Gain performance of cascaded and hybrid semiconductor optical amplifier in CWDM system

Abstract

The incorporation of cascaded and hybrid-type optical amplifiers into the optical fiber link is advantageous for the purpose of achieving wide gain bandwidth of multi-wavelength coarse wavelength division multiplexing (CWDM) systems. Different amplifiers whose operating gain region differ from each other are connected in cascade, thus providing better gain performance as the overall gain is combined and flattened over a larger spectrum. In this paper, the effect of the crossover of the uniform gain of the semiconductor optical amplifier (SOA) and the nonuniform gain of erbium-doped fiber amplifier (EDFA) is analyzed using an in-line cascaded SOA-SOA and an in-line hybrid SOA-EDFA configuration in the amplification of an 8-channels CWDM system obtained from the simulation using Optisystem software. It was observed that the cascaded SOA-SOA produces higher gain of 25 dB and wider gain bandwidth of 60 nm compared to the hybrid SOA-EDFA configuration with maximum gain of only 24 dB and 40 nm bandwidth. In addition, better bit-error-rate (BER) performance which is within the typical values in optical fiber communication is also achieved from the cascaded SOA topology. Wider gain bandwidth obtained with the SOA-SOA configuration would permit the transmission of video application at 1551 nm in the proposed Ethernet CWDM system transmitted at 100 Mb/s data rates.