Semiconductor lasers have developed rapidly with the steady growth of the global laser market. The use of semiconductor laser diodes is currently considered to be the most advanced option for achieving the optimal combination of efficiency, energy consumption, and cost parameters of high-power solid-state and fiber lasers. In this work, an approach for optical mode engineering in planar waveguides is investigated. The approach referred to as Coupled Large Optical Cavity (CLOC) is based on the resonant optical coupling between waveguides and allows the selection of high-order modes. The state-of-art of the CLOC operation is reviewed and discussed. We apply the CLOC concept in our waveguide design strategy. The results in both numerical simulation and experiment show that the CLOC approach can be considered a simple and cost-efficient solution for improving diode laser performance.

Injection microlasers with an active region based on arrays of InGaAs/GaAs quantum well-dots, formed by deep etching, have been studied. The manner in which the current–voltage characteristic...

An improved technique for thermal resistance measurement of edge-emitting diode lasers using spontaneous emission spectra, collected through the opening in the n-contact within the range of operating currents, has been proposed. The advantage of the proposed technique is that systematic errors typical for measurements based on lasing spectra are excluded. The accuracy of the method was verified by measuring the dependence of the thermal resistance on the cavity length for diode lasers with 100 μm strip width. Obtained results are in good agreement with the model, and the minimum measurement error was ±0.1 K/W. The proposed technique can be used in metrological support of fabrication process of semiconductor lasers. Keywords: laser diode, thermal resistance, spontaneous emission.

We study the applicability of InGaAs/GaAs quantum well-dots (QWDs) for active regions of broadband superluminescent diodes (SLDs) emitting in the 950–1150 nm spectral range; 2 mm long SLDs with a bent section and an active region based on seven chirped QWD layers show emission spectra centered at 1030 nm with a full-width at half-maximum of 80 nm and an output power of 2 mW. In a 250 µm long SLD with a tilted stripe that has an increased output loss, the width of the emission spectra is 113 nm at 20 °C and 120 nm at 60 °C.

Edge-emitting lasers with active regions based on novel InGaAs/GaAs quantum heterostructures of transitional dimensionality, i.e., quantum well-dots, which are intermediate in properties between quantum wells and quantum dots, are studied. It is shown that the rate of the lasing-wavelength blue shift decreases with increasing number of quantum well-dot layers in the active region and with increasing optical confinement factor as the cavity length decreases. In a laser with 10 quantum well-dot layers, the lasing-wavelength position remains within the limits of the fundamental optical transition down to the smallest cavity lengths (100 μm). In devices with a single quantum well-dot layer and/or with a low optical confinement factor, lasing directly switches from the ground state to waveguide states omitting excited states below ≤200 μm. Such an effect has not been observed in quantum-well- and quantum-dot lasers and can be attributed to the abnormally low density of excited states in quantum well-dots.

We report on an investigation of InGaAs/GaAs quantum well-dot superluminescent diodes (SLDs) based on what we believe to be a novel and simple design of stripe waveguides. The design employing a chip side facet as a component of the SLD structure allows effective suppression of optical feedback, thus increasing the optical power. The test SLDs under study emitting in 950–1150 nm spectral range show CW optical power as high as 150 mW in combination with broad emission spectra of 20 nm full width at half maximum (FWHM).