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High power QW SCH InGaAs/GaAs lasers for 980-nm band

Bugajski M., Mroziewicz B., Regiński K., Muszalski J., Kosiel K., Zbroszczyk M., Ochalski T., Piwoński T., Wawer D., Szerling A., Kowalczyk E., Wrzesińska H., Górska M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2005

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Vol. 53, nr 2

113-122

EN

Strained layer InGaAs/GaAs SCH SQW (Separate Confinement Heterostructure Single Quantum Well) lasers were grown by Molecular Beam Epitaxy (MBE). Highly reliable CW (continuous wave) 980-nm, broad contact, pump lasers were fabricated in stripe geometry using Schottky isolation and ridge waveguide construction. Threshold current densities of the order of Jth = 280 A/cm2 (for the resonator length L = 700 [mu]m) and differential efficiency [eta]= 0.40 W/A (41%) from one mirror were obtained. The record wall-plug efficiency for AR/HR coated devices was equal to 54%. Theoretical estimations of above parameters, obtained by numerical modelling of devices were Jth = 210 A/cm and [eta] = 0.47 W / A from one mirror, respectively. Degradation studies revealed that uncoated and AR/HR coated devices did not show any appreciable degradation after 1500 hrs of CW operation at 35°C heat sink temperature at the constant optical power (50 mW) conditions.

2

Numerical simulation of semiconductor lasers

Zbroszczyk M.

Optica Applicata

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2002

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Vol. 32, nr 3

461-468

EN

Numerical simulation based on the self-consistent solution of Poisson equation, current continuity equations, as well as on the wave equation and photon rate equation has been used to optimize lasers designs. Results of modelling for GaAs/AlGaAs, InGaAlAs/GaAs and InGaAs/GaAs quantum well lasers are presented.

3

Numerical calculation of electron density distribution in modulation-doped GaAs/AlGaAs heterostructures

Szymański M., Zbroszczyk M.

Optica Applicata

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2002

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Vol. 32, nr 3

529-534

EN

Electron density distribution in GaAs/AlGaAs heterostructure is calculated. In addition, the diagram of the conduction band edge is presented. The results were obtained through the self-consistent solution of one-dimensional Schrödinger–Poisson equations. For numerical calculations the finite-difference method with non-uniform mesh has been used.

4

High power AlGaAs/GaAs lasers with improved optical degradation level

Bugajski M., Zbroszczyk M., Sajewicz P., Muszalski J.

Optica Applicata

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2002

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Vol. 32, nr 3

469-475

EN

Accurate numerical simulation of AlGaAs/GaAs SQW SCH lasers and MQW SCH lasers is presented. We discuss the performance of both types of lasers with regard to high power operation at 808 nm spectral band which is of interest for diode pumped Nd:YAG lasers. Design rules for above-mentioned lasers are formulated. From the analysis presented it follows that MQW SCH lasers are better suited for high power applications and exhibit a superior tolerance to inherent construction parameters variations, as well as to external operation parameters. We also test different waveguide designs. The most important conclusion is that broader waveguides are suitable for obtaining higher optical powers and generally result in higher COD (catastrophic optical degradation) level.

5

High-performance 980-nm strained-layer InGaAs/GaAs quantum-well lasers

Bugajski M., Regiński K., Mroziewicz B., Kubica J.M., Sajewicz P., Piwoński T., Zbroszczyk M.

Optica Applicata

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2001

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Vol. 31, nr 2

267-271

EN

Reports fabrication of strained-layer InGaAs/GaAs separate-confinement-heterostructure single-quantum-well (SCH SQW) lasers operating in the wavelength range of 980 nm. Design process of the devices involved simulation of their above-threshold operation including all relevant physical phenomena. The lasers were characterized at room temperature in the pulsed operation regime at frequency v=5 kHz and pulse length tau =200 ns. Threshold current densities of the order J/sub th/=280 A/cm/sup 2/ and differential efficiency eta =0.40 W/A were obtained for devices with cavities of 700 mu m in length and broad contacts of 100 mu m in width

6

Surface energy of semiconductors covered with thin layers of various materials

Zbroszczyk M., Adamowicz L.

Electron Technology

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1998

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Vol. 31, No. 3/4

358-361

EN

Surface energy of III-V semiconductors edned by (110) clean surface and surface covered by atomic monolayer of aluminium, copper and sulphur has been calculated. We have used the Greens-fuction technique based on the scheme of linear muffin-tin orbitals in the atomic sphere approximation (LMTO-ASA) for the crystal potential and with the local density approximation (LDA) for electrons. Two types of coverage are considered: full monolayer with two additional atoms per two-dimensional until cell and half monolayer with one additional atom per until cell. Full monolayer of metallic atoms increase the surface energy. Cu atoms lead to great destabilization than Al atoms. Sulphur atoms stabilize the (110) surface for all considered compounds.