Dissertations / Theses on the topic 'Erbium'
To see the other types of publications on this topic, follow the link: Erbium.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Erbium.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Goldner, Philippe. "Processus de paires dans une perovskite hexagonale : luminescence anti-stokes dans les systemes erbium-erbium et erbium-ytterbium." Paris 6, 1993. http://www.theses.fr/1993PA066376.
Full textAbstract:
L'etude spectroscopique de differents processus de conversion de frequence est presentee dans cscdbr#3. Dope ou codope par l'erbium et l'ytterbium. Les impuretes trivalentes forment dans cette matrice des paires compensees en charge de facon quasi-exclusive. Une etude par spectroscopie a haute resolution et a basse temperature, de structures de paires a mis en evidence, outre les dimeres symetriques (lacune centrale), un complexe asymetrique (lacune laterale). Dans ce cas, les ions sont couples par un fort transfert d'energie. Dans les echantillons codopes, des paires mixtes ont ete identifiees. D'autre part, un fort couplage entre ions d'une meme paire a ete observe lors de l'etude de la conversion visible-ultraviolette. La position en energie et la duree de vie de niveaux de l'erbium situes a haute energie ont ete mesurees par absorption dans l'etat excite. A partir de ces resultats, l'ensemble des processus donnant naissance aux emissions anti-stokes ont ete analyses a travers la dynamique de fluorescence, ce qui a revele l'importance des mecanismes de competition entre relaxations croisees. Enfin la formation de paires mixtes s'est revelee defavorable au rendement de conversion infrarouge-visible
2
Gloag, Andrew John. "Tunable erbium doped fibre lasers." Thesis, University of Strathclyde, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249838.
Full text
3
Graydon, Oliver. "Advanced erbium-doped fibre devices." Thesis, University of Southampton, 1996. https://eprints.soton.ac.uk/396447/.
Full textAbstract:
Erbium-doped fibre devices, such as lasers and amplifiers, are important components in optical communication systems at 1.5µm. In this thesis four advanced erbium-doped fibre devices to help meet the needs of future systems are described. The first device, an optical limiting amplifier, provides a constant output power for a wide range of input powers. This functionality is required in long-haul amplified links and networks to protect against signal power fade. The other three devices are constructed from erbium-doped twincore fibre which exhibits inhomogeneous saturation characteristics at room temperature, conventional erbium-doped fibre only exhibits this property at cryogenic temperatures. The twincore fibre is demonstrated to particularly suit multi-channel amplification and generation and is used to construct a multiple wavelength laser and channel equalising amplifier. Both of these devices are needed for future wavelength division multiplexing (WDM) systems and are difficult to construct from conventional erbium-doped fibre because of its homogeneous saturation characteristics. Finally, a tracking bandpass filter is constructed from a single piece of unpumped twincore fibre. The filter automatically tunes to the wavelength of the optical signal and has potential for guiding solitons in ultralong communication links.
4
Chiossi, Federico. "Superfluorescence from Erbium-doped crystals." Doctoral thesis, Università degli studi di Padova, 2019. http://hdl.handle.net/11577/3425779.
Full textAbstract:
In Superfluorescence process, an initially incoherent ensemble of excited atoms (molecules, etc) gives rise to a macroscopic polarization due to spontaneously synchronization of the atomic dipoles. In this coupled system, every single dipole is correlated with all the others and the atomic transition rate is enhanced by a factor μN, with N the number of correlated atoms and μ a geometrical factor that accounts for the interference effects. The cooperative radiative decay results in the emission of coherent photon bunches whose peak intensity is proportional to μN^2 and the duration scales with (μN)^−1. In this thesis, we present the clear signatures of the Superfluorescence from Erbium-doped Y2SiO5 and YLiF4 crystals at liquid helium temperature. The process is observed for two transitions and involves the remarkable number of 10^12 Erbium ions, accelerating the radiative decay by millions of times. Several aspects of Superfluorescence are deeply investigated and a remarkable agreement with the theoretical expectation is reported.
5
Ruhge, Forrest. "EFFECT OF GERMANIUM DOPING ON ERBIUM SENSITIZATION IN THE ERBIUM DOPED SILICON RICH SILICA MATERIAL SYSTEM." Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2933.
Full textAbstract:
The continued size reduction in electronic integrated circuits has lead to a demand for on-chip high-bandwidth and low loss communication channels. Optical interconnects are considered an essential addition to the silicon electronics platform. A major challenge in the field of integrated Si photonics is the development of cost effective silicon compatible light sources. This thesis investigates the sensitization of group IV doped silica films emitting at 1.535μm for applications as silicon compatible light sources. Thin erbium-doped silica films containing excess silicon and germanium were deposited using a multi-gun sputter system. The composition of the deposited materials was verified by Rutherford Backscattering Spectrometry. Samples from each deposition were annealed in a controlled atmosphere tube furnace at temperatures between 500ºC and 1100ºC for 30 minutes. The photoluminescence spectra from the visible to the near-infrared region were acquired while pumping either near or far from the Er3+ absorption lines. Under both excitation conditions all samples annealed at temperatures below 1000ºC show clear emission at 1.535μm from Er3+ ions in the host material. In the current literature this is attributed to exciton mediated excitation of the Er3+. By contrast, in these studies indirect excitation was observed for samples annealed at temperatures well below the onset of nanocrystal nucleation and growth (between 500ºC and 1000ºC), suggesting excitation via small clusters or lattice defects. These findings could have significant implications in the further development of group IV sensitized silicon compatible gain media.M.S.
Other
Optics and Photonics
Optics
6
Siddiqui, Saiful Anam. "Erbium doped silicon light emitting diodes." Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/843408/.
Full textAbstract:
Erbium, a rare earth element, has been shown to exhibit characteristic luminescence at 1.54mum due to its internal 4f transition from the first excited state (4pi3/2) to the ground state (4pi5/2). As this emission wavelength falls inside the maximum transmission window of silicon based optical fibers, erbium doped silicon might lead to the opportunity of silicon based optoelectronics. The introduction of erbium in silicon allows excitation through electron-hole recombination and subsequent radiative emission from the rare earth centers. The works reported here describe the structural, electrical and optical properties of crystalline silicon codoped with erbium and boron by ion implantation technique. Four sets of samples, co-implanted with erbium and boron at different Er dose, implantation energy and at different conditions, were prepared. Post-implantation annealing has been performed to recover the implantation damage to an acceptable value and to activate the dopant atoms optically and electrically. PL and EL measurements have been performed in the temperature range between 80K to room temperature. The sample with the lowest erbium concentration and energy gives the best PL and EL results. The observed emission peaks in both PL and EL measurements were at around 1.129mum, ~1.303mum, 1.50mum and 1.597mum at 80K. At higher temperatures, a broader peak at around 1.50mum with long tail towards the both end of wavelength has been observed. The peak at 1.129mum corresponding to the Si band edge emission, the reason for the peaks at around l.303mum has not been identified while the remaining two peaks correspond the Er3+ emission. Virtually no temperature quenching of Er luminescence is observed in some samples rather room temperature intensity is higher than that at 80K. The improvement of the temperature quenching effect on Er luminescence at room temperature has been attained in our results, which is significant improvement in comparison to the result found in the literature. The structural properties were studied by TEM in both cross-sectional and plan view configurations. TEM analyses showed dislocation loops and other defects of random size and distribution from the surface to 600nm below the surface. Er precipitates defects were also seen in the sample doped with Er comparatively at higher dose (1x1015Er/cm2) and energy (1.0 MeV). No detectable room temperature PL and EL signals were observed from the sample implanted at higher doses and energies.
7
Campbell, Maya. "Energy transfer processes in erbium elpasolites." Thesis, Birkbeck (University of London), 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265854.
Full text
8
Purnawirman. "Integrated erbium lasers in silicon photonics." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108994.
Full textAbstract:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 109-114).
