Multiwavelength fiber-amplifier cascades with equalization employing Mach-Zehnder optical filter

Abstract
This paper introduces a simple optimization method for determining the transmittance characteristics of an MZ filter gain equalizer required for optical networks using 980-nm or 1480-nm pumped EDFA cascades. This approach is shown capable of supporting 10 WDM signals spaced 2 nm apart over a 20-nm optical bandwidth (1540-1560 nm) up to a cascade of 10 amplifiers, allowing a total system gain of more than 150 dB with inter-channel power differences of less than 5 dB.