Reduction of mode partition noise by using semiconductor optical amplifiers

Reduction of mode partition noise induced by spectral filtering of Fabry-Perot lasers is demonstrated by using a semiconductor optical amplifier (SOA). Because the SOA acts as a high-pass filter, the mode partition noise appearing at low frequencies can be suppressed. A 16-dB recovery of the signal-to-noise ratio and a 6.2-dB recovery of the Q factor are obtained.