We present results on the development of integrated erbium-doped aluminum oxide lasers on a silicon photonics platform. A key achievement in this work is a scalable laser design for high output power and ultra-narrow linewidth performance. Using a novel wavelength-insensitive design, a CMOS compatible waveguide structure is proposed to achieve high confinement factor and intensity overlap for both the pump (980 nm) and signal (1550 nm) wavelengths. Laser operation in the C- and L- bands of the erbium gain spectrum is obtained with both a distributed Bragg reflector and a distributed feedback structure. We demonstrate power scaling with output power greater than 75 mW and obtain an ultra-narrow linewidth of 5.3 t 0.3 kHz. We investigate the influence of gain film thickness uniformity in distributed feedback laser performance and show a compensation scheme based on a curved cavity design. We then consider the application in optical communications by demonstrating a multiwavelength cascaded laser to generate wavelength division multiplexing (WDM) light sources. Finally, we propose an integration scheme of laser in full silicon photonics platform by using an erbium trench. The approach is alignment free and allows the erbium-doped film deposition to be the last backend process, providing a pathway to a scalable CMOS compatible laser device.
by Purnawirman.
Ph. D.
9
Cowle, Gregory John. "Narrow-linewidth erbium-doped fibre lasers." Thesis, University of Southampton, 1991. https://eprints.soton.ac.uk/399361/.
Full textAbstract:
This thesis describes research towards narrow-linewidth and single-longitudinal-mode erbium-doped fibre lasers operating on the 1.55µm region. The work is concerned with the physics and technology of narrow-linewidth fibre lasers. Factors which affect the spectral width and number of modes oscillating in an erbium-doped fibre laser are described, with particular reference to spatial holeburning, the primary cause of multi-mode oscillation. Novel resonator configurations for narrow-linewidth operation are described, in both standing-wave and travelling-wave arrangements, with linewidths as narrow as 10Hz being achieved. The development of narrow-bandwidth distributed Bragg reflectors is discussed. Resonator configurations discussed include short fibre lasers with narrow bandwidth reflectors, polarimetric coupled-cavity fibre lasers, travelling-wave fibre ring lasers and travelling-wave fibre loop lasers. Travelling-wave operation is demonstrated to be a powerful technique for realising single-frequency fibre laser operation. Linewidths as narrow as 10kHz are demonstrated in long fibre laser resonators. The potential for high efficiency and broad tuning ranges are illustrated. The statistics of phase noise in erbium-doped fibre amplifiers are characterised, by measurements of spectral broadening of a signal passing through the amplifier. The process of spectral broadening is modelled using a rotating vector approach. The implications for amplification of narrow bandwidth signals are discussed.
10
Gengelbach, Aila. "Collectivity in Neutron-Rich Erbium Isotopes." Licentiate thesis, Uppsala universitet, Kärnfysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-442208.
Full textAbstract:
Neutron-rich rare-earth nuclei around the maximum of collectivity are predicted to exist with an extremely stable intrinsic configuration in their ground-state structure. Due to the high degree of axial symmetry and large deformation, these nuclei are also excellent candidates for having long-lived high-K isomers. The present work concerns a study of the structure of the yrast bands and a search for isomers in the neutron-rich 68Er isotopes. Excited states of 68Er isotopes were populated via multi-nucleon transfer reactions. A 859 MeV 136Xe-beam was used to bombard a 170Er-target. The experimental setup consisted of the high-resolution γ-ray spectrometer AGATA coupled to the heavy-ion magnetic spectrometer PRISMA. The experiment collected 2 TB of useful data corresponding to 3 days of effective beam time. Beam-like fragments were identified by the PRISMA specrometer placed at the grazing angle of 44 degrees. PRISMA allows for Z, A and q identification as well as TOF and velocity vector determination. This is required for the Doppler correction of the emitted γ rays detected in time coincidence with AGATA. A good Z and very clean A separation has been achieved in PRISMA. Making use of two-body kinematics, Doppler corrected γ-ray spectra for target-like fragments were obtained as well. Due to the novel techniques of PSA and γ-ray tracking, AGATA provided high-quality γ-ray spectra for both beam-like xenon and target-like erbium isotopes. Known yrast bands and isomeric states in neutron-rich erbium isotopes were observed. A candidate for the decay of an isomeric state with Eγ=184 keV in 173Er, which has no previously known excited states, was identified.
11
MONTEVILLE, ACHILLE. "Materiaux vitroceramiques fluores transparents dopes erbium." Rennes 1, 2000. http://www.theses.fr/2000REN10007.
Full textAbstract:
L'objectif de cette etude a ete de developper une nouvelle vitroceramique transparente, dopee aux terres rares, possedant les proprietes spectroscopiques de sa phase cristalline pour des applications optiques et plus particulierement pour l'amplification. Au cours de ce travail, nous avons developpe un verre de fluorozirconate dope erbium suffisamment stable et reproductible, contenant uniquement des elements trivalents et tetravalents (zrf 4, laf 3, alf 3, erf 3, gaf 3 et inf 3). La determination des temperatures caracteristiques, par analyse thermique differentielle, nous a permis d'etablir les conditions de traitement thermique necessaires pour obtenir le materiau final : la vitroceramique. Les modifications de composition apportees au verre de depart nous ont permis d'obtenir une phase cristalline de maille quadratique, obtenue apres traitement thermique, d'indice de refraction moyen proche de celui de la phase amorphe residuelle. Ce materiau biphase est caracterise par une morphologie proche de celle d'une eponge cristalline (cristallisation de type decomposition spinodale), occupant la majeure partie du volume (90%) et une phase amorphe residuelle intimement imbriquee tout en presentant visuellement une parfaite transparence. En absence de segregation, la terre rare se retrouve donc en majorite dans la phase cristalline. L'etude spectroscopique nous montre une reduction de la largeur inhomogene des raies spectrales, due a une reduction du nombre de sites pour l'ion er 3 +. Ceci ce traduit par une augmentation de 20 a 30% en section efficace d'absorption et d'emission pour la transition 4i 1 5 / 2 4i 1 3 / 2 a 1. 53 m. Un tel type de vitroceramique, alliant transparence et propriete spectrale d'un materiau cristallin, est ici obtenu pour la premiere fois a notre connaissance.
12
Hwang, Bor-Chyuan. "Short erbium doped phosphate fiber amplifiers." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289174.
Full textAbstract:
Spectroscopic properties of high concentration Er³⁺-doped phosphate glasses and performance of short Er³⁺-doped phosphate fiber amplifiers were studied and characterized. Systematic studies of cooperative upconversion of Er³⁺ ions in ⁴I₁₃/₂ level and energy transfer from Yb³⁺ to Er³⁺ in phosphate glasses were performed by a rate equation formalism. The cooperative upconversion coefficient for an Er³⁺ concentration of 4 x 10²⁰ ions/cm³ was found to be 1.1 x 10⁻¹⁸ cm³/s. An energy transfer coefficient of 1.1 x 10⁻¹⁶ cm³/s was found for an Yb³⁺ concentration of 6 x 10²⁰ ions/cm3 and an Er³⁺ concentration of 2 x 10²⁰ ions/cm³. Energy transfer efficiencies from ²F₅/₂ level of Yb³⁺ ions to ⁴I₁₃/₂ level of Er³⁺ ions higher than 95% were determined from our measurements under weak excitation. The performance of high concentration Er³⁺-doped phosphate fiber amplifiers were characterized in terms of gain, noise figure, and signal saturation for a series of active fiber lengths, pump powers, signal input powers, and signal wavelengths. A net gain of 21 dB were achieved in a 71 mm Er³⁺-doped phosphate fiber with a noise figure of ∼5.3 dB by a 980 nm pump power of 244 mW. In addition, a 10 dB net gain can be obtained with a pump power of 110 mW. Performance of short Er³⁺-doped phosphate fiber amplifiers demonstrates the potential for device applications.
