INTEGRATED OPTICAL YOUNG INTERFEROMETER

The integrated optical configuration of a Young interferometer is prop osed for refractometry and chemical sensing. We coupled light into an integrated optical Y branch by fixing a laser diode directly at the in put of the optical device. We solved the problem of ambiguity in the i nterference order by operating the laser diode at currents below thres hold, resulting in visibility modulation of the interference fringes c aused by the low coherence length of the emitted light. A very compact device results that measures the refractive index of liquids or gases . An electronic scanning technique by means of a CCD array provides a fast readout without the need for moving parts.