Effects of phase modulation used for SBS suppression on phase noise in an optical fibre

Abstract

Phase modulation is used for stimulated Brillouin scattering (SBS) suppression in fibre systems. A novel means is proposed to choose the modulation index and frequency of phase modulation. This means is based on the measurement of phase noise in fibre systems. The phase noise decreases due to SBS suppression first and then increases due to laser linewidth broadening with the modulation index. The phase noise decreases first and then exhibits fluctuations with the modulation frequency. The optimum modulation index and frequency increase with the input power. The visibility of the coherent optical field can be treated as a sign of the laser linewidth. The results provide a guide to the practical design of long-haul interferometric fibre sensing systems.

Recent Progress in Fiber-Optic Hydrophones

“…In the interferometric FOH system, the phase modulation method shows a great potential in SBS suppression for its convenience and high efficiency [120]. The effect of phase modulation on phase noise was studied in the interferometric fiber sensing systems, and the excess phase noise induced by phase modulation was observed in the experiment, which set a limit to the application of phase modulation [117]. A novel optical modulation method was proposed to suppress the phase modulation induced excess phase noise.…”

“…A novel optical modulation method was proposed to suppress the phase modulation induced excess phase noise. However, theoretical analysis has not been derived to explain the excess phase noise in [117]. A detailed analysis was derived about the excess phase noise in the interferometric fiber sensing system, and a matching condition was proposed to suppress the excess phase noise [121], as shown in Figs.…”

Performance improvement of power-over-fiber system using noise-modulated laser diode

“…Thus, another practical method, employing broadband laser sources, was proposed. In 2011, Chen et al suppressed the SBS effect through phase modulation with a phase-modulated broadband laser source [12]. In 2014, Hu et al used a dual-phasemodulated method to broaden the linewidth of the laser source, so as to suppress the SBS effect and the phase noise in the remote interferometric fiber sensing system [13].…”

Theoretical and experimental study of suppressing stimulated Brillouin scattering and phase noise in interferometric fiber sensing systems with phase modulation

“…In interferometric fiber sensing systems the phase modulation method shows great potential in practical SBS suppression for its convenience and high efficiency [16]. Chen and Meng studied the effect of phase modulation on phase noise in interferometric fiber sensing systems, and the excess phase noise induced by phase modulation was observed in the experiment, which sets a limit to the application of phase modulation to suppress SBS in interferometric fiber sensing systems [17]. However, the theoretical analysis has not been derived to explain the effect in that work.…”