A computational study of high-contrast gratings (HCG) in a vertical-cavity surface-emitting laser (VCSEL) on silicon-on-insulator (SOI) for multispectral laser sources is performed. The simulation model analyzes reflectivity of the HCG grating, formed in the SOI device layer. HCG filters higher-order modes, optimizing VCSEL performance. An algorithm is developed to determine HCG parameters, maximizing reflectivity with a SOI silicon layer fixed thickness.

The main results of the studies on designing high-power semiconductor laser diodes based on asymmetric semiconductor heterostructures InGaAs(P)/Al(In)GaAs(P)/GaAs with low internal optical loss, whose concept was proposed at the Ioffe Institute, are described in detail. The basic technological approaches to designing highly strained active laser media for the spectral range up to 1100 nm are considered. The results of studying the cw high-power multimode semiconductor lasers, emitting in the wavelength ranges of 780–850, 900–980, and 1000–1100 nm; high-power pulsed semiconductor lasers; and high-power lasers with a very wide emitting aperture are considered. The key factors, determining the saturation of the output optical power of high-power semiconductor lasers, are determined.

The effect of the active region design on the vertical far-field divergence is studied for high-power laser diodes based on asymmetric heterostructures with a 4-μm thick waveguide and active region designs based on single (SQW) and double (DQW) InGaAs quantum wells. It is shown that the number of quantum wells has a significant effect on the divergence determined by the angle with the 95

A heterostructure design aimed at a multiple increase of the l060nm laser output efficiency is proposed. To multiply the internal and external quantum efficiency, tunnel p-n junctions (T J) were placed in the waveguide. Designed and MOCVD-grown heterostructures including two TJs demonstrate. Fabricated laser diodes demonstrate a stable second-order mode operation and a slope efficiency of 2.4W / A.

High-power quasi-cw semiconductor lasers with an emitting aperture 800 mu m wide and a continuous p-contact are developed. Laser operation with a pulse duration of 1 ms, a repetition rate of 10 Hz, and a maximum peak power of 87 W at a wavelength 1060 - 1070 nm is demonstrated under pumping by current pulses with am amplitude of 97 A. Experimental estimates show that over-heating of the active region at the end of the laser pulse at a current of 97 A may reach 36.7 degrees C.

Ridge-waveguide semiconductor lasers operating in CW up to 500 mW with one TE00 mode and up to 2 W with few TE modes at RT are demonstrated. Highly dense arrays with stable Gaussian lateral far field (10 emitters, $200\ \mu\mathrm{m}$ total aperture) are shown to demonstrate 5 W in CW and 25 W in pulsed mode at RT.

Pulsed 910 nm laser sources based on triple tunnel-coupled AlGaAs/InGaAs/GaAs heterostructures were developed and studied. High fill-factor (96%) microbars with $3\times 800\ \mu \mathrm{m}$ aperture were fabricated and studied under pumping by high-current pulse source (up to 750A/130ns/1kHz). Peak optical power up to 1150W at 25°C and 905W at 75°C were demonstrated.

A pulsed source of radiation in the spectral region of 1060 nm with a kilowatt level peak output power is developed based on a vertical stack of microbars of stripe semiconductor lasers with an ultra-wide (800 μm) aperture. The laser stack contains three microbars with three emitters each, which ensures an emitting area of 2.6 × 0.4 mm. The highest radiative efficiency of the stack is 2.48 W A −1 . The maximum achieved peak power reached 1400 W under pumping by current pulses with an amplitude of 650 A and a duration of 100 ns and is limited by the current source capacity.

Semiconductor lasers with a 10-μm-wide lateral mesa-stripe waveguide are developed, and their radiative characteristics are studied. It is shown that the continuous wave (cw) optical power of lasers with a 4.6-mm-long cavity reaches 2.6 W at a heat-sink temperature of 25°C. Lasers with shorter cavities (<3 mm) showed lower maximum optical powers due to thermal rollover of the light–current characteristic.

Pulsed radiative characteristics of high-power semiconductor lasers based on an asymmetric InGaAs/AlGaAs/GaAs heterostructure with an active region including two quantum wells and a gradient waveguide on the side of the p-emitter are studied. It is shown that the use of the proposed design allows efficient laser operation under pumping by 100-ns current pulses in the temperature range 25 – 90 °C. The lasers with a Fabry – Perot cavity 2900 μm long demonstrated peak powers of 62 W (injection current 123 A) and 43 W (122 A) at temperatures of 25 and 90 °C, respectively. It is found that at room temperature and currents of ∼50A, a decrease in the cavity length to 600 μm does not cause a decrease in the output power with respect to the power of lasers with a long (2900 μm) cavity. An increase in temperature to 90 °C at high injection currents leads to a sharp decrease in the radiative efficiency of lasers with a short (600 μm) cavity and to the change of their operation regime to the two-band lasing.

