Optical Fiber strain sensor using fiber Bragg grating are poised to play a major role in structural health from
military to civil engineering. Fiber Bragg Grating sensor is a practical type of fiber optic sensors. Its measurement is
encoded with the wavelength of the optical signal reflected from fiber Bragg grating. The method of measuring the
absolute optical wavelength is a critical component of the fiber optic sensing system. To reliably detect very small
changes in the environment at the sensor, the interrogation system must provide accurate and repeatable wavelength
Energy sources are increasingly scarce in the world. Getting oil from the oil-wells has become more and more
difficult. Therefore, new technology to monitor the oil-well condition has become extremely important. The traditional
electrical sensor system is no longer useful because of the down-hole's high temperature and high pressure environment.
The optical fiber sensing system is the first choice to monitor this condition. This system will reduce the cost and
increase the productivity.
In the high pressure and high temperature environment, the traditional packed fiber grating pressure-temperature
sensor will be no longer reliability. We have to find a new fiber grating temperature-pressure sensor element and the
interrogation system. In this work we use the very narrow bandwidth birefringent fiber grating as the sensing element.
We obtain the interrogation system has 0.1 pm resolution.
A demodulation method for a quasi-distributed sensor based on an original interrogating
system for concatenated low reflective Fiber Grating is proposed. The system is based on
Optical Frequency Domain Reflectometer technology for which a commercial device has
been extended to a wavelength-tunable device. This interrogation system has the
advantage of allowing a large number of gratings to be addressed simultaneously. In our
application, except of the first grating (it has 20 times higher reflective than others) all
other gratings have low reflective (about 0.5% and 1 nm bandwidth at 3 dB) and have a
Fiber Bragg Grating central wavelength of about 1535 nm. Compare to conventional
Optical Frequency Domain Reflectometer technology, this interrogating system has very
fast measurement capability and higher precision.
There are many vibration damages happen in the world, such as Pipeline broken, Historical Relics stolen,
even for the board destroy. With conventional vibration detection methods there is a gap between what you
believe is occurring along area and what is actually happening. This information gap can result a delay in
your discovering and locating broken. Based on the non-linear optical scattering theory, we have developed
a new fiber grating vibration-monitoring system. This new system overcomes the limitations of
measurement technologies available today, thus closing the monitoring gap and improving system integrity
Modern oil production in the oilfield management needs a sensor which enable fast, reliable and cost-effective through highly integrated optical measurement systems. A sensor for accurate and long-term fluid high pressure and temperature monitoring in oil down-hole based on optical fiber Bragg grating is presented. This sensor, using fiber Bragg grating written in side-hole single mode fiber, has small size and simple construct. At different temperature, the pressure measurements from atmospheric pressure to 40 Mpa has been made. It has very linear relationship between peak separation and pressure.
In this paper a large mode area Yb3+-doped double cladding photonic crystal fiber laser is reported. The laser's output power reaches as high as 4.3W. The slope efficiency and the maximum optical-to-optical efficiency of laser output are 69.4% and 59.7%, respectively, with respect to absorbed pump power. Single transverse mode operation is obtained at central wavelength of 1072.3nm and the measured mode distribution agrees with the simulation by using scalar beam propagation method.