Highly Birefringence Photonic Crystal Fiber: A New Frontier to Optical Pressure Sensor

Photonic Crystal Fiber (PCF) is one of the latest inventions in the field of fiber optics where research concentrates on one of the emerging field in PCF family which is sensor. Most of the PCF are fabricated with lots of airholes arranged in a structured way with four or five or six layers of airholes surrounded the central region of the fiber. The primary focus of the study is to design a relatively simple structure PCF sensor which requires less design complexity and easy for fabrication. The proposed design in the study has three different pairs of airholes with different diameter which has similarity with conventional PANDA type fiber. Birefringence used as the prime factor in this research to detect pressure. For achieving high birefringence, the geometry of symmetry breaking of the fiber structure method is applied here. Breaking more symmetry brings more birefringence. The sensing analysis using birefringence is covered in the study and it provides a meaningful response wavelength shifting from operating wavelength. From the design proposed in the study, birefringence achieved is as high as 1.4×10−2 which is highest as far as known. The maximum sensitivity achieved for a certain design parameter is 38.95 nm/MPa for 1mm long PCF.