Influence of temperature on stimulated Brillouin scattering slow light in few-mode fibers

This study systematically investigates temperature-dependent slow light characteristics in few-mode fibers based on stimulated Brillouin scattering. By analyzing the three-wave coupled equations under small-signal conditions and employing a full-vectorial finite-element method, we quantify the slow light dynamics of the LP 01 and LP 11 modes across a temperature range of -20°C to 80°C. Simulation results show that with rising temperature increases the effective refractive index, Brillouin frequency shift, time delay, and pulse broadening factor of each mode. Conversely, both the effective field area and Brillouin threshold decrease. Notably, the slow light time delay of the LP 11 mode demonstrates significantly higher sensitivity to temperature variations compared to the LP 01 mode. Optimized results reveal that at a wavelength of 1550 nm, an effective length of 2 km, and a pump power of 0.5 W, the time delay for the LP 01 mode increases from 395.9 ns to 414.2 ns, whereas that for the LP 11 mode shows a more substantial increase from 219.7 ns to 261.0 ns. Correspondingly, the pulse broadening factor varies from 1.224 to 1.234 for LP 01 and from 1.130 to 1.154 for LP 11 .