Adaptively-tunable RF photonic filters

The emergence of silicon photonics has enabled potential implementations of RF photonic filters with the size, weight, and power requirements of radio systems with small form factors. This paper presents a fourth-order elliptic digital filter designed in the optical domain with all-pass filter (APF) unit cells. A monitor-based adaptive tuning algorithm is proposed to calibrate the optical filter response with high accuracy and provide rapid filter reconfiguration.