Full-duplex single fiber transmission using FSK downstream and IM remote upstream Modulations for fiber-to-the-home

Abstract
Full-duplex single fiber bidirectional transmission, using frequency-shift-keying modulation for downstream, by direct modulation of a tunable laser, and intensity modulation for upstream, in a wavelength-division-multiplexing passive optical access network is demonstrated. The optical network unit, located at the end user premises, reflects and orthogonally remodulates the received light. Rayleigh scattering effects are reported and analyzed. The system shows proper operation up to 1 Gb/s at 30-km reach.