A direct-conversion RF scanning receiver based on photonics

A photonics-based direct-conversion RF receiver has been realized and characterized. The innovative architecture uses coherent optical techniques to perform a fast and wideband scan of the RF spectrum avoiding bulky multiple crystal oscillators. The direct-conversion approach based on photonics enables filtering the input signal spectrum by means of a simple electrical low pass filter, and provide total immunity to local oscillator self-mixing and to RF-to-baseband feedthrough, which are typical drawbacks of conventional direct-conversion receivers. The experimental validation shows an operating bandwidth of 0.5÷10.5 GHz and instantaneous bandwidth of 1 GHz, with linear dynamic range of 141 dB/Hz and spurious-free dynamic range of 107 dB/Hz?. Further system developments will enhance the operating bandwidth up to 40 GHz. Implementing the scheme through integrated photonics technologies will also ensure high environmental stability and reduced size weight and power consumption.