Remote millimeter-wave antenna fiber optic communication system using dual optical signal with millimeter-wave beat frequency
First Claim
1. A transmission system comprising:
- (A) a transmitter station comprising,(1) a dual optical signal generator producing a first optical signal and a second optical signal respectively, wherein said first optical signal is offset in frequency from said second optical signal by a difference frequency,(2) a coupler for combining said first and second optical signals to produce a combined output signal;
(3) an external modulator for modulating, in accordance with a baseband signal, said combined output signal;
(B) an optical fiber having one end coupled to said combined output signal; and
(c) a remote antenna station comprising,(1) a photodetector coupled to another end of said optical fiber for converting said combined output signal to an electrical signal, and(2) an antenna coupled to said electrical signal.
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Accused Products
Abstract
The transmitter or receiver of the remote antenna system of the present invention includes a fiber optic link connecting the receiver or transmitter station with a remote antenna station. The optical carrier for the fiber optic link is produced by a dual optical signal generator, preferably in the form of two narrow-linewidth lasers frequency offset by a difference frequency corresponding to the millimeter-wave or microwave signal. If the invention is employed to convey a baseband signal from the transmitter station to the antenna station, a modulator at the transmitter station modulates the dual optical signal carrier with the baseband signal. The modulated signal is carried over the optical fiber to a photodetector at the remote antenna station which detects the millimeter wave difference frequency modulated by the baseband signal. If the invention is employed to convey a received millimeter wave signal from the remote antenna station to the receiver station, then a modulator at the remote antenna station modulates the dual optical signal carrier with the received millimeter wave signal. The modulated signal is carried over the optical fiber to a photodiode at the receiver station which detects the baseband contained in the millimeter wave signal.
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Citations
35 Claims
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1. A transmission system comprising:
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(A) a transmitter station comprising, (1) a dual optical signal generator producing a first optical signal and a second optical signal respectively, wherein said first optical signal is offset in frequency from said second optical signal by a difference frequency, (2) a coupler for combining said first and second optical signals to produce a combined output signal; (3) an external modulator for modulating, in accordance with a baseband signal, said combined output signal; (B) an optical fiber having one end coupled to said combined output signal; and (c) a remote antenna station comprising, (1) a photodetector coupled to another end of said optical fiber for converting said combined output signal to an electrical signal, and (2) an antenna coupled to said electrical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A receiving system comprising:
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(A) a dual optical signal generator producing a first optical signal and a second optical signal respectively, wherein said first optical signal is offset in frequency from said second optical signal by a difference frequency, and a coupler for combining said first and second optical signals to produce a combined output signal; (B) a remote antenna station comprising, (1) an antenna for receiving a carrier signal containing modulation comprising a baseband signal, (2) an external modulator for modulating, in accordance with a baseband signal, said combined output signal; (C) a first optical fiber having one end coupled to said combined output signal; and (D) a receiver station comprising, (1) a photodetector coupled to another end of said optical fiber for receiving said combined output signal and converting said combined output signal to an electrical signal. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35)
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34. A transmission system comprising:
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(A) a transmitter station comprising, (1) a dual optical signal generator producing a first optical signal and a second optical signal respectively, wherein said first optical signal is offset in frequency from said second optical signal by a difference frequency, (2) a coupler for receiving said first and second optical signals and combining said first and second optical signals to produce a combined output signal, wherein both of said first optical signal and said second optical signal are unmodulated by a baseband signal before said coupler combines said first and second optical signals; (3) an external modulator for modulating, in accordance with a baseband signal, said combined output signal; (B) an optical fiber having one end coupled to said combined output signal; and (C) a remote antenna station comprising, (1) a photodetector coupled to another end of said optical fiber for converting said combined output signal to an electrical signal, and (2) an antenna coupled to said electrical signal.
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Specification