Performance of Receivers and Detection Algorithms for Modal Multiplexing in Multimode Fiber Systems

We consider a multimode fiber system exploiting modal multiplexing using various direct-detection photoreceiver structures with zero-forcing detection algorithm. We show in theory how the squaring operation of the receivers and multimode excitations by a bit stream introduce bit detection errors even in the absence of noise. Numerical examples are provided to illustrate their impacts on system performance measured in terms of the bit-error ratio.