Study of the characteristics of 1.55 μm quantum dash/dot semiconductor lasers on InP substrate (original) (raw)

Semiconductor and Organic Optoelectronic Materials and Devices, 2005

Quantum dot (QDs) heterostructures structurally represent tiny 3D insertions of a narrow bandgap material, coherently embedded in a wide-bandgap single-crystalline matrix. The QDs are produced by conventional epitaxial techniques applying self-organized growth and behave electronically as artificial atoms. Strain-induced attraction of QDs in different rows enables vertically-coupled structures for polarization, lifetime and wavelength control. Overgrowth with ternary or quaternary alloy materials allows controllable increase in the QD volume via the island-activated alloy phase separation. Repulsive forces during overgrowth of QDs by a matrix material enable selective capping of coherent QDs, keeping the defect regions uncapped for their subsequent selective evaporation. Low-threshold injection lasing is achieved up to 1350 nm wavelength at 300K using InAs-GaAs QDs. 8 mW VCSELs at 1.3 µm with doped DBRs are realized. Edge-emitters demonstrate 10 GHz bandwidth up to 70 o C without current adjustment. VCSELs show ~4 GHz relaxation oscillation frequency. QD lasers demonstrate above 3000 h of CW operation at 1.5 W at 45 o C heat sink temperature without degradation. The defect reduction technique (DRT) applied to thick layers enables realization of defect-free structures on top of dislocated templates. Using of DRT metamorphic buffer layers allowed 7W GaAs-based QD lasers at 1500 nm.

Orientation dependence of the optical properties in InAs quantum-dash lasers on InP

Applied Physics Letters, 2002

The anisotropy of the modal gain and the linewidth enhancement factor was experimentally measured in InAs/AlGaInAs/InP semiconductor lasers with an active region composed of quantum confined structures in the form of short wires called quantum dashes. This anisotropy is due to the polarization dependence of the transition matrix element in these quantum nanostructures. The spectral dependence of the gain and linewidth enhancement factor was investigated in a wavelength range from 1540 to 1640 nm at subthreshold current densities. The largest gain and the smallest linewidth enhancement factor were obtained when the quantum dashes were oriented perpendicular to the axis of the laser cavity.

QD lasers: physics and applications

Storage and Retrieval for Image and Video Databases, 2005

Quantum dot lasers: breakthrough in optoelectronics

Thin Solid Films, 2000

Semiconductor heterostructures with self-organized quantum dots (QDs) have experimentally exhibited properties expected for zerodimensional systems. When used as active layer in the injection lasers, these advantages help to strongly increase material gain and differential gain, to improve temperature stability of the threshold current, and to provide improved dynamic properties. Molecular beam epitaxy (MBE) represents a developed technology well suited for fabrication of self-organized QDs. Optimization of deposition parameters can ensure that the self-organized islands are small (,10 nm), have a similar size and shape and form dense arrays. Saturation material gain is as high as 150000 cm 21 compared with QW values of about 3000 cm 21. Maximum differential gain reported for QD lasers approaches 10 212 cm 2 and exceeds the QW laser values by about three orders of magnitude. Direct observation of relaxation oscillations reveals present cutoff frequencies close to 10 GHz. High internal (.96%) and differential (70%) ef®ciencies at 300 K are realized. Using the novel concept of electronically-coupled QDs and oxide-de®ned 10 mm apertures, CW lasing with J th 180 A/cm 2 , is realized in surface-emitting QD lasers (300 K). Wall-plug ef®ciencies are up to 16%. Total currents as low as 68 mA are measured for 1mm apertures. GaAs-based lasers for the 1.3 mm range with low J th (65 A/cm 2) at room temperature (RT) are realized using InAs/InGaAs/GaAs QDs obtained by activated spinodal decomposition. In stripes the lasing occurs via the QD ground state (J th 90 A/cm 2) for cavity lengths L. 1 mm (uncoated). Differential ef®ciency is 55% and internal losses are 1.5 cm 21. A characteristic temperature near RT is 160 K. 3W CW operation at RT is achieved. The recent progress in lasers based on self-organized MBE QDs already made it possible to fabricate devices with dramatically improved characteristics as compared to recent QW devices for the most important commercial applications.

QD laser on InP substrate for 1.55 mu m emission and beyond

Quantum Sensing and Nanophotonic Devices Vii, 2010

InAs nanostructures formed on InP substrates allow the realization of devices working in telecommunication wavelength range between 1.4 and 1.65 µm. However due to the low lattice mismatch existing between InAs and InP, the self assembling process in InP is more complex than on GaAs substrates. First high density quantum wires obtained on InP(001) have been integrated in laser. Lasers emitting at room temperature have been achieved. For an infinite length cavity, a threshold current density per QD plane as low as 45 A/cm 2 is deduced. This result compares favourably with those obtained on quantum wells lasers. However, the stability of the threshold current with temperature, predicted for quantum dots laser is not observed. Thus, growth on non standard substrates such as miscut substrates or high index substrates have been investigated in order to achieve QDs on InP. On (113) B substrates, quantum dots in high density and with size comparable with those achieved on GaAs(001) have been obtained. Lasers with record threshold current have been obtained. However the modulation properties of the laser are not as good as predicted for ideal quantum dots lasers. Finally we present the attempts to extend the QD emission wavelength in the 2-3 µm region.

QD laser on InP substrate for 1.55 µm emission and beyond

2010

Ultrabroad stimulated emission from quantum-dash laser

Applied Physics Letters, 2007

The authors demonstrate the generation of ultrabroadband stimulated emission in the quasi-zero-dimensional InAs/ InAlGaAs quantum-dash laser grown on InP substrate. The laser exhibits lasing wavelength coverage of up to 76 nm at ϳ1.64 m from simultaneous multiple confined states lasing at room temperature. Unlike the conventional interband diode laser, the rule changing broadband lasing signature is achieved from the quasicontinuous interband transition formed by the inhomogeneous quantum-dash nanostructure.

Study of the characteristics of 1.55 μm quantum dash/dot semiconductor lasers on InP substrate (original) (raw)

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