Journal ArticleDOI
Nonlinear processes responsible for nondegenerate four-wave mixing in quantum-dot optical amplifiers
Tomoyuki Akiyama,Osamu Wada,Haruhiko Kuwatsuka,Takashi Simoyama,Yoshiaki Nakata,Kohki Mukai,Mitsuru Sugawara,Hiroshi Ishikawa +7 more
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TLDR
In this article, the authors considered the detuning frequency dependence of χ(3), derived from the conversion efficiency, and showed that, within the range of detuning in the experiment, spectral-hole burning and carrier heating are responsible, and that their time constants, i.e., carrier relaxation time to the ground state and the phonon scattering time, are in the range 60 −140 and 200 −400 fs, respectively.Abstract:
Wavelength conversion using nondegenerate four-wave mixing in quantum-dot optical amplifiers is investigated. From the detuning frequency dependence of χ(3), derived from the conversion efficiency, we consider that, within the range of detuning in the experiment, spectral-hole burning and carrier heating are responsible, and that their time constants, i.e., carrier relaxation time to the ground state and the phonon scattering time, are in the range of 60–140 and 200–400 fs, respectively. This indicates that the carrier supply to the ground level via relaxation from the higher levels is very fast and that a broad conversion bandwidth comparable to that of quantum-well devices is ensured.read more
Citations
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Journal ArticleDOI
Quantum-Dot Semiconductor Optical Amplifiers
TL;DR: In this article, a quantum-dot semiconductor optical amplifier with a gain of 25 dB, noise figure of 20 dBm, over the record widest bandwidth of 90 nm among all kinds of optical amplifiers, and also having a penalty-free output power of 23 dBm was realized by using quantum dots.
Journal ArticleDOI
Femtosecond all-optical devices for ultrafast communication and signal processing
TL;DR: In this paper, the authors review requirements of ultrafast all-optical devices and recent progress in ultrafast light sources and switches based on either novel device principles or ultrafast phenomena in novel materials such as quantum-confined nanostructures.
Quantum-Dot Semiconductor Optical Amplifiers
TL;DR: This paper reviews the recent progress of quantum-dot semiconductor optical amplifiers developed as ultrawideband polarization-insensitive high-power amplifiers, high-speed signal regenerators, and wideband wavelength converters and suggests a potential for low-cost realization of regenerative transmission systems.
Journal ArticleDOI
Symmetric highly efficient (/spl sim/0 dB) wavelength conversion based on four-wave mixing in quantum dot optical amplifiers
Tomoyuki Akiyama,Haruhiko Kuwatsuka,Nobuaki Hatori,Yoshiaki Nakata,Hiroji Ebe,Mariko Sugawara +5 more
TL;DR: In this paper, a reduction in linewidth enhancement factor due to the discreteness of the electron states in quantum dots is attributed to the reduction of the linearly-enhanced electron states.
Journal ArticleDOI
Nonlinear gain dynamics in quantum-dot optical amplifiers and its application to optical communication devices
Tomoyuki Akiyama,Haruhiko Kuwatsuka,Takashi Simoyama,Yoshiaki Nakata,Kohki Mukai,Mitsuru Sugawara,Osamu Wada,Hideaki Ishikawa +7 more
TL;DR: In this paper, the authors studied the gain dynamics in quantum-dot (QD) optical amplifiers and found that there are at least three nonlinear processes, which are attributed to carrier relaxation to the ground states, phonon scattering, and carrier capture from the wetting layers into the QDs.
References
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Journal ArticleDOI
Population pulsations and nondegenerate four-wave mixing in semiconductor lasers and amplifiers
TL;DR: In this article, the authors studied the physical processes that lead to population pulsations in nearly degenerate four-wave mixing, and showed that the gain and the index grating contribute to NDFWM.
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Self-assembled InGaAs/GaAs, quantum dots
TL;DR: Theoretical bases of the optical properties of Semiconductor quantum nano-structures were studied in this article, where the authors proposed a theoretical base of the Optical properties of semiconductor Quantum Nano-Structures.
Journal ArticleDOI
Observation of highly nondegenerate four-wave mixing in 1.5 mu m traveling-wave semiconductor optical amplifiers and estimation of nonlinear gain coefficient
TL;DR: In this article, the nonlinear gain coefficient epsilon, which induces a gain grating through the pump-probe beating, is estimated to be 1.75*10/sup -23/ m/sup 3/m/sup 4.
Journal ArticleDOI
Lasing with low threshold current and high output power from columnar-shaped InAs/GaAs quantum dots
Kohki Mukai,Yoshiaki Nakata,Hajime Shoji,Mitsuru Sugawara,K. Ohtsubo,Naoki Yokoyama,Hiroshi Ishikawa +6 more
TL;DR: In this paper, a new type of quantum dot achieved low threshold current and high output power by supplying a small amount of InAs and GaAs alternately on GaAs substrates.
Journal ArticleDOI
Terahertz four‐wave mixing spectroscopy for study of ultrafast dynamics in a semiconductor optical amplifier
TL;DR: In this article, a 1.5μm tensile-strained quantum-well optical amplifier has been studied by highly nondegenerate four-wave mixing at detuning frequencies up to 1.7 THz, and frequency response data indicate the presence of two ultrafast physical processes with characteristic relaxation lifetimes of 650 fs and <100 fs.
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