Rądio-photonic microwave receiving channel with optical heterodyning
Sergey F. Boev1, Victor V. Valuev1,2, Victor V.
Kulagin1,2,3, Vladimir A. Cherepenin2
Stock Company «RTI»
Institute of Radio-engineering and Electronics of RAS
Astronomical Institute of Lomonosov Moscow State University
The paper is received on December 15, 2014
Abstract. The use of continuous
wave (cw) stable laser together with amplitude modulators and narrow band
optical filters to convert radar signal to low (envelope) frequencies is
considered. An amplitude modulation of the cw optical carrier with microwave
signal results in creation of the signal sidebands. Then, the optical carrier
can be suppressed by filtering one sideband using optical band-pass filter based
on, e.g., microresonators or fiber Bragg gratings. Part of the laser beam
should be amplitude-modulated with the radar carrier and filtered as well to
suppress the optical carrier. After that, optical signals containing radar
signal and radar carrier can be mixed at a photodetector and digitized with a
slow electronic ADC. Performance capabilities for receiving channel using
optical heterodyning are estimated. Parameters for optimal system operation are
derived. It is shown that, for modern optical elements, signal-to-noise ratio
at the output can be about 60-70 db and more for a microwave signal with a
carrier frequency of tens of gigahertz and bandwidth of 100 MHz and higher.
Keywords: microwave photonics, rądio-photonic receiving channel, optical heterodyning.