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1

Non-line of sight analysis for vehicular visible light communication system : impact of artificial light source and weather conditions

Tawfik Nagwan I., El-Mokadem Eslam Samy, Aly Moustafa H., El-Deeb Walid S.

Opto-Electronics Review

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2024

|

Vol. 32, No. 2

art. no. e150180

EN

Visible light communication is seen as a crucial technology within optical wireless communication systems. The technology of vehicular visible light communication holds significant importance in the context of connected vehicles. This technology can serve as a supplementary solution to vehicular systems that are based on radio frequency. In this paper, the authors conduct an analysis of the performance of both line-of-sight and non-line-of-sight vehicle-to-vehicle visible light communication systems under the effect of artificial light source and weather conditions, including clear, hazy, and foggy weather. A practical vehicular laser diode, a street lamp, and an avalanche photodiode are used to design the proposed system model. Performance enhancement for the proposed system is achieved using an optical amplifier at the receiving end. An artificial light source of light-emitting diode Corn-type is used to represent an ambient artificial light source. Different metrics such as quality factor and bit error rate are used to assess the system performance of the non-line-of-sight-vehicular communication system. The proposed line-of-sight model achieves a data rate of 25 Gbps, supporting a distance of 80 m under clear sky and hazy atmospheric conditions. For foggy weather, an attainable link distance of 70 m is achieved. The achieved results emphasize the suitability of the suggested models for vehicular applications in real world environment.

2

Design and performance evaluation of vehicular visible light communication system under different weather conditions and system parameters

El-Mokadem Eslam S., Tawfik Nagwan I., Aly Moustafa H., El-Deeb Walid S.

Opto-Electronics Review

|

2023

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Vol. 31, No. 2

art. no. e145580

EN

Vehicular visible light communication is an emerging technology that allows wireless communication between vehicles or between vehicles and infrastructure. In this paper, a vehicular visible light communication system is designed using a non-return to zero on-off keying modulation scheme under the effect of different weather conditions such as clear, haze, and fog. The first model is a light emitting diode-based system and the second is a laser diode-based system. For both models, the influence of system parameters such as beam divergence, transceiver aperture diameters, and receiver responsivity is studied. The impact of the use of the trans-impedance amplifier is also investigated for both models. It was concluded that in the presence of the amplifier, output power of the light emitting diode and laser diode model are increased by 98.46 μW and 0.4719 W, respectively. The performance of the two proposed models is evaluated through bit error rate, quality factor, eye diagram, and output power to have some insightful results about the quality of service for the two proposed models. Under a specific weather condition, the performance of the system would be critical and other techniques should be applied. The maximum achievable link distance for the laser-based and light-emitting diode-based systems is 190 m at a data rate of 25 Gbps and 80 m at a data rate of 60 kbps, respectively, under the same system parameters and weather conditions. The obtained results provide a full idea about the availability of constructing our proposed model in a practical environment, showing a higher performance of the laser diode-based model than that of the light emitting diode-based model.

3

Laser Power Transmission and Its Application in Laser-Powered Electrical Motor Drive: A Review

Liu Hongzuo, Zhang Yixuan, Hu Yihua, Tse Zion, Wu Jing

Power Electronics and Drives

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2021

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Vol. 6 (41)

167--184

EN

Laser power transmission (LPT) is considered a potentially efficient way for power delivery, especially in long-distance wireless applications and harsh hazardous environmental conditions. In contrast to other wireless power transmission (WPT) methods, LPT has many advantages such as lower device size, focused transmitting direction and high power density. With the development of technology, LPT has been widely adopted in several fields. In conservative industries, the utilisation of LPT can resolve the limitation problem in a wired connection. The adverse influence of electromagnetic interference (EMI) concerning application and high-temperature fields can be reduced. This paper will give a simple review of LPT and demonstrate the basic concept of a photoelectric emitter, transmission channel and receiver material. Based on the recent research about diode laser beam combining technology and high-efficiency multi-junction photovoltaics (PV) materials, the advised LPT devices for simple application as laser power motor will be simply discussed.

