Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446970
N. Ben Sedrine, A. Bardaoui, J. Harmand, R. Chtourou
In this work, we propose, for the first time, an analysis of the rapid thermal annealing (RTA) effect on GaAs1-xNx layers using spectroscopic ellipsometry (SE) on a set of as-grown and RTA GaAs1-xNx (x=0.1%, 0.5% and 1.5%) samples. This material being dedicated to several optoelectronic applications, an accurate knowledge of its optical properties is required to improve the selection of the layer thickness in a device system. The complex refractive indices are accurately determined, and the RTA effect on the samples is deduced. We have found that post-growth treatment (RTA) affects more samples with high nitrogen content, leading to an improvement of the optical constants. In addition, RTA is found to decrease the E1 transition energy nitrogen blue-shift.
{"title":"Optical Constants of As-grown and RTA GaAs1-xNx Layers Analysed by Spectroscopic Ellipsometry","authors":"N. Ben Sedrine, A. Bardaoui, J. Harmand, R. Chtourou","doi":"10.1109/ICTONMW.2007.4446970","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446970","url":null,"abstract":"In this work, we propose, for the first time, an analysis of the rapid thermal annealing (RTA) effect on GaAs1-xNx layers using spectroscopic ellipsometry (SE) on a set of as-grown and RTA GaAs1-xNx (x=0.1%, 0.5% and 1.5%) samples. This material being dedicated to several optoelectronic applications, an accurate knowledge of its optical properties is required to improve the selection of the layer thickness in a device system. The complex refractive indices are accurately determined, and the RTA effect on the samples is deduced. We have found that post-growth treatment (RTA) affects more samples with high nitrogen content, leading to an improvement of the optical constants. In addition, RTA is found to decrease the E1 transition energy nitrogen blue-shift.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123110040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446940
J. Cihelka, S. Civiš, I. Matulková
The spectrum of formaldehyde was studied in the 4350 - 4361 cm-1 region using photoacoustic detection in combination with a semiconductor GalnAsSb/AlGaAsSb diode laser as a radiation source. This laser operates at laboratory and higher temperatures in the 4342 - 4362 cm-1 region with an output of about 1 mW. The spectrum of formaldehyde was measured photoacoustically and this was compared with other techniques, such as laser absorption in a single path 0.4 m long cell and Fourier transform spectroscopy. The dependence of the photoacoustic signal on the pressure of the measured gas was recorded. The same technique was employed to determine the detection limit (less than 0.1 ppmV) of formaldehyde diluted with nitrogen for the strongest absorption line in the emission region of the diode laser.
{"title":"MQW laser diode photoacoustic detection of formaldehyde in 2.3 μm spectral range","authors":"J. Cihelka, S. Civiš, I. Matulková","doi":"10.1109/ICTONMW.2007.4446940","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446940","url":null,"abstract":"The spectrum of formaldehyde was studied in the 4350 - 4361 cm-1 region using photoacoustic detection in combination with a semiconductor GalnAsSb/AlGaAsSb diode laser as a radiation source. This laser operates at laboratory and higher temperatures in the 4342 - 4362 cm-1 region with an output of about 1 mW. The spectrum of formaldehyde was measured photoacoustically and this was compared with other techniques, such as laser absorption in a single path 0.4 m long cell and Fourier transform spectroscopy. The dependence of the photoacoustic signal on the pressure of the measured gas was recorded. The same technique was employed to determine the detection limit (less than 0.1 ppmV) of formaldehyde diluted with nitrogen for the strongest absorption line in the emission region of the diode laser.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129584198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446964
Z. Hadjoub, A. Khoualdia, K. Cheikh, A. Doghmane
GaAs MESFETs, which form the basis of photonic MMIC's and OEIC's, have drawn considerable attention in recent years. However, their optical, microwave and electrical characteristics are largely dependent on internal parameters. In this context, we measure the frequency dependence of output conductance in GaAs MESFETs which may be an important concern for device design and reliability. Measurements were carried out, at room temperature, in the frequency range [10 Hz -10 MHz] under several drain-source polarization, Vds, ranging from 100 mV to 2 V and gate-source potentials, Vgs, from 100 mV to 200 mV. The novelty in the obtained gd(f) results lies in the co-existence, for the same device, of three distinct behaviours: a constant dependence observed for weak Vds < 0.7 V, followed by an increase or positive dispersion for 0.7 V < Vds < 1.5 V and then a negative dispersion for Vds > 1.5 V. This behaviour could be attributed to the effects of deep level traps in the depletion region (that could be nanometric) and to surface and interface recombination.
