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Superluminescent diodes based on AlGaInAs/InP separate-confinement double heterostructures with strain-compensated quantum wells are investigated. The influence of elastic strains in the active region on the output characteristics of the devices is analysed. It is shown that such a design of a superluminescent diode allows an optical power of more than 5 mW, a radiation spectrum width of more than 60 nm, a degree of output radiation polarisation up to 30 dB to be obtained at the output of a single-mode fibre, and has a great potential for further improvement.

Comprehensive physical and technological studies on the creation of mesastripe structures with a channel in the substrate and subsequent burying of the structure with a layer of zinc selenide are carry out. Planarity of heterointerfaces between the substrate and epitaxial layers is studied by electron microscopy. The atomic structure of epitaxial layers GaInAsP/InP is studied by transmission electron microscopy. The profiles of epitaxial layers of the heterostructure are analyzed by secondary ion mass spectroscopy (SIMS). Layers with required composition of In0.78Ga0.22As0.68P0.32 corresponding to a laser wavelength of 1.3 μm are obtained. A technique for creating laser diodes with a channel in the substrate, including etching of mesastripe structure and burying with a layer of zinc selenide, is developed for the first time. This technique makes it possible to create laser diodes both with an optical confinement of laser emission and with a confinement of the current flow along the laser strip. Etching of p–n junction layers between laser strips and burying with zinc selenide on the surface of etched structure are developed for the first time. This technique made it possible to create heterostructures for laser diodes operating in the microwave range up to 10 GHz by liquid phase epitaxy (LPE). The ability to create and operate laser diodes in this design and technology is shown. The current–voltage characteristics, watt–ampere characteristics, and spectral characteristics of laser diodes are investigated. Russian technology for the creation of a microwave laser diode on a heterostructure with a channel in the substrate and repeated burying with zinc selenide is proposed. The prospects of using laser diodes of mesastripe structure with a channel in the substrate and buried with a layer of zinc selenide to create fast-response devices are shown.

Buried light edge-emitting diodes (LEDs) with a wide emission spectrum in the wavelength range of 1380–1420 nm were developed. The design of an edge LED with a channel in a substrate and with the crescent active region and blocking layers of InP/GaInAsP/p-n-p-n/ZnSe was presented. Coupling of LED with an optical single-mode fiber and a microlens on the end of an optical fiber was performed. The characteristics of LEDs based on mesa-stripe heterostructures InP/GaInAsP were investigated. The dependences of the output power and the LED emission spectra based on mesa-stripe heterostructures InP/InGaAsP/InP with the crescent active region and p-n-p-n/ZnSe structure blocking the leakage current on the stabilization temperature of the active element and the injection current were studied. The dependence of the output parameters on the emitter stabilization temperature was demonstrated, which enables the creation of devices based on such LEDs both with and without forced cooling. The opportunity to develop buried LEDs with the crescent active region and a low degree of emission spectrum modulation was shown. The possibility of the entry of up to 45% of the LED radiation into a single-mode optical fiber using microlenses produced by chemical etching and fusion of a fiber end in a high-voltage arc of a welding machine was demonstrated.

A process has been developed for the liquid phase epitaxy of mesa stripe buried crescent InP/InGaAsP/InP heterostructures with a p–n–p–n/ZnSe leakage current-blocking structure. The salient feature of the process is a discontinuous mesa stripe which alternates with the structure of blocking layers. This technology allows one to fabricate linear edge-emitting diodes, mounted with the mesa stripe down or up, with an emission wavelength λ = 1.3–1.5 μm, high reproducibility, the possibility of coupling more than 50 μW of optical power into single-mode fiber at a current of 100 mA, an emission bandwidth of about 60 nm, and essentially negligible Fabry–Perot modulation.

We have developed two new types of lasers based on quantum-confined semiconductor optical amplifiers with an acousto-optic tunable filter in an external fibre ring cavity. The lasers offer continuous wavelength tuning ranges from 780 to 885 and from 880 to 1010 nm, 20 mW of cw output power, and a tuning rate up to 104 nm s-1 at an instantaneous spectral linewidth less than 0.1 nm.

