Fig. 2: Concept of clock- and optical-frequency-synchronized FDM upstream for time-critical applications.
From: Communications with guaranteed bandwidth and low latency using frequency-referenced multiplexing
a, A wide-bandwidth closely spaced frequency comb generated at the edge cloud, referenced to a source clock within an edge data centre. b, Filtered frequency comb sent from an edge cloud or optical line terminal to the users. c, Upstream FDM signals; each user wavelength locked to a selected tone in the distributed frequency comb, forming a wide-bandwidth optical signal that is detected by a single coherent receiver. d, Different WDM bands (for example, 100–200 GHz bandwidth) covers different passive split fibre networks. The blue, green and red colours indicate the different WDM bands. e, Exemplary time-critical applications including cooperative traffic system and VR.
