RF frequency multiplexed fiber optic data bus
AssigneeGeneral Dynamics Corporation, Electronics Division
InventorRonald F. Mathis
Life of this patent
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Abstract
A fiber optic data bus that includes a multiplexer means for generating a plurality of optical signals and for intensity modulating each of the optical signals in response to a respective one of a plurality of input RF signals each at a different RF carrier frequency to provide a plurality of intensity modulated optical signals. A signal collection means combines the plurality of intensity modulated optical signals into a combined optical signal. A conducting means conducts the combined optical signal to a signal distribution means which distributes the combined optical signal to each of a plurality of output ports. A demultiplexer means extracts from a portion of one of the distributed combined optical signals an output RF signal substantially identical to a predetermined one of the plurality of RF input signals.
Claims15
A fiber optic data bus for multiplexing, transmitting, and demultiplexing a plurality of input RF signals as a corresponding plurality of output RF signals comprising:
- a plurality of modulated light sources, each having an input adapted to receive a respective one of a plurality of input electrical RF signals each at a different RF carrier frequency wherein each modulated light source provides in response to a respective one of said input RF signals at an output a corresponding intensity modulated optical signal;
- signal collection means for combining said plurality of intensity modulated optical signals into a combined optical signal, said signal collection means comprising an input star coupler having an output and a plurality of inputs with each input of said input star coupler connected to a respective output of said plurality of modulated light sources;
- conducting means conncted to said signal collection means for conducting said combined optical signal, said conducting means comprising an optical fiber having a pair of ends with one end connected to said input star coupler output;
- signal distribution means connected to said conducting means for output distribution of said combined optical signal, said signal distribution means comprising an output star coupler having an input and a plurality of outputs with said input of said output star coupler connected to the other end of said optical fiber;
- a plurality of optical bandpass filters each having an input and an output, each optical bandpass filter input connected to a different output of said output star coupler, said optical bandpass filter comprising:
- a segment of multimode optical fiber of a predetermined length, L,;
- an input mirror on one end of said fiber segment;
- means for directing intensity modulated light into said fiber segment;
- and
- said fiber segment having a length substantially equal to half the wavelength of the modulation frequency in said fiber segment, with said fiber segment functioning as a resonant cavity and filtered output light exiting through said output mirror;
- a plurality of optical detectors each having an input and an output, each optical detector input connected to a different optical bandpass filter output;
- and
- wherein each of said optical filters extracts a predetermined portion of the distributed combined optical signal as an output optical signal which has a frequency corresponding to the modulation frequency of a respective one of said input RF signals and wherein each one of said optical detectors converts a respective output optical signal to an output electrical RF signal.
Dependencies are inferred from the claim text.