{"title":"Positive and negative frequency dispersion of output conductance in GaAs MESFETs used in optically controlled microwave amplifiers","authors":"Z. Hadjoub, A. Khoualdia, K. Cheikh, A. Doghmane","doi":"10.1109/ICTONMW.2007.4446964","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446964","url":null,"abstract":"GaAs MESFETs, which form the basis of photonic MMIC's and OEIC's, have drawn considerable attention in recent years. However, their optical, microwave and electrical characteristics are largely dependent on internal parameters. In this context, we measure the frequency dependence of output conductance in GaAs MESFETs which may be an important concern for device design and reliability. Measurements were carried out, at room temperature, in the frequency range [10 Hz -10 MHz] under several drain-source polarization, Vds, ranging from 100 mV to 2 V and gate-source potentials, Vgs, from 100 mV to 200 mV. The novelty in the obtained gd(f) results lies in the co-existence, for the same device, of three distinct behaviours: a constant dependence observed for weak Vds < 0.7 V, followed by an increase or positive dispersion for 0.7 V < Vds < 1.5 V and then a negative dispersion for Vds > 1.5 V. This behaviour could be attributed to the effects of deep level traps in the depletion region (that could be nanometric) and to surface and interface recombination.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125257915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446977
A. Waz, A. Grobelny, J. Pieńkowski
The possibility of stabilization of diode lasers, lasers with a wider spectral line based on the iodine absorption cell, has been examined with a stabilization method of a 3 harmonic deviation. Possible stability levels, according to the width of diode laser's spectral line, have been checked. It has also been checked the change of the signal of the 3 harmonic in dependence with the frequency and depth of the modulation of the stabilized diode laser.
{"title":"|Modelling of frequency stabilization of diode laser based on iodine absorption cell","authors":"A. Waz, A. Grobelny, J. Pieńkowski","doi":"10.1109/ICTONMW.2007.4446977","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446977","url":null,"abstract":"The possibility of stabilization of diode lasers, lasers with a wider spectral line based on the iodine absorption cell, has been examined with a stabilization method of a 3 harmonic deviation. Possible stability levels, according to the width of diode laser's spectral line, have been checked. It has also been checked the change of the signal of the 3 harmonic in dependence with the frequency and depth of the modulation of the stabilized diode laser.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128797496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446962
A. Chaieb, O. Halimi, B. Boudine, L. Bouhdjar, Z. Essaidi, M. Sebais, M. Bakasse
In this work, we firstly present the elaboration of CdSe nanocrystals (NCs) dispersed in a KBr crystalline matrix in order to build nanostructured composed materials showing monocrystalline structure, and also using another technique, to deposit thin film of amorphous silica (SiO2) containing CdSe quantum dots. These elaborated guest-host systems were investigated for potential applications in optoelectronic field. In the second part of this work, we present the structural and optical properties of these composite materials using several techniques: X-ray-diffraction (XRD), UV-visible absorption. Crystallites size estimated from XRD is equal 27 nm. Optical absorption shows size quantization effect marked by a blue shift by 0.308 eV from its standard bulk band gap value 1.7 eV. Comparing size determined by XRD crystallites size estimated from the blue shift was found to be smaller.
