Long-length fiber-optic remote Raman sensors are used for distributed temperature measurements. Toward this aim, we apply optical-fiber frequency-domain reflectometry. The Raman intensity generated in single- and multimode optical fibers is theoretically investigated for sinusoidally intensity-modulated probe light. Thus, a proper sensor element and wavelength for fiber-optic Raman sensing is determined. Further, the temperature error for long sensor fibers is theoretically analyzed.
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