Determination of emission and absorption cross sections of in waveguides from transversal fluorescence spectra
01 Nov 1998-Pure and Applied Optics: Journal of The European Optical Society Part A (IOP Publishing)-Vol. 7, Iss: 6, pp 1363-1371
TL;DR: In this article, a procedure for the determination of emission and absorption cross sections in integrated waveguides from transversal fluorescence spectra is presented based on an approximate treatment of McCumber's theory, which was demonstrated to provide accurate values for -doped silica fibres.
Abstract: A procedure for the determination of emission and absorption cross sections in integrated waveguides from transversal fluorescence spectra is presented. It is based on an approximate treatment of McCumber's theory, which was demonstrated to provide accurate values for -doped silica fibres. Results on the transition of in waveguides pumped by a 980 nm laser diode are shown and compared to results from attenuation measurements. Advantages over other procedures for waveguide characterization (less dependence on experimental inaccuracies, all measurements are made on the waveguide, consideration of codoping influence and no pump interference around ) are discussed in detail.
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TL;DR: In this paper, the spectroscopic properties of Al2O3 waveguides ion implanted with Er3+ and Yb3+ are investigated in view of their application in optical amplifiers operating at 1530 nm.
169 citations
TL;DR: In this article, a procedure based on the McCumber theory to determine emission and absorption cross sections in waveguides from transversal fluorescence spectra is presented for transitions involving thermalized states.
Abstract: An application to transitions involving thermalized states of a procedure based on the McCumber theory to determine emission and absorption cross sections in waveguides from transversal fluorescence spectra is presented. The procedure is tested in Er-doped Ti:LiNbO/sub 3/ waveguides to provide accurate cross-section values for the recently attractive 550-nm band. We also study the excited-state absorption transition around 860 nm and present, to our knowledge, the first published cross-section values for this transition.
30 citations
TL;DR: In this paper, a complete model for signal and fluorescence amplification in Ti,Er:LiNbO/sub 3/ waveguides under 1480 and 980 nm excitation, which includes transitions involving high energy levels, is presented.
Abstract: A complete model for signal and fluorescence amplification in Ti,Er:LiNbO/sub 3/ waveguides under 1480 and 980 nm excitation, which includes transitions involving high energy levels, is presented. Most of the waveguide parameters that the model requires have been determined or checked in situ. In order to numerically solve the proposed model, the overlapping factors method has been adapted to these waveguides and improved, obtaining a large computing time reduction with sufficiently accurate results. Finally, results from signal gain and ASE spectral measurements and numerical simulations have been compared. The remarkable agreement confirms both the model assumptions and the used characterization techniques. Moreover, the unusually short computing time which is consumed makes the model suitable for design and optimization processes.
24 citations
TL;DR: In this article, the polarization-resolved emission spectra of the 4I13/2, 4I15/2 and 4S3/2+2H11/2⇔
Abstract: The polarization-resolved emission spectra of the 4I13/2⇔ 4I15/2, 4I11/2⇔ 4I15/2, and 4S3/2+2H11/2⇔ 4I15/2 transitions have been measured in situ on an Er:Ti:LiNbO3 waveguide and used to determine the polarization-resolved emission and absorption cross-section distributions of these transitions. The significant differences caused by the Er3+-ion anisotropic environment may have important implications for optimizing Er:LiNbO3 integrated devices.
23 citations
TL;DR: In this paper, a new procedure for determining the prevalence of either excited-state absorption (ESA) or nonradiative cooperative energy transfer between erbium ions in transitions between excited states in Er-doped integrated waveguides is presented.
