Brillouin optical time domain analysis is the sensing of temperature and strain changes\nalong an optical fiber by measuring the frequency shift changes of Brillouin backscattering. Because\nfrequency shift changes are a linear combination of temperature and strain changes, their discrimination\nis a challenge. Here, a multicore optical fiber that has two cores is fabricated. The differences between the\ncoresââ?¬â?¢ temperature and strain coefficients are such that temperature (strain) changes can be discriminated\nwith error amplification factors of 4.57 ââ??¦C/MHz (69.11 Ã?¼/MHz), which is 2.63 (3.67) times lower than\npreviously demonstrated. As proof of principle, using the multicore optical fiber and a commercial\nBrillouin optical time domain analyzer, the temperature (strain) changes of a thermally expanding metal\ncylinder are discriminated with an error of 0.24% (3.7%).
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