Chalcogenide–Tellurite Composite Photonic Crystal Fiber: Extreme Non-Linearity Meets Large Birefringence

Abstract

In this paper, we propose a novel design of a photonic crystal fiber (PCF) with tellurite-cladding, three rings of air-holes and elliptical concentration of As2S3 in the fiber core. The combined effect of tight mode confinement (an effective mode area of nearly 0.6 µm2), large non-linear refractive index of As2S3 and significant variation between the effective modal index values of the two orthogonal states of the fundamental guided mode leads to extreme non-linear coefficient and birefringence values, all achieved at the zero dispersion wavelength (ZDW) of 1550 nm. The corresponding birefringence and non-linear coefficient (7 × 10−3 and 28 W−1 m−1, respectively) are more than three orders of magnitude larger than that of the regular silica-based highly non-linear PCFs. In addition, we numerically demonstrate that by modifying the core and air-hole dimensions one can easily control the dispersion curve and tune the ZDW of the proposed fiber to any excitation wavelength ranging from near-infrared to short-wave-infrared, including optical telecommunication windows close to 1550 nm. The superior characteristics of the proposed elliptical-core composite PCF including extreme non-linearity, nearly-zero confinement loss (2.47 × 10−12 dB/cm), the ability to maintain polarization of light, and tunable ZDW can open the door to new possibilities in non-linear optics, optical telecommunications, optical signal processing, and sensing devices.

Liquid-Filled Highly Asymmetric Photonic Crystal Fiber Sagnac Interferometer Temperature Sensor

“…The cross section of the proposed PCF is shown on Figure 1a. It should be noted that only two rings of airholes will be an advantage during the fabrication process of the PCF, as having fewer rings with low filling ratios (d/Λ and D/Λ) is technologically easier and can significantly reduce fabrication-induced imperfections [5].…”

“…A large TOC can be used to realize various effective mode indices of the fundamental guided mode in the fiber infiltrated with liquids at different temperatures [4]. By introducing an asymmetry in the fiber structure, the mode indices will also be sensitive to the polarization of the light, which can enable us to design highly birefringent PCFs [5]. By simultaneously infiltrating the PCF and introducing asymmetry in the design of the fiber, one can design an optical fiber that is sensitive to both the temperature and the polarization of the light.…”