Low effective Poisson's ratio and confinement loss photonic crystal fibers using negative Poisson's ratio air holes structure.

The additional confinement loss caused by external loads has so far restricted the wide applications of photonic crystal fibers (PCFs). With the rapid development of metamaterials, there is an increasing interest in negative Poisson's ratio (NPR) composite structure due to its outstanding advances in energy and vibration absorption capabilities. In this paper, a novel design concept of PCF with NPR air holes composite structure is proposed. The feasibility of this novel PCF structure is verified by photo-elastic theory and finite element method under compression and impact loads to test the mechanical and optical properties of the fiber. The results show that the PCF with NPR air holes structure effectively suppresses the fiber deformation caused by external loads, thereby reducing the additional fiber confinement loss. Meanwhile, this novel concept displays structural diversity. The macro effective Poisson's ratio of the fiber can still be reduced by maintaining the generalized NPR holes cladding structure, which provides support for the flexible core layer design of PCF under different application requirements. In sum, this design concept subverts the traditional design method of photonic crystal fibers with complex structures and looks promising for future applications in optical fiber sensors. [ABSTRACT FROM AUTHOR]