Photonics-Assisted Super-Octave Microwave Phase Shifter

• Published in: IEEE photonics journal Vol. 11; no. 1; pp. 1 - 11
• Main Authors: Lei, Mingzheng, Zheng, Zhennan, Qian, Jinwang, Xie, Mutong, Gao, Xinlu, Huang, Shanguo
• Format: Journal Article
• Language: English
• Published: Piscataway IEEE 01.02.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Frequency ranges; Mach-Zehnder interferometers; Microprocessors; Microwave photonics; Multiplexing; Optical amplifiers; Optical fibers; Optical filters; Optical modulation; Optical polarization; optical signal processing; Phase shifter; Phase shifters; Photonics; Polarization; radio frequency photonics; Sidebands; Single sideband transmission; spurious free dynamic range; Variation
• ISSN: 1943-0655; 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2019.2893059

A photonics-assisted super-octave microwave phase shifter is proposed. The super-octave frequency range is achieved by eliminating the second-order distortions (SDs) with the techniques of polarization interleaving and second-order optical sidebands (2-OSBs) phase processing. Polarization interleaving is based on a polarization-multiplexing dual-drive Mach-Zehnder modulator (PM-DMZM) and single sideband with carrier (SSB+C) modulation. 2-OSBs phase processing is implemented by introducing opposite phase shifts to the ±2-OSBs in a Fourier-domain optical processor (FD-OP). The proposed phase shifter is experimentally verified by proof-of-concept experiments. Experimental results show that flat phase shifts cover a full 360° range with less than 3-dB power variation over 11.5-25 GHz. Besides, excellent long-term stability is presented with a maximum phase/power fluctuation of only 1.49°/0.57 dB. Compared with the conventional FD-OP-based photonic microwave phase shifter, the proposed one improves the second-order spurious free dynamic range (SFDR 2 ) by 13.57 dB.