Integrated group delay units for real-time reconfigurable spectrum sensing of mm-wave signals

Real-time spectrum sensing is crucial to enable dynamic spectrum sharing for ubiquitous wireless communication with seamless high-quality wireless services. In this contribution, we demonstrate a reconfigurable real-time spectrum sensing photonic integrated chip (RTSS-PIC) for millimeter-wave (mm-wave) signals, based on the temporal discrimination of multi-channel input frequencies by the peak group delays of cascaded ring resonators. Large group delays and wide bandwidths are realized by the strategic tuning of thermal phase shifters. To make the spectrum sensing fully reconfigurable, positive and negative group delay profiles are utilized. Furthermore, a unique frequency-to-time mapping technique is introduced to analyze all input channels in real time. To illustrate the method, real-time spectrum sensing for two different mm-wave signals are finally tested by full-wave simulations of the proposed RTSS-PIC.