Automatic compensation fiber-optic differential pressure sensor

A novel multimode fiber-optic differential pressure sensor based on a rotating reflector is described. This sensing technique can automatically compensate the influence of source fluctuation, the losses in the input fiber, and the changes in reflectivity of the reflecting surface. Furthermore, if all the fibers are in one cable and subject to the same bending, much of the noise associated with fiber-bend losses will also be cancelled out. By the symmetric compensation principle, a pair of pressure-transfer devices was used in the fiber-optic differential pressure transducer, which can automatically compensate the effect of temperature on the sensor. To test this transducer, a prototype sensor has been constructed and the test results are given here.