Q-switched brillouin fibre laser with multi-wall carbon nanotube saturable absorber

A Q-switched Brillouin fibre laser (BFL) is successfully demonstrated using multi-walled carbon nanotubes (MWCNTs) embedded in polyvinyl alcohol (PVA) film as a passive saturable absorber (SA) for the first time. The SA is obtained by sandwiching the developed MWCNTs-PVA film between two FC/PC fibre connectors after depositing index-matching gel onto the fibre ends. The proposed Q-switched BFL incorporates a 5 km long dispersion shifted fibre in a ring cavity structure to generate Stokes shifted by 0.08 nm from the Brillouin pump wavelength. The BFL starts to generate a Q-switching pulse train at threshold pump power of 5 dBm. As the BP power is varied from 5.0 to 6.0 dBm, the repetition rate of the Q-switched BFL exhibits an increasing trend from 27.75 to 30.21 kHz, whereas the pulse width exhibits a decreasing trend from 3.25 mu s to 1.11 mu s. The maximum pulse energy of 0.13 nJ is obtained at maximum BP power of 6.0 dBm