Expanding WDM signal transport distance between photonic transport system nodes by using SOAs

This paper describes the effectiveness of compact semiconductor optical amplifiers (SOAs) in the photonic transport system (PTS). Such amplifiers are small enough to permit high-density packaging. SOAs, having unsaturated signal gain of 10 dB and saturation output power of 10 dBm, can improve the Q-value by 3 over the SOA input power range of 10 dB. Within this range, the signal transport distance can be expanded from 360 km to 600 km by placing SOAs on individual optical channels in a PTS even though the amplified spontaneous emission (ASE) generated by individual SOAs is combined with the optical signals and delivered to the same output fiber. This result indicates that it is useful to employ compact SOAs in the PTS for enlarging the distances between nodes.