Quantum-well superluminescent diodes (SLD) with extremely thin active (AlGa)As and (InGa)As layers and centre wavelengths about 810, 840, 860 and 880 nm are experimentally studied. Their emission spectrum possesses the shape close to Gaussian, its FWHM being 30 – 60 nm depending on the length of the active channel and the level of pumping. Under cw injection, the output power of light-emitting modules based on such SLDs can amount to 1.0 – 25 mW at the output of a single-mode fibre. It is demonstrated that the operation lifetime of these devices exceeds 30000 hours. Based on the light-emitting modules the prototypes of combined BroadLighter series light sources are implemented having a bell-shaped spectrum with the width up to 100 nm.

A method of service life tests of SLD-37 quantum-well superluminescent diodes (SLDs), which are widely used in optical coherence tomography, is described and the results of tests are presented. Special attention is given to variations in the emission spectra of SLDs during their aging. It is shown that this method can be used as an incoming test to select processed semiconductor heterostructures with the longest expected lifetime for fabrication of active elements of SLD modules.

Highly efficient and reliable single-mode superluminescent diodes (SLDs) with median wavelengths of 795, 840, 960 and 1060 nm and free-space output optical power (PFS) of up to 100 mW are developed. Main parameters of lightemitting modules based on these SLDs are presented.

Superluminescent diodes (SLDs) based on double quantum-well (AlGa)As/GaAs heterostructures emitting between 800 and 900 nm are studied experimentally. These SLDs provide a high enough output power in the emission bandwidth more than 55 nm at much shorter active channel lengths than SLDs based on similar single quantum-well heterostructures. Despite the high injection current density, the service life of the SLDs exceeds 10000 hours.

Quantum-well (QW) superluminescent diodes (SLDs) with an extremely thin (AlGa)As and (InGa)As active layers and central wavelengths of 810 nm, 840 nm, 860 nm and 880 nm are studied. Their emission spectra possess quasi-gaussian shape with FWHM of 30 - 60 nm depending on active channel length and pumping level. In CW operation mode light-emitting modules based on these SLDs exhibit optical power of 1.0 - 25 mW ex SMF and high enough life time exceeding 30 000 h. The prototypes of combined light sources of BroadLighter series based on these SLDs with bell-shaped spectra of up to 100nm FWHM are realized.

Methods and results of reliability tests of SQW broad-band superluminescent diodes (SLD-37 series), widely used in optical coherence tomography (OCT) are presented. Main attention was paid to the alteration of SLD spectral characteristics in the aging process. It is shown that the usage of these methods in the input control of processed epiwafers deployed in the production of active elements for SLD-modules ensures the estimation of their expected life time (MTTF).

Tapered semiconductor optical amplifier (SOA) based on SQW improved nanostructure (gain maximum at 840 nm) was used as output power amplifier in MOPA-system with SLD as master oscillator. CW output power of up to 0.5 W ex standard multimode fiber (MMF) was obtained.

Two types of superluminescent diodes (SLDs) based on DQW (InGa)As/(GaAl)As/GaAs nanostructures with 25 µm-width multimode active channels emitting at 890 nm and 950nm were studied. They ensure CW optical power of more than 100 mW ex standard 50 µm multimode fiber (MMF).

The results of recent studies of superluminescent diodes (SLDs) based on new quantum-well (QW) (GaAl)As and (InGa)As heterostructures of spectral range 800 - 900 nm with spectral bandwidths of up to 80 nm and output power ex SM fiber of up to 50 mW are presented.

The prototypes of high-efficiency SLDs with COD threshold of more than 5•10 6 W/cm 2 were investigated. Single spatial mode samples with 4 μm-wide active channel exhibited CW output power of more than 200 mW. Preliminary reliability tests at 100 mW level were successful. It was shown that in double-pass operation mode achieved using SM fiber reflector, external efficiency can be increased significantly. The estimations show that multimode SLD with 20-30 μm active channel width based on the same QW heterostructure may ensure reliable enough operation at output power level of more than 0.5W.

SLDs and SOAs for HR OCT basing on strained InGaAs/AlGaAs/GaAs QWs at 850 and 1060 nm with ASE/gain bandwidths of 40-50 nm and output power ex SM fiber of up to 50mW are reported.