Experimental Investigation of LP11 Mode to OAM Conversion in Few Mode-Polarization Maintaining Fiber and the Usage for All Fiber OAM Generator

In this paper, the LP
₁₁
mode evolution in a few mode-polarization maintaining fiber is experimentally investigated. Selective conversion from the LP
_11a
/LP
_11b
mode to the LP
_11b
/LP
_11a
, OAM
₊₁
, and OAM
₋₁
modes are demonstrated with varying wavelengths and fiber lengths. This property may have nice applications in spatial division multiplexing (SDM) systems, and one of them, i.e., the all-fiber compact and robust scalar orbital angular momentum (OAM) generator, which is cascaded by a mode-selective coupler and a few mode-polarization maintaining fiber, is also demonstrated with expected performance for conversion between LP
₀₁
mode and OAM
₊₁
/OAM
₋₁
.