13
BANERJEE, SIDDHARTHA. "OPTICAL PROPERTIES AND POPULATION STATISTICS OF ERBIUM IN OPTICALLY-PUMPED ERBIUM-DOPED ZINC SILICATE GERMANATE WAVEGUIDE AMPLIFIERS." University of Cincinnati / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1100892919.
Full text
14
Banerjee, Siddhartha. "Optical properties and population statistics of erbium in optically pumped erbium doped zinc silicate germanate (ZSG) waveguide amplifiers." Cincinnati, Ohio : University of Cincinnati, 2004. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1100892919.
Full text
15
Jones, Mark Alexander Goddard. "Luminescent erbium metallofullerenes for quantum information processing." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437365.
Full text
16
McMillan, Duncan. "Spectrum engineering in erbium doped fibre devices." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273815.
Full text
17
Morkel, Paul Roos. "Active neodymium and erbium doped fibre devices." Thesis, University of Southampton, 1990. https://eprints.soton.ac.uk/399485/.
Full textAbstract:
In this thesis a number of rare-earth-doped fibre devices are described including fluorescent and superfluorescent sources as well as several laser configurations. The laser configurations are all-fibre and include a neodymium-doped ring laser and recirculating delay line, a novel tunable neodymium-doped fibre laser and a single-frequency travelling-wave erbium-doped ring laser. The latter device has been the first description of a travelling-wave fibre laser device. Theory describing general fibre amplifier and laser devices is incorporated. A novel lumped element approach to fibre laser theory has been given applicable to 3 and 4-level laser devices which, under certain conditions, allows single pass gain of a fibre device to be described simply by the absorbed pump power. Numerical modelling of the erbium-doped fibre amplifier has been described which allows for analysis of a general device showing pump excited-state absorption. Results from the analysis have shown a difference in gain characteristics between co-propagating and counter-propagating signal/pump schemes when subject to pump excited-state absorption. In addition, the effect of pump direction on the noise figure is characterised in both small and large signal operating regimes. Characterisation of neodymium-doped fibres has shown a number of effects which will affect their use in amplifier and oscillator configurations. These include observation of sensitivity of the fluorescence characteristics to pump wavelength, observation of excited state absorption and polarisation of fluorescence. Additionally, the spectral gain-saturation characteristics have been investigated.
18
GARTER, MICHAEL JAMES. "ELECTROLUMINESCENT DEVICES FABRICATED ON ERBIUM DOPED GaN." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990545888.
Full text
19
Stoita, Ana Doina. "Piégeage radiatif dans des matériaux dopés erbium." Lyon 1, 2006. http://www.theses.fr/2006LYO10076.
Full textAbstract:
La diffusion de l'excitation est un processus qui consiste en une suite de transferts directes se produisant de proche en proche, jusqu'à ce l'énergie soit transférée à un atome qui joue le rôle d'un piège et qui la dissipe de manière non radiative. La diffusion radiative est un processus intervenant dans le cas des transitions résonantes des matériaux optiquement actifs : lorsqu'un centre actif émet un photon celui-ci peut être réabsorbé par un autre centre qui à son tour re-émettra des photons ; le phénomène se répétant de façon incohérente. Dans le cadre de notre travail, nous avons développé une nouvelle technique de mesure du coefficient de réabsorption dans des verres ZBLA dopés Er3+ de concentration 0. 1%, 1%, et 5%. Afin de déterminer le coefficient de réabsorption, nous mesurons le coefficient de visibilité v (contraste) d'un réseau d'excitation. Nous créons une distribution géométrique initiale de population à l'aide de deux faisceaux laser cohérents se croisant dans l'échantillon. L'excitation laser tend à créer une distribution spatiale de population, alors que les phénomènes de réabsorption tendent à homogénéiser la distribution spatiale. La mesure du contraste de l'image créée donne donc directement le résultat de la compétition entre l'excitation localisée et la réabsorption qui délocalise la population. Le coefficient de visibilité varie entre 0. 8 pour les pas de quelques µm jusqu'à 0. 3 pour les pas de 0. 4 µm. La fraction de la lumière piégée a été calculée à partir de l'équation d'Holstein-Biberman. 30 % de lumière reste piégée à l'intérieur d'un échantillon parallélépipédique pour les pas de quelques µm. A 0. 4 µm la présence de la diffusion non radiative n'est pas négligeable. Les effets de surfaces, de volume d'excitation, la dynamique des niveaux 4S3/2 et 4I11/2 et les durées de vie des niveaux 4I11/2 et 4I13/2 sont également étudiés
20
Breguet, Jacques. "Q-switching of 3 *m Erbium lasers /." [S.l.] : [s.n.], 1991. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Full text
21
Degliame, Gary. "Thermométrie par photoluminescence, application en micro/nanothermique." Thesis, Reims, 2017. http://www.theses.fr/2017REIMS021/document.
Full textAbstract:
Ce travail de thèse porte sur l’étude de la photoluminescence de microcristaux en vue de concevoir une sonde hybride permettant des mesures de la température et de la conductivité thermique d’un échantillon aux micro/nano-échelles. Pour cela, une sonde thermorésistive en Wollaston, utilisée en microscopie thermique (SThM), a été couplée à un microcristal de Cd0.7Sr0.3F2 (4% Er3+) dopé Erbium dont le spectre d’émission est sensible à la température. Dans un premier temps, les propriétés optiques du cristal massif ont été étudiées en vue de son application en thermométrie. Nous avons travaillé à l’interprétation de son spectre de luminescence obtenu par up-conversion avec une diode laser centrée à 655 nm de 4mW. Nous avons alors proposé trois méthodes de détermination des intensités de fluorescence pour accéder à cette température via la technique RIF (Rapport des Intensités de Fluorescence). Nous avons montré qu’il était possible de déterminer sa température en utilisant les intensités des émissions des sous-niveaux Stark des niveaux thermalisés. Nous avons, ensuite, étudié le comportement en température de microcristaux fixés individuellement à l’extrémité de sondes thermorésistives. Les résultats expérimentaux ont permis d’en déduire la taille optimale du microcristal et la méthode de détermination des intensités la plus adaptée à la nano/microthermométrie.Après avoir validé notre approche de la température aux microcristaux, nous nous sommes intéressés au principe d’imagerie en température à partir des spectres de photoluminescence. Nous présentons une application sur un microsystème composé de fils conducteurs de 350nm de diamètre recouverts par un film mince de SiO2This PhD work focuses on the study of microcrystals photoluminescence in order to design a hybrid probe allowing micro/nano-scales measurements of a sample’s temperature and the thermal conductivity. Thus, a Wollaston thermoresistive probe used in thermal microscopy (SThM), was coupled to an Erbium doped microcrystal of Cd0.7Sr0.3F2 (4% Er3+), whose emission spectrum is sensitive to the temperature.At first, for its applications in thermometry, the optical properties of the bulk crystal have been studied. We worked on the interpretation of its luminescence spectrum obtained by up-conversion using a laser diode centered at 655 nm and 4mW. Then, we proposed three methods to determine the fluorescence intensities to access this temperature via the RIF (Fluorescence Intensity Ratio) technique. We have shown that it is possible to determine its temperature using the Stark sub-levels of the thermalized levels emissions intensities.Furthermore, we studied the temperature behavior of the microcrystals individually fixed at the end of thermoresistive probes. The experimental results made it possible to deduce the optimal size of the microcrystal and the most adapted intensity determination method for nano/microthermometry.After validating our microcrystal temperature approach, we focused on the principle of temperature imaging from photoluminescence spectra. We present an application on a microsystem composed of wires with a diameter of 350nm covered by a SiO2 thin film
22
Meshkinfam, Peyman. "Erbium-ytterbium co-dopped ion-exchanged waveguide amplifiers." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0029/MQ38696.pdf.
