Multiplexing OAM states in an optical fiber: Increase bandwidth of quantum communication and QKD applications

We propose a noble method for multiplexing OAM states to increase bandwidth of communication in a birefringent single-mode optical fiber for quantum communication and QKD applications by minimizing the decoherence. We analytically derive and show that the rate of decoherence for OAM state in a birefringent optical fiber is proportional to $l^2$. We also show numerically that decoherence can be minimized with CPMG pulse sequence to preserve the state with $>90\%$ fidelity for smaller values of $l$ to allow for high-bandwidth communication.