Pub Date : 1998-07-01DOI: 10.1088/0963-9659/7/4/003
K. Hizanidis, B. Malomed, H. Nistazakis, D. Frantzeskakis
By means of systematic numerical simulations of pulse (soliton) transmission through a very long nearly dispersion-compensated nonlinear fibre link, including third-order dispersion (TOD), we demonstrate that, for a fixed pulse width, there is a broad interval of values of the pulse's peak power in which TOD stabilizes the transmission. In particular, TOD prevents decay of the pulse in the case when the mean second dispersion is (weakly) normal, , and in the case where , TOD suppresses strong internal vibrations of the non-fundamental soliton, making it close to the fundamental one.
{"title":"LETTER TO THE EDITOR: Stabilizing soliton transmission by third-order dispersion in dispersion-compensated fibre links","authors":"K. Hizanidis, B. Malomed, H. Nistazakis, D. Frantzeskakis","doi":"10.1088/0963-9659/7/4/003","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/003","url":null,"abstract":"By means of systematic numerical simulations of pulse (soliton) transmission through a very long nearly dispersion-compensated nonlinear fibre link, including third-order dispersion (TOD), we demonstrate that, for a fixed pulse width, there is a broad interval of values of the pulse's peak power in which TOD stabilizes the transmission. In particular, TOD prevents decay of the pulse in the case when the mean second dispersion is (weakly) normal, , and in the case where , TOD suppresses strong internal vibrations of the non-fundamental soliton, making it close to the fundamental one.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86674763","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/020
R. Haus, R. Wilkinson, J. Heland, K. Schäfer
Emissions from operational natural gas flares are examined by a remote sensing technique using a commercial moderate-resolution Fourier-transform infrared spectrometer. The thermal radiation emitted by the post-combustion gas is analysed to determine plume temperatures and concentrations of and . The multicomponent air pollution software (MAPS) is applied which is based on radiative transfer line-by-line calculations and least-squares fit procedures. Emission rates and combustion efficiencies are calculated which indicate that the local environmental impact of methane emissions from natural gas flares is small, while significant amounts of carbon dioxide are released.
{"title":"Remote sensing of gas emissions on natural gas flares","authors":"R. Haus, R. Wilkinson, J. Heland, K. Schäfer","doi":"10.1088/0963-9659/7/4/020","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/020","url":null,"abstract":"Emissions from operational natural gas flares are examined by a remote sensing technique using a commercial moderate-resolution Fourier-transform infrared spectrometer. The thermal radiation emitted by the post-combustion gas is analysed to determine plume temperatures and concentrations of and . The multicomponent air pollution software (MAPS) is applied which is based on radiative transfer line-by-line calculations and least-squares fit procedures. Emission rates and combustion efficiencies are calculated which indicate that the local environmental impact of methane emissions from natural gas flares is small, while significant amounts of carbon dioxide are released.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77072209","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/008
A. Miniewicz, S. Bartkiewicz, J. Sworakowski, J. Giacometti, M. M. Costa
Optical phase conjugation in polystyrene films containing the commercially available azobenzene dye Disperse Red 1 was measured using CW laser radiation generated by a frequency-doubled YAG laser of total power 50 mW. The degenerate four-wave mixing (DFWM) experiment allowed for measurement of the build-up time of the phase-conjugate signal and phase-conjugate reflectivity as a function of dye concentration and input beam intensities. The phase-conjugate reflectivities reached 0.1% in polystyrene films containing 2.5 wt% of the dye, with the phase-conjugate signal build-up time constants amounting to about 100 ms. The appearance of a phase-conjugate signal is linked with a build-up of absorption-induced gratings of a mixed (phase and amplitude) nature. Interesting thermally induced effects such as lensing effects and nonlinear chaotic behaviour of the phase-conjugate signal were observed.