Full text
23
Thảo. "Photoluminescence spectroscopy on erbium-doped and porous silicon." Amsterdam : Amsterdam : [s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/83659.
Full text
24
VanWiggeren, Gregory D. "Chaotic communication with erbium-doped fiber ring lasers." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/30299.
Full text
25
Ren, Yong-Gang Frank. "Erbium doped silicon as an optoelectronic semiconductor material." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/36468.
Full text
26
Tamura, Kohichi Robert. "Additive pulse mode-locked erbium-doped fiber lasers." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11851.
Full textAbstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 155-168).
by Kohichi Robert Tamura.
Ph.D.
27
Ye, Chen Chun. "Spectroscopy of erbium-doped fibre amplifiers and lasers." Thesis, University of Southampton, 1995. https://eprints.soton.ac.uk/399077/.
Full textAbstract:
This thesis describes work done in investigating Er3+-doped fibre amplifiers and lasers, with emphasis on the spectral properties and diagnosis of ion-ion interaction processes in the glasses and fibres. Ion-pair upconversion and uniform upconversion in Er3+-doped silicate fibres have been directly and separately observed for the first time, by examining upconversion fluorescence. An upper limit to the Er3+ ion-pair lifetime of a few microseconds has been determined. Different effects of the two upconversion mechanisms on the 1.54µm fluorescence have been examined. Ion-pair upconversion in an Al/Ge/Si or an Al/Si host increases far less with increasing Er3+ concentration than in a Ge/Si host, while there is no significant difference in uniform upconversion between them for a given Er3+ concentration. Uniform upconversion constants for various fibres are determined through measuring the maximum decay rate of the 1.54µm fluorescence. The 1.7µm ESA spectrum from the 4H13/2 level has been measured for Er3+-doped silicate fibre and ion-exchanged silicate planar waveguides, and the uniform upconversion constants are estimated. The existence of dual excited-state energy transfer (DESET) in Er3+/Yb3+- doped phospho-silicate fibres has been inferred from measurement of the ESA spectrum around 1.1µm. The absence of ESA at pump wavelength 1.064µm has also been confirmed. The DESET process has been examined for the first time by measurements of 1.064µm pump throughput characteristics of the fibre. Short Er3+/Yb3+ amplifiers pumped at around 970nm have been numerically characterized. The advantage of codoping of Yb3+ is shown to be the potential for higher gain at shorter amplifier length. By examining Er3+-doped fibre preforms with differing co-dopant ions, Ta5+- codoped fibre is shown to be competitive with Al3+-codoped fibre for Er3+-doped fibre devices. A SiGeTaEr fibre laser has been demonstrated for the first time. Spectral properties of Er3+-doped Ga2S3:La2S3 have been studied. Emission and absorption spectra, including for the first time the 2.7µm emission, are measured. Radiative and non-radiative transition rates are calculated and compared with the measured lifetimes. Characteristics of ion-ion energy transfer processes in the glass are discussed. A numerical model has been developed to predict the Performance of Er3+:Ga:La:S fibre devices, including short amplifiers operating at 1.54µm, 980nm upconversion lasers.
28
Peng, Xiang. "Erbium-doped tellurite glass microsphere amplifiers and lasers." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280529.
Full textAbstract:
Due to the properties of extremely high quality factor and small mode volume, microsphere resonators have attracted considerable attention for signal processing, fiber communication and photon computation applications. This research work studies the optical properties of microsphere amplifier and laser. The Er³⁺-doped tellurite glass was examined, including emission cross-section, absorption cross-section and lifetime analysis. McCumber and Judd-Ofelt theories were used for theoretical calculations. Whispering gallery modes in the microsphere were calculated by using the measured parameters. Signal enhancement was obtained in this Er³⁺-doped tellurite glass microsphere. The enhancement of this Er³⁺-doped tellurite glass microsphere exceeds 12dB. Besides, the mode in a single mode tapered fiber was analyzed. Theoretical analysis was also performed to optimize the coupling scheme. We also analyzed the lasing characteristics of microsphere laser, including threshold, lasing wavelength, output power optimization, and temperature dependence. Theoretical calculations for these properties were also presented. State-of-the-art L-band microsphere laser with maximum output power of 124.5 μW was demonstrated which has potential in various photonic applications.
29
Prtljaga, Nikola. "Silicon nanocrystals: from bio-imager to erbium sensitizer." Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/368704.
Full textAbstract:
The work in this thesis has been centred on the light emitting properties of silicon nanocrystals and the possible applications of this particular material platform to various topics ranging from bio-imaging to erbium ion sensitization. Silicon nanocrystals as bio-imaging agent have been investigated by employing colloidal dispersion of individual silicon nanocrystals where surface properties could be controlled to a great extent. By using a suitable functionalization scheme, high quality hydrophilic luminescent nanoparticles were produced. Using the improvements in the physical coating, bio-imaging on living cells (in vitro) was demonstrated showing that silicon nanocrystals have a great potential in bio-imaging and offer a promising alternative to commonly used fluorescence dyes.
A part from being good light emitters, silicon nanocrystals could also amplify the light. This is a reason why the part of the work in this thesis has been dedicated to the investigation of silicon nanocrystals as a gain material. While most of the studies on this topic are concentrated on the nanocrystal surface as a driving mechanism behind the optical amplification, the work presented in this thesis concerns the study of a zero phonon (direct) optical transition as a possible source of optical amplification in this material system. To this scope, investigation of the dynamics of the system on a nanosecond time-scale and under high excitation conditions has been employed. Additional insight on ultrafast dynamics has been obtained by using optical cavities in the form of optically active free-standing micro-disk resonators.
Finally, in the last part of this thesis a study of Er3+-doped Silicon-Rich-Oxide (SRO) materials and Er3+-doped SRO based devices is presented. This part of the work differs from the rest of the work reported in this thesis as is not focused on the light emitting properties of silicon nanocrystals but mostly on their non-radiative process engineering (energy transfer to erbium ions). Er3+ doped SRO opens the route towards compact waveguide amplifiers and lasers and allows for the possibility of electrical injection schemes, which are not realizable in standard erbium amplifiers used in EDFA for telecom applications. To that end, novel opto-electronic structures were proposed, modeled and manufactured and preliminary results of their performance were presented.
The sensitization mechanism between silicon nanoparticles and erbium ions was studied and its complex nature was illustrated. Although, the acquired knowledge of physics involved was not sufficient for formulation of a complete working theory of the energy transfer process, some important physical aspects of this process have been elucidated paving the way towards its complete understanding.
30
Prtljaga, Nikola. "Silicon nanocrystals: from bio-imager to erbium sensitizer." Doctoral thesis, University of Trento, 2012. http://eprints-phd.biblio.unitn.it/715/1/Silicon_nanocrystals_from_bio-imager_to_Er3%2B_sensitizer.pdf.
Full textAbstract:
The work in this thesis has been centred on the light emitting properties of silicon nanocrystals and the possible applications of this particular material platform to various topics ranging from bio-imaging to erbium ion sensitization. Silicon nanocrystals as bio-imaging agent have been investigated by employing colloidal dispersion of individual silicon nanocrystals where surface properties could be controlled to a great extent. By using a suitable functionalization scheme, high quality hydrophilic luminescent nanoparticles were produced. Using the improvements in the physical coating, bio-imaging on living cells (in vitro) was demonstrated showing that silicon nanocrystals have a great potential in bio-imaging and offer a promising alternative to commonly used fluorescence dyes.
A part from being good light emitters, silicon nanocrystals could also amplify the light. This is a reason why the part of the work in this thesis has been dedicated to the investigation of silicon nanocrystals as a gain material. While most of the studies on this topic are concentrated on the nanocrystal surface as a driving mechanism behind the optical amplification, the work presented in this thesis concerns the study of a zero phonon (direct) optical transition as a possible source of optical amplification in this material system. To this scope, investigation of the dynamics of the system on a nanosecond time-scale and under high excitation conditions has been employed. Additional insight on ultrafast dynamics has been obtained by using optical cavities in the form of optically active free-standing micro-disk resonators.
