Real-time optical fibre near-infrared chromatic dispersion analyser using collocated optical fibre gratings.

We present what we believe to be a novel optical fibre device for real-time measurements of near-infrared chromatic dispersion of a liquid medium from 1100 nm to 1700 nm. This inline optical fibre chromatic dispersion analyser is based upon collocated fibre long-period gratings written adjacently in the core by femtosecond laser inscription yielding 8 attenuation bands associated with different cladding modes, yielding 8 independent measurements. This fibre device is tested on a series of chemical compounds associated with wines.

Radiation-induced attenuation in aluminum- and aluminum-thulium-doped optical fibers.

Gamma-ray-induced attenuation in Al-doped and Al/Tm-co-doped optical fibers is investigated in the visible and near-infrared domain up to 1 Gy. The behavior of radiation-induced attenuation (RIA) regarding dose and dose rate is discussed. Our results reveal high sensitivities for both types of fibers at low gamma ray doses and also reveal that Al/Tm fibers are very promising at original interrogation wavelengths for dosimetry applications.

Dysprosium-doped silica fiber as saturable absorber for mid-infrared pulsed all-fiber lasers.

We report on a mid-infrared Q-switched erbium-doped all-fiber laser using a dysprosium-doped silica fiber as saturable absorber for the first time in this wavelength range. Moreover, we demonstrate the use of a highly reflective chirped fiber Bragg grating written in a silica fiber as the input coupler for such lasers. This Q-switched all-fiber laser generates a stable pulse train centered at 2798 nm with a maximum average power of 670 mW at a repetition rate of 140 kHz with a pulse duration of 240 ns and a pulse energy of 4.

Steady photodarkening of thulium alumino-silicate fibers pumped at 1.07 μm: quantitative effect of lanthanum, cerium, and thulium.

By pumping thulium-doped silica-based fibers at 1.07 μm, rapid generation of absorbing centers leads to photoinduced attenuation (PIA). This detrimental effect prevents exploiting laser emissions in the visible and near infrared.

Large-mode-area leaky optical fiber fabricated by MCVD.

A large-mode-area single-mode optical fiber based on leaky-mode filtering was prepared by a modified chemical vapor deposition (MCVD) technique. The fiber has a leaky cladding that discriminates the fundamental mode from higher-order modes. A preliminary version has a 25 μm core diameter and 0.

Theoretical modeling of fiber laser at 810 nm based on thulium-doped silica fibers with enhanced 3H4 level lifetime.

A compact upconversion fiber laser operating around 810 nm is proposed using thulium-doped silica-based fiber with locally modified thulium environment by high alumina codoping. Using a comprehensive numerical model of thulium doped fiber we investigate performance of the proposed laser. Comparison with two other thulium hosts, fluoride glass and standard silica, is presented.

Erbium emission properties in nanostructured fibers.

A new route was recently proposed to modify some spectroscopic properties of rare-earth ions in silica-based fibers. We had shown the incorporation of erbium ions in amorphous dielectric nanoparticles, grown in fiber preforms. Here we present the achieved stabilization of nanometric erbium-doped dielectric nanoparticles within the core of silica fibers.

Three-hole microstructured optical fiber for efficient fiber Bragg grating refractometer.

We present a photosensitive three-hole microstructured optical fiber specifically designed to improve the refractive index sensitivity of a standard fiber Bragg grating (FBG) sensor photowritten in the suspended Ge-doped silica core. We describe the specific photowriting procedure used to realize gratings in such a fiber. We then determine their spectral sensitivity to the refractive index changes of material filling the holes surrounding the core.

Tilted Fiber Bragg Grating photowritten in microstructured optical fiber for improved refractive index measurement.

We report what we believe to be the first Tilted short-period Fiber Bragg Grating photowritten in a microstructured optical fiber for refractive index measurement. We investigate the spectral sensitivity of Tilted Fiber Bragg Grating to refractive index liquid inserted into the holes of a multimode microstructured fiber. We measure the wavelength shift of the first four modes experimentally observed when calibrated oils are inserted into the fiber holes, and thus we determine the refractive index resolution for each of these modes.

Tunable red-light source by frequency mixing from dual band Er/Yb co-doped fiber laser.

We report an all solid state laser device producing tunable dual wavelength emission in the near IR region (1060nm, and 1550 nm) by use of an Er/Yb co-doped fiber. Generation of continuous-wave radiation around 630 nm is then demonstrated by extra-cavity sum frequency mixing in a Periodically Poled Lithium Niobate (PPLN) crystal. Quasi phase matching conditions are obtained over 7 nm to generate tunable coherent light in the red spectral range.

Evidence of thermal effects in a high-power Er3+-Yb3+ 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.

Coherent combining in an Yb-doped double-core fiber laser.

Coherent combining is demonstrated in a clad-pumped Yb-doped double-core fiber laser. A slope efficiency of more than 70% is achieved with 96% of the total output power in the fundamental mode of one of the two cores. This high combining efficiency is obtained when both cores are coupled via a biconical fused taper in a Michelson interferometer configuration.

Bragg gratings written in Sn-Er-Ge-codoped silica fiber: investigation of photosensitivity, thermal stability, and sensing potential.

Bragg gratings were fabricated in an Sn-Er-Ge-codoped silica fiber with a phase mask and ultraviolet radiation from a 248-nm KrF excimer laser. The photosensitivity of the fiber was examined by studying the initial growth rate of the gratings written into it. The thermal stability of the gratings was investigated and modeled in terms of both the refractive-index modulation and the effective refractive index of the fiber core.