Fluctuations in Brillouin shifts and acoustic-phonon speeds in multiwavelength Brillouin Raman erbium-doped fiber laser generation.
Brillouin-shift (B-S) fluctuations in multiwavelength Brillouin Raman erbium-doped fiber laser generation are investigated to obtain a probability distribution of acoustic-phonon speeds in the crystal lattice of a dispersion-compensating fiber (DCF) in a linear cavity. Even though the available B-S line spacing can be at 0.076 and 0.08 nm when Raman pump (RP) power is zero or 76 mW, the other B-S possibilities are obvious, especially at RP power 257 mW. A crystal effective mass participating in the crystal vibration is obtained 8937, 8943, 8954, and 12,106 times the electron rest mass by fitting a general form of a Boltzmann density function and the resulting most probable speed of 5445 m/s at a fixed Brillouin pump power of 6.5 dBm and RP powers of 0, 76, 163, and 257 mW, respectively. Finally, an uncertainty in the crystal dimension is also estimated by Heisenberg's uncertainty principle.