Fast optical vector network analysis based on dual optical frequency comb

An ultrafast optical vector network analysis (OVNA) based on dual optical frequency comb (OFC) and I/Q demodulation technology is proposed and demonstrated. The responses of the DUT with broadband are characterized by propagating the signal OFC through the DUT, and then detecting interference signals using digital signal processor with retrieval algorithm. Without the need of the acousto-optic modulator or optical filter in the scheme, the frequency aliasing can be eliminated by using the I/Q demodulation module, so that the spectral utilization efficiency of the OFC is improved significantly. Meanwhile, the wideband measurement with high acquisition rates can also be achieved. In simulation process, the single spectrum of HCN molecule with linewidth of 1 GHz and bandwidth of 10 GHz can be rapidly measured, and the measurement time is only 1 mu s in theory. Our proposed OVNA opens the door to realize a real-time detection in the field of trace molecular sensing.