A Stokes-Shift Light Amplifier

A.Ya. Goikhman, Yu. M. Popov

L. Mandeļ, E. Wolf

Cheng Cheng

Doped with PbSe nanocrystals of different sizes, a multiquantum-dot-doped fiber amplifier (MQDFA) is proposed. Performance of the MQDFA is simulated by solving light-propagation equations and rate equations for a three-level system, and by applying superposed emission-absorption cross sections of the quantum dots (QDs). Pumped with 980 nm, this proposed MQDFA has characteristics of broader band, flatter gain, and lower noise than those of the erbium-doped fiber amplifiers at present. There is evidence to show that two factors, i.e., the equivalent Stokes shifts and the full wave at half maximum of the superposed spectra, dominate the performances of the MQDFA. Also, the equivalent Stokes shift and the FWHM are tunable by adopting the QDs in different sizes and choosing the doped number available. It is expected that such a MQDFA may be able to cover the all waveband in telecommunications if it is optimized on the doped number, sizes, and doped concentrations of the QDs.

Jörg Bialas, W. J. Firth, P. E. Toschek

Zhaoming Zhu, Andrew M. C. Dawes, Daniel J. Gauthier +2 more

In this paper, we investigate slow light via stimulated Brillouin scattering (SBS) in a room temperature optical fiber that is pumped by a spectrally broadened laser. Broadening the spectrum of the pump field increases the linewidth Deltaomegapof the Stokes amplifying resonance, thereby increasing the slow-light bandwidth. One physical bandwidth limitation occurs when the linewidth becomes several times larger than the Brillouin frequency shift OmegaBso that the anti-Stokes absorbing resonance substantially cancels out the Stokes amplifying resonance and, hence, the slow-light effect. We find that partial overlap of the Stokes and anti-Stokes resonances can actually lead to an enhancement of the slow-light delay-bandwidth product when Deltaomegapsime1.3OmegaB. Using this general approach, we increase the Brillouin slow-light bandwidth to over 12 GHz from its nominal linewidth of ~30 MHz obtained for monochromatic pumping. We controllably delay 75-ps-long pulses by up to 47 ps and study the data-pattern dependence of the broadband SBS slow-light system

Jörg Bialas, W. J. Firth, P. E. Toschek