Patent ID: 7104331

Claim:
A system for controlling a downhole flow, comprising; a. a flow control device in a tubing string in a well, said flow control device having a first member engaged with said tubing string and a second member moveable with respect to said first member and acting cooperatively with said first member for controlling the downhole flow through said flow control device; b. an actuator for driving said second member; c. an optical position sensing system acting cooperatively with said first member and said second member for detecting a position of said second member relative to said first member and generating a signal related thereto, wherein said optical position sensing system comprises; i. an optical fiber disposed in said first member; ii. a light source for injecting a broadband light signal into said optical fiber; iii. a plurality of optical elements disposed alone the optical fiber at predetermined positions for reflecting at least a portion of said broadband light signal, each of said optical elements reflecting an optical signal at a different predetermined optical wavelength from any other of said elements; iv. a plurality of corresponding microbend elements disposed proximate said optical elements and acting cooperatively with said second member to change an optical transmission characteristic of interest of said optical fiber when said second member actuates at least one of said microbend elements; v. a spectral analyzer for detecting the optical transmission characteristic of interest of said reflected optical signals and generating an analyzer signal in response thereto; and d. a controller receiving said signal and determining, according to programmed instructions, the position of the second member relative to the first member, and driving said actuator to position said second member at a predetermined position for controlling said downhole flow.