This paper reports a preliminary experimental investigation and
characterization of an optical fiber-based submersion sensor system for applications in
water flooding and leakage. The sensor system comprises a multi-mode fiber spliced
with fiber Bragg grating and an intensity-based interrogator. Submersion tests were
conducted in water-air and Glycerin-air environments. By the refractive index of the
fiber-probe surrounding materials, the reflectance and the detecting power level is
determined. When the probe is dipped into the water, the optical output power
dramatically decreases from -7.5dBm to -17.5dBm. But, the center of Bragg wavelength
is not affected in spite of external material changes. Temporal response characteristics
of the sensor system is investigated to verify the real-time reaction. When the probe is
immersed into the liquid, there is no transition time.