1. Field of the Invention
This invention relates to pressure sensors incorporating a fiber optic cable which provides an indication of pressure upon the onset of microbending and, more particularly, a pressure sensor incorporating a fiber optic cable which is placed in physical contact by interweaving the cable through rungs of a ladder-like structure.
2. Description of the Prior Art
Techniques for providing pressure detection are known in the art. One such technique includes conducting light through a fiber optic cable and sensing a reduction in light transmission therethrough as a result of deformation (i.e., microbending) of the cable. In addition, several techniques exist for enhancing the sensitivity of a fiber optic cable to microbending. Among these include the technique of wrapping a relatively thinner diameter member in a serpentine fashion about a fiber optic cable. Another technique comprises placing small protrusions on the peripheral surface of the fiber optic cable itself. Both of these techniques require processing the fiber optic cable in a special manner. Thus, an expensive secondary operation must be performed on the fiber optic cable to accomplish preparation of such pressure sensors. As such, the fiber optic cable is relatively expensive and subject to damage during such secondary operations. Another approach known in the art for accomplishing microbending of fiber optic cable is to place a fiber optic cable in affiliation with a separate structural member having a multitude of protrusions disposed thereon. Any pressure between the fiber optic cable and the protrusions will result in microbending of the fiber optic cable. Such a technique requires placing the fiber optic cable in contact with the separate structural member. The effectiveness of the interrelationship between these two members is substantially impaired if the fiber optic cable and the structural member are not properly positioned with respect to one another. As such, an investment is required in structure to achieve and maintain this affiliation. Therefore, there is a need for a pressure sensor that is inexpensive to construct and uses a standard fiber optic cable.
USPTO Backgrounds
USPTO Backgrounds