Rayleigh backscattering lasing control based on Raman amplification

In this work, a method to induce controlled Raman gain profile in the far L- and U-bands using only an E-band Raman pump with co-located passive elements in C-band is presented and experimentally assessed. This process gains control of C-band spontaneous Rayleigh backscattering (RB) by means of one set of fibre Bragg gratings (FBG), providing resonant cavities that generate lasing effect. This technique differs from the traditional ones previously reported which use pairs of reflectors to achieve the required resonant cavities.