Lead phthalocyanine based mode-locked fiber laser for near-infrared supercontinuum generation

Abstract In this paper, we employ lead phthalocyanine (PbPc), an organic macrocyclic compound, for generating ultrashort laser pulses that are subsequently amplified and injected into a nonlinear gain medium to produce supercontinuum (SC) light in the near-infrared region. The work emphasizes the function of PbPc as a saturable absorber (SA) integrated into an erbium-doped fiber laser (EDFL) cavity to achieve mode-locked pulsed operation. The PbPc-based SA film is fabricated by inserting PbPc within a polymer host matrix. Incorporating this film into the EDFL cavity enables stable mode-locking, producing ultrashort pulses centered at 1530.5 nm with a duration of 910 fs. Stable operation is sustained within a pump power range of 141.38–210.62 mW, corresponding to a repetition rate of 1.821 MHz and a peak power of 5.20 kW at 210.6 mW. After amplification, the seed laser intensity increases to 25.12 mW, and the amplified pulses are launched into a highly nonlinear photonic crystal fiber exhibiting near-zero dispersion at 1550 nm. This configuration enables broadband SC generation in the near-infrared region. At a pump power of 25.12 mW, an ultra-wide spectral bandwidth extending from 1300 nm to beyond 2100 nm is achieved, with an output power around − 30 dBm. This work introduces PbPc SA as an alternative organic SA platform for generating stable femtosecond pulses and broadband near-infrared supercontinuum.