4

Optimization of technology of diode laser mirror processing to maximize the threshold of catastrophic optical degradation

Dąbrowska Elżbieta, Teodorczyk Marian, Szymański Michał, Maląg Andrzej

Optica Applicata

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2020

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Vol. 50, nr 4

593--607

EN

In this paper, optimization works on the technology of passivation and optical coatings of laser diode facets are described. The main goal is to increase the optical power at which the catastrophic optical mirror damage occurs. The coatings and passivation processes have been done in an ion source-aided electron-beam evaporator. The essence of passivation was to remove native oxides and produce a native thin nitride layer with simultaneous saturation of the dangling atomic bonds. The procedure has been realized with the help of nitrogen or forming gas (N2 + H2) beam. As a result, we present sets of technological parameters allowing to increase the catastrophic optical mirror damage threshold of diode lasers.

5

Influence of InGaN waveguide on injection efficiency in III-nitride laser diodes

Hajdel Mateusz, Muzioł Grzegorz, Nowakowski-Szkudlarek Krzesimir, Siekacz Marcin, Wolny Paweł, Skierbiszewski Czesław

Optica Applicata

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2020

|

Vol. 50, nr 2

311--321

EN

The influence of using InGaN waveguides on blue laser diodes was theoretically studied using 1D drift diffusion model and 2D optical mode calculation. Despite of the known effect of increased confinement of an optical mode, especially for long wavelengths, an unexpected influence on the efficiency of carrier injection into the active region is discussed. It is found that InGaN-AlGaN interface is crucial to achieving high injection efficiency. A numerical model is created, which describes the influence of InGaN waveguide and Mg doping of electron blocking layer on basic properties of laser diodes. It is found that an increase of injection efficiency allows to reduce the doping level in an electron blocking layer and take advantage of decreased optical losses.

6

A diode-pumped high-repetition-frequency passively Q-switched Nd:LaMgAl11O19 laser

Xu Yan, Gao Ziye, Xia Guangqiong, Wu Zhengmao

Optica Applicata

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2020

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Vol. 50, nr 3

415--423

EN

High-repetition-frequency Q-switched laser is realized through adopting a Nd:LaMgAl11O19 (Nd:LMA) disordered crystal as the gain material, a laser diode lasing at 796 nm as the pumped source, and a semiconductor saturable absorber mirror (SESAM) as the Q-switched device. The out-put characteristics are analyzed under using different transmittance T plane mirrors as an output coupler. Without adopting SESAM, the laser is operating at a CW state, and a relatively high transmittance is helpful for achieving high output power, slope efficiency and light-to-light efficiency. ForT = 7.5% and an absorbed power of 6.17 W, the output power arrives at its maximum of 1160 mW,and the corresponding slope efficiency and light-to-light efficiency are 20.71% and 18.78%, respectively. After introducing SESAM into the cavity, the laser operates at a passively Q-switched state, and the largest slope efficiency is 13.14% under T = 5.0%. Adopting five different output couplers, with the increase of the absorbed power, the pulse repetition frequencies, the pulse energies and the peak powers will ascend while the pulse widths will decline. The observed narrowest pulse width, the maximum pulse repetition frequency, the highest pulse energy and peak power are 1.745 μs, 175.88 kHz, 3.21 μJ and 1.84 W, respectively.

7

Delayed differential detection for absorption spectroscopy recovery

Cong Menglong, Sun Dandan

Optica Applicata

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2019

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Vol. 49, nr 2

303--315

EN

An elaborately designed system has been devoted to the recovery of the line shape function of absorption spectrum. Laser power passing through trace gas has been divided into the real-time and delayed components, and their difference, i.e. the equivalent of the first-order derivative spectrum, is recorded and integrated to reconstruct the absorption line profile. Since the real-time and delayed signals are derived from the only gas cell and photodetector, the elimination of background is more effective, relative to the general used double beam detection that involves two gas cells and photodetectors. Compared with the 1st harmonic detection used in the wavelength modulation spectroscopy, here the generation of derivative spectrum is achieved without modulating the injection current of laser. Additionally, the expensive lock-in amplifier working for wavelength modulation spectroscopy is replaced by a homemade device, which is made of an all-pass filter and an instrumentation amplifier. Therefore, the complexity and cost are significantly reduced, and the stability is improved. For the purpose of validation, recovering of the absorption spectroscopy is carried out using a methane sample at its R(3) absorption line of the 2ν3 overtone, and the obtained data are found to be in a high agreement with theoretical deductions.

