Q-switched Triple-Wavelength Erbium-Doped Fiber Laser with Black Phosphorus Absorber

Abstract

We achieved a notable advance in laser technology by generating a triple-wavelength output in a Q-switched Erbium-doped fiber laser (EDFL) using a new black phosphorous saturable absorber (BPSA). The BPSA was made by exfoliating multilayer BP material from a bulk crystal and transferring it onto a fiber ferrule tip. Upon integration into an EDFL ring cavity, this BPSA facilitated the production of Q-switched pulses at wavelengths of 1530.4, 1531.5, and 1532.6nm. This distinctive triple-wavelength lasing phenomenon, characterized by uniform spacing, arises from standing wave interference within the ring cavity, leveraging the highly nonlinear active gain medium. With an increase in pumping strength from 147mW to 223mW, the repetition rate escalated from 41.15 to 60.83kHz, accompanied by a reduction in pulse width from 8.45 µs to 6.06 µs. Notably, the highest recorded pulse energy peaked at 11.8 nJ. These findings highlight the efficacy of BP as a Q-switcher for the generation of multi-wavelength pulses, marking a significant advancement in laser technology.