High Conversion Efficiency Short or Ultra-Short Gain-Lengths Excellent L-Band Capabilities with MetroGain™ 12 Broad Spectrum Ideal for ASE Sources. Not all EDFAs are complex, multi-stage, high channel-count DWDM units that demand the flat, broad spectrum and extensive 'pre-qualification' of Fibercore's IsoGain™ products. Many designs just need a simple and low-cost fiber that provides consistent and efficient gain in single-stage, few channel-count designs - MetroGain™ offers just this. Based on Fibercore's original, tried-and-tested DF1500F fiber design, MetroGain™ is available in all three variants, all optimized for 980 nm pumping and each offering specific benefits in different 'Metro-style' EDFA configurations.