Erbium-doped glasses for fiber amplifiers at 1500 nm
TL;DR: In this paper, material-dependent properties influencing the performance of fiber amplifiers are reviewed together with the available data for Er/sup 3+/. The major glass types potentially useful in this application are considered and compared to silica.
Abstract: Material-dependent properties influencing the performance of fiber amplifiers are reviewed together with the available data for Er/sup 3+/. The major glass types potentially useful in this application are considered and compared to silica. The topics addressed include quenching processes and the solubility of rare-earth ions, transition strengths and bandwidths at the 1500-nm gain transition, and the characteristics at the 800-, 980-, and 1480-nm pump bands. Aluminum is shown to be an extremely useful codopant for silica, improving its ability to dissolve rare-earth ions and providing desirable spectroscopic properties for Er/sup 3+/. For some of the attributes considered, other glasses have advantages over Al silica, but only with respect to gain bandwidth and pumping performance at 800 nm is significantly better than expected from other glass compositions. >
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2,877 citations
TL;DR: The role of implantation defects, the effect of annealing, concentration dependent effects, and optical activation are discussed and compared for different Er-doped thin film photonic materials.
Abstract: Erbium doped materials are of great interest in thin film integrated optoelectronic technology, due to their Er3+ intra-4f emission at 1.54 μm, a standard telecommunication wavelength. Er-doped dielectric thin films can be used to fabricate planar optical amplifiers or lasers that can be integrated with other devices on the same chip. Semiconductors, such as silicon, can also be doped with erbium. In this case the Er may be excited through optically or electrically generated charge carriers. Er-doped Si light-emitting diodes may find applications in Si-based optoelectronic circuits. In this article, the synthesis, characterization, and application of several different Er-doped thin film photonic materials is described. It focuses on oxide glasses (pure SiO2, phosphosilicate, borosilicate, and soda-lime glasses), ceramic thin films (Al2O3, Y2O3, LiNbO3), and amorphous and crystalline silicon, all doped with Er by ion implantation. MeV ion implantation is a technique that is ideally suited to dope these materials with Er as the ion range corresponds to the typical micron dimensions of these optical materials. The role of implantation defects, the effect of annealing, concentration dependent effects, and optical activation are discussed and compared for the various materials.
1,089 citations
TL;DR: The site isolation of lanthanide cations (Er3+, Tb3+, and Eu3+) has been achieved through self-assembly of three convergent polyether dendrons, each with a carboxylate anion focal point, around the central trivalent cation.
Abstract: The site isolation of lanthanide cations (Er3+, Tb3+, and Eu3+) has been achieved through the self-assembly of three convergent polyether dendrons, each with a carboxylate anion focal point, around the central trivalent cation. Evidence for the self-assembly of the dendritic complexes can be obtained by a variety of spectroscopic and other analytical means both in solution and in the solid state. The luminescence properties of these new dendrimers measured both in solution and in the bulk show a dependence of luminescence activity on the size of the dendritic shell. The observed enhancement in luminescence properties can be attributed both to a large antenna effect, involving the nonconjugated phenyl benzyl ether dendrimer framework, and to a shell effect that results from the effective site isolation of each lanthanide cation within a dendritic sphere, preventing their mutual interaction and decreasing their rate of self-quenching. The site isolation afforded by self-assembly and the antenna effect provi...
427 citations
TL;DR: Fiber Bragg gratings (FBGs) have emerged as important components in a variety of lightwave applications and their unique filtering properties and versatility as in-fiber devices is illustrated by their use in wavelength-stabilized lasers, fiber lasers, remotely pump amplifiers.
Abstract: Fiber Bragg gratings (FBGs) have emerged as important components in a variety of lightwave applications. Their unique filtering properties and versatility as in-fiber devices is illustrated by their use in wavelength-stabilized lasers, fiber lasers, remotely pump amplifiers. Raman amplifiers, phase conjugators, wavelength converters, passive optical networks, wavelength division multiplexers (WDMs) demultiplexers, add/drop multiplexers, dispersion compensators, and gain equalizers.
383 citations
Cites background from "Erbium-doped glasses for fiber ampl..."
...This is particularly important with 980 nm pumping as the erbium absorption bandwidth is only 7‐10 nm [ 14 ]; pump wavelength fluctuations from temperature, injection current and aging are then significant risks to optimum amplifier performance....
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TL;DR: In this paper, two different approaches to dope a polymer waveguide with rare-earth ions are presented, one based on organic cage-like complexes that encapsulate the rare earth ion and the other based on Er-doped silica colloidal spheres.
Abstract: Optical waveguide amplifiers based on polymer materials offer a low-cost alternative for inorganic waveguide amplifiers. Due to the fact that their refractive index is similar to that of standard optical fibers, they can be easily coupled to existing fibers with low coupling losses. Doping the polymer with rare-earth ions that yield optical gain is not straightforward, as the rare-earth salts are poorly soluble in the polymer matrix. This review article focuses on two different approaches to dope a polymer waveguide with rare-earth ions. The first approach is based on organic cage-like complexes that encapsulate the rare-earth ion and are designed to provide coordination sites to bind the rare-earth ion and to shield it from the surrounding matrix. These complexes also offer the possibility of attaching a highly absorbing antenna group, which increases the pump efficiency significantly. The second approach to fabricate rare-earth doped polymer waveguides is obtained by combining the excellent properties of SiO2 as a host for rare-earth ions with the easy processing of polymers. This is done by doping polymers with Er-doped silica colloidal spheres.
