Q-switched and soliton pulses generation based on carbon nanotubes saturable absorber

Abstract

This paper presents Q-switched and soliton mode-locked fiber lasers using a single-walled carbon nanotubes (SWCNT) based saturable absorber (SA). The SA is fabricated by dripping the SWCNT sodium dedocyl sulfate (SDS) solution onto the fiber ferrule, which is then mated to another clean ferrule before it is incorporated into a ring Erbium-doped fiber laser (EDFL) cavity. The laser Q-switched and mode-locked pulses as the cavity length is fixed at 23 m and 223 m, respectively. The Q-switched laser is self-started to produce a pulse with repetition rate that can be widely tuned from 10.25 kHz to 41.87 kHz by varying the pump power from 30 mW to 129 mW. At the pump power of 129 mW, the Q-switched EDFL has a pulse width of 10.92 μs and pulse energy of 5.2 nJ. The mode-locked EDFL produces a self-started soliton pulses with a repetition rate of 907 kHz, pulse duration of 2.52 ps and signal-to-noise ratio (SNR) of more than 53 dB.