Simultaneously photonic frequency downconversion, multichannel phase shifting, and IQ demodulation for wideband microwave signals

A single photonic system that can simultaneously perform frequency downconversion, multichannel phase shifting, and in-phase (I) and quadrature (Q) demodulation for microwave signals is proposed and experimentally demonstrated. Using an integrated polarization-division multiplexing Mach-Zehnder modulator, radio frequency (RF) signals can be frequency downconverted to multichannel intermediate frequency (IF) signals and the phase of each IF signal can be independently and arbitrarily tuned. Using two quadrature channels, the RF signal can be IQ demodulated. In the experiment, high and flat conversion gains from 8 to 40 GHz and continuously tunable phase shifts over the 360-deg range are demonstrated. In addition, vector signals with various modulation formats at 40 GHz are frequency downconverted to baseband and the IQ data are successfully extracted.