Brillouin optical spatial Fourier domain analyzer

We propose an approach to Brillouin optical frequency domain analysis for measuring temperature or strain along an optical fiber. In this approach, we modulate the pump by a cosine function over a range of frequencies. By measuring only the probe power at the edge of the fiber for each modulation frequency, we obtain the cosine transform of the Brillouin gain coefficient of the fiber. We describe the operation principle of the proposed method, introduce additional advantages of the frequency domain analysis, such as compressed representation of the spatial information and better field of view, and use simulations and experimental work to demonstrate the capabilities of the proposed technique. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE)