Impact of passive EDF location on the performance of L-band Brillouin-Erbium fiber laser

A simple L-band multiwavelength Brillouin-Erbium fiber laser (MBEFL) that utilizes a passive erbium doped fiber (PEDF) at two different locations within the linear cavity was successfully demonstrated. The impact of the inclusion of such PEDF sections on the number of the generated Stokes lines, laser tunability and the laser cavity threshold are experimentally investigated. The proposed laser structure in which the PEDF was inserted closer to the active EDF exhibits 21 Brillouin Stokes lines and a tuning range of 18nm at 100 mW and 4 mW of 1480 nm pump and Brillouin pump powers, respectively. In addition laser cavity threshold of 10.7mW is recorded at the same Brillouin pump power of 4mW. On the other side, the proposed laser structure in which the PEDF location is changed to be inserted at the far end of the single mode fiber shows 17 Brillouin Stokes lines, a tuning range of 24.4nm and a laser cavity threshold of 10.4mW under the same pump powers conditions. These two different cavity structures are compared with the conventional linear cavity MBEFL as a benchmark.