8

Zastosowanie tlenku grafenu i grafenu w technologii diod laserowych

Dąbrowska E., Teodorczyk M., Lipińska L., Krzyżak K., Dąbrowski A., Sobczak G., Kozłowska A., Matkowski P., Młożniak A., Maląg A.

Przegląd Elektrotechniczny

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2015

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R. 91, nr 9

1-4

PL

Wykazano, że tlenek grafenu na krawędziach bocznych chipa laserowego powoduje zmniejszenie rezystancji termicznej diody laserowej. Obserwowane jest również zmniejszenie temperatury samego chipa laserowego. Natomiast tlenek grafenu na n-kontakcie powoduje zwiększenie temperatury chipa. Na n-kontakcie korzystne jest zastosowanie grafenu. Pokazano przesuwanie się charakterystyk spektralnych przy zastosowaniu tlenku grafenu i grafenu, jak również zmiany ugięcia chipa laserowego w obecności tlenku grafenu i grafenu. Pomiary wykonano dla diod na pasmo 880 nm.

EN

It has been shown that covering side walls of a laser diode’s chip with graphene oxide (GO) results in reduction of the laser diode's thermal resistance. Reduction of the temperature of the diode itself is also observed. In turn, additional covering the n-contact of the chip with GO results in the diode's temperature increase. On the other hand, alternative application of a chemical graphene layer in this place gives further temperature decrease. This can be explained by much higher emissivity of graphene layer compared to GO. The shifts of lasing spectral characteristics (in the 880 nm band) as well as changes in chip's deflection connected with GO and graphene applications are also shown.

9

Układ stabilizacji temperaturowej zestawu niezależnie pracujących diod laserowych

Zając A., Gryko Ł., Gilewski M.

Przegląd Elektrotechniczny

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2015

|

R. 91, nr 2

196-198

PL

W publikacji zawarto techniczne aspekty zasilania diod laserowych. Przedstawione zostały również autorskie rozwiązania stabilizacji termicznej diod laserowych w układzie sprzężenia zwrotnego, zrealizowany elektroniczny układ stabilizatora oraz cyfrowy system sterujący jego pracą.

EN

In the paper was presented the technical aspects for supply of laser diodes. Article includes author's solutions of thermal stabilization of laser diodes in the system of feedback circuit, implemented an electronic stabilization set and a digital control system of its work.

10

Diffractive wavefront correction of remote sensing systems based on pulsed laser diodes

Wojtanowski J., Traczyk M., Mierczyk Z., Zygmunt M., Przybyszewski B.

Opto-Electronics Review

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2015

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Vol. 23, No. 3

222-229

EN

A variety of optoelectronic devices (rangefinders, velocity meters, terrestrial scanners, lidars, free space optics communication systems and others) based on semiconductor laser technology feature low-quality and highly asymmetric beams. It results from optical characteristics of the applied high-peak-power pulsed laser sources, which in most cases are composed of several laser chips, each containing one or a few active lasers. Such sources cannot be considered as coherent, so the resultant beam is formed by the superposition of many optically uncorrelated sub-sources. Far-field distribution of laser spots in such devices corresponds to the shape of laser emitting area, which instead of desired symmetry shows layout composed of one or several discrete lines or rectangles. In some applications, especially if small targets are concerned, it may be crucial to provide more symmetrical and uniform laser beam cross-section. In the paper, the novel strategy of such correction, combining coherent and incoherent approaches, is presented. All aspects of technological implementations are discussed covering general theoretical treatment of the problem, diffractive optical element (DOE) design in the form of computer generated hologram (CGH), its fabrication and testing in case of selected laser module beam correction.

