Dark pulse generation in mode-locked erbium-doped fiber lasers using chromium gallium carbide film-based pulse transducer

In this study, we successfully demonstrated the production of dark pulses via mode-locking for the first time using chromium gallium carbide (Cr₂GaC) as a pulse transducer. The Cr₂GaC film was fabricated by embedding the Cr₂GaC material into a polyvinyl alcohol matrix. When incorporated into the laser cavity, a stable mode-locked laser was achieved, exhibiting dissipative solitons with two sharp-edged spectra centred at 1529.6 nm and 1531.6 nm. This stability was maintained across a pump power range of 83.68 to 99.83 mW. The laser operated at a fixed repetition rate of 1.27 MHz, corresponding to the cavity length, consistently producing pulses with a pulse width of 300 nanoseconds. At its optimal performance with a pump power of 99.83 mW, the laser achieved an average output power of 4.56 mW. The laser displayed exceptional stability, as indicated by a signal-to-noise ratio of 69.30 dB at its fundamental frequency. These findings confirm that Cr₂GaC is an effective SA for enabling dark pulse mode-locking in erbium-doped fiber lasers.