RIU for the fiber. Therefore, the simultaneous applications of the designed fiber make it an interesting device for optical systems.