{"title":"On optical phase conjugation in polystyrene films containing the azobenzene dye Disperse Red 1","authors":"A. Miniewicz, S. Bartkiewicz, J. Sworakowski, J. Giacometti, M. M. Costa","doi":"10.1088/0963-9659/7/4/008","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/008","url":null,"abstract":"Optical phase conjugation in polystyrene films containing the commercially available azobenzene dye Disperse Red 1 was measured using CW laser radiation generated by a frequency-doubled YAG laser of total power 50 mW. The degenerate four-wave mixing (DFWM) experiment allowed for measurement of the build-up time of the phase-conjugate signal and phase-conjugate reflectivity as a function of dye concentration and input beam intensities. The phase-conjugate reflectivities reached 0.1% in polystyrene films containing 2.5 wt% of the dye, with the phase-conjugate signal build-up time constants amounting to about 100 ms. The appearance of a phase-conjugate signal is linked with a build-up of absorption-induced gratings of a mixed (phase and amplitude) nature. Interesting thermally induced effects such as lensing effects and nonlinear chaotic behaviour of the phase-conjugate signal were observed.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90280423","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/016
G. Agati
The laser-induced chlorophyll (Chl) fluorescence spectrum in vivo at the steady state was investigated as a function of the leaf temperature between 25 and at low light intensity . The ratio between the red and far-red fluorescence bands, F685/F730, was seen to decrease with decreasing leaf temperature, while the fluorescence intensity at both the 685 and 730 nm peaks increased going from 25 to . This behaviour appears to be the same in chilling-sensitive plants ( Lycopersicon esculentum and Phaseolus vulgaris) as well as in chilling-tolerant species ( Pisum sativum and Vicia faba). Under high light intensity , at controlled temperature, F685/F730 as well as the total fluorescence intensity was seen to decrease with irradiation time. Since photosystem I (PSI) contributes to the F730 emission band only, while photosystem II (PSII) contributes to both F685 and F730, the above results can be explained as being due to the change with light intensity and temperature of quenching processes that affect PSII more than PSI. Changing the light intensity impinging on the leaf, the total Chl fluorescence increases with increasing light intensity to a maximum reached at about , then it decreases to values close to the dark level of fluorescence . The Chl fluorescence spectrum was seen to vary in shape by changing the excitation wavelength. The well known process of Chl fluorescence reabsorption is responsible for the decrease in the F685/F730 going from less (440 nm) to more (635 nm) penetrating excitation light. With UV excitation at 337 nm, an unexpected lower value for F685/F730 with respect to blue excitation was found.
{"title":"Response of the in vivo chlorophyll fluorescence spectrum to environmental factors and laser excitation wavelength","authors":"G. Agati","doi":"10.1088/0963-9659/7/4/016","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/016","url":null,"abstract":"The laser-induced chlorophyll (Chl) fluorescence spectrum in vivo at the steady state was investigated as a function of the leaf temperature between 25 and at low light intensity . The ratio between the red and far-red fluorescence bands, F685/F730, was seen to decrease with decreasing leaf temperature, while the fluorescence intensity at both the 685 and 730 nm peaks increased going from 25 to . This behaviour appears to be the same in chilling-sensitive plants ( Lycopersicon esculentum and Phaseolus vulgaris) as well as in chilling-tolerant species ( Pisum sativum and Vicia faba). Under high light intensity , at controlled temperature, F685/F730 as well as the total fluorescence intensity was seen to decrease with irradiation time. Since photosystem I (PSI) contributes to the F730 emission band only, while photosystem II (PSII) contributes to both F685 and F730, the above results can be explained as being due to the change with light intensity and temperature of quenching processes that affect PSII more than PSI. Changing the light intensity impinging on the leaf, the total Chl fluorescence increases with increasing light intensity to a maximum reached at about , then it decreases to values close to the dark level of fluorescence . The Chl fluorescence spectrum was seen to vary in shape by changing the excitation wavelength. The well known process of Chl fluorescence reabsorption is responsible for the decrease in the F685/F730 going from less (440 nm) to more (635 nm) penetrating excitation light. With UV excitation at 337 nm, an unexpected lower value for F685/F730 with respect to blue excitation was found.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88626782","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/017
H. Bach
