Semiconductor optical amplifier cavity length impact over data erasing/rewriting

The erasing of optical carrier intensity modulation and posterior data rewriting are analyzed for two semiconductor optical amplifiers with different active lengths: 2 mm and 8 mm long.Input signal extinction ratios (ER in ) varying from 3.5 dB up to 10 dB are tested for the downstream channel at different bit rates (from 7 Gb/s up to 56 Gb/s), followed by remodulation of the upstream channel at 7 Gb/s. The ultra‐long 8 mm device shows superior performance, working error‐free for bit rates up to 30 Gb/s, with negligible power penalties for moderate ER in . However, for high bit rates (>40 Gb/s) and high input extinction ratios (ER in = 10 dB), the 8 mm device shows error‐floor at BER = 10 −6 . In comparison, even for moderate ER in at 40 Gb/s, the 2 mm device already presents error‐floors at BER = 10 −3 . © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:998–1001, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27496