Multimode fibers are widely used for short and medium haul links, but the data rates through multimode fibers (MMFs) is limited due to modal dispersion. Recently, it has been shown that signaling in the set of "principal modes" (PMs) of the MMF can reduce dispersion significantly. However, accurate knowledge of the PMs is required at the transmitter to utilize them effectively. In this talk, we will first describe the concept of principal modes and their utility. Then, we propose the use of Grassmannian line packing and vector quantization as quantization schemes for communicating the PMs to the transmitter, and describe various codebook designs for few-mode and large-core MMFs. Simulations reveal that the channel frequency response can be improved by 5 dB for few-mode fibers and 2 dB for large-core MMFs using quantized PMs when mode-dependent losses are small
Kumar Appaiah is an Assistant Professor in the Department of Electrical Engineering, IIT Bombay. He earned BTech and MTech degrees in Electrical Engineering from the Indian Institute of Technology Madras in 2008, and the PhD degree in Electrical and Computer Engineering from the University of Texas at Austin in 2013. From 2013 to 2014, he was a Senior Engineer at Qualcomm Flarion Technologies, Bridgewater, NJ. His research interests are wireless and optical fiber communication, and signal processing for communication.