11

Towards improvement of beam quality of wide-stripe high-power laser diodes

Maląg A., Sobczak G., Dąbrowska E., Teodorczyk M., Dąbrowski A., Nakielska M.

Materiały Elektroniczne

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2015

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T. 43, nr 3

7--14

EN

Selected ways of improving an emitted beam quality of high-power laser diodes (LDs) are proposed in both vertical and horizontal directions. Appropriate heterostructure design leads to a vertical beam divergence reduction to 12º (FWHM) while simultaneously maintaining a high power conversion efficiency of LDs. In turn, the spatial stabilization of an optical field distribution in the junction plane results in horizontal beam profile stabilization as a function of the device drive current. This spatial stabilization (with preferred high-order lateral modes) is forced by ion-implanted lateral periodicity built into the wide-stripe waveguide of a LD.

PL

Przedstawione zostały wybrane przykłady poprawy jakości wiązki promieniowania diod laserowych (DL) dużej mocy w płaszczyźnie prostopadłej do złącza (pionowej) i w płaszczyźnie złącza (poziomej). Odpowiedni projekt heterostruktury umożliwia ograniczenie rozbieżności wiązki w płaszczyźnie pionowej do 12º przy utrzymaniu wysokiej sprawności energetycznej DL. Z kolei stabilizacja pola optycznego w płaszczyźnie złącza wymuszona przez strukturę periodyczną wbudowaną w szerokopaskowy światłowód heterostruktury laserowej prowadzi do stabilizacji profilu wiązki w płaszczyźnie poziomej w funkcji poziomu wysterowania przyrządu. Ta struktura periodyczna (preferująca wysokie mody boczne) jest formowana techniką implantacji jonów.

12

Pulsed near infrared laser stimulates the rat visual cortex in vivo

Mou Z. X., Hou W. S., Zheng X. L., Yao J. P., Shang G. B., Yin Z. Q.

Biocybernetics and Biomedical Engineering

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2015

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Vol. 35, no. 4

247--254

EN

Pulsed infrared irradiation is an alternative neural stimulation with the advantages of being non-contact, spatially precise and artifact-free. Although infrared neural stimulation (INS) is well characterized in the peripheral nervous system, research has been limited in the central nervous system (CNS), especially the near infrared with wavelength around 800 nm. To establish feasibility of INS in the CNS, pulsed near infrared laser (λ = 808 nm, pulse duration = 300–1000 μs, radiant exposure = 0.73–2.45 J/cm2, fiber size = 105 μm, repetition rate = 2 Hz) was used to stimulate the primary visual cortex (V1) of anesthetized Long Evans (LE) rats and the near-infrared-evoked neural activities in V1 was recorded. The impact of the duration of infrared pulse on the intensity and the latency of evoked potentials was assessed. We found that V1 was activated by 808 nm laser and the optical evoked potential (OEP) included a descending wave (D1) and an ascending wave (A1) after optical stimuli. Furthermore, with the increase of the stimulation pulse duration, both the amplitude of D1 and the latency of A1 were increased. The results from this paper will facilitate the applications of near infrared neural stimulation on central nervous system.

13

ATLAS simulation of a laser diode for free space optical communication (FSOC) in mid-infrared spectral region

Sanjeev, Chakrabarti P.

Opto-Electronics Review

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2014

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Vol. 22, No. 3

147-151

EN

In this paper, simulation studies on an N+−InAs0.61Sb0.13P0.26/n0−InAs0.97Sb0.03/P+−InAs0.61Sb0.13P0.26 double heterostructure laser diode suitable for use as a source in a free space optical communication system at 3.7 μm at room temperature has been presented. The device structure has been characterized in terms of energy band diagram, electric field profile, and carrier concentration profile using ATLAS simulation tool from Silvaco. The current-voltage characteristics of the structure have been estimated taking into account the degeneracy effect. The results of simulation have been validated by the reported experimental results.