{"title":"Elaboration and study of optical properties of CdSe nanocrystals dispersed in a KBr monocrystalline crystalline matrix and in a thin film of SiO2 amorphous matrix","authors":"A. Chaieb, O. Halimi, B. Boudine, L. Bouhdjar, Z. Essaidi, M. Sebais, M. Bakasse","doi":"10.1109/ICTONMW.2007.4446962","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446962","url":null,"abstract":"In this work, we firstly present the elaboration of CdSe nanocrystals (NCs) dispersed in a KBr crystalline matrix in order to build nanostructured composed materials showing monocrystalline structure, and also using another technique, to deposit thin film of amorphous silica (SiO2) containing CdSe quantum dots. These elaborated guest-host systems were investigated for potential applications in optoelectronic field. In the second part of this work, we present the structural and optical properties of these composite materials using several techniques: X-ray-diffraction (XRD), UV-visible absorption. Crystallites size estimated from XRD is equal 27 nm. Optical absorption shows size quantization effect marked by a blue shift by 0.308 eV from its standard bulk band gap value 1.7 eV. Comparing size determined by XRD crystallites size estimated from the blue shift was found to be smaller.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128381796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446963
A. Mokeddem, A. Midoun, N. Ziani, D. Kadri, S. Hiadsi
This paper presents the results of tests carried out at the Algerian University of Science and Technology of Oran (USTO), on a solar photovoltaic water pumping system. This comprises a 1.5 kWp PV array directly coupled to a DC motor and a centrifugal pump. The system was tested for its performance over a period of four months and for two static head configurations. Although the motor-pump efficiency did not exceed 30%, which is typical for directly-coupled photovoltaic pumping systems, such a system is clearly suitable for low head irrigation in remote areas not covered by the national electricity grid, and where access to water comes as first priority issue than access to technology.
{"title":"Test and analysis of a photovoltaic DC-motor pumping system","authors":"A. Mokeddem, A. Midoun, N. Ziani, D. Kadri, S. Hiadsi","doi":"10.1109/ICTONMW.2007.4446963","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446963","url":null,"abstract":"This paper presents the results of tests carried out at the Algerian University of Science and Technology of Oran (USTO), on a solar photovoltaic water pumping system. This comprises a 1.5 kWp PV array directly coupled to a DC motor and a centrifugal pump. The system was tested for its performance over a period of four months and for two static head configurations. Although the motor-pump efficiency did not exceed 30%, which is typical for directly-coupled photovoltaic pumping systems, such a system is clearly suitable for low head irrigation in remote areas not covered by the national electricity grid, and where access to water comes as first priority issue than access to technology.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127768223","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446978
J. Pieńkowski, A. Grobelny
Construction of a simple single-frequency diode laser 632.8 nm, used as a frequency standard in the laser interferometers is demonstrated. Two different systems applied for frequency stabilization of diode laser were used . For diode laser used as the secondary standard, the system stabilizes diode temperature, the frequency stability of the laser reaches value 1 part in 106. For diode laser used as the primary standard is developed stabilization system using narrow absorption in iodine, the frequency stability of constructed diode laser reaches value 1 part in 1010 . The stabilization method can be used for another diode lasers with different wavelength using in fiber communications systems.
{"title":"Frequency stabilized 633 nm diode laser","authors":"J. Pieńkowski, A. Grobelny","doi":"10.1109/ICTONMW.2007.4446978","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446978","url":null,"abstract":"Construction of a simple single-frequency diode laser 632.8 nm, used as a frequency standard in the laser interferometers is demonstrated. Two different systems applied for frequency stabilization of diode laser were used . For diode laser used as the secondary standard, the system stabilizes diode temperature, the frequency stability of the laser reaches value 1 part in 106. For diode laser used as the primary standard is developed stabilization system using narrow absorption in iodine, the frequency stability of constructed diode laser reaches value 1 part in 1010 . The stabilization method can be used for another diode lasers with different wavelength using in fiber communications systems.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120988428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446954
E. Poves, J. A. Martín-González, F. J. López-Hernández
This work presents the application of optical orthogonal codes (OOC) for intra-spacecraft communications within a sensor network with a large number of terminals. In particular, a novel family of optical codes named random optical codes is introduced for the target application. These codes allow a simple optimization of the length and weight of the code while maintaining a controlled probability of error and a low duty cycle. Also, due to a straightforward generation process they can be adjusted almost in real-time to adapt to new conditions like including new channels. This flexibility makes this family a good candidate for systems with strict restrictions over this parameters.