In order to test remote sensing data with advanced yield formation models for accuracy and timeliness of yield estimation of corn, a project was conducted for the State Ministry for Rural Environment, Food, and Forestry of Baden-Wurttemberg (Germany). This project was carried out during the course of the `Special Yield Estimation', a regular procedure conducted for the European Union, to more accurately estimate agricultural yield. The methodology employed uses field-based plant parameter estimation from atmospherically corrected multitemporal/multispectral LANDSAT-TM data. An agrometeorological plant-production-model is used for yield prediction. Based solely on four LANDSAT-derived estimates (between May and August) and daily meteorological data, the grain yield of corn fields was determined for 1995. The modelled yields were compared with results gathered independently within the Special Yield Estimation for 23 test fields in the upper Rhine valley. The agreement between LANDSAT-based estimates (six weeks before harvest) and Special Yield Estimation (at harvest) shows a relative error of 2.3%. The comparison of the results for single fields shows that six weeks before harvest, the grain yield of corn was estimated with a mean relative accuracy of 13% using satellite information. The presented methodology can be transferred to other crops and geographical regions. For future applications hyperspectral sensors show great potential to further enhance the results for yield prediction with remote sensing.
{"title":"Yield estimation of corn based on multitemporal LANDSAT-TM data as input for an agrometeorological model","authors":"H. Bach","doi":"10.1088/0963-9659/7/4/017","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/017","url":null,"abstract":"In order to test remote sensing data with advanced yield formation models for accuracy and timeliness of yield estimation of corn, a project was conducted for the State Ministry for Rural Environment, Food, and Forestry of Baden-Wurttemberg (Germany). This project was carried out during the course of the `Special Yield Estimation', a regular procedure conducted for the European Union, to more accurately estimate agricultural yield. The methodology employed uses field-based plant parameter estimation from atmospherically corrected multitemporal/multispectral LANDSAT-TM data. An agrometeorological plant-production-model is used for yield prediction. Based solely on four LANDSAT-derived estimates (between May and August) and daily meteorological data, the grain yield of corn fields was determined for 1995. The modelled yields were compared with results gathered independently within the Special Yield Estimation for 23 test fields in the upper Rhine valley. The agreement between LANDSAT-based estimates (six weeks before harvest) and Special Yield Estimation (at harvest) shows a relative error of 2.3%. The comparison of the results for single fields shows that six weeks before harvest, the grain yield of corn was estimated with a mean relative accuracy of 13% using satellite information. The presented methodology can be transferred to other crops and geographical regions. For future applications hyperspectral sensors show great potential to further enhance the results for yield prediction with remote sensing.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78745850","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/024
H. Walmsley, Simon J. O'Connor
Shell Research Ltd has been using an infrared DIAL (differential absorption lidar) facility for two and a half years to measure hydrocarbon emissions to the atmosphere from petroleum industry process units. This paper describes the procedures used for measurement, emission rate calculation and data display, and then discusses the factors that affect the accuracy and detection limits of column content and emission rate measurements under practical operating conditions.
{"title":"The accuracy and sensitivity of infrared differential absorption lidar measurements of hydrocarbon emissions from process units","authors":"H. Walmsley, Simon J. O'Connor","doi":"10.1088/0963-9659/7/4/024","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/024","url":null,"abstract":"Shell Research Ltd has been using an infrared DIAL (differential absorption lidar) facility for two and a half years to measure hydrocarbon emissions to the atmosphere from petroleum industry process units. This paper describes the procedures used for measurement, emission rate calculation and data display, and then discusses the factors that affect the accuracy and detection limits of column content and emission rate measurements under practical operating conditions.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76515725","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/006
L. Janicijevic, T. Tufekcieva, M. Jonoska
It is shown that curvilinear zone plates can be constructed as phase representatives of plane curvilinear light sources. The ring zone plate is one representative of this type of diffracting optical element. At the same time, it is an optical device which can be used as a lens substitute for ring lenses, especially in the UV region. The diffracted wave amplitude and the intensity distribution for both binary, positive and negative, computer-generated ring zone plates, are determined by the use of the Fresnel-Kirchoff approximation. It is found that the ring zone plate exhibits manifold real and virtual focal rings.
