B. Mroziewicz - Academia.edu (original) (raw)

Papers by B. Mroziewicz

ABSTRACT Threshold current and differential quatnum efficiency of broad contact lasers with optic... more ABSTRACT Threshold current and differential quatnum efficiency of broad contact lasers with optically asymmetric mirrors is discussed with the purpose to reveal factors essential for optimization of the power efficiency of such lasers.

ASDAM 2000. Conference Proceedings. Third International EuroConference on Advanced Semiconductor Devices and Microsystems (Cat. No.00EX386), 2000

ASDAM 2000. Conference Proceedings. Third International EuroConference on Advanced Semiconductor Devices and Microsystems (Cat. No.00EX386), 2000

The operation of InGaAs/GaAs SCH SQW lasers emitting at the wavelength 1.02-1.03 μm, fabricated b... more The operation of InGaAs/GaAs SCH SQW lasers emitting at the wavelength 1.02-1.03 μm, fabricated by MBE technology, is reported. Longer wavelength of emission was achieved by applying high indium content in the active region. The paper presents characteristics of fabricated structures measured at room temperature (T=300 K) under pulsed operation. The results are promising and give hope for fabricating structures

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Strained layer InGaAs/GaAs SCH SQW (Separate Confinement Heterostructure Single Quantum Well) las... more 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 J th ≈ 280 A/cm 2 (for the resonator length L = 700 µm) and differential efficiency η = 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 J th = 210 A/cm and η = 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.

Lasers and Applications, 2005

ABSTRACT External cavity lasers (ECLs) have been around for many years and are recognised as usef... more ABSTRACT External cavity lasers (ECLs) have been around for many years and are recognised as useful tunable narrow line light sources. In this communication we present space resolved spectral characteristics of the ECLs with a standard glass grating and ridge-waveguide broad-contact optical amplifiers (SOAs). The gain of the SOAs was centered in the range of 960 to 980 nm. The spectral characteristics have been measured with an optical spectrum analyzer. The results are compared with the ones obtained after the glass grating was substituted by a grating made from silicon. Application of such silicon gratings can be considered as a first step towards ECLs made fully in a MEMS configuration.

Deep insight into thermal effects in the broad-area lasers is the main condition of obtaining the... more Deep insight into thermal effects in the broad-area lasers is the main condition of obtaining the improved devices. We present the analytical solution of the two-dimensional, stationary heat conduction equation yielding the temperature profile in the laser cross-section in plane parallel to the mirrors. Our approach allows for considering various heating mechanisms and assessing their contribution to the total temperature of the device.

Optical and Quantum Electronics, 2014

The intra-pulse measurements of the beam steering in an AlGaAs/GaAs quantum cascade laser are pre... more The intra-pulse measurements of the beam steering in an AlGaAs/GaAs quantum cascade laser are presented in this paper. The experimental results are explained by a twomode theoretical model. The near field of the laser radiation is calculated according to the effective index method and transposed to the far field numerically according to Huygens principle. The maximal observed value of deflection of the beam has been found to be 17 • . For supply currents in the range from 1.6 to 2.4 times the threshold the beam steering occurs only on one side of the resonator axis, and stays is the same for all current values. For higher supply current, it occurs alternately on both sides and exhibits a bistability. The time period of the beam direction change has been found to be about 40 ns for the lowest current and was decreasing with the current increase to about 20 ns.

Proceedings of SPIE - The International Society for Optical Engineering, 2013

ABSTRACT Quantum cascade lasers (QCL's) have proven their usefulness as light sources in ... more ABSTRACT Quantum cascade lasers (QCL's) have proven their usefulness as light sources in many applications, like remote gas sensing, molecular spectroscopy or free-space communication. In most cases the high-quality low-divergence beam is desired. This work presents the theoretical analysis of QCL's beam divergence. The electromagnetic field in the resonator is calculated according to effective index method. Theoretical results are compared with measurements.

Proceedings of SPIE - The International Society for Optical Engineering, 2013

The paper presents results of experimental investigations of spatial distribution of radiation em... more The paper presents results of experimental investigations of spatial distribution of radiation emitted by quantum cascade lasers. Measurements have been performed by means of a unique goniometric profilometer specially designed for the large angle laser beams. The advantages and limitations of the set-up and the applied experimental method are discussed. The obtained results have enabled the analysis of dependence of geometry of the beam on the geometry of the laser structure and on the mount method of the laser chips. The angular divergence of the beams has also been tested as a function of laser power supply.

