0000000000230820
AUTHOR
Juan Carlos Martín
Study of upconversion in highly Er-doped photonic crystal fibers through laser-transient dynamics
The dynamic response after pump switch-on of a 980 nm pumped-ring laser based on an active photonic crystal fiber with an Er3+ ion concentration of ≈1020 ions cm−3 was registered. Then a numerical fitting procedure of a theoretical model was followed to the experimental values of the relaxation oscillation parameters as a function of the input pump power. Non-radiative energy-transfer mechanisms’ coefficients: homogeneous upconversion coefficient (Cup) and critical radii for upconversion (Ru) and migration (Rm) were determined. The calculated best-fit coefficients (Cup = 1.3 × 10−24 m3 s−1, Ru = 9 × 10−10 m, Rm = 13 × 10−10 m) were compared to those obtained with other steady-state an…
Ranking World Tourism Competitiveness: A Comparison of Two Composite Indicators
Assessing travel and tourism competitiveness (T&TC) is becoming an issue of paramount importance for stakeholders, mainly policymakers and practitioners. The availability of new databases such as the Travel and Tourism Competitiveness Report from the World Economic Forum (WEF) has boosted this interest. This chapter contributes to the current literature in this field with an assessment of the T&TC of 136 world tourist destinations. In doing so, two well-known approaches are employed: Data Envelopment Analysis (DEA) with endogenous common weights, and the Technique for Order of Preference by Similarity to Ideal Solutions (TOPSIS). World tourist destinations are ranked using these approaches,…
Study of the use of methanol-filled Er-doped suspended-core fibres in a temperature-sensing ring laser system
We report on an experimental/numerical investigation into the use of methanol-filled Er-doped suspended-core fibres (SCFs) in temperature-sensing ring laser systems. We have adopted a ring laser configuration that includes an Er-doped SCF as a temperature-dependent attenuator (TDA) with a step-index Er-doped fibre (EDF) as the laser active medium. The laser performance dependence on the temperature was measured both in continuous wave (CW) and transient regimes. CW laser output power and build-up time values are compared with those of similar laser systems based on other types of Er-doped PCFs or using other laser configurations. A notable variation of 0.73% °C−1 was achieved in CW operatio…