Yves Jaouën

Phase-sensitive optical low-coherence reflectometry technique applied to the characterization of photonic crystal fiber properties.

Localized measurements of group-velocity dispersion and birefringence of photonic crystal fibers are achieved with a phase-sensitive optical low-coherence reflectometry technique. This technique is efficient for fiber samples no longer than 1 m. Theoretical simulations are in good agreement with experimental results. As a result, the stress-induced birefringence proves to be at most 1 order of magnitude below the geometrical-shape birefringence.

Dynamics of high-power erbium–ytterbium fiber amplifiers

Dynamic regimes of high-peak-power erbium–ytterbium (Er3+–Yb3+) codoped fiber amplifiers are analyzed for nanosecond-to-microsecond pulses. High-energy pulse generation requires a large-core fiber amplifier to increase energy storage and the threshold of nonlinear effects. A numerical model of large-core Er3+–Yb3+ fiber amplifiers is described. Dynamics of peak powers, amplified spontaneous emission, and population inversion are presented. Influence of radial dependence and reflections at the extremities are studied. Modeling and experimental results are compared for simple-pass and double-pass amplifier configurations. The role of parasitic reflections is highlighted. A semianalytical model is derived for low and high repetition rates.

Evidence of thermal effects in a high-power Er 3+ –Yb 3+ fiber laser

We analyze the influence of heat generation caused by nonradiative transitions in a high-power 1.55 microm double-clad erbium-ytterbium fiber laser on the Stark level population. At strong pumping rates, 1 microm lasing can start as a result of parasitic reflections. We present a model that allows us to simulate the effect of self-generated heat on the Stark level population by using the MacCumber relation. Heat generation plays a significant role and improves the 1.5 microm lasers efficiency by increasing the 1 microm lasing threshold.

Electrostriction-induced acoustic effect in ultralong-distance soliton transmission systems.

The electrostriction-induced acoustic effect introduces a time-dependent index evolution for the following optical pulses and results in an additional temporal shift of solitons. The acoustic effect is incorporated into the nonlinear Schrödinger equation as a perturbative term. We investigate the evolution of timing jitter, taking into account both the Gordon-Haus and the acoustic effect contributions for a 10-Gbit/s sliding-frequency in-line-filter soliton system.

Phase-sensitive OLCR technique applied to fiber group-velocity dispersion and birefringence measurements

The increasing complexity of specialty optical fibers, such as dispersion compensating and photonic crystal fibers, requires the development of high precision measurement techniques. Phase-sensitive optical low-coherence reflectometry is very well suited because it permits complex reflectivity measurements. This technique allows for an accurate and direct characterization of birefringence and group-velocity dispersion from a single measurement of short fiber samples.

Eight wavelength amplifying combiner/splitter module based on erbium/ytterbium doped planar technology

Following the early demonstrations of Er/Yb doped silica and glass planar amplifiers [1-4], research is now being focused on the integration of this amplification function together with passive functions, such as lossless wavelength combiner, power splitter or wavelengths multiplexers [5].

High power pulsed sources based on fiber amplifiers

Cladding-pumped rare-earth-doped fiber laser technologies are currently among the best sources for high power applications. Theses extremely compact and robust sources appoint them as good candidate for aeronautical and space applications. The double-clad (DC) fiber converts the poor beamquality of high-power large-area pump diodes from the 1st cladding to laser light at another wavelength guided in an active single-mode core. High-power coherent MOPA (Master Oscillator Power Amplifier) sources (several 10W CW or several 100W in pulsed regime) will soon be achieved. Unfortunately it also brings nonlinear effects which quickly impairs output signal distortions. Stimulated Brillouin scattering (SBS) and optical parametric amplification (OPA) have been shown to be strong limitations. Based on amplifier modeling and experiments we discuss the performances of these sources.