A tunable optoelectronic oscillator based on a tunable microwave attenuator

• A wideband tunable optoelectronic oscillator based on microwave attenuator is realized.
• The generated microwave frequency could be tuned from 5.81 GHz to 11 GHz.
• The phase noise of generated microwave signal could reach −107.4 dBc/Hz@10 kHz.

A novel realization of a wideband tunable optoelectronic oscillator (OEO) based on dual-port electrode Mach–Zehnder modulator (DMZM), a tunable microwave attenuator (TMA), and a chirped fiber Bragg grating (CFBG) is proposed and demonstrated. By simply adjusting the power ratio between the two arms of DMZM, the chirp of the DMZM will be tuned, and the center frequency of the microwave photonic filter will be tuned. When the OEO loop in the proposed system is closed, the output frequency of OEO is determined by the microwave photonic filter, and a high spectral purity microwave signal with a tunable frequency from 5.8 to 11 GHz is generated. The single sideband (SSB) phase noise of the generated signal could reach −107.4 dBc/Hz at an offset frequency of 10 kHz.