14

Zmiany parametrów optycznych i elektrycznych diod laserowych na pasmo 808 nm i 880 nm w czasie długotrwałej pracy

Dąbrowska E., Teodorczyk M., Krzyżak K., Romaniec M., Sobczak G., Maląg A.

Materiały Elektroniczne

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2014

|

T. 42, nr 3

5--10

PL

Zaprezentowane zostały zmiany parametrów optycznych i elektrycznych diod podczas długotrwałej pracy: zmniejszenie mocy wyjściowej, zwiększenie prądu progowego jak i zmiana długości fali emisji - dla diod na pasmo 880 nm w kierunku fal krótszych oraz dla diod na pasmo 808 nm w kierunku fal dłuższych.

EN

The following changes in optical and electrical parameters for diodes during long-term operation are presented: reduction in the output power, increase in the threshold current and change in the emission wavelength for diodes emitting at 880 nm towards shorter wavelengths and for diodes emitting at 808 nm towards longer wavelengths.

15

Optymalizacja poziomu domieszkowania podłoża InP w elektrycznie pompowanych laserach o emisji powierzchniowej z zewnętrzną wnęką rezonansową (E-VECSEL)

Walczak J., Wasiak M., Sarzała R. P., Sirbu A., Czyszanowski T.

Przegląd Elektrotechniczny

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2013

|

R. 89, nr 10

142-145

PL

W artykule przedstawiono komputerową analizę wpływu domieszkowania substratu InP w elektrycznie pompowanym laserze o emisji powierzchniowej z zewnętrzną wnęką rezonansową (Electrically Pumped Vertical External Cavity Surface Emitting Laser – E-VECSEL) emitującym promieniowanie o długości fali 1480 nm na próg akcji laserowej. Pokazano, że minimalna moc elektryczna dostarczana do lasera umożliwiająca osiągnięcie progu jego akcji laserowej może być uzyskana dla struktury z podłożem o domieszkowaniu n = 2•1016 cm-3.

EN

In the following paper computer aided analysis of InP substrate doping level in 1480 nm Electronically Pumped Vertical External Cavity Surface Emitting Lasers is presented. It is shown that in such structure the lowest threshold power is obtained for substrate n-doping level n = 2•1016 cm-3.

16

Kierunki rozwoju sprzężonych fazowo matryc krawędziowych diod laserowych

Sobczak G.

Przegląd Elektrotechniczny

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2013

|

R. 89, nr 4

53-61

PL

Przedstawiony artykuł opisuje główne kierunki rozwoju sprzężonych fazowo matryc krawędziowych diod laserowych. Zaprezentowane zostały opisy teoretyczne typu struktur oraz najważniejsze i najciekawsze rozwiązania konstrukcyjne wprowadzane do technologii tego typu laserów na przestrzeni lat. Zwrócono również uwagę na możliwe przyszłe kierunki rozwoju oraz na przyrządy wykonane w Polsce.

EN

In this paper, there are shown the main trends in development of phase locked arrays of edge emitting laser diodes. There are shown theoretical descriptions of such structures and the most important and interesting technological solutions. Future possibilities of development and the devices manufactured in Poland are described.

17

Badania degradacji diod laserowych na pasmo 808 nm

Dąbrowska E., Teodorczyk M., Sobczak G., Kalbarczyk J., Krzyżak K., Maląg A.

Przegląd Elektrotechniczny

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2012

|

R. 88, nr 11b

48-51

PL

Przedstawiono zmianę charakterystyk mocowo-prądowych i spektralnych diod laserowych (DL) pracujących w paśmie 808 nm podczas trwania testów starzeniowych. Ujawniono zmiany zachodzące w obrębie paska (obszaru) aktywnego poprzez obserwacje elektroluminescencji przez okno wytrawione w n-kontakcie. Zauważono, że defekty w pasku aktywnym dla wszystkich diod propagują się pod kątem 45 ° do kierunku rezonatora. Uzyskano lepszą wydajność mocy optycznej dla DL montowanych na podkładkach CuC w porównaniu z DL montowanymi bezpośrednio na chłodnicy Cu. Stwierdzono, że o długości życia diod laserowych decydują przede wszystkim jakość wykonania lusteroraz technologia wprowadzającego naprężenia montażu chipów na chłodnicach a nie zastosowanie podkładki.