ABSTRACT Threshold current and differential quatnum efficiency of broad contact lasers with optic... more ABSTRACT Threshold current and differential quatnum efficiency of broad contact lasers with optically asymmetric mirrors is discussed with the purpose to reveal factors essential for optimization of the power efficiency of such lasers.

ASDAM 2000. Conference Proceedings. Third International EuroConference on Advanced Semiconductor Devices and Microsystems (Cat. No.00EX386), 2000

ASDAM 2000. Conference Proceedings. Third International EuroConference on Advanced Semiconductor Devices and Microsystems (Cat. No.00EX386), 2000

The operation of InGaAs/GaAs SCH SQW lasers emitting at the wavelength 1.02-1.03 μm, fabricated b... more The operation of InGaAs/GaAs SCH SQW lasers emitting at the wavelength 1.02-1.03 μm, fabricated by MBE technology, is reported. Longer wavelength of emission was achieved by applying high indium content in the active region. The paper presents characteristics of fabricated structures measured at room temperature (T=300 K) under pulsed operation. The results are promising and give hope for fabricating structures

[

Strained layer InGaAs/GaAs SCH SQW (Separate Confinement Heterostructure Single Quantum Well) las... more 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 J th ≈ 280 A/cm 2 (for the resonator length L = 700 µm) and differential efficiency η = 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 J th = 210 A/cm and η = 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.

Lasers and Applications, 2005

ABSTRACT External cavity lasers (ECLs) have been around for many years and are recognised as usef... more ABSTRACT External cavity lasers (ECLs) have been around for many years and are recognised as useful tunable narrow line light sources. In this communication we present space resolved spectral characteristics of the ECLs with a standard glass grating and ridge-waveguide broad-contact optical amplifiers (SOAs). The gain of the SOAs was centered in the range of 960 to 980 nm. The spectral characteristics have been measured with an optical spectrum analyzer. The results are compared with the ones obtained after the glass grating was substituted by a grating made from silicon. Application of such silicon gratings can be considered as a first step towards ECLs made fully in a MEMS configuration.

Deep insight into thermal effects in the broad-area lasers is the main condition of obtaining the... more Deep insight into thermal effects in the broad-area lasers is the main condition of obtaining the improved devices. We present the analytical solution of the two-dimensional, stationary heat conduction equation yielding the temperature profile in the laser cross-section in plane parallel to the mirrors. Our approach allows for considering various heating mechanisms and assessing their contribution to the total temperature of the device.

Optical and Quantum Electronics, 2014

The intra-pulse measurements of the beam steering in an AlGaAs/GaAs quantum cascade laser are pre... more The intra-pulse measurements of the beam steering in an AlGaAs/GaAs quantum cascade laser are presented in this paper. The experimental results are explained by a twomode theoretical model. The near field of the laser radiation is calculated according to the effective index method and transposed to the far field numerically according to Huygens principle. The maximal observed value of deflection of the beam has been found to be 17 • . For supply currents in the range from 1.6 to 2.4 times the threshold the beam steering occurs only on one side of the resonator axis, and stays is the same for all current values. For higher supply current, it occurs alternately on both sides and exhibits a bistability. The time period of the beam direction change has been found to be about 40 ns for the lowest current and was decreasing with the current increase to about 20 ns.

Proceedings of SPIE - The International Society for Optical Engineering, 2013

ABSTRACT Quantum cascade lasers (QCL's) have proven their usefulness as light sources in ... more ABSTRACT Quantum cascade lasers (QCL's) have proven their usefulness as light sources in many applications, like remote gas sensing, molecular spectroscopy or free-space communication. In most cases the high-quality low-divergence beam is desired. This work presents the theoretical analysis of QCL's beam divergence. The electromagnetic field in the resonator is calculated according to effective index method. Theoretical results are compared with measurements.

Proceedings of SPIE - The International Society for Optical Engineering, 2013

The paper presents results of experimental investigations of spatial distribution of radiation em... more The paper presents results of experimental investigations of spatial distribution of radiation emitted by quantum cascade lasers. Measurements have been performed by means of a unique goniometric profilometer specially designed for the large angle laser beams. The advantages and limitations of the set-up and the applied experimental method are discussed. The obtained results have enabled the analysis of dependence of geometry of the beam on the geometry of the laser structure and on the mount method of the laser chips. The angular divergence of the beams has also been tested as a function of laser power supply.