Strain engineered bilayers for extending the operating wavelength of quantum dot lasers

Abstract

The analysis of molecular-beam epitaxy (MBE) grown bilayer quantum dot (QD) laser material is reported here. Specifically, gain characteristics of 5× 'bilayer' QDs with GaAs caps and 5× 'single' QD layers with InGaAs caps were studied experimentally. A transition of lasing from the ground state to lasing via the first excited state, and subsequently the second excited state is observed with increasing threshold gain for both the laser structures. A 50% increase in saturated modal gain is observed for bilayer laser as compared to single-layer samples. Further analysis of the bilayer sample using the multi-section technique allows the gain and absorption spectrum to be obtained.

Wafer-Scale Epitaxial Low Density InAs/GaAs Quantum Dot for Single Photon Emitter in Three-Inch Substrate

“…As shown in ( 4)-( 11), the QD density increases gradually from center to the edge within the radius of 2 cm, but increase more rapidly from 2 cm to the edge. Other crystallographic directions including [1][2][3][4][5][6][7][8][9][10], diagonal 1, diagonal 2 demonstrate the same regularity as well, as shown in Figure 2c. These results indicate that there is a temperature distribution over the threeinch wafer.…”

“…Semiconductor quantum dots (QDs), due to its discrete energy levels as artificial atoms, serve as a core element in the emerging application of optoelectronic devices including lasers [ 1 ], solar cells [ 2 ], and photodetectors [ 3 ]. The rapid development of quantum computing [ 4 ], quantum cryptography [ 5 ], as well as quantum key distribution (QKD) [ 6 ] in recent years, busting many researches in low-density quantum dots for the generation of ideal single-photons and entangled-photon pairs via external optical/electrical pulses [ 7 , 8 ].…”

Excited State Bilayer Quantum Dot Lasers at 1.3 µm

“…10) Absorption measurements and analysis of gain spectra at long wavelengths indicate an internal loss of 3 AE 1 cm À1 for GaAs capped and 5 AE 1 cm À1 for the InGaAs capped sample. 12) These values for internal loss are combined with net modal gain values to plot the peak modal gain per dot of the excited state for both samples as a function of current density in Fig. 5.…”

The Impact of Cap Layers on the Structural and Optical Properties of Self-Assembled InAs/GaAs Quantum Dots

“…Self-assembled quantum dots (QDs) have been attracted intense interest in optoelectronic device such as quantum dot laser [1][2][3] , quantum dot semiconductor optical amplifiers and quantum dot detectors etc. [4][5][6][7] due to their three-dimensional carrier confinement and unique physical and optical properties.…”