Abstract: A new procedure for determining the prevalence of either excited-state absorption (ESA) or nonradiative cooperative energy transfer between erbium ions in transitions between excited states in Er-doped integrated waveguides is presented. These transitions are currently very attractive for the development of upconversion lasers. The procedure is based on the analysis of the dependence on the transition-originating mechanisms of the modulation transfer from the pump to the excited levels' population. The accuracy and validity range of the method are studied numerically using ordinary integrated structures. By using this procedure, the ratio of the contributions of the two competing mechanisms to the /sup 4/I/sub 13/2/ /spl rArr/ /sup 4/I/sub 9/2/ transition is determined from fluorescence measurements on a Er,Ti:LiNbO/sub 3/ sample excited by a 1480-nm pump. Moreover, new values of the excited-state pump-absorption cross section from level /sup 4/I/sub 13/2/, /spl sigma//sub 24/ (/spl ap/1480 nm) = 0.8 /spl times/ 10/sup -26/ m/sup 2/, and of the parameter associated with nonradiative cooperative energy transfer between Er/sup 3+/ ions, C/sub 22/ = 3 /spl times/ 10/sup -24/ m/sup 3/ s/spl middot//sup -1/, are reported.
18 citations
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TL;DR: In this article, the authors present a comprehensive overview of the fundamental principles and applications of erbium-doped fiber amplifiers (EDFAs) in optical fiber communications.
Abstract: It is now widely recognized that erbium-doped fiber amplifiers have revolutionized optical fiber communications. EDFAs not only made single-channel, multigigabit-rate, long-distance optical communications possible, but they also opened up a wide variety of additional possibilities Such as soliton generation and transmission and multichannel wavelength-division multiplexing communications. While at AT&T Bell Labs (he is now at Alcatel-Alsthom Recherche in a suburb of Paris, France) Emmanuel Desurvire became heavily involved in and contributed enormously to the theoretical and experimental investigation of EDFA characteristics and system applications. His pioneering work has been internationally recognized. In my view, Desurvire is one of those best qualified to cover the subject of EDFAs, in Erbium-Doped Fiber Amplifiers: Principles and Applications, he has accepted the challenge. According to the author, the purpose of the book is "to provide the basic materials of a comprehensive introduction to the principles and applications of EDFAs." The book is divided into three major parts, which to some extent can be considered independently. Nonetheless, it keeps its cohesion throughout. It provides a thorough understanding of the fundamentals in optical amplification while considering the practical issues related to the device and system performance of EDFAs. The first part of the book explores all the fundamental issues related to EDFAs. It introduces the main concepts necessary for the modelling of the erbium atomic transition. The analysis is detailed and covers such parameters as field distributions and overlap integrals under different operating conditions. This section and the numerous relevant appendices contain a number of useful generalizations of existing models that are published for the first time. The author also considers the fundamental quantum properties of noise generation and accumulation in single- and multiple-stage amplification of classical light. The analysis discusses in great depth the nature, origin and inevitability of noise associated with optical amplification - it also provides useful engineering formulas for the measurement of the noise introduced by amplification. I found the treatment of noise and photon statistics particularly detailed and original. Researchers working on this subject can benefit enormously from the analysis. The second part is primarily experimental and focuses on EDFA device characteristics. However, when specific characteristics of the erbium transition are discussed, the necessary theoretical modifications and additions, supplementary to the general formulations given in the first part, are provided. I found that on the important issue of pulse amplification requirements, the book considers briefly only the special (but very exciting) case of solitons and misses the many problems associated with general pulse amplification. The third and final section of the book, on applications, is primarily concerned with some of the up-to-date linear and nonlinear communication systems and local area networks and the enormous impact that EDFAs have had on their successful implementation. The significance of the EDFAs in optically preamplified receivers is stressed. The most significant digital (linear) and soliton (nonlinear) system experiments performed to date are also reviewed. Initations imposed on linear systems by fiber nonlinearities and dispersion are briefly mentioned. The ground that Desurvire sought to cover in the third part is quite diverse and could well have been the subject of several separate volumes. Therefore, its inclusion in this book is inevitably of a review type. However, the book clearly points out how and to what degree these applications are benefited or enhanced by EDFAs. Overall the book gives one of the most comprehensive and detailed accounts of the physics and fundamental principles of erbium-doped fiber amplifiers published so far. I have not the slightest doubt that the book will be of great help to all scientists and engineers working in the field who are struggling to understand EDFAs. The unified and in-depth presentation of the subject will benefit in particular researchers and graduate students who are dealing with problems involving optical amplification. The book imparts the fundamental concepts quite skilfully and can be used as collateral reading The sections dealing with modelling and the entire second part could well be used in undergraduate courses. I do not hesitate to recommend the book enthusiastically to anybody having an interest in EDFAs and their applications.