Finally, in the last part of this thesis a study of Er3+-doped Silicon-Rich-Oxide (SRO) materials and Er3+-doped SRO based devices is presented. This part of the work differs from the rest of the work reported in this thesis as is not focused on the light emitting properties of silicon nanocrystals but mostly on their non-radiative process engineering (energy transfer to erbium ions). Er3+ doped SRO opens the route towards compact waveguide amplifiers and lasers and allows for the possibility of electrical injection schemes, which are not realizable in standard erbium amplifiers used in EDFA for telecom applications. To that end, novel opto-electronic structures were proposed, modeled and manufactured and preliminary results of their performance were presented.
The sensitization mechanism between silicon nanoparticles and erbium ions was studied and its complex nature was illustrated. Although, the acquired knowledge of physics involved was not sufficient for formulation of a complete working theory of the energy transfer process, some important physical aspects of this process have been elucidated paving the way towards its complete understanding.
31
Silva, Reginaldo da. "Avaliação experimental das caracteristicas de ampliação de fibras de vidro telurito dopado com erbio." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261917.
Full textAbstract:
Orientador: Aldario Chrestani BordonalliDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
Made available in DSpace on 2018-08-12T12:54:47Z (GMT). No. of bitstreams: 1 Silva_Reginaldoda_M.pdf: 5147387 bytes, checksum: 92c87077ec69edec6939f972e198910e (MD5) Previous issue date: 2008
Resumo: Com o atual e constante crescimento das taxas de transmissões em comunicações ópticas, a busca por novos materiais com aplicações em amplificadores ópticos tem servido de fonte de constantes pesquisas. Motivado por essa necessidade, este trabalho apresenta os resultados alcançados para uma análise experimental das características de amplificação de fibras ópticas feitas com vidro telurito dopado com érbio e sem a utilização do túlio (Tm) como co-dopante, produzidas no IFGW/ UNICAMP. Os procedimentos adotados para as medições de dois tipos de fibra (perfil de índice degrau e microestruturada) são descritos para diferentes configurações de aplicação de bombeio. Quando comparadas às fibras de sílica dopadas com érbio, estas fibras apresentaram banda disponível para amplificação, aproximadamente, duas vezes mais ampla (~90 nm). Medindo-se as variações no nível de potência óptica de um sinal antes e depois da aplicação de bombeio, pode-se alcançar um aumento de potência de saída de até 15 dB, sugerindo propriedades de amplificação óptica, no entanto não se obteve ganho real no sistema. Este valor máximo foi obtido para amostras de 10 cm e 5 cm de fibra de perfil de índice degrau e microestruturada, respectivamente. A fragilidade da fibra dificultou o seu manuseio e impossibilitou sua conectorização, de maneira que os resultados alcançados podem, potencialmente, ser melhorados se as grandes perdas no processo de acoplamento da luz entre os diferentes materiais vítreos forem minimizadas.
Abstract: The continuous growth of the optical communication transmission rate has stimulated the search for new materials that can be applied to the manufacturing of optical amplifiers. Motivated by this, the results for an experimental analysis of the amplification characteristics of erbium doped tellurite fibers (EDTFs) without thulium co-doping are presented. The measurement procedures for two distinct fiber structures (step index and microstructured) fabricated at the IFGW/UNICAMP labs were described for different pump coupling configurations. In comparison with erbium-doped silica fibers, the EDTF shows an available optical amplification bandwidth twice as broader (~90 nm). By measuring the optical power variations of a signal before and after pumping application, an optical output power increase as high as 15dB was possible, suggesting optical amplification properties. This maximum value was achieved for 10-cm long step index fiber and 5-cm long microstructured fiber samples. The fiber sample mechanical fragility has made difficult its manipulation and prevented its connectorization in such a way that improvement in the measured results could be attained if the high losses during light coupling among different glass materials were minimized.
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
32
Strümpel, Claudia. "Application of erbium-doped up-converters to silicon solar cells." Konstanz Hartung-Gorre, 2007. http://d-nb.info/988193930/04.
Full text
33
PENNA, STEFANO. "Design processing and characterization of organic devices for optical communications." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2009. http://hdl.handle.net/2108/991.
Full textAbstract:
La recente esplosione dei servizi a larga banda e i limiti imposti dalla legge di Moore hanno spinto la ricerca verso il concetto di chip ottico integrato, inteso come un dispositivo che implementa le principali funzioni ottiche, tipicamente nella banda C, su di un'unica piattaforma.
In questi dispositivi l'integrazione e la compattezza giocano un ruolo fondamentale. Tra i diversi materiali disponibili, i composti semiconduttori organici sono particolarmente attraenti perchè a basso costo di fabbricazione e particolarmente predisposti all'integrazione per via della loro struttura amorfa.
Tra le diverse funzioni da implementare in un chip ottico integrato, l'amplificazione e la generazione di luce sono ancora limitate. Questo è dovuto principalmente al fatto che l'erbio, necessario per l'emissione in banda C, ha proprietà sfavorevoli come basse sezioni d'urto di assorbimento ed emissione. Per questo motivo vengono utilizzati dei materiali host in grado di ospitare l'erbio al loro interno e di fungere da antenne, captando l'energia di eccitazione con maggiore efficienza e di trasferirla all'atomo di erbio. Un tipico esempio di questo tipo di sistema è dato dall'EDFA, in cui la matrice vetrosa delle fibra funge da host per l'erbio. Tecnologie come gli EDFA non sono però predisposte all'integrazione ottica, dal momento che fibre di circa 40 m di lunghezza sono richieste per ottenere una sufficiente amplificazione. In questo contesto i composti organici drogati con erbio, detti organolantanidi, sono promettenti per un'applicazione all'ottica integrata dal momento che possiedono proprietà interessanti come buone sezioni d'urto di assorbimento ed emissione e basso costo di lavorazione. Lo scopo di questo lavoro è di fornire una dimostrazione pratica delle potenzialità di applicazione dei composti organolantanidi per la realizzazione di un amplificatore DFB integrato in banda C a pompaggio elettrico
I diversi aspetti del dispositivo sono stati studiati separatamente, utilizzando l'uso di tecniche a basso costo come il solution processing e il pompaggio ottico tramite LED per l'eccitazione dei composti attivi. La possibilità del pompaggio elettrico è stata esplorata con la realizzazione di un LED organico (OLED) realizzato tramite spin-coating. Le cavità DFB sono state fabbricate tramite litografia per nanoimprinting ed interferenza laser e depositate con organolantanidi in funzione di strato attivo, ottenendo una linea di emissione a 1530 nm. Infine, le proprietà guidanti del dispositivo sono state studiate mediante la strutturazioen della cavità come guida d'onda di canale. La discontinuità d'indice planare è stata ottenuta tramite foto-patterning UV, ottimizzato per il composto organico attivo utilizzato in questo lavoro di tesi.The recent explosion of broadband services and the limits imposed by the Moore’s law have stimulated strong research activities towards the integrated optical chips, that are composed of a platform on which many different optical functions, typically in the C-band, are implemented. Such devices are particularly challenging because integration and compactness play fundamental roles. Among the different materials used to process the optical integrated devices, three main classes can be identified: semiconductors, glasses and organic materials. The last ones are particularly attractive because of the low cost of processing and the high integration related to the amorphous structure, resulting in not required lattice matching conditions. A common design approach in integrated optics is to optimize a particular optical function with a specific material, then to integrate it on the platform. Among the functions to be implemented, amplification and light generation are still limited with respect to the other functions such as modulation or coupling/splitting. This is due to the limits imposed by erbium for the C-band operation. Indeed, erbium is difficult to be optically excited because of the small absorption cross section, so host sensitizers such as glasses are needed to efficiently collect the outer excitation and transfer it to the erbium ions. The most famous example of erbium sensitizer scheme is provided by the Erbium Doped Fiber Amplifiers (EDFAs), wherein erbium ions are incorporated in glass matrices. However, EDFAs are not suitable for integrated chips since a long interaction length is required to achieve a sufficient gain level. Erbium-doped organic compounds are promising erbium sensitizers for the application to integrated chips as they exhibit attractive features such as high absorption and emission cross section, semiconducting behavior and low cost processing. The aim of this work is to provide a demonstration of the potential of Er-doped compounds for the processing of an electrically driven integrated laser amplifier for the C-band of the optical communications. The different issues involved in such a challenging device have been studied separately, emphasizing the use of low cost techniques such as solution processing for organic deposition and LED pumping for the excitation of the active compounds. The opportunity for electrical pumping has been demonstrated with the processing of a spin-coated Er-doped organic LED. The optically pumped DFB cavities have been fabricated by nano-imprinting lithography and laser interference lithography and coated by Er-doped organic compound as active layer, resulting in a narrow emission line centered at 1530 nm. Finally, the waveguide issue has been addressed by designing a channel waveguide. Planar index discontinuity has been achieved by mean of a UV photo-patterning technique, purposed for the erbium-doped compound used in this work.
