All Optical Image Reject Down Converter
Patent Application, Filed 9 Aug 2000
DEPARTMENT OF THE NAVY WASHINGTON DC
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The optical image reject down converter maps a received radio frequency RF into an arbitrary intermediate frequency range and precludes interference between the received signals. A received radio frequency signal is downconverted into an intermediate frequency band for use by an electronic circuit in other devices. Optical light is divided, in a first path light is transferred into an optical sideband by a first optical modulator or phase modulator. Light in a second path is converted into 18 GHZ sidebands by a simarly. The signal is amplified and additional sidebands are generated by a received 9 GHz signal. The light is then passed through a tunable narrow-band optical filter which selects the 27 GHz sideband. The optical spectrum of the second path consists only of light at the frequency equal to the original laser frequency plus the 27 GHz signal. The filtered sideband is heterodyned with the 25 0Hz signal of path one, resulting in downconversion to 2 GHz Image frequencies which are present in the optical link are filtered and are rejected.
- Electrical and Electronic Equipment
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