Efficient Brillouin lasing and multi-Stokes generation at 2004 nm

We demonstrate efficient single- and multi-wavelength lasers at 2 μm exploiting Brillouin scattering in a SM1950 fiber. Using a SM1950 fiber as the Brillouin gain medium, higher output Stokes power and slope efficiency are achieved for a threshold pump power that is three to four times lower than the Brillouin lasing threshold in a longer length SMF with similar or higher feedback factors. We realize single and multi-Stokes Brillouin lasers with low threshold pump powers of ∼ 130 mW and ∼ 385 mW, respectively, using a 100 m SM1950 fiber ring and a Fabry-Perot resonator. For a fixed SM1950 cavity length, as the feedback factor is varied from 90% to 50%, the output Stokes power and slope efficiency increased four times with only a small penalty on lasing threshold. For multi-Stokes Brillouin lasing, we observe 14 lines, including four-wave mixing components, at a maximum pump power of 822 mW. To the best of our knowledge, this is the first detailed study of Brillouin lasing at 2 μm that studies the effect of different cavity parameters such as length, feedback factor, and resonator geometry on Brillouin lasing.