World-first coexistence trial of TDM and CDM giga-bit passive optical networks (PONs) was successfully completed. A very shallow minimum isolation of 7 dB between G- and CDM-PON at OLT and ONU in the ITU-T G.984.5 enhancement band was demonstrated. The feasibility of bidirectional transmission on the same wavelength was confirmed. The backscattering optical noise does not seriously affect the maximum reach of CDM-PON. Adding the CDM-PON onto GPON can provide following technical and economical impacts: low-cost coexistence, minimum service outage, and combination of best-effort and guaranteed-bandwidth for efficient and high-quality network services due to CDM feature.