Laser diode coherence length variation with drive current: a tool for dispersion measurements

摘要

A visible light (670 nm) laser diode was used as a variable coherence length source to measure dispersion characteristics in single-mode fibers. The diode's spectral width, measured against increasing drive current, was found to change from about 16 nanometers to less than 0.2 nanometer. The corresponding change in coherence length is from about 25 $mu@m to 2.5 mm.