FUSED TENSION-BASED FIBER GRATING PRESSURE SENSOR

摘要

A fused tension-based fiber grating pressure sensor (8) includes an opticalfiber (10) having a Bragg grating (12) impressed therein.The fiber (10) is fused to tubes (20) on opposite sides of the grating (12)and an outer tube (30) is fused to the tubes (20) to form a chamber(34). The tubes (20, 30) and fiber (10) may be made of glass. Light (14) isincident on the grating (12) and light (16) is reflected fromthe grating (12) at a reflection wavelength (.lambda.1). The grating (12) isplaced in tension pre-strain and as the pressure (P) increases, thetension on the grating (12) is reduced and the reflection wavelength shiftsaccordingly. A temperature grating (50) may be used to measuretemperature and allow for a temperature-corrected pressure measurement. Theshape of the outer tube (20) may have geometries otherthan a straight cylinder. Also, the axial ends of tubes (20) where the fiber(10) exits the tubes (20) may have an inner region (22) and/or aprotruding tapered (or fluted) axial section (27), to provide strain relief orimproved pull strength of the fiber (10). More than one gratingor pair of gratings may be used and more than one fiber (10) may be used. Thefiber (10) may be doped at least between a pair of gratings(150, 152) to form a tunable fiber laser or the grating (12) or gratings (150,152) may be constructed as a tunable DFB fiber laser.