Discrete optical fiber microsensor of immicible liquid interfaces

We demonstrate and present a novel semidrop optical fiber refractometric microsensor, which by contact is capable to distinguishing immiscible liquid interfaces. Microsensor consists of a couple of 8.3/125 monomodal fibers, parallel placed, and with one pair of their ends are joined by electrical arch fusion. In this junction we shaped a glass semidrop, as a half ldquodonutrdquo. 1.55 mum laser beam was injected by one of fiber ends, propagating and reflecting across the semidrop/surrounding media interface, up to reaching another ends of the fiber. Output power value depends on refractive index of surrounding media, in according to Fresnel theory.