Mode Excitation and Multiplexing for MIMO Systems Focusing on Digital Mirror Devices

Abstract

In the fiber-optic telecommunication community space division multiplex, synonymously referred to as optical multiple-input multiple-output (MIMO), is a potential candidate to overcome the imminent capacity crunch. The concept of transmitting parallel data streams on different optical modes of a few-mode or multi-mode fiber is in the focus of this work. Thus, different approaches for mode-selective excitation, mode multiplexing and demultiplexing are presented. This includes a completely new approach in this field based on digital mirror devices (DMDs) which benefits from its high flexibility when it comes to pattern generation and its theoretical low insertion loss of around -1.27 dB. However, the blazed grated structure of the micromirror array (MMA) makes it complex to find the optimal coupling conditions. This work shows an intuitive solution for that problem. In addition to the DMDs, photonic lanterns and optical fusion couplers combined with offset splices are studied with respect to their optical MIMO suitability.