Time-domain filtering to reduce signal-spontaneous beat noise for a pulse-type multiwavelength light source

A novel time-domain noise filtering scheme improves the signal-to-noise ratio (SNR) after an optical amplifier in pulse-type multiwavelength light sources. A reduction of signal-spontaneous beat noise is possible by using a synchronous time gate, which is not possible by conventional frequency domain filtering. Investigation of the amplifier noise reveals that this scheme significantly reduces minimum power required for a low SNR in amplifier output.