Efficient multiwavelength generation of Brillouin/erbium fiber laser at 1600‐nm region

An efficient Brillouin/erbium fiber laser, which operates in the 1600‐nm (L‐band) region, is demonstrated for potential applications in future dense‐wavelength division multiplexing communication systems. The laser configuration consists of an L‐band EDFA (to enable L‐band amplification) where two 3‐dB couplers take a portion of the generated BEFL signal and re‐inject it into the single‐mode fiber in order to seed a cascaded BEFL line in the same direction as the first BEFL line. An efficient BEFL can be obtained by recycling backward a 1550‐nm‐band amplified spontaneous emission as a secondary pump source for the unpumped EDF in the L‐band EDFA section. As a result, the lasing threshold is reduced and slope efficiency is improved. A stable and strong laser comb of up to five lines with 10‐GHz spacing has been obtained with a Brillouin pump of 4.8 mW and a 980‐nm pump of 92 mW.