A review of recent research progress on optimization in D-shaped photonic crystal fiber

Surface Plasmon Resonance (SPR) sensors play an important role in the increasing trend of new detecting technology in recent years. D-shaped photonic crystal fiber (PCF) has been a good candidate for external environmental monitoring because of easy manufacturing and excellent performance. In the paper, the optimization methods of the D-shaped PCF are divided into three types (optimization of fiber core, cladding, and metallic layer) according to the sensing principle. The sensing and optimizing principle are introduced and discussed respectively. Research developments of optimization methods for D-shaped PCF sensors were reviewed in the recent years. The advantages and disadvantages of are compared and discussed, and the future prospects are pointed out.