Educação matemática pela arte
Gusmão, Lucimar Donizete
2013-08-28
Search results
9 records were found.
The relative accuracy of temperature and strain determination using Brillouin frequency shift and power change in standard single-mode fibre and the frequency shifts of the two Brillouin peaks in large effective area fibre is reported.
A recently proposed method of measuring the two Brillouin frequencies in a multicompositional fiber core for unambiguously resolving temperature and strain in a distributed sensor is compared with the previously established technique of measuring the intensity and frequency of the single Brillouin peak in a standard single-mode fiber.
We report the longest distributed temperature sensor based on microwave heterodyne detection of the frequency of the anti-Stokes Brillouin signal. At a sensing range of 100km, the temperature accuracy was 8degC, with a spatial resolution of 50m.
Key results: The temperature change measurement at 60km of sensing fibre is reported for the first time. How does the work advance the state-of-the-art?: Measuring temperature change at this long range will help the development of long range high performance temperature distributed optical sensors.
Motivation (problems addressed): Long range temperature sensors above 57km have not been previously realised. Existing applications demand greater range.
We present the longest reported sensing range of temperature change measurement along single-ended optical sensing fibre. The technique is based on spontaneous Brillouin scattering and microwave heterodyne detection. Brillouin frequency shift was used to obtain temperature change at range of 81km with temperature error less than 5C, and spatial resolution of 30m, at relatively low input pulse power of 70mW.
We demonstrate enhanced performance of a single-ended spontaneous-Brillouin-intensity-based distributed- temperature sensor with a sensing length of 50km and a spatial resolution of 15m by use of Raman amplification of the probe pulse within the sensing fiber. The Raman amplification was achieved with a copropagating pump pulse at 1450nm. The standard deviation error of the temperature resolution was 1C at the front end and increased to less than 13C at 50km with Raman pulse amplification.
We report on the use of remote Raman amplification to improve the accuracy of spontaneous Brillouin measurements for long range distributed sensor applications. The enhancement of the signal to noise was demonstrated in a long range distributed temperature sensor exploiting the temperature dependence of the spontaneous Brillouin backscattered signal. A temperature resolution of 8 °C and a spatial resolution of 20 m were obtained at a sensing range of 100 km. The Brillouin signal was averaged 2 (20) times.
We present a microwave detection system for long range Brillouin-based sensing with a potential spatial resolution of 60cm. It was demonstrated over 30km, with temperature accuracy of 1.6C, and spatial resolution of 2m.
We report the enhanced performance of an 85 km single-ended distributed Brillouin based temperature sensor using an EDFA and Raman amplification. A temperature resolution of 3°C and spatial resolution of 20 m was achieved.
