Derivation of the mode division multiplexed information transmission principles based on the spinor representation of Maxwell´s equations

In this paper we introduce a novel approach for analysis of the information transmission process in mode-division-multiplexed (MDM) optical fiber communications. This approach is based on the representation of Maxwell´s equations in the form of quantum-mechanical Schrödinger and Dirac equations. This representation allows application of the well-developed quantum electrodynamics formalism for the case of classical EM fields and reveals key properties of the optical fiber mode distribution in MDM systems following from the total angular momentum conservation law. We demonstrate the need of using coupled mode compositions instead of separate eigenmodes for realization of MDM communications based on angular momentum transfer. Such coupled modal compositions obey the law of total angular momentum conservation within spatial transformation and allow information transmission.