Directly exfoliated and imprinted graphite nano-particle saturable absorber for passive mode-locking erbium-doped fiber laser

• Published in: Laser physics letters Vol. 8; no. 12; pp. 880 - 886
• Main Authors: Lin, G.-R., Lin, Y.-C.
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.12.2011; WILEY‐VCH Verlag; Wiley
• Subjects: erbium-doped fiber laser; Exact sciences and technology; exfoliation and imprinting; Fiber lasers; Fundamental areas of phenomenology (including applications); graphite; Laser optical systems: design and operation; Lasers; Modulation, tuning, and mode locking; Nonlinear optics; Optical solitons; nonlinear guided waves; Optics; passively mode-locking; Physics; saturable absorber; Optical fibers; Saturable absorbers; Optical solitons; Line widths; saturable absorber; Laser beams; Layer thickness; Transmittance; Alcohols; Nanoparticles; exfoliation and imprinting; passively mode-locking; Laser mode locking; Erbium-doped fiber; erbium-doped fiber laser; Polyvinyls; Graphite; fs range; PVA; Polymers; Nonlinear optics; ps range; Fiber lasers
• ISSN: 1612-2011; 1612-202X
• DOI: 10.1002/lapl.201110078

By directly brushing and scribing an ultra‐thin (<5‐µm thick) polymer polyvinyl alcohol (PVA) film on one end‐face of a FC/APC connector in erbium‐doped fiber laser (EDFL), and then imprinting it with the graphite nano‐particles exfoliated from a graphite foil, the intra‐cavity graphite nanoparticle based saturable absorber can be formed to induce passive mode‐locking effect in the EDFL. Such a novel approach greatly suppresses the film‐thickness induced laser‐beam divergent loss to 3.4%, thus enhancing the intra‐cavity circulating power to promote the shortening on mode‐locking pulsewidth. The saturable absorber with area coverage ratio of graphite nano‐particles is detuned from 70 to 25% to provide the modulation depth enhancing from 11 to 20% and the saturated transmittance from 27 to 60%. Optimizing the coverage ratio reduces the non‐saturable loss to 40% and enhances the modulation depth to 21%, such that the sub‐ps soliton mode‐locking can be initiated to provide a chirped pulsewidth of 482 fs and a linewidth of 2.87 nm. (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA) (© 2011 by Astro Ltd., Published exclusively by WILEY‐VCH Verlag GmbH & Co. KGaA)