Fiber Bragg Gratings are structures with remarkable characteristics that have induced new qualitative developments in the broad field of optical fiber technology, most notably in optical communications and in optical sensing. When these devices are applied for sensing, the underlying concept is the modulation of the grating Bragg wavelength by the measured and, therefore, a central issue is the sensitive and accurate conversion of the resonant wavelength into a proportional electrical signal with the adequate format for further processing. This topic is broadly known as Fiber Bragg Grating interrogation and is the subject of the present chapter. It is organized in two parts: in the first one, the techniques developed by the scientific community looking for this functionality are reviewed, with emphasis on the identification of general conceptual classes where they fit; in the second part, illustrative and state-of-the-art commercial Fiber Bragg Grating interrogation systems are described.