338 citations
References
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TL;DR: In this paper, an expression for the oscillator strength of a transition between two states of the ground configuration $4{f}^{N}, on the assumption that the levels of each excited configuration of the type $4 {f} n{n}^{\ensuremath{'n}d$ or $4
Abstract: Electric dipole transitions within the $4f$ shell of a rare-earth ion are permitted if the surroundings of the ion are such that its nucleus is not situated at a center of inversion. An expression is found for the oscillator strength of a transition between two states of the ground configuration $4{f}^{N}$, on the assumption that the levels of each excited configuration of the type $4{f}^{N}{n}^{\ensuremath{'}}d$ or $4{f}^{N}{n}^{\ensuremath{'}}g$ extend over an energy range small as compared to the energy of the configuration above the ground configuration. On summing over all transitions between the components of the ground level ${\ensuremath{\psi}}_{J}$ and those of an excited level ${{\ensuremath{\psi}}^{\ensuremath{'}}}_{{J}^{\ensuremath{'}}}$, both of $4{f}^{N}$, the oscillator strength $P$ corresponding to the transition ${\ensuremath{\psi}}_{J}\ensuremath{\rightarrow}{{\ensuremath{\psi}}^{\ensuremath{'}}}_{{J}^{\ensuremath{'}}}$ of frequency $\ensuremath{
u}$ is found to be given by $P=\ensuremath{\Sigma}{T}_{\ensuremath{\lambda}}\ensuremath{
u}{({\ensuremath{\psi}}_{J}\ensuremath{\parallel}{U}^{(\ensuremath{\lambda})}\ensuremath{\parallel}{{\ensuremath{\psi}}^{\ensuremath{'}}}_{{J}^{\ensuremath{'}}})}^{2},$ where ${\mathrm{U}}^{(\ensuremath{\lambda})}$ is a tensor operator of rank $\ensuremath{\lambda}$, and the sum runs over the three values 2, 4, and 6 of $\ensuremath{\lambda}$. Transitions that also involve changes in the vibrational modes of the complex comprising a rare-earth ion and its surroundings, provide a contribution to $P$ of precisely similar form. It is shown that sets of parameters ${T}_{\ensuremath{\lambda}}$ can be chosen to give a good fit with the experimental data on aqueous solutions of Nd${\mathrm{Cl}}_{3}$ and Er${\mathrm{Cl}}_{3}$. A calculation on the basis of a model, in which the first hydration layer of the rare-earth ion does not possess a center of symmetry, leads to parameters ${T}_{\ensuremath{\lambda}}$ that are smaller than those observed for ${\mathrm{Nd}}^{3+}$ and ${\mathrm{Er}}^{3+}$ by factors of 2 and 8, respectively. Reasons for the discrepancies are discussed.
6,575 citations
"Erbium-doped glasses for fiber ampl..." refers methods in this paper
...A useful semiempirical technique for the analysis of rare-earth transitions was developed independently by Judd [ 61 ] and Ofelt [62]....
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TL;DR: In this article, the transition probability of pure-electronic electric dipole transitions between levels of the 4-fluorescence configuration perturbed by a static crystalline field is treated.
Abstract: Magnetic and electric dipole transitions between levels of the 4fx configuration perturbed by a static crystalline field are treated. The expression obtained for the pure‐electronic electric‐dipole transition probability involves matrix elements of an even‐order unit tensor between the two 4fx states involved in the transition. The contributions to the transition probability from interactions, via the crystalline field, with the nd 94fx−1, 4fx−1 nd, 4fx−1 ng configurations are shown to add linearly, in such a manner as to multiply each odd k crystal‐field parameter Ak q by a constant. If ``J mixing'' in the 4fx configuration is neglected ΔJ between the upper and lower 4fx levels is restricted to six units or less. If ``L mixing'' is neglected then ΔL is also restricted to six units or less. Application is made to the fluorescence spectra of PrCl3 and EuCl3. Many of the missing and weak transitions are explained.
6,445 citations
TL;DR: In this paper, a 3m-long erbium-doped fiber was used for high gain amplification of up to 28 dB at a bit rate of 140 Mbit/s.
Abstract: High gain amplification of up to 28 dB has been observed in a 3m-long erbium-doped fibre. The amplifier has a spectral bandwidth of greater than 300GHz in the region of 1.536µm and a measured sensitivity of -42dBm at a bit rate of 140 Mbit/s.
901 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
01 Jun 1973
TL;DR: In this paper, the basic phenomena involved in double-pumped phosphors with energy transfer are described and discussed and the role played by successive multiple transfers as well as cooperative processes giving rise to antistokes fluorescence is emphasized for the different kinds of doping which have been used.
Abstract: The basic phenomena involved in double-pumped phosphors with energy transfer are described and discussed. The role played by successive multiple transfers as well as cooperative processes giving rise to antistokes fluorescence is emphasized for the different kinds of doping which have been used. The field of the different physical experiments is reviewed. Preparation of the most useful hosts is described and examples of applications are given as well as suggestions for future developments.
620 citations
"Erbium-doped glasses for fiber ampl..." refers background in this paper
...The major cause of inefficiency for E?+-doped glasses is believed to be the cooperative upconversion process [20] illustrated in Fig. 6. Auzel [ 22 ] and Wright 1231 have comprehensively reviewed cooperative upconversion, although only recently has this phenomenon been extensively investigated in glass hosts....
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