The generation of 0π pulses in coherent pulse propagation is studied for a simple initial pulse profile consisting of two separated square pulses with one inverted to give a total pulse area of zero. When the two pulses are close together, it is found that the threshold for lossless propagation occurs at an absolute area of 21/2π. But as the pulses become farther separated, one finds two thresholds. The first one occurs for an absolute area of about π and the second one at about 2π. Although one can have lossless propagation occurring for the absolute area between π and 2π, it is accomplished only by generating very low amplitude 0π pulses. It is only after the second threshold, 2π, is achieved that one can expect to find moderate to large amplitude 0π pulses, and these may be accompanied by several low amplitude 0π pulses.The generation of 0π pulses in coherent pulse propagation is studied for a simple initial pulse profile consisting of two separated square pulses with one inverted to give a total pulse area of zero. When the two pulses are close together, it is found that the threshold for lossless propagation occurs at an absolute area of 21/2π. But as the pulses become farther separated, one finds two thresholds. The first one occurs for an absolute area of about π and the second one at about 2π. Although one can have lossless propagation occurring for the absolute area between π and 2π, it is accomplished only by generating very low amplitude 0π pulses. It is only after the second threshold, 2π, is achieved that one can expect to find moderate to large amplitude 0π pulses, and these may be accompanied by several low amplitude 0π pulses.

Journal of the Optical Society of AmericaFeb 1, 198018 citations

Coherent π-pulse propagation with pulse breakup in an erbium-doped fiber waveguide amplifier

Masataka Nakazawa, Kazunori Suzuki, Yasuo N. Kimura +1 more

Coherent \ensuremath{\pi}-pulse propagation with pulse breakup has been observed in an erbium-doped fiber waveguide amplifier. The waveguide was pumped by a 1.48-\ensuremath{\mu}m ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$ ${\mathrm{Ga}}_{\mathit{x}}$ ${\mathrm{As}}_{\mathit{y}}$ ${\mathrm{P}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$ laser diode. The waveguide had an erbium ion concentration of 8900 ppm and was cooled to 4.2 K. The pulse source was a 1.53-\ensuremath{\mu}m mode-locked Er-doped glass laser with a pulse width of 400 ps. A pulse advance of approximately 130 ps was observed between a low-intensity transmitted pulse with a low pump power and an amplified \ensuremath{\pi} pulse in a 1.5-m-long fiber.Coherent \ensuremath{\pi}-pulse propagation with pulse breakup has been observed in an erbium-doped fiber waveguide amplifier. The waveguide was pumped by a 1.48-\ensuremath{\mu}m ${\mathrm{In}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ga}}_{\mathit{x}}$${\mathrm{As}}_{\mathit{y}}$${\mathrm{P}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$ laser diode. The waveguide had an erbium ion concentration of 8900 ppm and was cooled to 4.2 K. The pulse source was a 1.53-\ensuremath{\mu}m mode-locked Er-doped glass laser with a pulse width of 400 ps. A pulse advance of approximately 130 ps was observed between a low-intensity transmitted pulse with a low pump power and an amplified \ensuremath{\pi} pulse in a 1.5-m-long fiber.

Physical Review AMar 1, 199253 citations

Self-focusing and defocusing of self-similar π pulses in an amplifying two-level medium

M. B. Krylov, С. В. Сазонов

The effect of transverse perturbations on the propagation of electromagnetic π pulses in an amplifying two-level medium is studied. The cases of quasi-monochromatic and extremely short pulses are considered. The equations describing the behavior of the transverse size of the pulse during its propagation in the medium are derived. It is shown that, if the ratios of the diffraction length to the length of dispersion spreading are smaller than certain critical values, self-focusing regimes are realized for both types of pulses. Otherwise, at a finite distance, blowup of defocusing occurs, after which the amplified pulse propagates as if it is a one-dimensional pulse, with the velocity equal to the velocity of light in vacuum. Similarities and distinctions in the dynamics of propagation of extremely short and quasi-monochromatic pulses are indicated.The effect of transverse perturbations on the propagation of electromagnetic π pulses in an amplifying two-level medium is studied. The cases of quasi-monochromatic and extremely short pulses are considered. The equations describing the behavior of the transverse size of the pulse during its propagation in the medium are derived. It is shown that, if the ratios of the diffraction length to the length of dispersion spreading are smaller than certain critical values, self-focusing regimes are realized for both types of pulses. Otherwise, at a finite distance, blowup of defocusing occurs, after which the amplified pulse propagates as if it is a one-dimensional pulse, with the velocity equal to the velocity of light in vacuum. Similarities and distinctions in the dynamics of propagation of extremely short and quasi-monochromatic pulses are indicated.

Optics and SpectroscopyFeb 1, 20060 citations

{\mathrm{Ga}}_{\mathit{x}}

{\mathrm{As}}_{\mathit{y}}

${\mathrm{P}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$ laser diode. The waveguide had an erbium ion concentration of 8900 ppm and was cooled to 4.2 K. The pulse source was a 1.53-\ensuremath{\mu}m mode-locked Er-doped glass laser with a pulse width of 400 ps. A pulse advance of approximately 130 ps was observed between a low-intensity transmitted pulse with a low pump power and an amplified \ensuremath{\pi} pulse in a 1.5-m-long fiber.