| 摘要 |
The invention relates to a fiberoptic current or magnetic field sensor having a plurality of sensor heads (H), and to a corresponding measurement method. The sensor has: a light source (1); N>=2 sensor heads (H); at least one phase modulation unit (PME) having at least one phase modulator (PM); a detector (2); a control and evaluation unit (5). The at least one phase modulation unit (PME) is optically connected to at least one of the sensor heads (H). Linearly polarized lightwaves can be differentially phase-modulated in a non-reciprocal fashion by means of the at least one phase modulation unit (PME). N modulation amplitudes phi0,n and N modulation frequencies nun are provided for the non-reciprocal differential phase modulations, the modulation frequencies nun and two prescribable positive whole numbers p, q with p<>q being selected in such a way that it holds for all positive whole numbers z and for all whole numbers n, m with n<>m and 1<=n,m<=N THAT: p.nun<>z.num and q.nun<>z.num. The modulation amplitudes phi0,n and the modulation frequencies nun are selected as a function of modulation-relevant optical path lengths ln. An improved signal-to-noise ratio can be achieved.
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