A new dual band erbium doped fiber amplifier configuration that provides 120 nm of optical bandwidth is simulated. This configuration employs a split band architecture in which optical signals are splitted using a 1550/1610 nm port filter into two independent sub bands which then pass in parallel through separate branches of the optical amplifier. Each branch may be optimized for the sub band that traverses it. The independent sub bands are combined and flattened before output, resulting in a 120 nm bandwidth gain flattened optical amplifier. A new dual band erbium doped fiber amplifier configuration that provides 120 nm of optical bandwidth is simulated. This configuration employs a split band architecture in which optical signals are splitted using a 1550/1610 nm port filter into two independent sub bands which then pass in parallel through separate separate of the optical amplifier. Each branch may be optimized for the sub band that traverses it. The independent sub bands are combined and flattened before output, resulting in a 120 nm bandwidth gain flattened optical amplifier.