Abstract
Turbidity measurement using a U-shaped fiber-optic refractometer and an optical time domain reflectometer (OTDR) has been investigated. Refractive index sensors placed serially along a single fiber transmission line from the OTDR detect light backscattered by particles suspended in the medium surrounding the sensor. When the medium is turbid, a spike signal is generated in the OTDR waveform due to the backscattered light. The amplitude of this spike was measured for various sample turbidities and was found to be proportional to the degree of turbidity of the medium. These results indicate that this particular method can be used to measure the turbidity of solutions. This method can also be employed to obtain information on the refractive index of the medium independent of its turbidity.
