Refractive Index Measurement by Using an Optoelectronic Oscillator

The purpose of this letter is to present a preliminary experiment, showing that an optoelectronic oscillator can be used for measuring refractive index by detecting the change of the oscillation frequency. The uncertainty of the measurement is of about 10^-2. However, this value can decrease to 10^-3 or less if the mechanic vibrations, the temperature control of liquid, and the long-term stability of the oscillator are improved. Measurements have been performed for acetonitrile, acetone, dioxane, and chloroform at the wavelength of 1535 nm and at 25°C approximately.