We report here a novel lightwave modulator using an electrically controlled liquid crystal device1 as the modulator for duplex fiber-optic systems. It also provides a tapping port to monitor the data and power at the customer premises without system insertion loss. It can be used as the low-cost modulator for a WDM transmission system in which one of the downstream channels from the central office can be modulated at the customer end as the transmitting light source.2 This is an attractive architecture for the upcoming wideband information services distribution network. Since the customers in that network will be charged for what they subscribe to, they will be able to select such high-quality multichannel downsteam services as HDTV high-bit- rate data to their houses. But a significant number of the customers also prefer to keep only voice band (POT and telemetry) upstream services, which is transparent to their current services. In anticipation of the mixed bit-rate pattern in transmitting and receiving needs at future homes, the WDM duplex system using a low-cost modulator becomes a desirable alternative.
© 1988 Optical Society of AmericaPDF Article