Frequency-Selectable Microwave Generation Based on On-Chip Switchable Spectral Shaping

Spectral shaping and wavelength-to-time mapping (SS-WTTM) has been proved as an effective method for the microwave signal generation. With the development of integrated photonic technology, the integrated spectral shaping chip is increasingly significant because of the advantages of power-efficiency, small footprint, etc. Here, we propose and experimentally demonstrate an on-chip spectral shaping scheme based on cascaded asymmetric Mach-Zender interferometers (AMZIs), which enables the generation of frequency-selectable microwave signals. In this scheme, n AMZIs are cascaded to generate 2ⁿ-1 switchable free spectral ranges (FSRs), which are adopted to generate 2ⁿ-1 frequency-switchable microwave signals by using the SS-WTTM method. The microwave signal generation experiment was constructed by adopting a five-stage cascade AMZI chip. Experimental results show that 31 frequency-selectable microwave signals in the frequency range of 0.98 to 29.35 GHz with a frequency step interval of 0.98 GHz were generated successfully. The proposed scheme has the advantages of simplicity, high tunability, and easy expansion, which may have great potential for radar and telecommunication applications.