Influence of Carbon Nanotubes Saturable Absorbers Diameter on Mode-Locking Erbium-Doped Fiber Laser Performance

We present a study about the influence of saturable absorbers single-wall carbon nanotubes (CNT) diameter on the passive mode-locking Erbium doped fiber laser performance. We used several samples of CNT with different mean diameters (from 0.8 to 1.4 nm) and distributions to fabricated CNT/polymer films. Films with 1.0 nm mean diameter CNT showed best results in terms of larger laser bandwidths and shorter pulse durations, compared to the other CNT samples used in our experiments. This result is due to the fact that 1.0 nm diameter CNT absorption energy gap (~0.8 eV) is close to the photon energy of operating Erbium-doped fiber laser wavelength (~1557 nm). Laser bandwidths up to 8.7 nm and pulse durations as short as 0.55 ps were obtained.