Modeling of surface plasmon resonance in metalized optical waveguides with low V number by eigenmode expansion method.

Abstract

The paper reports on the numerical study of surface plasmon resonance excitation in a bent metal-coated single mode optical fiber with a low V-number. It was shown that by choosing a proper combination of normalized frequency, bend radius, and metal film thickness one can achieve strong coupling between the fundamental mode guided by the fiber core, and symmetric surface plasmon mode supported by the metal layer applied to the fiber cladding. The effect is demonstrated to allow precision refractive index measurement, with spectral sensitivity and resolution estimated at 70 μm/refractive index unit and 3⋅10(-7), respectively.