Bidirectional lightwave transmission system
AssigneeAT&T Bell Laboratories
InventorsPeter P. Bohn, Thomas H. Wood
Life of this patent
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Abstract
Bidirectional, non-interfering transmission of broadband services on a single fiber is accomplished by simultaneously combining wavelength-division, time-division, and subcarrier multiplexing on the downstream and upstream transmissions. High speed electrical data signals are time-division multiplexed at the exchange into a composite signal which modulates a standard diode laser operating at a first wavelength. Data signals from an individual subscriber are modulated onto a subcarrier designated solely for the particular subscriber which, in turn, modulates a laser operating at a second wavelength. Extraction and insertion of the upstream and downstream transmissions at the subscriber and exchange locations is accomplished with wavelength selective couplers.
Claims19
A lightwave transmission system having a first end transceiver coupled to a lightwave transmission medium wherein the transmission medium connects the first end transceiver to at least a first second end transceiver coupled to a remote end of the lightwave transmission medium, the transmission medium including at least one optical fiber, the first end transceiver including outbound apparatus and inbound apparatus,
- the outbound apparatus operating substantially at a first optical wavelength for transmitting a first optical signal on the transmission medium via baseband signalling,
- the inbound apparatus operating substantially at a second optical wavelength different from the first optical wavelength for receiving a second optical signal from the transmission medium via at least a first subcarrier multiplexed signal at a first assigned subcarrier frequency,
- the transceiver further comprising means for coupling optically and wavelength selectively an input port of the inbound apparatus and an output port of the outbound apparatus to one optical fiber of the lightwave transmission medium.
Dependencies are inferred from the claim text.