Ball Lens Based Common Path Fiber Optic Interferometer Sensor

Abstract

A common path interferometer has been made with a ball lens packaged in a metal cylinder, dielectric mirror, and lucent type connector (LC) fiber patch cord. By simply placing metal cylinder packaged mirror and a ball lens directly in front of a fiber patch cord, a compact and potentially disposable sensing probe for optical bio-sensor could be implemented. To achieve a sufficiently long working distance, the proper ball lens diameter and the distance between the ball lens and the fiber patch cord were investigated. A working distance of up to 1.6 mm was achieved. With common path sensing probe, measurements of the index matching oil and glucose solutions were implemented and used to demonstrate the fesibility as the liquid sensing probe.