BROAD-BAND UPGRADE OF AN OPERATING NARROW-BAND SINGLE-FIBER PASSIVE OPTICAL NETWORK USING COARSE WAVELENGTH-DIVISION MULTIPLEXING AND SUBCARRIER MULTIPLE-ACCESS

We demonstrate an overlay of a broadband passive optical network (PON) on the same fiber network as an operating baseband digital system. Th e baseband system is modeled after cui rent-generation narrowband PON' s, and the two PON's can be operated simultaneously, The broadband PON incorporates coarse wavelength division multiplexing to increase the down-stream bit rate, and,subcarrier multiple access for the upstream upgrade, We examine the RF interference between baseband and subcarrie r signals, and provide guidelines on channel spacing and means for acc ommodating differing power levels for the two signals, The broadband a rchitecture described here provides a graceful upgrade path for provid ing advanced digital services on a PON without having to modify the ne twork or terminal equipment used for providing narrowband services.