Detection of high-speed radio signals is a challenge for next generation radio-over-fibre links, requiring high bandwidth and linearity in the receiver. By using photonic downconversion in a coherent receiver, detection of high bit-rate 16-QAM signals, up to 4 Gbit/s, at a 40 GHz carrier frequency using low bandwidth electronics, has been experimentally demonstrated.
Caballero Jambrina, A., Zibar, D., & Tafur Monroy, I. (2010). Digital coherent detection of multi-gigabit 40 GHz carrier frequency radio-over-fibre signals using photonic downconversion. Electronics Letters, 46(1), 58-58. https://doi.org/10.1049/el.2010.2827