Wavelength division multiplexed fiber optic link for RF polarization diversity receiver
First Claim
1. An optical fiber transmission link for transmitting signals representing first and second RF signals of different polarizations, comprising:
- first laser transmitter means for generating a first optical laser signal at a first optical wavelength;
first modulating means for intensity modulating said first laser signal with said first RF signal;
second laser transmitter means for generating a second optical laser signal at a second optical wavelength;
second modulating means for intensity modulating said second laser signal with said second RF signal;
optical combining means for combining said first and second modulated optical signals into a combined optical signal;
a single transmission optical fiber for conducting said combined optical signal from said optical combining means to a receiving apparatus;
said receiving apparatus comprising a wavelength selective optical dividing means for separating said combined signal into first and second optical received signals at said respective first and second wavelengths, and first and second photodetecting means responsive respectively to said first and second received signals to provide first and second photodetector signals corresponding to said first and second RF signals.
2 Assignments
0 Petitions
Accused Products
Abstract
A single transmission optical fiber is used to transmit RF signals of the same frequency but different polarization from a source to a polarization diversity receiver without introducing interference between the signals. The incoming signal of one polarization modulates a first laser transmitter operating at one wavelength, and the incoming signal of the other polarization modulates a second laser transmitter operating at a different, second wavelength. The two modulated optical beams are combined in an optical coupler whose output is connected to the transmission fiber leading to the polarization diversity receiver. At the receiver, a wavelength division multiplexing coupler is used to separate out the two modulated optical carriers. The two RF signals used to modulate the laser transmitters are separately recovered via photodiode detectors to provide inputs to the polarization diversity receiver.
145 Citations
19 Claims
-
1. An optical fiber transmission link for transmitting signals representing first and second RF signals of different polarizations, comprising:
-
first laser transmitter means for generating a first optical laser signal at a first optical wavelength; first modulating means for intensity modulating said first laser signal with said first RF signal; second laser transmitter means for generating a second optical laser signal at a second optical wavelength; second modulating means for intensity modulating said second laser signal with said second RF signal; optical combining means for combining said first and second modulated optical signals into a combined optical signal; a single transmission optical fiber for conducting said combined optical signal from said optical combining means to a receiving apparatus; said receiving apparatus comprising a wavelength selective optical dividing means for separating said combined signal into first and second optical received signals at said respective first and second wavelengths, and first and second photodetecting means responsive respectively to said first and second received signals to provide first and second photodetector signals corresponding to said first and second RF signals. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. An optical fiber transmission link for transmitting vertically and horizontally polarized RF signals from a remote antenna system to a polarization diversity receiver, comprising:
-
antenna means for generating a vertical polarization RF signal in response to incident vertically polarized RF signals and a horizontal polarization RF signal in response to incident horizontally polarized RF signals; first laser transmitter means for generating a first optical laser signal at a first optical wavelength; first modulating means for intensity modulating said first laser signal with said vertical polarization RF signal; second laser transmitter means for generating a second optical laser signal at a second optical wavelength; second modulating means for intensity modulating said second laser signal with said horizontal polarization RF signal; optical combining means for combining said first and second modulated optical signals into a combined optical signal; a single transmission optical fiber for conducting said combined optical signal from said optical combining means to a link receiving apparatus; said link receiving apparatus comprising a wavelength selective optical dividing means for separating said combined signal into first and second optical received signals at said respective first and second wavelengths, and first and second photodetecting means responsive respectively to said first and second received signals to provide first and second photodetector signals corresponding to said respective vertical polarization and horizontal polarization RF signals; and a polarization diversity RF receiver responsive to said first photodetector signal and said second photodetector signal. - View Dependent Claims (9, 10, 11, 12, 13)
-
-
14. A receiver for a wireless cellular telephone communication system, comprising:
-
antenna means for generating a vertical polarization RF signal in response to incident vertically polarized RF signals and a horizontal polarization RF signal in response to incident horizontally polarized RF signals; first laser transmitter means for generating a first optical laser signal at a first optical wavelength; first modulating means for intensity modulating said first laser signal with said vertical polarization RF signal; second laser transmitter means for generating a second optical laser signal at a second optical wavelength; second modulating means for intensity modulating said second laser signal with said horizontal polarization RF signal; optical combining means for combining said first and second modulated optical signals into a combined optical signal; receiving apparatus comprising a wavelength selective optical dividing means for separating said combined signal into first and second optical received signals at said respective first and second wavelengths; a single transmission optical fiber for conducting said combined optical signal from said optical combining means to said optical dividing means; first and second photodetecting means responsive respectively to said first and second received signals to provide first and second photodetector signals corresponding respectively to said vertical and horizontal polarization RF signals; and a polarization diversity RF receiver responsive to said first photodetector signal and said second photodetector signal. - View Dependent Claims (15, 16, 17, 18, 19)
-
Specification