The invention concerns a process comprising the following steps: injecting, in an optical fiber, N time limited replica optical signals at distinct frequencies, each replica signal being temporally shifted relative to the other replica signals; then propagating the temporally shifted replica signals along the optical fiber; then receiving, at an output of the optical fiber, N output time-limited optical signals at distinct frequencies resulting from the replica signals, each output signal being temporally shifted relative to the other output signals; and constructing a useful signal by temporally superimposing the N output signals, such that the useful signal comprises a combination of the N output signals that are not temporally shifted anymore. Application to distributed sensors.