Efficiency and Crosstalk in Demultiplexing Orbital Angular Momentum Modes Using a Spiral Phase Plate

Using Optical Angular Momentum as an orthogonal degree of freedom to multiplex data is an emerging solution for enhancing system capacity in optical communication. Spiral phase plates are used to convert a Gaussian beam to a Laguerre-Gauss beam with a desired topological charge. Analytical formulas for calculating conversion ratio of OAM modes passing through a spiral phase plate is demonstrated. With this conversion ratio efficiency and crosstalk of the communication link is also discussed.