Direct Generation of 7 W, 360 μJ Multi-Pulse Laser From an Ultra-Compact All-Fiber Gain Switched Tm³+-Doped Double-Clad Fiber Laser

We report on the investigation of multi-pulse Tm
³⁺
-doped double clad fiber laser (TDCFL) with an ultra-compact four devices-based all-fiber structure. This multi-pulse is implemented by the long relaxation time of gain-switched process. The number of pulse in a pulse cluster can be tuned from 1 to 8 by changing the pump pulse energy. With laser cavity design (i.e. large laser output coupling ratio and high gain mutual balance), the multi-pulse laser can finally generate an average output power of 7.25 W with corresponding pulse energy of
$362.5~\mu \text{J}$
. The 2017 nm multi-pulse TDCFL has a high laser conversion efficiency of ~30% and the good operation stability with signal to noise ratio (SNR) of 77 dB. The experimental results would be fruitful to the communities interested in all-fiber multi-pulse lasers.