Distributed Measurement of Fermi–Pasta–Ulam Recurrence in Optical Fibers

We experimentally demonstrate the distributed measurement of Fermi-Pasta-Ulam (FPU) recurrence in an optical fiber. Square-shaped pulses with weak modulation are injected into a single-mode fiber to exhibit FPU recurrence. Rayleigh backscattering signals of various sidebands are recorded to measure the power vibration along the optical fiber. The validity of the distributed method is confirmed both by the numerical simulation and the cutting-back method. Compared with the traditional cutting-back method, the distributed method has significant advantages, such as short measurement time, low cost, and good repeatability. We also believe that the distributed method has a great potential for the measurement of other nonlinear effects in optical fiber.