Dynamic LP01–LP11 Mode Conversion by a Tilted Binary Phase Plate

We propose and demonstrate efficient LP
₀₁
- LP
₁₁
selective mode conversion over a wide spectral range based on tilted binary phase plate. Due to the extended optical path length of the transverse wave through the tilted phase plate, the matched wavelength for efficient mode conversion can be tuned toward longer wavelength by controlling the tilt angle. In the mode profile characterization, the mode purity of the output LP
₁₁
beam profile has been theoretically analyzed based on the difference in peak intensities between the two lobes of the LP
₁₁
mode. The presented model is used for determining the LP
₀₁
: LP
₁₁
ratio of an impure LP
₁₁
mode in the experiment. The proposed instrument is a simple yet powerful tool for efficient mode conversion in SDM communication network.