Dynamic Filtering of Microwave Signals Through Brillouin-Based Polarization-Sensitive Balanced Detection

A new photonic technique to implement both stopband and passband microwave filters is presented and demonstrated. The principle of operation relies on controlling the state of polarization of the band of interest using stimulated Brillouin scattering-based polarization rotation and the optoelectronic conversion of this polarization-structured signal by means of a polarization sensitive balanced photodetection. Using the proposed architecture, the filter response can be dynamically switched to implement a stopband or a passband response with the same scheme, thus enhancing its flexibility and application potential. Experiments with a single stage show that very high stopband rejection can be implemented, 67 dB, which for the best of our knowledge is the highest stopband rejection for a photonic microwave notch filter reported to date. Measurements also show that the filter response can be dynamically changed to implement a bandpass response.

Automated summary

A new photonic technique is presented for implementing both stopband and passband microwave filters, with high stopband rejection. By controlling polarization state and optoelectronic conversion, the filter response can be dynamically switched and has high application potential. Experiments show a very high stopband rejection of 67dB and the ability to dynamically change the filter response to implement a bandpass response.