Simultaneous distributed strain and temperature measurement

Brillouin-scattering-based sensors are capable of measuring either the stra in or the temperature along the length of an optical fiber in a distributed fashion through measurement of the Brillouin-frequency shift. The cross se nsitivity of the frequency shift to these two parameters makes it impossibl e to differentiate between them by measurement of the frequency shift alone . We report on a new technique that permits the simultaneous measurement of strain and temperature to resolutions of +/-178 mu epsilon and +/-3.9 degr ees C at a spatial resolution of 3.5 m by incorporation of the Brillouin-lo ss peak power with the conventional Brillouin-frequency measurement. (C) 19 99 Optical Society of America. OCIS codes: 290.5900, 060.2370.