Thulium Doped Fiber Amplifier (TDFA) for S-band WDM Systems

A comprehensive numerical model based on solving rate equations of a thulium-doped silica-based fiber amplifier is evaluated. The pump power and thulium-doped fiber (TDF) length for single-pass Thulium-Doped Fiber Amplifiers (TDFA) are theoretically optimized to achieve the optimum Gain and Noise Figure (NF) at the center of S-band region. The 1064 nm pump is used to provide both ground-state and excited state absorptions for amplification in the S-band region. The theoretical result is in agreement with the published experimental result

Schematic Representation for Illustrating the Procedure of Optical Noise Figure in Erbium-doped Fiber Amplifier (EDFA) and Praseodymium-doped Fiber Amplifier (PDFA)

The erbium-doped fiber amplifier (EDFA) operating at 1530 nm wavelength and the praseodymium-doped fiber amplifier (PDFA) at 1300 nm wavelength are promising components for optical fiber communications due to their high gain, high saturation powers, low noise and low crosstalk. In this paper, using comprehensive models which take into account the spectroscopic properties of the fiber amplifiers, we have analyzed the temperature-dependent noise figure effects on both EDFAs and PDFAs

Optimizing the thulium doped fiber amplifier (TDFA) gain and noise figure for S-band 16× 10 Gb/s WDM systems

This paper aims to evaluate a comprehensive numerical model based on solving rate equations of a thulium-doped silica-based fiber amplifier. The pump power and thulium-doped fiber (TDF) length for single-pass thulium-doped fiber amplifiers (TDFA) are theoretically optimized to achieve the optimum gain and noise figure (NF) at the center of S-band region. The 1064 nm pump is used to provide both ground-state and excited state absorptions for amplification in the S-band region. The theoretical result is in agreement with the published experimental result

Optimal design of 32 channels spectrum slicing WDM for optical fiber access network system

In this article, the spectrum sliced dense wavelength division multiplexed passive optical network (SS-DWDM–PON) has been investigated as a power efficient and cost effective solution for optical access networks. In this work an AWG demultiplexer is used to operate as slicing system. The high speed SS-DWDM system has been realized and investigated for 32 channels with data rate up to 3 Gb/s using broadband ASE source (LED). The 3 Gb/s signals both non-return-to-zero (NRZ) and return-to-zero (RZ) were demonstrated in 40 km optical fiber link with BER < 10−12. The results obtained here demonstrate that SS-DWDM is well suited for Fiber-to-the-Home (FTTH) network

Noise figure and gain temperature dependent of praseodymium-doped fiber amplifier by using rate equations

A theoretical study of the temperature dependent noise effects of praseodymium-doped fiber amplifiers (PEDFAs) has been examined. The Pr3+-doped ZBLAN fiber amplifier pumped at 1017 nm and Pr3+-doped GeGa-sulfied fiber amplifier pumped at 1028 nm are chosen. The temperature-dependent rate and propagation equation related to four-level system consideration which is based on the population difference among amplification levels has been used. The population difference depends on pump and signal powers, Boltzman factor KB, cross-sections, noise figure (NF) and Pr3+ concentration. The numerical results obtained over the temperature range from −20 °C to + 60 °C are used to present an analytical expression for the signal gain and noise figure effects in PDFAs length and noise figure with input pump power. The amplified spontaneous emission (ASE) has been taken into account

The gain and noise figure of Yb–Er-codoped fiber amplifiers based on the temperature-dependent model

A novel temperature-dependent model for Yb3+–Er3+-codoped fiber amplifier (EYDFA) based on the energy transfer from Yb3+ to Er3+ is established. Using appropriate fiber and energy transfer parameters, the coupled rate equations is numerically solved at 25 and 40 °C. The pumping powers are 100 and 200 mW at a pump wavelength of 1060 nm. The signal gain and noise characteristics of a 0.3 m erbium/ytterbium co-doped fiber (EYDF) in a single-pass configuration are investigated by using 1, 10 and 100 μW signals at 1535 nm. A maximum signal gain of 40.5 dB and a corresponding noise figure of 3.65 dB at the temperature of 25 °C are achieved

Association of self-rated health with multimorbidity, chronic disease and psychosocial factors in a large middle-aged and older cohort from general practice: a cross-sectional study.

BACKGROUND: The prevalence of coexisting chronic conditions (multimorbidity) is rising. Disease labels, however, give little information about impact on subjective health and personal illness experience. We aim to examine the strength of association of single and multimorbid physical chronic diseases with self-rated health in a middle-aged and older population in England, and to determine whether any association is mediated by depression and other psychosocial factors. METHODS: 25 268 individuals aged 39 to 79 years recruited from general practice registers in the European Prospective Investigation of Cancer (EPIC-Norfolk) study, completed a survey including self-rated health, psychosocial function and presence of common physical chronic conditions (cancer, stroke, heart attack, diabetes, asthma/bronchitis and arthritis). Logistic regression models determined odds of "moderate/poor" compared to "good/excellent" health by condition and number of conditions adjusting for psychosocial measures. RESULTS: One-third (8252) reported one, around 7.5% (1899) two, and around 1% (194) three or more conditions. Odds of "moderate/poor" self-rated health worsened with increasing number of conditions (one (OR = 1.3(1.2-1.4)) versus three or more (OR = 3.4(2.3-5.1)), and were highest where there was comorbidity with stroke (OR = 8.7(4.6-16.7)) or heart attack (OR = 8.5(5.3-13.6)). Psychosocial measures did not explain the association between chronic diseases and multimorbidity with self-rated health.The relationship of multimorbidity with self-rated health was particularly strong in men compared to women (three or more conditions: men (OR = 5.2(3.0-8.9)), women OR = 2.1(1.1-3.9)). CONCLUSIONS: Self-rated health provides a simple, integrative patient-centred assessment for evaluation of illness in the context of multiple chronic disease diagnoses. Those registering in general practice in particular men with three or more diseases or those with cardiovascular comorbidities and with poorer self-rated health may warrant further assessment and intervention to improve their physical and subjective health.EPIC-Norfolk is supported by programme grants from Medical Research Council UK (G9502233, G0300128) and Cancer Research UK (C865/A2883), with additional support from the European Union, Stroke Association, Research into Ageing, British Heart Foundation, Department of Health and Wellcome Trust.This is the final version. It was first published by BioMed Central at http://www.biomedcentral.com/1471-2296/15/18

Temperature Dependency of Ytterbium-Doped Fiber Laser (YDFL) Based on Fabry-Perot Design Operating at 915 nm and 970 nm High Power Pumping Configuration

The variation of the output power of Ytterbium-doped fiber lasers (YDFLs) with temperature has been evaluated. Temperature-dependent rate equations of ytterbium fiber laser based on Fabry-Perot design have been discussed. The results demonstrate that the output power decrease with the increase of temperature. The effect of the temperature on the output performance increases by increasing the pump power. The effect of temperature can be ignored only for lower pump power. The theoretical result is in agreement with the published experimental results