We present the first experimental demonstration of an S-shaped two-cou
pler single-mode optical fiber ring resonator. The full resonances of
the transmitted and reflected output intensities under different reson
ance conditions, Butterworth-like response, and the splitting of the r
esonance peak of the reflected output intensity are observed. A compar
ison between the observed results and the theoretical results shows th
at they are in reasonable agreement.