We demonstrate a novel photonic link that simultaneously achieves frequency conversion, optical amplification, polarization sensitivity elimination, and fiber dispersion effect minimization. The link also uses low loss and less expensive phase modulators to replace intensity modulators and thus eliminates modulator bias problems.
Local oscillator provided to down convention the remote antenna. Use a PBS and a bi-directional Phase modulation for down Converntion and achieve polarization indenpedence.
Down convertion - direct detecton, nothing to do with linearity.