Coherence length of a Yb fibre superfluorescent source with an adjustable linewidth

Abstract

Characterization of coherence for superfluorescent light emitted from a diode-pumped Yb-doped fiber source is reported. We have constructed a superfluorescent light source with an adjustable linewidth employing a Yb-doped fiber master oscillator and two power-amplifier stages and measured its coherence length as a function of a linewidth in a Michelson interferometer. The experimental values are in good agreement with the numerically calculated values using the given spectral intensity distribution. The results indicate that the mechanism for linewidth broadening of the fiber superfluorescent output can be attributed to inhomogeneous line broadening of an atomic transition. The prospect of the fiber superfluorescent source with a tailored coherence length will be discussed.