Márk Csörnyei, Tibor Berceli
Fiber-delay lines for intensity noise suppression in optical links
In case of short haul optical links, optical local area networks or optical-mobile networks the most important noise source is the relative intensity noise (RIN) of the laser diodes. This paper will report on a new all-optical technique of intensity noise suppression for semiconductor lasers. The new scheme we have used is based on an Unbalanced Mach-Zehnder Interferometer (UMZI), which is able to cancel the intensity noise enhancement in the microwave domain and thus improve the link signal-to-noise ratio. Extending the UMZI to fiber-delay line filter the noise reduction capability can be further increased. Additionally the condition of stable, incoherent operation is detailed.