U.S. scientists have developed a new type of optical fiber sensors.

U.S. scientists have developed a <P> can be used under extreme conditions, new optical pressure sensor. .The fiber optic sensor can not only measure up to 18 million Pa (2620 pounds / square inch) of pressure to the sensor head into the -196 ° C in liquid nitrogen or heated to 538 ° C, the performance would not be significantly changed. .</ P> <P> the concept of the sensor detection equipment from the University of Mississippi and Analysis Laboratory (DIAL) of ChujiWang and SusanScherrer, they will be known as "cavity ring down spectroscopy" (cavityring-downspectroscopy, CRDS) technology .used in fiber optic sensors to create a file named \ "fiberringdownsensor \" of the instrument. .The operation key is a strong light pulse decay time depends on the attenuation caused by fiber optic ring, so any change in optical transmission caused by phenomena such as the external pressure (the pressure), can be by monitoring decay time measurements. .Wang said the new sensor has a lot better than the Bragg fiber (FBGs) and fiber Fabry-Perot interferometer (FPPI) of the Department, and that this new design can bring a new generation of physical sensors. .</ P> <P> The sensor is composed of two identical 2 × 1 fiber coupler (branching ratio of 99:1) and and a standard single-mode fiber (CorningSMF-28) are connected to form long-65M .circuit. .A wavelength of 1650nm researchers will pulse injection through a coupler circuit; the pulse of each bypass around the ring, the intensity will be slightly weakened by the decay time and intensity should be monitored continuously to another coupler. .Experiments on a 8mm-long optical fiber sensor showed that the weight applied, the sensor can measure up to 18 million Pa pressure. .If the protection layer (Jacket) removed, although it will reduce the sensing range, but can increase its sensitivity. .</ P>.