A surface sensing system including at least two sensors located on the end
of the same optical fiber. The sensors are configured such that they
exhibit resonant frequencies or Q-factors that are distinguishable from
each other, where the Q-factor is defined as the resonant frequency
divided by the resonance spectrum at full-width half maximum (FWHM).
Because the sensors have distinguishable resonant frequencies or
Q-factors and are located on the end of the same optical fiber, they can
be monitored in parallel with little or no optical interference.