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1

Resonant cavity enhanced photonic devices.

Bugajski M., Muszalski J., Mroziewicz B., Regiński K., Ochalski T.J.

Optica Applicata

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2001

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Vol. 31, nr 2

273-288

EN

We review our recent works on technology, basic physics and applications of one-dimensional photonic structures. We demonstrate spontaneous emission control in In/sub x/Ga/sub 1-x/As/GaAs planar microcavities with DBR reflectors. The room temperature emission in lambda -sized cavities is enhanced in comparison with its free space value, while in lambda /2-sized cavities suppression of spontaneous emission is observed. The characteristics of spontaneous emission in microcavities depend on the wavelength difference between the emitter and the cavity resonance. It has been shown that ideal tuning of the cavity can be achieved by adjusting sample temperature. In general, observed trends are in agreement with theoretical predictions. These changes to the spontaneous emission process directly affect vertical-cavity laser (VCSEL) properties. An increased coupling efficiency of spontaneous emission into the lasing mode is observed in VCSELs with lambda -sized cavities. We demonstrate the operation of resonant-cavity light emitting diodes (RC LED) and optically pumped VCSELs developed recently at the Department of Physics and Technology of Low Dimensional Structures of the Institute of Electron Technology. The epitaxial growth issues, fabrication technology and basic characteristics of these devices are discussed

2

Operation of arsenide diode lasers at elevated temperatures

Czyszanowski T.

Optica Applicata

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2001

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Vol. 31, nr 2

301-311

EN

Some design modification and optimisation of the GaAs/(AlGa)As separate-confinement-heterostructure (SCH) as well as the graded-index separate-confinement-heterostructure (GRIN-SCH) semiconductor lasers are discussed to reduce their threshold concentrations at elevated temperatures. A detailed optical model of arsenide lasers is used to compare an impact of some structural details on lasing thresholds at various temperatures. In the analysis, both optical gain and losses are modelled rigorously. It has been demonstrated that operation of the arsenide lasers considered is not changing dramatically at elevated temperatures not exceeding 400 K.

3

Modelling of radial steam oxidation of AlAs layers in cylindrically symmetric mesa structures of vertical-cavity surface-emitting lasers

Nakwaski W., Maćkowiak P.

Optica Applicata

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2001

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Vol. 31, nr 2

289-299

EN

During the last several years selective steam oxidation process has evolved into a key technology in fabrication of high-performance vertical-cavity surface-emitting lasers (VCSELs). In the paper, kinetics of AlAs steam oxidation process in cylindrically symmetric VCSEL mesa structures is investigated theoretically. Compact analytical formulae describing the oxidation process are derived and discussed. The process parameters are extracted from existing experimental data. The parameters are found to be strongly dependent on the AlAs layer thickness and temperature. It is shown that significant differences exist between the predictions of the cylindrical model and those of widely used one-dimensional Cartesian model. Our detailed model can therefore be very important for achieving a good control of the oxidation process in fabrication of modern VCSELs

4

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

5

Design considerations for GaAs/(AlGa)As SCH and GRIN-SCH quantum-well laser structures. II. The results

Czyszanowski T., Wasiak M., Nakwaski W.

Optica Applicata

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2001

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Vol. 31, nr 2

325-336

EN

A detailed optical model of complex multi-layered structures of the separate-confinement-heterostructure (SCH) lasers as well as graded-index (GRIN) SCH lasers presented in the first part of the paper is used to discuss some of the possible modifications of their structure to reduce room-temperature thresholds. Recommended design parameters have been found for each structure. Surprisingly, performance of relatively simple SCH lasers is found to be at least comparable with that of much more complex GRIN-SCH lasers.

6

Design considerations for GaAs/(AlGa)As SCH and GRIN-SCH quantum-well laser structures. I. The model

Czyszanowski T., Wasiak M., Nakwaski W.

Optica Applicata

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2001

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Vol. 31, nr 2

313-323

EN

Some design modifications and optimization of the GaAs/(AlGa)As separate-confinement-heterostructure (SCH) as well as graded-index separate-confinement-heterostructure (GRIN-SCH) semiconductor lasers to reduce their room-temperature (RT) thresholds are discussed. To this end, a detailed optical model of arsenide diode lasers is developed and used to compare the impact of some structure details on RT lasing thresholds. In the model presented in the first part of the paper, both optical gain and losses are modeled rigorously. Optical fields within complex multi-layered structures of the SCH lasers are found using the downhill method. Threshold carrier concentrations are determined from the general balance of radiation gain and losses. As a result of the simulation, recommended basic design parameters for the above structures are deduced in the second part of the paper.