Optical: systems and elements – Deflection using a moving element – Using a periodically moving element
Patent
1995-07-14
1997-01-21
Chin, Wellington
Optical: systems and elements
Deflection using a moving element
Using a periodically moving element
359125, 359179, H04J 1402
Patent
active
055964362
ABSTRACT:
An SCM system for simultaneously reducing the concomitant problems of receiver complexity and dispersion penalty and without requiring the use of an expensive, high-bandwidth optical detector. The system provides both a dispersion reduction and a direct detection to the receiver, with microwave mixers and lithium niobate external modulators that produce sidebands that are only separated by a few gigahertz from a principal laser optical carrier. Digital data streams are independently impressed upon these sidebands for transmission over an ordinary single-mode fiber. Independent high-speed data streams are upconverted to microwave frequencies. These subcarriers are then combined with a microwave power combiner and amplified with a microwave amplifier. A solid-state 1550-nm laser carrier is modulated by the microwave subcarriers. An erbium-doped fiber amplifier (EDFA) is used just prior to long-distance transmission over ordinary single-mode fiber. The transmitted optical signal may then traverse multiple EDFAs to compensate for long-haul optical fiber losses prior to detection. At a receiving end, the optical signal is split into multiple paths. The subcarrier channels are optically pre-selected using a narrowband optical filter, such as a fiber Fabry-Perot (FFP) filter. An optical detector converts the selected optical signal into a baseband electrical data stream.
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Haigh Ronald E.
McCammon Kent G.
Sargis Paul D.
Bacares Rafael
Chin Wellington
Main Richard B.
Sartorio Henry P.
The Regents of the University of California
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