Demonstration and Performance of Colorless ONU for Coexistence-Type WDM-PON Using a Wavelength-Tunable $L$ -Band DWDM-SFP Transceiver

An advanced dense wavelength division multiplexing small form factor pluggable (DWDM-SFP) transceiver for the $L$ -band, which features a wavelength tunability of 3 nm, is proposed and developed. By using the developed wavelength-tunable DWDM-SFP transceiver, a colorless optical network unit (ONU) prototype for coexistence-type wavelength division multiplexing passive optical networks (WDM-PONs) that enable coexistence with existing PONs is achieved. Both wavelength and temperature dependencies of the colorless ONU prototype are evaluated and the applicability to the existing Class B+ optical distribution network that has a 28 dB loss is discussed.