The Surface Plasmon Resonance Polarizing Management in Helical Microstructure Fiber

Surface plasmon resonance (SPR) is a useful phenomenon in many application fields, such as communication and sensing field. In this paper, for the first time, the SPR phenomenon in helical microstructure fiber coated with Ag (HMFA) is analyzed. Compared with untwisted microstructure fiber, multi-wavelength polarizing filtering performance can be achieved. Tunable filtering wavelength of two orthogonal modes can be achieved by adjusting the twisting rate of HMFA. Besides, at a special twisting rate, the SPR mode with the same order can couple with two orthogonal fundamental modes in HMFA, and the jumping point of the refractive index anti-cross of the SPR mode equals to that of the sum of the orthogonal fundamental modes. In addition, the loss anti-crossing point generates at 1.56 μm. These performances indicate that the helical microstructure fiber can effectively improve the characteristics of the SPR in the aspects of multi-wavelength filtering and mode polarization control and show great potentials in the field of communication and the fields related.