45 research outputs found
InAs Quantum Dots of Engineered Height for Fabrication of Broadband Superluminescent Diodes
Peer reviewed: YesNRC publication: Ye
Tuning the electrically evaluated electron Lande g factor in GaAs quantum dots and quantum wells of different well widths
We evaluate the Lande g factor of electrons in quantum dots (QDs) fabricated
from GaAs quantum well (QW) structures of different well width. We first
determine the Lande electron g factor of the QWs through resistive detection of
electron spin resonance and compare it to the enhanced electron g factor
determined from analysis of the magneto-transport. Next, we form laterally
defined quantum dots using these quantum wells and extract the electron g
factor from analysis of the cotunneling and Kondo effect within the quantum
dots. We conclude that the Lande electron g factor of the quantum dot is
primarily governed by the electron g factor of the quantum well suggesting that
well width is an ideal design parameter for g-factor engineering QDs
Stable mode-locked pulses from mid-infrared semiconductor lasers
We report the unequivocal demonstration of mid-infrared mode-locked pulses
from a semiconductor laser. The train of short pulses was generated by actively
modulating the current and hence the optical gain in a small section of an
edge-emitting quantum cascade laser (QCL). Pulses with pulse duration at
full-width-at-half-maximum of about 3 ps and energy of 0.5 pJ were
characterized using a second-order interferometric autocorrelation technique
based on a nonlinear quantum well infrared photodetector. The mode-locking
dynamics in the QCLs was modelled and simulated based on Maxwell-Bloch
equations in an open two-level system. We anticipate our results to be a
significant step toward a compact, electrically-pumped source generating
ultrashort light pulses in the mid-infrared and terahertz spectral ranges.Comment: 26 pages, 4 figure
Optical characterization of In-flushed InAs/GaAs quantum dots emitting a broadband spectrum with multiple peaks at ~1 μm
Modeling of an optical memory based on tunable lasers suitable for optical integrated circuits
Simulations of two laser systems of which the output wavelength can be switched by optical pulses are presented. The first system is based on two laser cavities containing a phased array waveguide (PHASAR) grating and an optical amplifier, that are coupled with a third optical amplifier. The second system consists of a single laser that contains a PHASAR, amplifier and two or more saturable absorbers. The rate equation model shows that the systems can be switched using pulses with a specific amount of energy. Switching speeds, requirements on the control pulses and the relation with design parameters are discussed
Microphotoluminescence mapping of laterally overgrown GaN layers on patterned Si (111) substrates
Ultrawide-bandwidth, superluminescent light-emitting diodes using InAs quantum dots of tuned height
An ultrawide-bandwidth, superluminescent light-emitting diode (SLED) utilizing multiple layers of dots of tuned height is reported. Due to thermal effect, the superluminescent phenomenon is observed only under pulse-mode operation. The device exhibits a 3 dB bandwidth of 190 nm with central wavelength of 1020 nm under continuouswave (cw) conditions. The maximum corresponding output power achieved in this device under cw and pulsed operation conditions are 0.54 mW and 17 mW, respectively.Peer reviewed: YesNRC publication: Ye