Advanced phase modulation techniques for stimulated brillouin scattering suppression in fiber optic parametric amplifiers
Fiber optical parametric amplifiers (FOPAs) are an innovative type of amplifier with many promising applications both in and outside the telecommunications band. The strictest limitation that FOPAs currently face is that of Stimulated Brillouin Scattering (SBS) which causes significant backreflection of the incident light to a fiber under conditions of sufficient power, called the SBS threshold. This severely limits the available pump power in fiber and thus the achievable FOPA gain. In this study we propose and demonstrate the effectiveness of using a chirped sinusoidal waveform to phase modulate the pumps and mitigate SBS. The effectiveness of the system for SBS suppression was confirmed by phase dithering a pump with the proposed chirp and measuring the increase in the SBS threshold. The system effect on the idler signal integrity was also measured following amplification from a two pump FOPA. Using the proposed systems, we successfully achieved as much as 38dB of conversion efficiency gain with an OSNR penalty of 0.8dB at a BER of 10e-9 from the back to back case after accruing 160ps/nm of dispersion from propagation.