Depletion in a distributed Brillouin fiber sensor: practical limitation and strategy to avoid it

Energy transfer between the interacting waves in a distributed Brillouin sensor can result in a distorted measurement of the local Brillouin gain spectrum, leading to systematic error. We demonstrate here that this behavior can be fully and precisely modeled, and an excellent quantitative agreement is found with experimental tests. Strict guidelines can be enunciated from this description to make the impact of depletion negligible, for any type and any length of fiber.