{"title":"Diffraction characteristics of the ring zone plate as a representative of curvilinear zone plates","authors":"L. Janicijevic, T. Tufekcieva, M. Jonoska","doi":"10.1088/0963-9659/7/4/006","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/006","url":null,"abstract":"It is shown that curvilinear zone plates can be constructed as phase representatives of plane curvilinear light sources. The ring zone plate is one representative of this type of diffracting optical element. At the same time, it is an optical device which can be used as a lens substitute for ring lenses, especially in the UV region. The diffracted wave amplitude and the intensity distribution for both binary, positive and negative, computer-generated ring zone plates, are determined by the use of the Fresnel-Kirchoff approximation. It is found that the ring zone plate exhibits manifold real and virtual focal rings.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75885005","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/001
A. Boscolo, L. Placentino, L. Poletto
The quantum efficiency of an uncoated channel electron multiplier (CEM) working in the photon-counting regime has been evaluated over a wide spectral range, which comprises the EUV and soft x-ray regions. Three different experimental set-ups have been used: a Johnson - Onaka monochromator for the 30 - 160 nm region, a grazing incidence monochromator for the 0.3 - 30 nm region and a test facility mounting filters for the 0.14 - 0.3 nm region. As a secondary standard, both silicon and aluminium photodiodes have been used. The efficiency has been evaluated at normal incidence angle. The measured values range from 2% to 15% in the range 0.14 - 100 nm, while a rapid decrease is present over 120 nm. Changes in the efficiency due to carbon contamination in the vacuum system are discussed, and also effects due to variations of the illuminated area on the CEM entrance cone.
{"title":"LETTER TO THE EDITOR: Quantum efficiency measurements of an uncoated CEM in the range 0.14 - 160 nm (9 keV - 8 eV)","authors":"A. Boscolo, L. Placentino, L. Poletto","doi":"10.1088/0963-9659/7/4/001","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/001","url":null,"abstract":"The quantum efficiency of an uncoated channel electron multiplier (CEM) working in the photon-counting regime has been evaluated over a wide spectral range, which comprises the EUV and soft x-ray regions. Three different experimental set-ups have been used: a Johnson - Onaka monochromator for the 30 - 160 nm region, a grazing incidence monochromator for the 0.3 - 30 nm region and a test facility mounting filters for the 0.14 - 0.3 nm region. As a secondary standard, both silicon and aluminium photodiodes have been used. The efficiency has been evaluated at normal incidence angle. The measured values range from 2% to 15% in the range 0.14 - 100 nm, while a rapid decrease is present over 120 nm. Changes in the efficiency due to carbon contamination in the vacuum system are discussed, and also effects due to variations of the illuminated area on the CEM entrance cone.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81618812","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 : 1998-07-01DOI: 10.1088/0963-9659/7/4/004
M. Ahmed, M. Shalaby, F. Misk
A preamplifier system for a submarine communication link working at is considered. It is composed of a lumped erbium-doped fibre amplifier (EDFA) backward pumped at spaced from the detector by a span length of a standard fibre. The standard fibre shows a bonus gain to the system due to stimulated Raman scattering (SRS). A theoretical model for the contributions to the gain from the EDFA and the SRS based on nonlinear rate equations of the EDFA coupled with the rate equations of the Raman amplification is studied. While the erbium amplification is calculated using a numerical technique for a backward pumping boundary value problem, the Raman gain is obtained from a straightforward non-depleted pump analytical solution of the rate equations. Numerical optimization shows that there is an optimum EDFA and standard fibre lengths that optimize the overall performance of the system. We have introduced the standard fibre lengths in the design through the definition of a new parameter, the budget improvement. The results show a good agreement with experimental results of this system.
