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Thermally induced changes of broad contact pulse-operated single quantum well (SQW) separate confinement heterostructure (SCH) laser spectra

Kowalczyk E., Ornoch L., Szerling A., Mroziewicz B.

Optica Applicata

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2005

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Vol. 35, nr 3

573-578

EN

A technique of time-resolved laser spectra mapping has been developed to assess thermo-optical properties of diode lasers. Using this technique the emission spectra of broad contact pulse operated diode lasers were measured for consecutive time points within the pulse duration width. The emitted wavelength was found to be highly dependent on the time elapsing from the pulse front and a time shift of wavelength was clearly observed in the spectrum of pulse-operated lasers.

2

Deep centers in InGaAs/InP layers grown by molecular beam epitaxy

Kowalczyk A. E., Ornoch L., Muszalski J., Kaniewski J., Bąk-Misiuk J.

Optica Applicata

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2005

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Vol. 35, nr 3

457-463

EN

The deep level transient spectroscopy (DLTS) method was applied to study deep centers in lattici mismatched InGaAs/InP layers grown by molecular beam epitaxy. The composition and the strair state of the layers were determined using X-ray diffraction technique. Electron trap with therma; activation energy Ec - (0.06 + 0.03) eV and electron capture cross-section b(beta)e = 9.0x10-19 cm-2 have been detected in In0.524Ga0.476As layers being under tensile strain. Additionally two other centers with thermal activation energy Ec - (0.10 š 0.02) eV, and Ec - (0.48 š 0.02) eV have been revealed in In0.533Ga0.467As/InP layers subjected to small compressive strain. The electron capture cross-sections of these traps, determined from emission processes, are equal to be = 6.7x10-18 cm-2 and be= 1.6x10-14 cm-2, respectively. Due to temperature stresses, defect states in the In0.533Ga0.467As/InP layers are modified and the center Ec - (0.06 š 0.03) eV is created. This center is identical to that observed in In0.524Ga0.476gAs layers, as it has been confirmed by electron capture process measurements. The Ec - (0.06 š 0.03) eV state exhibits a point-like defect character.

3

Analysis of thermal conditions of pulse operated single quantum well separate confinement heterostructure (SQW SCH) lasers

Ornoch L., Kowalczyk E., Mroziewicz B.

Optica Applicata

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2005

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Vol. 35, nr 3

591-595

EN

Junction temperature affects laser diode performance in many ways. Magnitude of the light output power, a center wavelength of the spectrum and diode reliability are all strongly dependent on the junction temperature. A simple electrical method to measure laser diode junction temperature has been developed. It is based on the measurement of the junction voltage change, which is due to the change of its temperature and is induced by supplying the laser with DC current in parallel to the pulsed driving current. Junction temperature dynamics in the pulse operated GaAs based SQW SCH quantum well broad contact lasers designed for emission at 980 nm was studied and results are presented. Additionally, junction cooling in these lasers as a function of time was also assessed.