1,128 citations
TL;DR: In this article, a simple dielectric theory is used to describe the operating properties of phonon-terminated masers of the type reported by Johnson, Dietz, and Guggenheim.
Abstract: A simple dielectric theory is used to describe the operating properties of phonon-terminated masers of the type reported by Johnson, Dietz, and Guggenheim. Basic to this model is a broadband gain characteristic which describes the frequency-dependent gain of the active maser material as a function of the populations of metastable electronic levels and of the temperature or temperatures describing lattice vibrations. The power levels required to produce phonon saturation are estimated to be extremely high (typically, \ensuremath{\sim}${10}^{10}$ W/${\mathrm{cm}}^{2}$ power output). Because phonon saturation does not ordinarily occur, a single-lattice temperature is generally sufficient. In that case, details of the electron-phonon coupling are unimportant, and the gain can be related by detailed balance to fluorescence and absorption spectra. Effects of phonon saturation are briefly discussed in the event that they might pertain to exceptional systems and because they give insight into the principles of operation of these masers.
708 citations
TL;DR: An approximate treatment that eliminates the McCumber theory's requirement of detailed electronic structure has been developed and found to usually provide more accurate values than an Einstein analysis.
Abstract: We have applied the theory of McCumber to the (4)4I(13/2) ? (4)I(15/2) transition of Er(3+) -doped glasses and confirmed its ability to provide both spectra and accurate values of cross sections. For an Al/P-silica fiber, the exact McCumber treatment is within 3% of the measured emission cross section, whereas an Einstein analysis is off by >50%. An approximate treatment that eliminates the McCumber theory's requirement of detailed electronic structure has been developed and found to usually provide more accurate values than an Einstein analysis.
565 citations
TL;DR: In this article, the contrast of Fabry-Perot resonances in low-finesse (end face polished) integrated optical resonators is measured to determine an upper limit of the waveguide attenuation coefficient.
Abstract: We propose to measure the contrast of Fabry-Perot resonances in low-finesse (end face polished) integrated optical resonators to determine an upper limit of the waveguide attenuation coefficient. The method is discussed; its absolute accuracy increases with decreasing loss. As example, experimental results are presented for 3 and 10 μm wide Ti: LiNbO3 strip guides; the attenuation coefficients are 0.46 dB/cm (EH11) in the narrower guide at λ=0.63 μm, respectively 0.19 dB/cm (EH11) and 0.09 dB/cm (HE11) in the 10 μm wide guide at λ=1.15 μm.
368 citations
TL;DR: In this article, two different techniques for the calculation of optical modes of Ti: LiNbO/sub 3/ channel waveguides and finite element method are presented, and the effective indices and field distributions obtained by both techniques are compared for wavelengths of 0.6 and 1.2 mu m, for both quasi-TE and -TM polarization, considering Y-cut and Z-cut crystal orientation and both isotropic and anisotropic Ti/sup 4+/ diffusion.
Abstract: Two different techniques for the calculation of optical modes of Ti:LiNbO/sub 3/ channel waveguides are presented. The first one is an almost analytical technique based on the effective-refractive-index method. The second one is based on the well-known finite-element method. Both approaches use a rather realistic waveguide model considering crystal anisotropy, wavelength dispersion of the refractive index distributions, and also the nonlinear dependence of the ordinary refractive index on the Ti/sup 4+/ concentration. Effective indices and field distributions obtained by both techniques are compared for wavelengths of 0.6 and 1.2 mu m, for both quasi-TE and -TM polarization, considering Y-cut and Z-cut crystal orientation and both isotropic and anisotropic Ti/sup 4+/ diffusion. >
171 citations