Effect of core geometry on the channel capacity of a multimode optical fiber

We employ complex wavefront shaping methods to investigate the frequency correlations of multimode interference in circular and rectilinear core geometry fibers. Our measurements reveal an up to 40% increase in the frequency correlation bandwidth in rectilinear core fibers compared to conventional circular core fibers commonly used for spatial-multiplexed optical communication. We show that harnessing this increased frequency correlation bandwidth can improve the channel capacity of optical communication by over 20%. This enhancement and the convenient rectilinear core geometry could find immediate application as chip-to-chip interconnects in scaling up photonic quantum processors.