Investigation on the polarization dependence of an angled polished multimode fibre structure

An angled polished multimode (APM) fibre structure is described for the first time, to the best our knowledge, and its polarization dependence investigated theoretically and experimentally. Two angled planes are established in the multimode fibre (MMF) section of a single-mode-multimode-single-mode (SMS) fibre structure using the fibre side-polishing technique, forming the APM fibre structure. This designed circular asymmetric geometry induces different propagation characteristics for the TE and TM modes within the MMF. Simulated and experimental results both show that this difference is enhanced as the polishing angle increases, and a maximum extinction ratio (ER) of the spectrum of 13 dB is achieved at a polishing angle of 85°. This polarization-dependent device has a simple fabrication process and is free from the limitation of coating functional materials, which is expected to be applied in non-linear optics, fibre laser and optical fibre sensing fields.