Dynamic Characterization of Upconversion in Highly Er-Doped Silica Photonic Crystal Fibers

Optimized active multicore fiber bending sensor

“…The well-known models commonly used for step index fibers [9] can be used to describe the signal and pump evolution, together with the amplified spontaneous emission (ASE), along the erbium-doped MCF. As we are dealing with highly-doped waveguides, it is mandatory to take into account the upconversion process which has disadvantageous impact on the pump efficiency [10]. Fig.…”

The Influence of Nonlinear Effects Upon Oscillation Regimes of Erbium-Doped Fiber Lasers

“…where ε s =σ 24 (7) where s s0 is the on-axis saturation parameter that depends on the pump power, P s , as P s =I s sat s s0 (πw s 2 /2), a is the EDF core radius, w s is the modal radius of the Gaussian wave, and Γ s is the mode's to fiber core's radii overlap factor at λ s . The parameter ξ s comprises the ESA parameter ε s , the measured EDF low-signal absorption coefficient α s0 =Γ s σ 12 N 0 , and the full-saturated fiber gain g s =Γ s σ 21 N 0 -Γ s σ 24 N 0 =g s0 -ε s α s0 (g s0 is the EDF net gain at λ s ):…”

“…Refs. [22][23][24]. Note that the quantity attributing the HUC phenomenon ( C HUP * constant) should be proportional to the ESA cross-section (see e.g.…”

Study of upconversion in highly Er-doped photonic crystal fibers through laser-transient dynamics

“…Critical radii determine the distances where the interaction probabilities are equal to the probability of spontaneous relaxation. Then, when averaging the solution of the rate equation of an arbitrary Er ion in level 4 I 13/2 (equation (3) in [11]) with respect to uniform Er distribution, the average probability n n / 2 Er (and subsequently, the upconversion coefficient) can be found as a solution to a transcendental equation (equation (6) in [11]). A non-quadratic character of the HUC contribution is obtained, and the homogeneous upconversion coefficient in an erbium-doped silica fiber turns out to be a function of various spectroscopic parameters and working conditions (erbium concentration, cooperative upconversion and migration-critical radii, input pump power, and pump wavelength).…”

“…In this regard, modeling of various macroscopic and microscopic formalisms (quadratic model, microscopic statistical, pair-induced quenching) has been elaborated to describe these processes [5]. On the other hand, steady-state and dynamic characterization techniques (numerical fitting to CW-pump gain and to amplified spontaneous emission relaxation after pump switch-off, respectively) have been developed, and been shown to offer complementary information on the active PCF characteristic parameters [5,6].…”