At ultrahigh levels of pulsed current pumping, the characteristics of semiconductor lasers based on an asymmetric heterostructure with a broadened lateral waveguide of a mesa-stripe design are studied. A peak power of 5.1 W is demonstrated at a pump current amplitude of 10 A. Three types of spatial dynamics of laser radiation are determined: the first one is a slow (~ 200 ns) intensity profile variation along the lateral near field at initial level of pump currents; the second one is a presence of fast (~ 10 ns) processes of mode competition at moderate pump currents; the third one is a chaotic temporal behavior of the output power at maximum pump currents.

Semiconductor lasers with a 10 μm wide lateral waveguide of a mesa-stripe design were developed and their light characteristics were studied. Lasers with a 4.6mm long cavity is shown to have a continuous wave (CW) optical power of 2.6W at a heatsink temperature of 25◦C. Lasers with a shorter cavity (< 3mm) showed a lower value of the maximum optical power due to a thermal rollover of the light-current curve.

Рассмотрены основные типы полупроводниковых лазеров, используемых в системах радиофотоники для передачи СВЧ-энергии и информации. Приведены характеристики разработанных мощных многомодовых и одномодовых полупроводниковых лазеров, а также оптоволоконных приемо-передающих модулей на их основе.

We report on the unusually large blue shift of electroluminescence spectrum with increase of the drive current at 77 K in a double-barrier nanoheterostructure with a deep AlSb/InAs0.83Sb0.17/AlSb quantum well grown by MOVPE on n-GaSb:Te substrate. The rise of drive current from 20 to 220 mA led to shift of the electroluminescence spectrum maximum towards higher photon energies by 100 meV. It was shown that this effect is due to indirect (tunneling) radiative transitions between electrons in InAsSb quantum well and heavy holes localized near AlSb/p-GaSb heterointerface. Energy of radiative transition was linearly dependent on applied voltage. In the drive current range of 50–220 mA electroluminescence blue shift was accompanied by the spectrum narrowing by 40 meV and noticeable change of the spectrum shape. With rise in drive current superlinear increase of electroluminescence intensity caused by the nonlinear dependence of tunneling radiative recombination rate on transition energy was observed at 300 and 77 K.

Characteristics of semiconductor lasers based on asymmetric heterostructures with broadened lateral waveguide of mesa-stripe design have been studied at ultrahigh levels of pulsed current pumping. A peak power of 5.1 W was demonstrated at a drive current amplitude of 10 A. Three types of spatial dynamics of laser emission were determined: slow (~200 ns) rearrangement of the intensity along the lateral near field is characteristic of the initial level of drive currents, fast processes of mode competition (~10 ns) are characteristic of moderate drive currents, and rearrangements are not repeated from pulse to pulse, being of chaotic nature, at maximum drive currents.

For the first time, an analysis of a series of laser heterostructures with different active-region designs and cavity parameters is performed to solve the problem of generating sub-ns pulses with different characteristics (duration and peak optical power). For the study, semiconductor lasers of a mesa-stripe design with an aperture width of 100 μm and current pulses with a pulse base from 1 ns to 3 ns and an amplitude up to 50 A were used. It is shown that the minimum pulse width of the first relaxation peak was 50 ps at a peak power of up to 3 W with a combination of such parameters as a single QW, an optical confinement factor of 1.23 % and a cavity length of 700 μm. The use of multiple quantum well heterostructures provided the generation of pulses with a peak power of up to 30 W and a pulse width of 100-200 ps.

A comparative analysis of two types of heterostructures (1) symmetric with a single-mode ultrathin waveguide (0.1 μm thick) and (2) asymmetric with a multimode ultra-wide waveguide (1.7 μm thick). In the case of heterostructure (2) the maximum CW optical power reached is 1.6 W at 25 degrees and 2 W at -8 degrees, while the maximum efficiency reached is 54 %. Under the pulsed pump for both types of heterostructures, there is a time domain of unstable lasing.

Longitudinal spatial hole burning (LSHB) in high-power semiconductor lasers is analysed by numerically solving one-dimensional (1D) rate equations. Calculations are performed for GaAs-based lasers operating at a wavelength of 1.06 μm. It is shown that the LSHB-induced decrease in output power can be accounted for by two mechanisms: build-up of spontaneous recombination and decrease in slope efficiency, equivalent to a rise in internal optical loss. We analyse the influence of different laser chip parameters on the magnitude of the LSHB effect. In particular, it is shown that to suppress LSHB it is preferable to increase the optical confinement factor Γ. We examine the relationship between LSHB and other mechanisms capable of reducing the output power.

Design of a structure with QWs distributed in a broadened waveguide layer is presented, which ensures mode selection, preserves the fundamental mode, provides minimum difference of optical confinement factors between QWs for matching the threshold conditions. A peak optical power of 15 W is demonstrated with a pulse width of 80 ps.