Multi-wavelength pump enabled spectral manipulation scalability of random Raman fiber laser

This study presents a broadband random Raman fiber laser (RRFL) with a threefold increase in wavelength coverage compared to single-wavelength pumping, along with flexible Raman gain manipulation. The system utilizes a half-open cavity configuration facilitated by a spectrally programmable multi-wavelength ytterbium-doped fiber laser as the pump source. Under single-wavelength pumping, the RRFL achieves an output wavelength range of 16 nm with a maximum output power of 4.77 W. By optimizing the pump parameters, including a wavelength spacing of 16 nm and a power ratio of ∼4:2:2, a three-wavelength pumping scheme enables multi-wavelength tunability over a range of 1102–1148 nm (46 nm, 10.9 THz), supporting outputs with two to five wavelengths. This work demonstrates an effective approach for enhancing broadband Raman transitions and advancing multi-wavelength RRFLs, with promising applications in sensing, communication systems, and precision spectroscopy.