All-Fiber Tunable LP11 Mode Rotator With 360° Range

We propose and experimentally demonstrate an all-fiber tunable LP
₁₁
mode rotator with 360° range, based on the bending and twisting of the two-mode fiber (TMF). A theoretical model of TMF perturbation and its effect on the spatial pattern of LP
₁₁
mode is put forward. We experimentally characterize the implementation of the LP
₁₁
mode rotator by an all-fiber polarization controller configuration. The results agree well with the theoretical investigations. We are able to demonstrate arbitrary LP
₁₁
mode rotation with 360° range. The insertion loss is less than 0.4 dB when the operation wavelength is varied from 1540 to 1560 nm.