34
Reza, Selim. "Acoustooptically tunable waveguide lasers in erbium doped lithium niobate." [S.l.] : [s.n.], 2006. http://ubdata.uni-paderborn.de/ediss/06/2006/reza.
Full text
35
Al, Choueiry Antoine. "NANOPARTICULES DE SILICIUM ET IONS ERBIUM POUR L'AMPLIFICATION OPTIQUE." Phd thesis, Université Claude Bernard - Lyon I, 2007. http://tel.archives-ouvertes.fr/tel-00333585.
Full textAbstract:
Les ions erbium trivalents (Er3+) ont joué un rôle important dans le développement de la technologie des télécommunications optiques dans les dernières années. L'émission des ions Er3+ à 1.53?m est cruciale pour lestélécommunications optiques car cette émission correspond au minimum d'atténuation des fibres de silice utilisée pour transporter l'information. Malheureusement, la section efficace d'absorption des ions Er3+ est faible, de l'ordre de 10-21cm2. Pour cette raison, la sensibilisation des ions Er3+ par des espèces dont la section efficace d'absorption est élevée, comme les nano particules de silicium (Np-Si) par exemple, présente un intérêt majeur.Plusieurs études ont été effectuées sur des couches minces de silice codopée par des Np-Si et des ions Er3+, mais plusieurs questions restent sans réponses. Par exemple, les mécanismes d'excitation et de désexcitation des ions Er3+, le faible pourcentage des ions Er3+ excités et l'environnement local des ions Er3+.
Nous avons utilisé une technique d'affinement de raie de fluorescence pour étudier l'environnement local des ions Er3+. Nous avons quantifié la largeur inhomogène de la transition 4I13/2--> 4I15/2 des ions Er3+ dans des couches minces de silice dopées par des Np-Si. Nous avons mis en évidence la présence d'un seul type de site. Une étude de la dynamique du niveau 4I13/2 nous a permis de proposer l'existence du phénomène de migration d'énergie entre les ions Er3+. Nous n'avons pas observé l'existence d'un transfert retour entre les ions Er3+ et les Np-Si. De plus, nous avons remarqué la présence d'une émission rapide (nanoseconde) dans le domaine de l'infrarouge. Nous avons attribué cette émission aux défauts liés aux Np-Si.
36
Curry, Richard James. "Luminescence characterisation of aluminium and erbium tris (8-hydroxyquinoline)." Thesis, Queen Mary, University of London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312173.
Full text
37
O, Cochlain Ciaran R. "Tunable erbium doped fibre lasers for lightwave communication systems." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283935.
Full text
38
Gupta, Rita 1970. "Defect characterization of erbium doped silicon light emitting diodes." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11695.
Full text
39
Ali, Muhammad Irshad. "Sol-gel routes to erbium doped waveguide amplifiers (EDWAs)." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/11098.
Full textAbstract:
The potential of new erbium doped materials has been assessed with the aim of enhancing and tailoring the emission properties of ERIII ions (such as PL spectrum and lifetime) in pure and modified SiO2 hosts through sol-gel methodologies. The main focus has been to investigate potential use of novel precursor, erbium triflate, in combination with different organophosphorus ligands, and aluminium co-dopants, for the synthesis of sol-gel thin films, bulk and power materials. This thesis describes two main approaches. In the first approach, sols were synthesised using standard sol-gel hydrolysis and condensation process. This was followed by the deposition of thin films by spin coating. After the deposition the films were thermally treated at high temperature to produce compact inorganic SiO2 networks. Finally, the optical characterisation of the films has been studied. The films were optically inactive. The second approach consisted of synthesis of sol-gel bulk materials in the form of glasses and glass ceramics co-doped with AlIII and PV ions, transparent glasses and glass ceramics incorporating ErIII ions concentration as high as ~10 mol % were prepared containing active nanocrystallites of erbium phosphate in amorphous SiO2 matrix. Optical characterisation of these glass ceramics has shown that broad and flat emission photoluminescence spectra of ErIII ions with FWHM greater than 100 nm are obtained only in the materials containing ErPO4 nanocrystals with average diameter of 4-5nm combined with a narrow and uniform size distribution. Visible upconversion was also detected in the Er-doped sol-gel SiO2 powders under excitation at 800 and 980 nm. Excited state absorption (ESA) and energy transfer up-conversion (ETU) have been discussed as possible mechanism for visible up-conversion.
40
Lim, Ee Leong. "Pump conditioning and optimisation for erbium doped fibre applications." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/350230/.
Full textAbstract:
This thesis presents my investigation into in-band pumped erbium doped fibre amplifiers (EDFAs) and their performance under high power continuous wave (cw) operation and high energy low repetition rate pulsed operation. In addition, Q-switched erbium doped fibre lasers were investigated and used as the seed laser for a high energy low repetition rate EDFA system. Furthermore, the power scaling of all-fibre frequency doubled fibre lasers based on periodically poled silica fibre (PPSF) was also investigated. In Q-switched fibre lasers, the multiple-peak phenomenon (MPP) is an undesirable effect in which the Q-switched pulse develops sub-structure or even breaks into multiple sub pulses. I demonstrated that the MPP can be eliminated by increasing the acousto-optic modulator rise time. An experimentally validated numerical model was also used to explain the origin of MPP. Next, I showed that the interplay between MPP and modulation instability (MI) changes the detail of the spectral evolution of the Q-switched pulses. The in-band EDFAs were investigated using 1535 nm pump fibre lasers. For cw operation, a highly efficient (~ 80%), high power (18.45 W) in-band, core pumped erbium/ytterbium co-doped fibre laser was demonstrated. Using a fitted simulation model, I showed that the significantly sub-quantum limit conversion efficiency of in-band pumped EDFAs observed experimentally can be explained by concentration quenching. I then numerically studied and experimentally validated the optimum pumping configuration for power scaling of in-band, cladding pumped EDFAs. My simulation results indicate that a ~ 77% power conversion efficiency with high output power should be possible through cladding pumping of current commercially available pure erbium doped active fibres providing the loss experienced by the cladding guided 1535 nm pump due to the coating absorption can be reduced to an acceptable level by better coating material choice. The power conversion efficiency has the potential to exceed 90% if concentration quenching of erbium ions can be reduced via improvements in fibre design and fabrication. For low repetition rate pulsed operation, I demonstrated and compared high-energy, in-band pumped EDFAs operating at 1562.5 nm under both a core pumping scheme (CRS) and a cladding pumping scheme (CLS). The CRS/CLS sources generated smooth, single-peak pulses with maximum pulse energies of ~1.53/1.50 mJ, and corresponding pulse widths of ~176/182 ns respectively, with an M^2 of ~1.6 in both cases. However, the conversion efficiency for the CLS was >1.5 times higher than the equivalent CRS variant operating at the same pulse energy due to the lower pump intensity in the CLS that mitigates the detrimental effects of concentration quenching. With a longer fibre length in a CLS implementation a pulse energy of ~2.6 mJ was demonstrated with a corresponding M^2 of ~4.2. Using numerical simulations I explained that the saturation of pulse energy observed in my experiments was due to saturation of the pump absorption. For the frequency doubling work, the fundamental pump source of the PPSF was a master oscillator power amplifier seeded with a tuneable external cavity laser. During the high power operation, the heat deposition along the PPSF shifted the optimal quasi-phase matched wavelength to a longer wavelength. This shift must be compensated to achieve optimal performance of the PPSF under test and was achieved in my experiment by tuning the central wavelength of the pump source. At the end of the high power experiment, the PPSF samples degraded to ~40% of their pristine PPSF normalised efficiencies. The glass property of the PPSF had also been changed by the high power exposure. A high power all-fibre frequency doubled laser was demonstrated with 1.13 W of second harmonic average power with ~27% internal conversion efficiency.
