A 1.65-μm fibre Raman amplifier

A fibre Raman amplifier operating at a wavelength of 1.65-μm is fabricated. A two-stage phosphosilicate fibre Raman converter of 1.53-μm radiation for pumping the Raman amplifier is designed and tested. The amplifier pumped by a phosphosilicate fibre Raman converter can operate with a maximum of the gain band ranging from 1.6 to 1.7 μm. A fibre with a core of a high (25%) molecular content of GeO₂ serves as an active medium for the Raman amplifier. The gain obtained for different powers of the input signal is 22 – 25 dB. Our calculations show that the use of a standard telecommunication fibre (with a lower content of GeO₂) allows one to increase the gain in this scheme by reducing fibre splicing losses.