{"title":"Combined erbium and Raman amplification at ? in submarine links using backward pumping at ?","authors":"M. Ahmed, M. Shalaby, F. Misk","doi":"10.1088/0963-9659/7/4/004","DOIUrl":"https://doi.org/10.1088/0963-9659/7/4/004","url":null,"abstract":"A preamplifier system for a submarine communication link working at is considered. It is composed of a lumped erbium-doped fibre amplifier (EDFA) backward pumped at spaced from the detector by a span length of a standard fibre. The standard fibre shows a bonus gain to the system due to stimulated Raman scattering (SRS). A theoretical model for the contributions to the gain from the EDFA and the SRS based on nonlinear rate equations of the EDFA coupled with the rate equations of the Raman amplification is studied. While the erbium amplification is calculated using a numerical technique for a backward pumping boundary value problem, the Raman gain is obtained from a straightforward non-depleted pump analytical solution of the rate equations. Numerical optimization shows that there is an optimum EDFA and standard fibre lengths that optimize the overall performance of the system. We have introduced the standard fibre lengths in the design through the definition of a new parameter, the budget improvement. The results show a good agreement with experimental results of this system.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83078602","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 : 1998-05-01DOI: 10.1088/0963-9659/7/3/007
I. Kašík, V. Matějec, J. Kaňka, P. Honzátko
The fabrication, properties and performance of ytterbium-erbium co-doped silica optical fibres for high-power lasers generating ultra-short pulses at when pumped at are described. The fibre cores composed of glass immobilizing the rare-earth ions are prepared by the modified solution-doping method. Improved sintering conditions have allowed us to increase the concentration to about 18 mol % and to prevent the depletion of this dopant in the central part of the core. The prepared fibres have been tested in an experimental ring laser. A maximum power conversion efficiency of 24% and intra-cavity signal powers of about 600 mW at have been measured for contradirectional pumping with a CW Nd:YAG laser. The results of these measurements are related to the fibre waveguiding properties and the concentration profiles of the rare-earth ions in the tested fibres. In the conditions of active mode-locking, a stable 4 GHz train of 2 ps solitons with an average power of 130 mW has been generated with this laser.
{"title":"Properties and fabrication of ytterbium-erbium co-doped silica fibres for high-power fibre lasers","authors":"I. Kašík, V. Matějec, J. Kaňka, P. Honzátko","doi":"10.1088/0963-9659/7/3/007","DOIUrl":"https://doi.org/10.1088/0963-9659/7/3/007","url":null,"abstract":"The fabrication, properties and performance of ytterbium-erbium co-doped silica optical fibres for high-power lasers generating ultra-short pulses at when pumped at are described. The fibre cores composed of glass immobilizing the rare-earth ions are prepared by the modified solution-doping method. Improved sintering conditions have allowed us to increase the concentration to about 18 mol % and to prevent the depletion of this dopant in the central part of the core. The prepared fibres have been tested in an experimental ring laser. A maximum power conversion efficiency of 24% and intra-cavity signal powers of about 600 mW at have been measured for contradirectional pumping with a CW Nd:YAG laser. The results of these measurements are related to the fibre waveguiding properties and the concentration profiles of the rare-earth ions in the tested fibres. In the conditions of active mode-locking, a stable 4 GHz train of 2 ps solitons with an average power of 130 mW has been generated with this laser.","PeriodicalId":20787,"journal":{"name":"Pure and Applied Optics: Journal of The European Optical Society Part A","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1998-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85410988","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}
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