Eric Maurice

Blue light-emitting-diode-pumped point temperature sensor based on a fluorescence intensity ratio in Pr3+: ZBLAN glass

A fluorescence intensity ratio technique has been applied to Pr3+: ZBLAN glass, realising a point temperature sensor. We present data for a blue light emitting diode-pumped prototype which provides accurate and self-referenced measurements.

Rare-earth-doped optical fibers for point temperature sensing

Use of rare-earth doped fiber as the sensing element for temperature sensing is reviewed. The advantages of employing a fluorescence intensity ratio technique is discussed and examples of practical applications of the technique are given.

Thermal variation of absorption in Yb3+-doped silica fiber for high-temperature sensor applications

Rare-earth materials doped into low-loss silica fibers are of interest for temperature sensing applications since the absorption properties of such are temperature dependant. Such absorption properties have been studied in ytterbium doped silica fiber using relative absorption and cut-back techniques at temperatures between 77 and 1163 K in the wavelength range 800 to 1150 nm. The wavelength dependant thermal sensitivity varies from -0.012 to 0.033 dB/K for a standardized one meter long 1000 ppm-doped fiber. These significant changes in absorption with temperature have been attributed to homogeneous line broadening. The fibers investigated show excellent potential for use as the sensing element in intrinsic fiber-optic high-temperture sensors.

High-Temperature Point Sensor using Green Fluorescence Intensity Ratio in Er-Doped Silica Fibre.

The advantages of optical fibre temperature sensors over traditional technologies in hostile environments are now well accepted with commercial application of such sensors established1. However, optical fibre temperature sensing systems with improved dynamic range, system reliability, accuracy and unit cost are desirable.

Fluorescence and superfluorescence line narrowing and tunability of Nd/sup 3+/ doped fibers

The inhomogeneous behavior of the 1.06 /spl mu/m-neodymium transitions in doped optical fibers have been investigated, using the fluorescence line narrowing technique, pumping on the /sup 4/F/sub 3/2/ and /sup 4/F/sub 5/2/ sublevels at 4 K. Each observed transition has been identified. As the pump wavelength varies, the shift of the main fluorescence line is 40 nm, with the two pumping levels. We have studied the spectral behavior of the superfluorescence as a function of the pump wavelength, the temperature, and the absorbed power. The spectral evolution depends on /spl lambda//sub p/ with 19 nm-tuning range at low temperature. At 300 K, the quasihomogeneous behavior of the transition decreases the tunability to 14 nm. Based on these results, we present a simple technique permitting precise prediction of gain and spectral line shapes of superfluorescent Nd-doped fiber sources. >

Q-switched operation of a 810 nm thulium-doped fluorozirconate fibre laser

Pulsed emission (350 ns, 810 nm) has been obtained in a 790 nm-pumped thulium doped fluorozirconate ring cavity fibre laser. Calculations of the pump power laser threshold and pulse duration are consistent with experimental measurements. Optimization of this laser is analysed.

Simultaneous measurements of lifetime, gain and emission cross section in a neodymium-doped fiber

A method for measuring the gain and the emission cross section of the four-level neodymium system in doped waveguides is presented. The method is based on a temporal analysis of the fluorescence decay occurring when the pump is switched off, after establishing a steady-state with high levels of absorbed power. For the case of doped fibers, results obtained using this method are compared with the usual low signal amplification technique, using a launched signal in the fiber, and the agreement is good. It is shown that the technique allows a rapid, simple method of determining low signal gain.<<ETX>>

Near infrared emission in Ho3+ fluorozirconate fibres

Near infrared absorption and emission of Ho3+ in fluorozirconate fibres are studied at room and nitrogen temperature. Stimulated emission cross sections are deduced, sigma (1.19 mu m)=0.7*10-20 cm2, sigma (2.06 mu m)=1.45*10-20 cm2, and self-consistency with stimulated spectra is verified and discussed.

Quasi-distributed temperature sensor based on the 1.2-μm transition in erbium-doped fibers

We propose the principle of a high-dynamic, quasi-distributed temperature sensor. We previously have demonstrated the possibility of realizing a high-dynamic point sensor based on the behavior of the green emission in erbium doped silica fibers. We present here the study of the 1.13 micrometers and 1.24 micrometers emission lines, coming from the same levels. Those lines present the same temperature dynamic as the green ones. As the lower level of these transitions is the 4I11/2 level and not the fundamental one, the signal is absorption free. The signal wavelength also corresponds to a transparence region of the intermediate fibers. These arguments permit developing an efficient quasi-distributed configuration. In addition, the intensity ratio of the emission lines is only temperature dependant, so the measurement is self-calibrated. We also demonstrate that the emitting levels can be excited around 800 nm, by the excited state absorption process, which allow using a standard laser diode as pumping source.

Amplified spontaneous emission in Ho3+ doped ZBLA fibres

Abstract Amplified spontaneous emission at 1.19 and 2.04 μm is studied in Ho3+ doped ZBLA fibres. Modeling of spontaneous and stimulated spectra from basic principles allows determination of the optical gain in a fibre. Self-consistency with spectroscopic data on Ho3+ doped fibre is verified and discussed.