Measurement of liquid droplet parameters using optical fiber

The measurement of liquid droplet parameters such as size, number, concentration, viscosity, and refractive index is reported. The droplets are sprayed either from a pressure nozzle or a gas atomizing nozzle. The parameters are measured by detecting the clad mode power in the leaky ray zone of a three-region fiber by a new clad-probing technique, using normal core-clad fiber. The refractive index of the liquid is close to that of cladding. Taking the loss characteristics into account, the variation of output power with the deposition of droplets on the fiber is analyzed and compared with experimental results. The measurement sensitivity for different probing conditions is shown experimentally and verified by theoretical analysis. The change in bound power with the number of liquid droplets depositing on unclad fiber is also shown.