All-Optical Full-Band RF Receiver Based on an Integrated Ultra-High-Q Bandpass Filter

Ultra-broadband radiofrequency (RF) receivers are required in higher frequency-band wireless communications, radar communications or multi-band applications in radio telescopes. Such ultra-broadband receivers are inherently difficult to establish with electronics because of limits in the bandwidth of the devices. Photonic means of RF photonic receivers/frontends can overcome the bandwidth limitation in electrical receivers. One aspect that should be considered is the precise signal processing in the optical domain. Here, a full-band (from the L-band to the W-band) all-optical RF receiver based on the Si3N4 microring filter is proposed and experimentally demonstrated. The resolution and processing range of the filter are lower than 420 MHz and larger than 112.9 GHz (FSR larger than 225.78 GHz), respectively, and the out-band suppression of this filter is greater than 40 dB. The center frequency of the filter can be altered for more than one FSR by tuning the phase-shifter on top of the ring. The performance of the full-band all-optical RF-receiver has been discussed, and the spurious free dynamic range of the receiver from the L-band to the Ka-band (limited by the bandwidth of the modulator in our experiment) has been measured to be larger than 111.6 dB·Hz2/3.