Fiber Length Measurement Technique Employing Self-Seeding Laser Oscillation of Fabry–Perot Laser Diode

Abstract

A simple fiber length measurement technique has been proposed and demonstrated that uses the self-seeding laser oscillation of a Fabry–Perot laser. We measured the length of an optical fiber from the modulation frequency changes required to induce single-mode laser oscillations through an optical closed-loop including the fiber and the laser diode. The maximum error of the proposed technique was less than 0.24% for various fiber lengths from 0.1 to 75 km.