Fiber optic flaw detector system and calibration apparatus

Abstract

A system for detecting flaws in an optical fiber includes a light source which generates a beam of collimated light rays to illuminate the optical fiber substantially orthogonal to a longitudinal axis thereof. The beam is scattered by a flaw-free optical fiber into an in-plane scattered segment which is scattered in a radial plane substantially perpendicular to the longitudinal axis of the optical fiber. A flaw in the optical fiber scatters the light rays into an out-of-plane scattered segment which are scattered outside of the radial plane. A light attenuator removes the in-plane scattered segment of the beam and a light detector detects the remaining out-of-plane scattered segment. An electrical circuit monitors the light detected by the light detector and determines whether a flaw is present in the optical fiber. To compensate for fluctuations in the power output of the light source, a linear light detector replaces the light attenuator to detect the in-plane scattered segment of the beam. The total detected light is then used to compensate for fluctuations in the power output of the light source. An apparatus for calibrating the system is also provided which includes an optical test fiber having a known flaw mounted in a cartridge. The cartridge is removeably mounted in a moveable carriage such that the known flaw can be passed into and out of the beam to calibrate the system.