An investigation of the temperature dependency of the relative population inversion and the gain in EDFAs by the modified rate equations

The dependence of the relative population inversion in Er3+-doped fiber amplifiers (EDFAs) upon temperature and cross sections, taking into account the amplified spontaneous emission (ASE), are investigated theoretically by the modified rate equation model for 980 nm and 1470 nm pumping conditions. For the temperature range from 0 to +50 oC and at the different signal wavelengths, the temperature and cross section dependent gain characteristics with respect to pump powers are also examined in detail for the both conditions. As a consequence, the dependence of the performance of EDFAs on temperature for 980 nm pumping is weaker than that for 1470 nm pumping, not only at room temperature but also at the temperature range of 0 to +50 oC. However, the performance of EDFAs is more efficient at the pumping wavelength of 1470 nm than that of 980 nm for a wide range of temperature and high-pump powers. The results of this theoretical model are a good agreement with the experimental ones in the literature.Comment: 17 pages, 6 figures. submitted to Optics Communication

Spectroscopic signature of phosphate crystallization in Erbium-doped optical fibre preforms

In rare-earth-doped silica optical fibres, the homogeneous distribution of amplifying ions and part of their spectroscopic properties are usually improved by adding selected elements, such as phosphorus or aluminum, as structural modifier. In erbium ion (Er3+) doped fibres, phosphorus preferentially coordinates to Er3+ ions to form regular cages around it. However, the crystalline structures described in literature never gave particular spectroscopic signature. In this article, we report emission and excitation spectra of Er3+ in a transparent phosphorus-doped silica fibre preform. The observed line features observed at room and low temperature are attributed to ErPO4 crystallites

A Mixed Method Approach for Evaluating and Improving the Design of Learning in Puzzle Games

Despite the acknowledgment that learning is a necessary part of all gameplay, the area of Games User Research lacks an established evidence based method through which designers and researchers can understand, assess, and improve how commercial games teach players game-specific skills and information. In this paper, we propose a mixed method procedure that draws together both quantitative and experiential approaches to examine the extent to which players are supported in learning about the game world and mechanics. We demonstrate the method through presenting a case study of the game Portal involving 14 participants, who differed in terms of their gaming expertise. By comparing optimum solutions to puzzles against observed player performance, we illustrate how the method can indicate particular problems with how learning is structured within a game. We argue that the method can highlight where major breakdowns occur and yield design insights that can improve the player experience with puzzle games

Selective amplification of scars in a chaotic optical fiber

In this letter we propose an original mechanism to select scar modes through coherent gain amplification in a multimode D-shaped fiber. More precisely, we numerically demonstrate how scar modes can be amplified by positioning a gain region in the vicinity of specific points of a short periodic orbit known to give rise to scar modes

Wavelength converter using a highly erbium doped optical fiber ring laser

RESUMEN: En este trabajo se presenta un conversor de longitud de onda ultra-estrecho, de alta eficiencia y todo-fibra basado en el efecto de la competición de modos en un láser de fibra dopada con erbio. Se han llevado a cabo estudios experimentales con frecuencias que van desde varios kilohercios hasta las decenas de gigahercios y para más de una longitud de onda de emisión, demostrando así que este efecto puede ser utilizado para la conversión en longitud de onda de múltiples longitudes de emisión simultáneamente.ABSTRACT: This work presents an all-fiber wavelength converter based on a highly Erdoped fiber laser which has been experimentally demonstrated. Frequencies from several kilohertz up to tens of gigahertz have been investigated. Making use of the gain competition in the amplifying medium, the wavelength conversion can be carried out over not only one lasing wavelength but over several ones. These analyses have been also carried out for more than one all-fiber ring structure, demonstrating the viability of this wavelength converter.Este trabajo ha sido financiado por la Comisión Interministerial de Ciencia y Tecnología dentro de los proyectos TEC2013-47264-C2 y TEC2016-76021-C2

Information capacity of optical fiber channels with zero average dispersion

We study the statistics of optical data transmission in a noisy nonlinear fiber channel with a weak dispersion management and zero average dispersion. Applying path integral methods we have found exactly the probability density functions of channel output both for a non-linear noisy channel and for a linear channel with additive and multiplicative noise. We have obtained analytically a lower bound estimate for the Shannon capacity of considered nonlinear fiber channel.Comment: 4 pages, subbmited to Phys. Rev. Let

Periodic and Quasi-Periodic Compensation Strategies of Extreme Outages caused by Polarization Mode Dispersion and Amplifier Noise

Effect of birefringent disorder on the Bit Error Rate (BER) in an optical fiber telecommunication system subject to amplifier noise may lead to extreme outages, related to anomalously large values of BER. We analyze the Probability Distribution Function (PDF) of BER for various strategies of Polarization Mode Dispersion (PMD) compensation. A compensation method is proposed that is capable of more efficient extreme outages suppression, which leads to substantial improvement of the fiber system performance.Comment: 3 pages, 1 figure, Submitted to IEEE Photonics Letter

Development of low loss, wide bandwidth hollow core photonic bandgap fibers

We present a detailed overview of progress in the development of hollow-core photonic bandgap fibers with improved transmission and modal properties which demonstrates the feasibility and potential of this fiber solution for future telecom systems