Mid-infrared high birefringence bow-tie-type Ge₂₀Sb₁₅Se₆₅ based PCF with large nonlinearity by using hexagonal elliptical air hole

ABSTRACT

A high birefringence Ge₂₀Sb₁₅Se₆₅ based photonic crystal fiber (PCF) is proposed. It consists of a central defect core surrounded by two kinds of elliptical air holes with different size. The Finite Difference Time Domain method (FDTD) is used to simulate the guided modes of the designed PCF. The properties of this PCF are investigated including the birefringence, nonlinearity, and polarization mode dispersion in the mid-infrared range. The results show that for the optimized structure parameters, the highest birefringence of 0.1176 is obtained. The maximum nonlinearity coefficients of 38390 w⁻¹km⁻¹ and 49760 w⁻¹km⁻¹ for x- and y-polarization modes are achieved.

KEYWORDS:

• Birefringence
• mid-infrared
• nonlinearity
• photonic crystal fiber

Acknowledgements

This work is supported by the National Nature Science Fund of China [No. 61775180], the Xi’an Municipal Science and Technology Bureau Scientific Research Program (No.CXY1436), Shaanxi International Science and Technology Cooperation and Exchange Program (No.2017KW-027), Shaanxi Provincial Education Department Scientific Research Program (No.2013JK0628), and New Star Team of Xi’an University of Posts & Telecommunications (2016) respectively.