Photonics generation of microwave linearly chirped signal with amplitude and phase modulation capability

Abstract

A photonics method is proposed to generate a microwave linearly chirped signal with improved central frequency, doubling bandwidth, amplitude and phase modulation capability. In the scheme, a dual-polarization integrated modulator combined with an optical filter are utilized to generate an orthogonally polarized optical signal. Then, the optical signal is injected into a polarization modulator (PolM) to perform data modulation. By controlling the polarization state of the orthogonally polarized optical signal, amplitude or phase of the generated microwave linearly chirped signal will be changed according to the driving data sequence. The proposed scheme is verified by simulation. Linearly chirped signals with central frequency tuned from 14 to 29 GHz, bandwidth tuned from 4 to 10 GHz are generated. ASK linearly chirped signals with bit-rate tuned from 156.25 to 1250 Mbps are demonstrated. Generation of a PSK linearly chirped signal and its coherent demodulation are verified. Besides, 4ASK, 4PSK and QPSK linearly chirped waveforms are achieved, and time-bandwidth product improvement is confirmed. The proposed method features parameter tunability and modulation format agility, which can be potentially employed in radar and wireless covert communication systems.

KEYWORDS:

• Linearly chirped waveform
• polarization modulation
• amplitude shift keying
• phase shift keying

Acknowledgements

This work was supported by the National Natural Science Foundation of China (61901507) and the Natural Science Basis Research Plan in Shaanxi Province of China (2019JQ-707).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 61901507] and the Natural Science Basis Research Plan in Shaanxi Province of China [grant number 2019JQ-707].