Nanosecond-pulse fiber laser mode-locked with polyaniline saturable absorber

We prove that mode-locking of an Erbium-doped fiber laser (EDFL) with a Polyaniline (PANI) saturable absorber (SA) can produce nanosecond pulses at repetition rate of 962 kHz in the elongated ring cavity. The SA is fabricated by embedding a PANI into PVA. The conducting polymer-based SA exhibits a good optical nonlinear property with a modulation depth of 2.3%. The laser operated in nanosecond regime due to the saturable absorption of the PANI PVA SA instead of nonlinear polarization evolution. A clean single pulse is observed, and the pulse train exhibits low jitter. It operated at 1530.8 nm with a pulse duration of 228 ns and a maximum pulse energy of 3.1 nJ. Due to its extremely large chirp property, the proposed laser is suited for application in the chirped-pulse amplification systems. •Demonstration of nanosecond pulses with polyaniline absorber for the first time.•We used elongated Erbium-doped fiber laser cavity.•We prepared polyaniline thin film using a simple drop-casting method.•The repetition rate and pulse duration are 962 kHz MHz and 228 ns, respectively.•The laser is suited for application in the chirped-pulse amplification systems.