{"title":"Use of optical orthogonal codes for intra-spacecraft communications","authors":"E. Poves, J. A. Martín-González, F. J. López-Hernández","doi":"10.1109/ICTONMW.2007.4446954","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446954","url":null,"abstract":"This work presents the application of optical orthogonal codes (OOC) for intra-spacecraft communications within a sensor network with a large number of terminals. In particular, a novel family of optical codes named random optical codes is introduced for the target application. These codes allow a simple optimization of the length and weight of the code while maintaining a controlled probability of error and a low duty cycle. Also, due to a straightforward generation process they can be adjusted almost in real-time to adapt to new conditions like including new channels. This flexibility makes this family a good candidate for systems with strict restrictions over this parameters.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127498359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446939
S. Batti, M. Kachout, M. Zghal, N. Boudriga
Buffering in all-optical networks is an important need and there are several approaches that have attempted to propose partial solutions, since optical memories are out of reach, nowadays. In this paper, we review the major approaches based on architectures using fixed length fiber delay lines (FDL). The main idea of these architectures is to lead optical packets in fiber and to profit from the transmitting time to delay transmitted signals. Secondly, we study less bulky architectures based on a combination of optical fiber components. The principle of these systems is to transmit the signal over a specified path depending on the required delay. Then, we propose a novel architecture based on the use of fiber Bragg gratings, optical circulator, wavelength converter, and optical amplifier. Optical packets flowing in such an architecture are captured in a virtual loop and may leave it as soon as the control unit decides that. To evaluate the performances of the proposed architecture, we formally assess the dispersion, the loss, the signal to noise ratio and the achieved delay on departure.
{"title":"A fiber bragg grating based buffer: Architecture and performances evaluation","authors":"S. Batti, M. Kachout, M. Zghal, N. Boudriga","doi":"10.1109/ICTONMW.2007.4446939","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446939","url":null,"abstract":"Buffering in all-optical networks is an important need and there are several approaches that have attempted to propose partial solutions, since optical memories are out of reach, nowadays. In this paper, we review the major approaches based on architectures using fixed length fiber delay lines (FDL). The main idea of these architectures is to lead optical packets in fiber and to profit from the transmitting time to delay transmitted signals. Secondly, we study less bulky architectures based on a combination of optical fiber components. The principle of these systems is to transmit the signal over a specified path depending on the required delay. Then, we propose a novel architecture based on the use of fiber Bragg gratings, optical circulator, wavelength converter, and optical amplifier. Optical packets flowing in such an architecture are captured in a virtual loop and may leave it as soon as the control unit decides that. To evaluate the performances of the proposed architecture, we formally assess the dispersion, the loss, the signal to noise ratio and the achieved delay on departure.","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125236502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-12-01DOI: 10.1109/ICTONMW.2007.4446926
Jean-Luc Fillaut, J. Luc, B. Sahraoui
Carbon-rich organometallics containing rigid pi-conjugated chains are important targets for the investigation of push-pull chromophores and materials for linear and non linear applications. This approach provides a way of realizing new materials with improved optical properties including nonlinear properties and formation of surface-relief gratings (SRGs).
{"title":"Design of push-pull chromophores based on the incorporation of transition metal acetylides in the main π conjugated system","authors":"Jean-Luc Fillaut, J. Luc, B. Sahraoui","doi":"10.1109/ICTONMW.2007.4446926","DOIUrl":"https://doi.org/10.1109/ICTONMW.2007.4446926","url":null,"abstract":"Carbon-rich organometallics containing rigid pi-conjugated chains are important targets for the investigation of push-pull chromophores and materials for linear and non linear applications. This approach provides a way of realizing new materials with improved optical properties including nonlinear properties and formation of surface-relief gratings (SRGs).","PeriodicalId":366170,"journal":{"name":"2007 ICTON Mediterranean Winter Conference","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122303058","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：