Gain stabilization in gain clamped EDFA cascades fed by WDM burst-mode packet traffic

This paper studies via simulation the stabilizing effect of all-optical gai n-clamping (AOGC) in a chain of erbium-doped fiber amplifiers (EDFA) fed by wavelength-division multiplexing (WDM) burst-mode packet traffic. AOGC is necessary to suppress swings of output power and optical signal-to-noise ra tio (OSNR), A case study is selected, in which only the first EDFA in a cas cade of six amplifiers is clamped using a ring laser configuration. A numer ical model which solves the transcendental equation for the average inversi on at each EDFA is used for the analysis, The traffic is generated on the e ight WDM channels by ON-OFF time-slotted sources, with statistically indepe ndent ON and OFF durations, randomly generated by a truncated Pareto distri bution with infinite variance. The simulation model includes the generation of amplified spontaneous emission within each amplifier and the propagatio n of the lasing power generated in the AOGC EDFA through the cascade. It is shown that the sizable power and OSNR swings arising in an unclamped casca de of EDFA's can be effectively suppressed when a lasing signal a few decib els above the aggregate signal power develops in the AOGC EDFA and propagat es along the cascade.