Mode-dependent characteristics of Rayleigh backscattering in weakly-coupled few-mode fiber

Characterization of Rayleigh backscattering arising in various two-mode fibers

“…Although the mode dependent power distribution is different due to various fiber refractive index profiles, the backscattering light always propagates mainly at the mode, which is the same with the forward one. Finally we compare the experimental results with the theoretical calculations [27]. When the operation wavelength is swept over the C band, the experimentally obtained total RB power agrees well with the theoretical ones for all the TMFs under test, as shown in Figs.…”

“…Due to the low propogation loss of TMF, the two parameters becomes saturated when the TMF is longer than 25 km. Especially, the stable value of the RB power ratio has the same value as the recapture factor defined in [27]. Furthermore, such procedure can be further extended to the RB measurement of FMF with more higher order modes, as well as to the situation of optical pulse input to measure the RB at discrete point along the fiber.…”

“…Meanwhile, the RMDP is defined as the ratio of the RB power at individual higher order mode to the RB power at LP 01 mode. Recently, we have theoretically investigated the mode dependent characteristics of RB in weakly-coupled FMF [27]. The RB power ratio and the RMDP are found to be sensitive to the mode profile of forward propagation light.…”