Generation of Reconfigurable Linearly Chirped Microwave Waveforms Based On Fourier domain Mode-Locked Optoelectronic Oscillator
Lin Wang, Yifan Liu, Yu Chen, Weilei Gou, Shuai Cui, Yu Yu, Xi Xiao, Yuan Yu, Xinliang Zhang
Abstract
We propose and experimentally demonstrate an approach to generating reconfigurable linearly chirped microwave waveforms (LCMWs) based on a Fourier domain mode-locked (FDML) optoelectronic oscillator (OEO), in which a tunable and reconfigurable microwave photonic filter (MPF) based on a high-Q microring resonator (MRR) is used for mode selection. The MPF can be electrically tuned to achieve Fourier domain mode-locking by using a micro-heater deposited on the MRR. Adjusting the state of polarization of the optical carrier, the MPF is reconfigured and multi-band and multi-format LCWMs can be generated based on the FDML OEO. In the experiment, a dual-chirp LCMW with a bandwidth of 12 GHz consisting of an up-chirped waveform from 7 to 13 GHz and a down-chirped waveform from 19 to 13 GHz is realized, with a time-bandwidth product (TBWP) as high as 1.004×10<sup>6</sup>. By reconfiguring the MPF, we can also obtain LCMWs with a single chirp at C-band (from 4 to 8 GHz), X-band (from 8 to 12 GHz) and Ku-band (from 13 to 19 GHz), respectively. Further, the bandwidth and center frequency of the LCMWs and the dual-chirp LCMWs can be changed by adjusting the magnitude of the driving signal and the laser wavelength, respectively. This kind of reconfigurable LCMWs can be applied to advanced multi-band radar and wireless communication systems.