41
Lynch, Jonathan William. "Laser (Cooling) Refrigeration in Erbium Based Solid State Materials." Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/358684.
Full textAbstract:
PhysicsPh.D.
The objective of this study was to investigate the potential of erbium based solid state materials for laser refrigeration in bulk material. A great deal of work in the field has been focused on the use of ytterbium based ZBLAN glass. Some experiments have also reported cooling in thulium based solid state materials but with considerably less success. We proposed that erbium had many attractive features compared to ytterbium and therefore should be tried for cooling. The low lying energy level structure of erbium provides energy levels that could bring obtainable temperatures two orders of magnitude lower. Erbium transitions of interest for cooling fall in the near IR region (0.87 microns and 1.5 microns). Lasers for one of these transitions, in the 1.5 micron region, are well developed for communication and are in the eye-safe and water and atmosphere transparent region. Theoretical calculations are also presented so as to identify energy levels of the eleven 4f electrons in Er3+ in Cs2NaYCl6:Er3+ and the transitions between them. The strengths of the optical transitions between them have been calculated. Knowledge of such energy levels and the strength of the laser induced transitions between them is crucial for understanding the refrigeration mechanisms and different energy transfer pathways following the laser irradiation. The crystal host for erbium was a hexa-chloro-elpasolite crystal, Cs2NaYCl6:Er3+ with an 80% (stoichiometric) concentration of erbium. The best cooling results were obtained using the 0.87 micron transition. We have demonstrated bulk cooling in this crystal with a temperature difference of ~6.2 K below the surrounding temperature. The temperatures of the crystal and its immediate surrounding environment were measured using differential thermometry. Refrigeration experiments using the 1.5 micron transition were performed and the results are presented. The demonstrated temperature difference was orders of magnitude smaller. Only a temperature of ~0.015 K below the temperature of the surrounding environment was observed in this case. These results are in agreement with another group’s that has observed cooling, though a slightly poorer temperature difference, using this transition of erbium (Condon et. al., 2009). Cooling was also attempted in the 0.87 micron transition of another crystal host, KPb2Cl5:Er, which has a concentration of about one percent of erbium. We did not observe any cooling in this crystal. However, the first cooling reports in erbium based systems were with this crystal where another group observed cooling by 0.7 K using the same transition (Fernández, García-Adeva, & Balda, 2006).
Temple University--Theses
42
Cheney, Glenn P. (Glenn Peter) Carleton University Dissertation Engineering Electrical. "All-optical gain switching of erbium-doped fibre amplifiers." Ottawa, 1992.
Find full text
43
Hu, Yongdan. "High-concentration erbium-doped glasses, fiber amplifiers and lasers." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279804.
Full textAbstract:
Upconversion coefficients in a new high-concentration erbium-doped tellurite glass were obtained a schematic study of experiments and modeling. The upconversion coefficient for ⁴I₁₃/₂ + ⁴I₁₃/₂ → ⁴I₉/₂ + ⁴I₁₅/₂ is found to be 2.74 x 10⁻¹⁸ cm³/s and for ⁴I₁₁/₂ + ⁴I₁₁/₂ → ⁴I₁₅/₂ + ²F₇/₂ is 1.09 x 10⁻¹⁸ cm³/s. The performance of high concentration Er³⁺+-Yb³⁺ -codoped phosphate fiber amplifiers and the performance of a high-power Er³⁺-Yb³⁺-codoped phosphate fiber laser were presented. From a 3.6cm-long fiber, 18 dB internal gain i.e. 5 dB/cm, for small signal input at 1535 nm, was achieved. With a cleaved facet as the output mirror, a fiber laser has been demonstrated from the same fiber with an output power of 33.8 mW at 1549.92 nm. A high slope efficiency of 40.2% was observed. Modeling results of gain and noise figure of four phosphate EDFAs with different lengths were presented with previous measured results. 34% erbium ions were found to be paired in our 3.5wt% erbium-doped phosphate fiber amplifiers. The onset of erbium concentration for pair induced quenching is suggested to be around 3wt% in phosphate fiber amplifiers.
44
Shah, M. "Excitation mechanisms in erbium-doped silicon-rich silicon oxide." Thesis, University College London (University of London), 2014. http://discovery.ucl.ac.uk/1420212/.
Full textAbstract:
Since the invention of the first silicon transistor in 1947, the electronics industry has grown at a rapid rate, famously predicted and guided by Moore’s law. However, it has recently become apparent that satisfying Moore’s law is becoming increasingly difficult; we are now approaching the fundamental limits of device miniaturization and device speed, and alternative solutions for this problem are continuously being pursued. Over the past couple of decades, silicon photonics has emerged as a promising alternative solution. By carrying data through photons instead of electrons, many of the problems faced in an electronic device become irrelevant in an equivalent photonic device. The challenge of silicon photonics is to demonstrate lasing in a material that is compatible with existing CMOS processing technology, namely silicon. Light emission from silicon, however, is very inefficient, due to its indirect electronic bandgap. Silicon nanostructures, on the other hand, exhibit far higher light emission efficiencies, which has been attributed to quantum confinement effects. Erbium is one of the most interesting rare earth impurities for optical functionality, as it emits photons at 1.54µm, the wavelength that corresponds to minimum attenuation in silica fibres. However, erbium has a relatively low excitation cross section, and narrow excitation bands, necessitating expensive lasers for amplifier operation. It has been found that, by co-doping erbium with silicon-nanocrystals (Si-ncs), far higher excitation efficiencies of erbium can be attained, along with broadband excitation, through energy transfer from excited Si-ncs. To date, a clear understanding of the physics involved in the excitation mechanism is lacking. In this thesis, I identify erbium excitation processes in the Er doped silicon rich silicon oxide material, through photoluminescence (PL) spectroscopy. In particular, time resolved decay data of erbium emission is analysed through exponential fitting and rate equation modelling. The significance of Purcell enhanced radiative emission, and Er ion-ion interactions are highlighted. Furthermore, a characterisation study of Er doped silicon rich silicon oxide thin films will be carried out, revealing the significance and differences between defect, Si- nanocluster, and Si-nanocrystal sensitisation of Er ions. The prospects of device fabrication will also be discussed.
45
Wilkins, James. "THE SYNTHESIS, CHARACTERIZATION, AND UPCONVERTING PROPERTIES OF ERBIUM DOPED; YTTERBIUM, ERBIUM CO-DOPED YTTRIUM OXYSULFIDE PHOSPHORS UNDER 808, 980, AND 1560 nm EXCITATION." VCU Scholars Compass, 2011. http://scholarscompass.vcu.edu/etd/221.