EN

In this paper changes in light vs. current (L-C) and in spectral characteristics of laser diodes (LDs) emitting at 808 nm band, being performed while aging tests, are shown. The electroluminescence observations made by etched window in n-contact revealed the changes in the active stripe (region). It is significant that defects in the active stripe for all diodes are propagated at 45 ° angle measured from the direction of laser resonator. Better optical power efficiency was obtained for LDs mounted at CuC heat spreader than for those mounted directly at Cu heat sink. It was found out that the lifetime of LDs are not limited by using heat spreader but mainly by the quality of performance of laser mirrors and the technology of mounting laser chips which induce the strains.

18

Badania degradacji diod laserowych na pasmo 880 nm

Dąbrowska E., Nakielska M., Teodorczyk M., Sobczak G., Romaniec M., Malag A.

Materiały Elektroniczne

|

2012

|

T. 40, nr 1

3-13

PL

Celem pracy było zbadanie przyczyn degradacji laserów mocy i ich związku z wykonywaniem poszczególnych operacji technologicznych (processing, montaż, napylanie luster) na degradację diod na pasmo 880 nm. Dla badanych diod o długości ich życia decydowały przede wszystkim poprawność wykonania luster oraz wprowadzający naprężenia montaż. Praca posłużyła do modernizacji technologii wytwarzania diod laserowych celem zwiększenia zysku.

EN

The influence of following technology processes (such as: wafer processing, montage, mirror deposition) on degradation of laser diodes emitting at 880 nm band was studied. Those investigations helped to improve technology of laser diode production.

19

Metody pomiaru rezystancji termicznej diod laserowych

Dąbrowska E., Maląg A.

Przegląd Elektrotechniczny

|

2011

|

R. 87, nr 4

232-238

PL

Przedstawiono pięć różnych sposobów pomiarów rezystancji termicznej diod laserowych. Przeanalizowano ich przydatność do charakteryzacji praktycznie wytwarzanych przyrządów różnej jakości, także takich, których charakterystyki są nietypowe. Porównano dokładności przedstawionych metod.

EN

Five different measurement methods of the laser diodes thermal resistance have been presented. Usability of these methods to characterize practical devices of different quality including those of untypical characteristics is analyzed. Also the exactness of the methods is compared.

20

Analiza laserowych źródeł promieniowania do wykonywania pomiarów odległości pod wodą

Cywiński A.

Polish Hyperbaric Research

|

2011

|

nr 1(34)

55-66

PL

W artykule zawarto syntetyczne zależności pozwalające oszacować wartości mocy sygnału tła oraz echa dla dalmierzy laserowych działających pod wodą. Przedstawiono skrótowo wnioski wynikające z badań dalmierza Nd:YAG do badań pod wodą. Zaprezentowano przykładowe dane półprzewodnikowych diod laserowych jako alternatywnych do tego typu zastosowań. Część końcowa to wyniki symulacji zasięgu działania diod laserowych. Artykuł zamykają wnioski będące wynikiem symulacji i spostrzeżeń wynikających z praktycznych zastosowań różnych laserów do badań pod wodą.

EN

In the following article the synthetic relations allowing to estimate the power values of background signal and echo signal for underwater laser rangefinders has been presented. Conclusions follow from underwater researches of laser rangefinder Nd:YAG has been briefly presented. Example data of laser LEDs as an alternative source for such a purposes has been also presented. At the end of article the results of computation of laser’s LEDs operation range has been presented. The article is finished with conclusions followed from simulations and observations based on practical application of various lasers to underwater researches.