58 research outputs found
Optical characteristics of single wavelength-tunable InAs/InGaAsP/InP(100) quantum dots emitting at 1.55 um
We have studied the emission properties of individual InAs quantum dots (QDs)
grown in an InGaAsP matrix on InP(100) by metal-organic vapor-phase epitaxy.
Low-temperature microphotoluminescence spectroscopy shows emission from single
QDs around 1550 nm with characteristic exciton-biexciton behavior, and a
biexciton antibinding energy of more than 2 meV. Temperature-dependent
measurements reveal negligible optical-phonon induced broadening of the exciton
line up to 50 K, and emission from the exciton state clearly persists above 70
K. Furthermore, we find no measurable polarized fine structure splitting of the
exciton state within the experimental precision. These results are encouraging
for the development of a controllable photon source for fiber-based quantum
information and cryptography systems.Comment: 3 pages, 4 figures, submitted AP
Non inverting and non filtered wavelength converter based on an InAs/InP (100) QD ring laser at 1.55 μm
A novel wavelength conversion concept based on InAs/InP(100) quantum-dot ring- laser structure is demonstrated requiring no external laser, optical inversion or optical filtering. Demonstration at 622 Mb/s for a 2 mm ring, suggests applicability for much higher speeds
Wavelength tuning of InAs/InP quantum dots: Control of As/P surface exchange reaction
Wavelength tuning of single and vertically stacked InAs quantum dot [QD] layers embedded inInGaAsP/InP [100] grown by metal organic vapor-phase epitaxy is achieved by controlling theAs/P surface exchange reaction during InAs deposition. The As/P exchange reaction is suppressedfor decreased QD growth temperature and group V-III flow ratio, reducing the QD size andphotoluminescence [PL]emission wavelength. The As/P exchange reaction and QD PL wavelengthare then reproducibly controlled by the thickness of an ultrathin [0¿2 ML] GaAs interlayerunderneath the QDs. Submonolayer GaAs coverages result in a shape transition from QDs toquantum dashes at low group V-III flow ratio. Temperature dependent PL measurements revealexcellent optical properties of the QDs up to room temperature with PL peak wavelengths in thetechnologically important 1.55 ¿region for telecom applications. Widely stacked QD layers arereproduced with identical PL emission to increase the active volume, while closely stacked QDlayers reveal a systematic PL redshift and linewidth reduction due to vertical electronic couplingwhich is proven by the linear polarization of the cleaved-side PL changing from in plane toisotropic. ¿ 2006 American Vacuum Society
Ultrafast nonlocal control of spontaneous emission
Solid-state cavity quantum electrodynamics systems will form scalable nodes
of future quantum networks, allowing the storage, processing and retrieval of
quantum bits, where a real-time control of the radiative interaction in the
cavity is required to achieve high efficiency. We demonstrate here the dynamic
molding of the vacuum field in a coupled-cavity system to achieve the ultrafast
nonlocal modulation of spontaneous emission of quantum dots in photonic crystal
cavities, on a timescale of ~200 ps, much faster than their natural radiative
lifetimes. This opens the way to the ultrafast control of semiconductor-based
cavity quantum electrodynamics systems for application in quantum interfaces
and to a new class of ultrafast lasers based on nano-photonic cavities.Comment: 15 pages, 4 figure
Fast Purcell-enhanced single photon source in 1,550-nm telecom band from a resonant quantum dot-cavity coupling
High-bit-rate nanocavity-based single photon sources in the 1,550-nm telecom
band are challenges facing the development of fibre-based long-haul quantum
communication networks. Here we report a very fast single photon source in the
1,550-nm telecom band, which is achieved by a large Purcell enhancement that
results from the coupling of a single InAs quantum dot and an InP photonic
crystal nanocavity. At a resonance, the spontaneous emission rate was enhanced
by a factor of 5 resulting a record fast emission lifetime of 0.2 ns at 1,550
nm. We also demonstrate that this emission exhibits an enhanced anti-bunching
dip. This is the first realization of nanocavity-enhanced single photon
emitters in the 1,550-nm telecom band. This coupled quantum dot cavity system
in the telecom band thus provides a bright high-bit-rate non-classical single
photon source that offers appealing novel opportunities for the development of
a long-haul quantum telecommunication system via optical fibres.Comment: 16 pages, 4 figure
Passively Mode-Locked 4.6 and 10.5 GHz Quantum Dot Laser Diodes Around 1.55 mu m With Large Operating Regime
tum dot laser diodes operating at wavelengths around 1.55 µm is reported. For a 4.6-GHz laser, a large operating regime of stable mode-locking, with RF-peak heights of over 40 dB, is found for injection currents of 750 mA up to 1.0 A and for values of the ab-sorber bias voltage of 0 V down to −3 V. Optical output spectra are broad, with a bandwidth of 6–7 nm. However, power exchange between different spectral components of the laser output leads to a relatively large phase jitter, resulting in a total timing jitter of around 35 ps. In a 4-mm-long, 10.5-GHz laser, it is shown that the operating regime of stable mode-locking is limited by the appear-ance of quantum dot excited state lasing, since higher injection current densities are necessary for these shorter lasers. The out-put pulses are stretched in time and heavily up-chirped with a value of 16–20 ps/nm. This mode of operation can be compared to Fourier domain mode-locking. The lasers have been realized using a fabrication technology that is compatible with further photonic integration. This makes such lasers promising candidates for, e.g., a coherent multiwavelength source in a complex photonic chip. Index Terms—Mode-locked lasers, quantum dots, semiconduc-tor lasers. I
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