Observation of quasi-phase matched four-wave mixing assisted by periodic power variation in a long-distance optical amplifier chain

Abstract

We observe the quasi-phase matched four-wave mixing in a long-distance optical amplifier chain. The spectrum of amplified spontaneous emission measured by using a recirculating fiber loop shows the enhancement of noise at well-defined frequencies where the quasi-phase matching condition is satisfied owing to the periodic power variation along the fiber link.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>