Super-dense WDM detection technique with single coherent receiver employing wavelength-swept local light

A novel coherent detection technique for super-dense wavelength-division-multiplexing (WDM) signals is described. By shifting the local light wavelength periodically, WDM signals are converted to electrical time-division-multiplexing data at a coherent receiver. This enables a single wavelength-swept local light source and coherent receiver pair to detect WDM signals. Applying this technique to coherent WDM passive optical networks greatly simplifies the optical line terminal configuration and local light wavelength control for the upstream. The demodulation of two-channel 1.5 Gbit/s signals is shown as a proof-of-concept.