Энергопотребление при высокочастотной модуляции неохлаждаемого InGaAs/GaAs/AlGaAs-микродискового лазера
The energy consumption of an uncooled microdisk quantum well-dot laser under high-frequency modulation was investigated. For a microlaser with a diameter of 20 μm, the lowest power consumption of 1.6 pJ was obtained per one bit of data transmitted using an optical signal.
We report on broad-area lasers, mode-locked lasers (MLLs), and superluminescent light-emitting diodes (SLDs) based on a recently developed novel type of nanostructures that we refer to as quantum well-dots (QWDs). The QWDs are intermediate in properties between quantum wells and quantum dots and combine some useful properties of both. 1.08 μm InGaAs/GaAs QWDs broad area edge-emitting lasers based on coupled large optical cavity waveguides show high internal quantum efficiency of 92%, low internal loss of 0.9 cm-1 and material gain of ~1.1∙104 cm-1 per one QWD layer. CW output power of 14.2 W is demonstrated at room temperature. Superluminescent light-emitting diodes with one QWD layer in the active region exhibit stimulated emission spectra centered at 1050 nm with the maximal full width at half maximum of 36 nm and the output power of 17 mW. First results on mode-locked operation in QWD lasers are also presented. 2 mm long two-section devices demonstrate the pulse repetition rate of 19.3 GHz and the pulse duration of 3.5 ps. The width of the radio frequency spectrum is 0.2 MHz.
We analyzed the localized charge dynamics in the system of interacting single-level quantum dots (QDs) coupled to the continuous spectrum states in the presence of Coulomb interaction between electrons within the dots. Different dots geometry and initial charge configurations were considered. The analysis was performed by means of Heisenberg equations for localized electrons pair correlators. We revealed that charge trapping takes place for a wide range of system parameters and we suggested the QDs geometry for experimental observations of this phenomenon. We demonstrated significant suppression of Coulomb correlations with the increasing of QDs number. We found the appearance of several time scales with the strongly different relaxation rates for a wide range of the Coulomb interaction values.
The rate equations are used to analyze the characteristics of a tandem consisting of a laser diode and a semiconductor optical amplifier made of a single heterostructure with quantum dots. The optimal value of the current distribution coefficient the amplifier and the laser, as well as the optimal resonator length that provides the highest output power of the tandem were determined. It is shown that the use of the tandem allows, at the same total consumed current, to significantly (more than 4 times for 1A) increase the power emitted through the groundstate optical transition in comparison with that achievable with a laser diode solely being limited by the onset of lasing through an excited-state optical transition.
The problems of creation of a low intensity optical radiation signal standard sources based on the nanosized apertures and semiconductor quantum dots are considered. The use of technology of the focused ionic beam technology for isolation of a single quantum dot is offered suggested.
Quantum dot based monolithic edge-emitting semiconductor lasers at 1.25 m are ideal sources for the generation of broad optical frequency combs for optical communication applications. In this work, InAs/InGaAs quantum dot lasers with dierent total laser length to absorber length ratio and with dierent p-doping concentrations in the GaAs barrier sections are investigated experimentally in dependence on the gain injection current and absorber reverse bias voltage. A smaller mode-locking area is found for the p-doped device in dependence on the laser biasing conditions. For the undoped active region 1.3 ps short pulse widths at a pulse repetition rate of 20 GHz with a pulse-to-pulse timing jitter of 111 fs are reported for an absorber section length of 12% to the total cavity length. For an undoped and p-doped device short pulse emission between 2.5 ps and 5.5 ps is attained and a shorter absorber section length of 8% or 5%.
We present an analysis of spectral and threshold characteristics of InGaAs/GaAs quantum well-dot microdisk laser operated under cw current injection at room temperature without external cooling. The experimental values of the threshold current for the disk and ring microlasers are compared. We observe that the threshold current can be significantly decreased in devices with large diameters (more than 30 m) by using the ring geometry
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.