Patent ID: 6618153
Filing Date: 2003-09-09
Classification: G01M

Abstract:
An on-line Sagnac interferometric distributed fiber-optic leakage detection device, comprising:a light generator for producing a beam of light; an optical fiber coupler having a first light input/output port coupled to the light generator, wherein the optical fiber coupler splits up the light going from the light generator to the first light input/output port into three equal intensity light beams; a hollow pipe for transporting a liquid or a gas; a Faraday rotator mirror installed at an end of a sensing optical fiber installed in the hollow pipe for compensation of the polarization induced signal fading, wherein the sensing optical fiber coupled to a second light input/output port of the optical fiber coupler and the Faraday rotator mirror for transmitting a beam of light to or from the second light input/output port; a delaying optical fiber coupled to a third light input/output port and a fourth light input/output port of the optical fiber coupler for transmitting light from the third input/output port to the fourth input/output port; a photo detection device coupled to a fifth light input/output port of the optical fiber coupler for receiving the beam of light emerging from the fifth light input/output port and converting the beam into an electrical signal; and a spectrum analyzer connected to the photo detection device for picking up the electrical signal from the photo detection device; wherein the sensing optical fiber is a linear element having no bends so that losses due to light bending are greatly reduced.