Threshold characterization of double brillouin frequency shift of L-band Brillouin-erbium fiber laser

In this paper, a multiwavelength Brillouin-erbium fiber laser with double Brillouin frequency shift in the long wavelength band is experimentally demonstrated. Two three-port circulators are incorporated in the laser structure to circulate the odd-order Brillouin Stokes signal in the single-mode fiber. The laser utilizes pre-amplification technique of Brillouin pump power and first Stokes signal within the laser cavity. Owing to this pre-amplification technique, the laser exhibited a low threshold operation of S mW pump power to create the first 22 GHz Brillouin Stokes signal. Eight Brillouin Stokes signals with 0.174 nm (~22 GHz) line spacing were generated at SO mW of 1480 nm pump power and 1598.6 nm Brillouin pump wavelength with power of 10 dBm.