On November 17, 2025, the research team headed by Professor Bi Xiaojun from the School of Integrated Circuits at Huazhong University of Science and Technology achieved a significant breakthrough in the realm of microwave photonic integrated circuits. Their research paper, entitled "A Monolithic Silicon - Germanium Electronic Path Incorporating an Active Balun Phase Shifter with Enhanced Common - Mode Rejection Ratio for Parity - Time Symmetric Optoelectronic Oscillators," was published in the prestigious journal IEEE Transactions on Circuits and Systems I: Regular Papers (TCAS - I).

This research puts forward an innovative integrated circuit that combines an optoelectronic oscillator (OEO) and an electrical path. It successfully attains a frequency tuning range spanning from 4 to 12 GHz. When a 300 - meter - long optical fiber is employed with a 10 kHz offset, the phase noise can drop to as low as - 110.4 dBc/Hz, and the side - mode suppression ratio (SMSR) can reach 47.3 dB. This achievement offers a viable solution for the development of highly integrated OEOs.

The lead author of the paper is Li Jian, a doctoral candidate from the 2025 cohort, and the corresponding author is Professor Bi Xiaojun.