Spectral analysis of waveguide tapered microfiber with an ultrathin metal coating

This work demonstrates the feasibility of a novel dispersion engineered ultrathin metal film coated on a tapered fiber with a thickness of around 10nm. To our knowledge, the dispersion characteristics of the proposed device induced by such an extremely thin metal film are described here for the first time. Experimental and simulation results indicate that the metal thin film has unique dispersion properties and intrinsic optical characteristics of strong absorption and high reflection in the near infrared light of a wavelength range of 1.25 approximately 1.65 microm, making the material and waveguide dispersions of tapered-fibers more tailorable. In addition to the ability to flatten the slope of the fundamental-mode cutoff of the transmission spectrum, the dispersion profile is heavily influenced when the ultrathin metal film is coated around the proposed tapered fibers. The optical characteristics of the spectral response caused by the ultrathin film on tapered microfibers are also investigated and analyzed.