Patent ID: 7668466

Claim:
A demodulator operable to demodulate a signal, comprising: an input splitter operable to split an input signal to yield a plurality of signals, the input signal comprising a plurality of symbols; a plurality of optical device sets comprising: a first optical device set operable to direct a signal of the plurality of signals along a first path; and a second optical device set operable to direct another signal of the plurality of signals along a second path to yield a delayed signal, a path length difference between the first path and the second path introducing a symbol delay between the first signal and the second signal, at least a larger portion of the second path being in free space, the free space comprising a liquid and free from solid material; and a plurality of couplers, a coupler of the plurality of couplers operable to: receive a portion of the signal and a portion of the delayed signal to generate interference, the interference indicating a phase shift between a phase corresponding to a symbol of the plurality of symbols and a successive phase corresponding to a successive symbol of the plurality of symbols.