The futuristic 5G/6G communication and RADAR signal processing systems operating beyond X-band (>10 GHz) demand scalable microwave photonic integrated circuits for re-configurable multi-band operations. CMOS-compatible silicon photonics technology is being studied intensively for programmable optical signal processors (OSP) for high-frequency microwave to mm-wave applications. The bandpass filter is an essential microwave receiver architecture block to separate the signal of interest from the noise and eliminate cross-talks. The microring resonator is a popular device for designing an efficient optical signal processor for RF photonic filters. One significant challenge is implementing bandpass programmable microwave photonic filters with symmetrical out-of-band rejection around the central carrier frequency.



In this talk, we will first discuss the design of an integrated OSP (based on cascaded microring resonators) using CMOS-compatible silicon photonics technology to realise a tunable RF bandpass filter with a programmable bandwidth and symmetric out-of-band rejection. Next, the experimental results of the RF photonic filter with the in-house and foundry-fabricated OSP structures, along with their limitations and improvement scopes, will be presented.