Temperature resilient measurement of refractive index for liquids

The measurement of refractive index of liquids is of great importance as it is its prime optical property. There are several methods of refractive index measurement for liquids. But the accuracy of measurement is influenced by temperature fluctuations. In this paper, a method is proposed for the implementation of an accurate, portable and temperature resilient, fiber based refractometer for liquids. The analog front end of the refracto meter alone is a cost effective adulteration detector. It can be calibrated to measure the amount of adulteration or absolute refractive index of liquids. The temperature resilience in measurement is achieved using an instrumentation amplifier with high Common Mode Rejection Ratio (CMRR). This refractometer is implemented both using glass and plastic fibers.