Ultra-broadband high performance distributed Raman amplifier employing pump modulation

A novel 110 nm, ultra-broadband distributed Raman amplifier has been constructed where pumps may be modulated to reduce non-linear interactions between pump wavelengths. This gave about I dB improvement in effective noise figure for shorter signal wavelengths channels and eliminated noise from an in-band four-wave mixing product produced by beating of pump wavelengths in the low dispersion transmission fibre.