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Thermoreflectance study of temperature distribution on the semiconductor laser mirrors

Piwoński T., Wawer D., Szymański M., Ochalski T., Bugajski M.

Optica Applicata

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2005

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Vol. 35, nr 3

611-617

EN

In the high power semiconductor lasers, the surface of the mirror is the key element of the construction, which has the main impact on the reliability and degradation processes. In the case of lasers fabricated with the use of GaAs compounds the highest power emitted by the structure is limited by the catastrophic optical damage (COD) effect due to increase of temperature on the air-semiconductor edge. The technique which enables examining the temperature distribution on the mirror surface is thermoreflectance. In this paper, we present the technique of temperature mapping on the mirror surface of the high power semiconductor lasers based on the thermoreflectance method.

2

Thermoreflectance and micro-Raman measurements of the temperature distributions in broad contact laser diodes

Ochalski T. J., Piwoński T., Wawer D., Pierściński K., Bugajski M., Kozłowska A., Maląg A., Tomm J. W.

Optica Applicata

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2005

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Vol. 35, nr 3

479-484

EN

In this paper we describe a number of optical techniques suitable for estimation of the semiconductor surface temperature. High spatially resolved thermoreflectance will be shown as a powerful tool to measure temperature distribution at the laser diode front facet. For determination of the absolute value of the front facet temperature we use micro-Raman spectroscopy. Both techniques will be presented as a complementary ways to determine surface temperature distribution on the working laser diode.

3

Analysis of mounting induced strain in semiconductor structures by means of spatially resolved optical modulation techniques

Pierściński K., Piwoński T., Ochalski T. J., Kowalczyk E., Wawer D., Bugajski M.

Optica Applicata

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2005

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Vol. 35, nr 3

605-610

EN

A wide range of applications of high-power diode lasers is connected with the tendency towards device miniaturization resulting in increased power densities. To manage the thermal load, the chips or arrays of chips (the so-called laser lines or cm-bars) have to be mounted with low thermal resistance on a heat sink of high thermal conductivity. These measures potentially introduce mechanical strain and defects into the semiconductor chips affecting the parameters of laser emission, e.g., spectral position. The ability of optical modulation techniques to monitor spatial strain distribution along the devices was evaluated.

4

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.

5

The influence of MBE growth conditions on optical properties of InGlGaAs/AlGaAs structures

Kosiel K., Regiński K., Szerling A., Piwoński T., Bugajski M.

Electron Technology : Internet Journal

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2004

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Vol. 36, nr 4

1-3

EN

Optical properties of compressively strained In₀.₂₄Al₀.₁₉Ga₀.₅₇As layers were investigated as a function of the MBE growth conditions. The optimum temperature of the crystal surface (Ts) for MBE growth of this quaternary layer as well as the optimal cooling down process necessary for achieving appropriate Ts for InAlGaAs were experimentally found.

6

Reflectance study of SiO2/Si3N4 dielectric Bragg reflectors

Szerling A., Wawer D., Hejduk K., Piwoński T., Wójcik A., Mroziewicz B., Bugajski M.

Optica Applicata

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2002

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Vol. 32, nr 3

523-527

EN

We present the results of reflectance investigations into SiO2/Si3N4 dielectric distributed Bragg reflectors (DBR). The dielectric multilayers forming reflectors have been deposited by plasma enhanced chemical vapour deposition (PECVD) on silicon substrates. Such structures can be utilised in vertical cavity surface emitting lasers (VCSELs) and resonant cavity light emitting diodes (RC LEDs)

7

Photoreflectance study of AlGaN/GaN heterostructures grown by MOCVD process

Wójcik A., Piwoński T., Ochalski T.J., Kowalczyk E., Bugajski M., Grzegorczyk A., Macht Ł., Haffouz S., Larsen P.K.

Optica Applicata

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2002

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Vol. 32, nr 3

431-435

EN

In this paper we report the results of photoreflectance (PR) spectroscopy of GaN/AlGaN heterostructures used for realisation of high electron mobility transistors (HEMTs). For the proper operation of such structures a triangular quantum well created at the interface between GaN and AlGaN is required. Due to quantum confinement in this area 2DEG is created. The data obtained from PR technique allow to estimate a real shape of 2DEG confinement potential, what is necessary for verification of design and correctness of the growth process.

8

Strained layer SCH SQW InGaAs/GaAs lasers for 980-nm band

Bugajski M., Mroziewicz B., Regiński K., Muszalski J., Kubica J., Zborszczyk M., Sajewicz P., Piwoński T., Jachymek A., Rutkowski R., Ochalski T., Wójcik E., Kowalczyk E., Maląg A., Kozłowska A., Dobrzański L., Jagoda A.

Opto-Electronics Review

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2001

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Vol. 9, No. 1

35-47

EN

Strained layer InGaAsIGaAs SCH SQW (separate confinement heterostructure single quantum well) lasers were grown by a molecularbeam epitaxy (MBE). Highly reliable CW (continuous wave) 98O-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 um) and differential efficiency ƞ = 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/cm² and ƞ = 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 3000 hr of CW operation at at 35°C heat sink temperature at the constant optical power (50 mW) conditions

9

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