eng Ansari Education and Research Society Journal of Ultra Scientist of Physical Sciences April 2010 22 1 19 24 juc 892 article R.S. Kasana (irkasana7158@gmail.com 1 Arvind Kumar Deshmukh (deshmukh1278@gmail.com 1 Department of Physics & Electronics, Dr Hari Singh Gour Central University, Sagar, (Formerly University of Saugor) M.P. - 470003 (INDIA) <p style="text-align: justify;">A technique for the study of variation of refractive index of liquid has been reported in this paper. The proposed approach is superior to the existing ones because of its significant role in the industry, instrumentation, optical and chemical engineering etc. The fiber optic interferometric refractometer consist of fiber optic probe, a bottom sided fully silver polished plano parallel glass plate, a rectangular temperature controller cell filled with liquid, photodiode detector, and digital millimeters etc. The fiber optic probe is immersed into the measuring liquid. The light from the fiber optic transmitter is coupled into the transmitting fiber. After the multiple reflection of light from the plano parallel glass plate equally distanced narrow and dark fringes are develop in to the reflected region of light. The intensity of fringes is collected by the receiving fiber and forwarded to the detector and digital millimeter. The output intensity is measured by changing the position of fiber optic probe and the measurement carried out for the various concentration of sodium chloride and compared the result.<br /> &nbsp;</p> https://ultraphysicalsciences.org/paper/892/ fiber optic Refractometry Refractive Index