Effects of temperature on high concentration erbium-doped fiber intrinsic parameters

The effects of temperature on high concentration Erbium-doped fibers are characterized using parameters of transcendental equation model. The intrinsic parameters (intrinsic saturation power, excited-state lifetime and linear absorption coefficient) of six Erbium doped and Erbium codoped with Lanthanum fibers have been measured for different temperatures. The temperature dependence of intrinsic parameter has been compared respect to Erbium concentration and Lanthanum-Erbium concentration ratio

50 cm of Zirconia, Bismuth and Silica Erbium-doped Fibers for Double-pass Amplification with a Broadband Mirror

Erbium-doped fiber amplifiers (EDFAs) have saturated the technological market but are still widely used in high-speed and long-distance communication systems. To overcome EDFA saturation and limitations, its erbium-doped fiber is co-doped with other materials such as zirconia and bismuth. This article demonstrates and compares the performance using three different fibers as the gain medium for zirconia-erbium-doped fibers (Zr-EDF), bismuth-erbium-doped fibers (Bi-EDF), and commercial silicaerbium-doped fibers (Si- EDF). The optical amplifier was configured with a double-pass amplification system, with a broadband mirror at the end of its configuration to allow double-pass operation in the system. The important parameters in amplifiers such as optical properties, optical amplification and noise values were also examined and discussed. All three fibers were 0.5 m long and entered with different input signals: 30 dBm for low input and 10 dBm for high input. Zr-EDF turned out to be the most relevant optical amplifier as it had the highest optical gain, longest transmission distance, highest average flatness gain with minimal jitter, and relevant noise figures suitable for the latest communication technology

Design of Radiation-Hardened Rare-Earth Doped Amplifiers Through a Coupled Experiment/Simulation Approach

We present an approach coupling a limited experimental number of tests with numerical simulations regarding the design of radiation-hardened (RH) rare earth (RE)-doped fiber amplifiers. Radiation tests are done on RE-doped fiber samples in order to measure and assess the values of the principal input parameters requested by the simulation tool based on particle swarm optimization (PSO) approach. The proposed simulation procedure is validated by comparing the calculation results with the measured degradations of two amplifiers made with standard and RH RE-doped optical fibers, respectively. After validation, the numerical code is used to theoretically investigate the influence of some amplifier design parameters on its sensitivity to radiations. Simulations show that the RE-doped fiber length used in the amplifier needs to be adjusted to optimize the amplifier performance over the whole space mission profile rather than to obtain the maximal amplification efficiency before its integration in the harsh environment. By combining this coupled approach with the newly-developed RH RE-doped fibers, fiber-based amplifiers nearly insensitive to space environment may be designed in the future

Coupled experiment/simulation approach for the design of radiation-hardened rare-earth doped optical fibers and amplifiers

We developed an approach to design radiation-hardened rare earth -doped fibers and amplifiers. This methodology combines testing experiments on these devices with particle swarm optimization (PSO) calculations. The composition of Er/Yb-doped phosphosilicate fibers was improved by introducing Cerium inside their cores. Such composition strongly reduces the amplifier radiation sensitivity, limiting its degradation: we observed a gain decreasing from 19 dB to 18 dB after 50 krad whereas previous studies reported higher degradations up to 0°dB at such doses. PSO calculations, taking only into account the radiation effects on the absorption efficiency around the pump and emission wavelengths, correctly reproduce the general trends of experimental results. This calculation tool has been used to study the influence of the amplifier design on its radiation response. The fiber length used to ensure the optimal amplification before irradiation may be rather defined and adjusted to optimize the amplifier performance over the whole space mission profile rather than before integration in the harsh environments. Both forward and backward pumping schemes lead to the same kind of degradation with our active fibers. By using this promising coupled approach, radiation-hardened amplifiers nearly insensitive to radiations may be designed in the future

High power (60mW) single frequency erbium:ytterbium codoped fiber laser

The characteristics of a high power Er3+:Yb3+ single frequency fiber laser pumped at 980nm are reported. The device gives 60mW output power with RIN 10MHz and linewidth 500kHz. At low output powers (< 30mW) the slope efficiency is as high as 25%, falling to 12% at higher powers, the saturation behaviour is related to a bottleneck effect due to the finite Yb-Er transfer rate. Improved performance can be obtained using new fibers with an increased rare-earth concentration which show negligible signs of erbium clustering

