POLARIMETRIC OPTICAL-FIBER SENSOR FOR BIOCHEMICAL MEASUREMENTS

The use of an optical-fibre polarimeter as a chemical sensor is demonstrated. The compound to be detected is allowed to adsorb onto a decladded 5 cm length of the fibre, The fibre is polarization maintaining with an elliptical fibre core and a D-shaped geometry. The overall retardation stability of this fibre polarimeter is almost-equal-to 0.5 x 2pi rad m-1 K-1. With this sensor adsorption processes of proteins can be followed on-line. The resulting relative phase retardations caused by the growth of a monolayer of antibodies (alphahCG, alphahSA) are congruent-to 0.25 x 2pi. For the much smaller protein hSA, this value is congruent-to 0.1 x 2pi.