Full textAbstract:
Bulk yttrium oxysulfide phosphors were prepared using the polysulfide flux method. The morphology and structure was characterized using transmission electron microscopy and x-ray powdered diffraction. Visible emissions occurring near 530 and 550 nm and 660 - 670 nm consistent with the 2H11/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2 transitions, respectively, were observed under 808, 980, and 1560 nm excitation. The upconverting mechanisms excited at 808, 980, and 1560 nm have been investigated in detail. The power dependent behavior of the upconverted emission intensities for singly doped erbium phosphors excited at 808 and 980 nm indicated a two-photon excitation process. Likewise, the ytterbium and erbium co-doped phosphors excited at 980 nm also indicated a two-photon excitation process. Doping with 10% erbium showed the most intense emissions under 808 and 1560 nm excitation. Yttrium oxysulfide co-doped with 15% ytterbium and 3% erbium showed the most intense emissions under 980 nm excitation. Upon 1560 nm excitation, the intensity of the red emission band was significantly enhanced by co-doping erbium with ytterbium. Concentration quenching became apparent when either the concentration of erbium or ytterbium reached 20%.
46
Ye, Huanqing. "Organo-sensitised erbium system for optical amplification at telecommunication wavelength." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9079.
Full textAbstract:
The erbium-based optical amplifier (EDFA) plays a vital role in the global fibre-optic telecommunication network. However, there are two main issues with current EDFAs, their bulky size means that they cannot be integrated into silicon-based photonic devices, and they need high pump power to produce optical gain. Here, a potential organo-erbium gain system has been invented, which could be operated under a low pump power and integrated onto a silicon-based device. The fully-fluorinated organic erbium complex [Er(ftpip)3] was mixed with a fully-fluorinated organic zinc complex [Zn(F-BTZ)2], acting as a chromophore over the visible range. The composite provides extraordinary sensitisation from the Zn(F-BTZ)2 to Er(ftpip)3 over a broad-visible band, which is compatible with high power LEDs, whilst the erbium ions have a new record of IR emission lifetime of ~ 0.8 ms (quantum yield = ~ 7%). The integrated sensitisation is ~ 104 times that of the intrinsic excitation into erbium. This system has been integrated into an organic light emitting diodes (OLEDs) demonstrating that the energy transfer is dominated by triplet states of the Zn(F-BTZ)2. This is used for explaining the photoluminescence saturation and large pump-rate, with the composite being excited by a low power diode laser on the chromophore units. This composite-system was used to fabricate a slab waveguide, in which an relative gain of 3.4 dB/cm was achieved when excited by a diode laser with 3 mW. A microscopic-optic setup was designed to measure IR line strengths of erbium ions in crystals of complexes, which were included in theoretical calculation to obtain accurate quantum yield for IR emission of erbium ions. The inclusion of IR line strengths measured from crystals is found to be crucial for Judd-Ofelt parameterisation on organic erbium complexes. It was demonstrated that fluorination could increase the line strengths of hypersensitive transitions and IR transition for 1.5 μm band.
47
Ernst, Holger. "Optimierung und Anwendung eines diodengepumpten, hochrepetierenden 3mm-Er:YAG-Lasers [3-my-m-Er:YAG-Lasers]." [S.l. : s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972358870.
Full text
48
Hoffman, Mark Brandon. "Sub-picosecond pulse propagation in an erbium-doped fiber amplifier with ion-induced dispersion." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/14961.
Full text
49
Saintenoy, Stéphanie. "Structures atomiques et électroniques de volume et de surface de couches très minces de siliciures d'erbium épitaxiées sur Si(111)." Mulhouse, 1995. http://www.theses.fr/1995MULH0414.
Full textAbstract:
Ce travail de thèse porte sur l'étude des siliciures d'erbium ErSi1, 7 épitaxiés sur Si(111), obtenus par coévaporation des espèces Er et Si (technologie MBE) sur substrats maintenus à température ambiante, suivies de recuits entre 450°C et 850°C. L'analyse in situ conjugue essentiellement la diffraction des électrons lents (DEL) et la photoémission UV angulaire haute résolution (ARUPS). La surstructure 3x3R30- observée en DEL est attribuée à un arrangement ordonné de lacunes de silicium dans la couche qui contribuent fortement à susciter l'intérêt fondamental porté par ce système. Le suivi des spectres UPS sous l'effet de différents paramètres physiques nous ont permis d'identifier les différentes structures électroniques enrichissant la bande de valence de ErSi1,7 était constituée d'une couche bouclée de silicium de type Si(111) idéale. La structure de bandes de surface expérimentale exclut l'hypothèse d'un réseau ordonné de lacunes en surface, ce qui est confirmé par les courbes de dispersion théoriques (méthode de Huckel) et l'analyse d'images haute résolution obtenues en STM. Un raisonnement en théorie des groupes appliqué à un état de surface particulier, nous a permis, par comparaison avec les effets de polarisation constatés en photoémission de préciser la position (suggérée par l'analyse des images STM) des atomes de surface par rapport aux lacunes du volume
50
Gueorguiev, Evguenii. "Conception et réalisation d'amplificateurs de forte puissance à base de fibre dopée Erbium et Erbium-Ytterbium double gaine fonctionnant en régimes continu et impulsionnel." Paris, ENST, 2009. http://www.theses.fr/2009ENST0068.
Full textAbstract:
La puissance moyenne des amplificateurs à fibre pour des applications dans les lignes de transmission des réseaux optiques ne cesse d’augmenter depuis les dernières années. D’autre part, les sources optiques à fibre dopée fonctionnant en régime d’impulsions ont connu récemment une évolution très rapide. De grands efforts de recherche ont été réalisés dans ce domaine afin d’utiliser ces sources pour des applications militaires, aérospatiales et médicales. L’introduction des fibres à double gaine dans la conception des amplificateurs optiques a permis l’obtention de puissances très élevées, impossibles à imaginer quelques années auparavant. L’objectif de mon travail était le développement et la réalisation d’amplificateurs WDM dans la bande–C en régime continu et des sources optiques fonctionnant en régime d’impulsions d’une durée de quelques nanosecondes à 1,55 µm à base de fibres double gaines. Au cours de ma thèse, j’ai été amené à travailler assez largement sur l’amplification à l’aide de fibres dopées dans divers régimes de fonctionnement. Je montre combien l’obtention d’une puissance importante peut être limitée par l’apparition d’effets indésirables. Mon étude a été ainsi très fortement guidée par l’objectif de résolution ou de minimisation des conséquences induites par l’apparition de ces effets, ou bien encore d’augmentation de leur niveau de seuil. Mon travail a donc permis le développement et la commercialisation d’une famille d’amplificateurs WDM et une famille de sources à forte brillance et de forte énergie à 1,55 µm. J’ai ainsi optimisé et réalisé ces produits à partir de composants disponibles commercialementThe average power of fiber amplifiers for applications in the transmission lines on optical networks is increasing in recent years. On the other hand, the sources based on doped optical fiber operating in pulse mode have recently experienced a dramatic development. Major research efforts have been made in this area in order to use these sources for military, aerospace and medical applications. The introduction of double clad fiber in the optical amplifier design has allowed obtaining very high power, impossible to imagine a few years ago. The purpose of my work was the development and implementation of WDM amplifiers in the C-band operating under continuous emission and optical sources operating in pulsed mode of a few nanoseconds at 1,55 µm based on double clad fibers. During my PhD, I was working fairly widely on optical amplification using doped fbers in various operating modes. I have showed that obtaining significant power may be limited by the occurence of side effects. My study has been so strongly guided by the goal of resolution or minimization of the consequences induced by the appearance of these effects and increases their threshold level. My work has allowed the development and commercialization of a family of WDM amplifiers and a family of sources with high brightness and high energy at 1,55 µm. I have thus optimized and built these devices from commercially available components