Index matching between passive and active tellurite glasses for use in microstructured fiber lasers: Erbium doped lanthanum-tellurite glass

Active and passive variants of La-containing tellurite glasses have been developed with matched refractive indices. The consequences of adding lanthanum to the glass was studied through measurements of the crystallization stability, glass viscosity and the loss of unstructured fibers. Doping the glass with erbium allowed for any spectroscopic changes to be observed through measurements of the absorption and energy level lifetimes. The fluorescence emission spectra were measured at 1.5 microm and, to the best of our knowledge, for the first time in tellurite glass at 2.7 microm.Michael R. Oermann, Heike Ebendorff-Heidepriem, Yahua Li, Tze-Cheung Foo, and Tanya M. Monrohttp://www.opticsinfobase.org/abstract.cfm?URI=oe-17-18-1557

Er doped oxide nanoparticles in silica based optical fibres

Erbium doped materials are of great interest in optical telecommunications due to the Er3+ intra-4f emission at 1.54 ?m. Erbium doped fibre amplifiers (EDFA) were developed in silica glass because of the low losses at this wavelength and the reliability of this glass. Developments of new rare earth doped fibre amplifiers aim to control their spectroscopic properties including shape and width of the gain curve and optical quantum efficiency. Standard silica glass modifiers, such as aluminium, result in very good properties in current EDFA. However, for more drastic spectroscopic changes, more important modifications of the rare earth ions local environment are required. To address this aim, we present a fibre fabrication route creating rare earth doped calcia?silica or calcia?phosphosilica nanoparticles embedded in silica glass. By adding alkaline earth elements such as calcium, in low concentration, one can obtain a glass with an immisci- bility gap so that phase separation occurs with an appropriate heat treatment. We investigated the role of two elements: calcium and phosphorus (a standard silica modifier). Scanning electron microscopy shows that nanoparticles are only observed when calcium is incorporated. The size of the particles is determined to be around 50 nm in preform samples. The nature of these particles depends on phosphorus content: without P, electron diffraction shows that the particles are amorphous whilst they are partially crystalline when phosphorus is added. In addition through use of energy dispersive x-ray techniques, we have shown that erbium ions are located in the nanoparticles

Erbium-doped nanoparticles in silica-based optical fibres

Developing of new rare-earth (RE)-doped optical fibres for power amplifiers and lasers requires continuous improvements in the fibre spectroscopic properties (like shape and width of the gain curve, optical quantum efficiency, resistance to spectral hole burning and photodarkening...). Silica glass as a host material for fibres has proved to be very attractive. However, some potential applications of RE-doped fibres suffer from limitations in terms of spectroscopic properties resulting from clustering or inappropriate local environment when doped into silica. To this aim, we present a new route to modify some spectroscopic properties of RE ions in silica-based fibres based on the incorporation of erbium ions in amorphous dielectric nanoparticles, grown in-situ in fibre preforms. By adding alkaline earth elements, in low concentration into silica, one can obtain a glass with an immiscibility gap. Then, phase separation occurs under an appropriate heat treatment. We investigated the role of three alkaline-earth elements: magnesium, calcium and strontium. We present the achieved stabilisation of nanometric erbium-doped dielectric nanoparticles within the core of silica fibres. We present the nanoparticle dimensional characterisation in fibre samples. We also show the spectroscopic characterisation of erbium in preform and fibre samples with different compositions. This new route could have important potentials in improving RE-doped fibre amplifiers and laser sources.Comment: arXiv admin note: text overlap with arXiv:1201.111

Measuring absolute spectral radiance using an Erbium Doped Fibre Amplifier

We describe a method to measure the spectral radiance of a source in an absolute way without the need of a reference. Here we give the necessary detail to allow for the device to be reproduced from standard fiber-optic components. The device is suited for fiber-optic applications at telecom wavelengths and calibration of powermeters and spectrometers at light levels from 1nW to 1uW