Power Scaling of Ytterbium-doped Fiber Superfluorescent Sources

• Published in: IEEE journal of selected topics in quantum electronics Vol. 13; no. 3; pp. 580 - 587
• Main Authors: Pu Wang, Sahu, J.K., Clarkson, W.A.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.05.2007; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplification; Amplified spontaneous emission (ASE); Amplifiers; Bandwidth; Beams (radiation); Cladding; cladding-pumping; Diodes; fiber amplifiers; Fiber lasers; Fibers; High power amplifiers; Laser excitation; Oscillations; Power amplifiers; Power generation; Pump lasers; Pumps; rare-earth-doped optical fibers; Spontaneous emission; superfluorescence; Termination of employment
• ISSN: 1077-260X; 1558-4542
• DOI: 10.1109/JSTQE.2007.897181

Power scaling of ytterbium-doped fiber superfluorescent sources based on single-stage and two-stage cladding-pumped fiber configurations is reported. For the single-stage configuration, a novel fiber-end termination scheme was employed to suppress laser oscillation in combination with a simple all-fiber scheme for achieving a predominantly single-ended output. The fiber was cladding-pumped by a diode stack at 976 nm and yielded ~62 W of single-ended amplified spontaneous emission output for 119 W of launched pump power, limited by the onset of parasitic lasing. At pump powers in excess of 40 W, the slope efficiency with respect to the launched pump power was 67%. The emission spectrum spanned the wavelength range from 1030 to 1100 nm and the bandwidth (FWHM) was 12 nm. Scaling to higher power levels was demonstrated using a two-stage cladding-pumped fiber configuration comprising of a low-power fiber superfluorescent seed source and a high-power amplifier. The two-stage source yielded 122 W of amplified spontaneous emission output (limited by available pump power) in a beam with M 2 ap 2.1. The slope efficiency for the amplifier with respect to the launched pump power was 77%. The prospects for further improvement in performance and output power are considered.