Cost and architectural comparisons for analog-digital hybrid and all-digital photonic subscriber loop networks for broadband ISDN

An analog-digital hybrid photonic subscriber loop network, which provides video distribution services using analog video optical transmission while providing interactive communication services using ATM (asynchronous transfer mode) digital optical transmission, has been compared with its all-digital counterpart from cost and architecture viewpoints. The cost comparison reveals that the per-subscriber cost for the hybrid network is some 30% lower than that for all-digital network. The analysis also suggests that the cost for the photonic subscriber interface unit dominates the per-subscriber cost. The architectural comparison, together with the cost comparison, shows that the hybrid network lends itself to the early introduction of broadband services to subscribers, while the penetration of the all-digital network will have to wait for the establishment of UNI (user-network interface) standards