Six papers first-authored by graduate students from the research group of Associate Professor Lei Shao at Shanghai Jiao Tong University Global College (SJTUGC, abbreviated as GC) have been selected for oral presentations at the 23rd International Conference on Solid-State Sensors, Actuators and Microsystems (Transducers 2025) . One paper out of the six has been awarded a Best Paper Finalist.
As one of the world’s leading conferences in the field of MEMS sensors, actuators and microsystems, Transducers is held biennially and has played a pivotal role in advancing international research since 1981. This year’s conference, held from June 29 to July 3 in Orlando, Florida of the United States, gathered experts and scholars from universities, research institutions, industries and government agencies worldwide to discuss the latest breakthroughs in electronic, mechanical, optical, magnetic, thermal and biological microsystems. Out of 520 accepted papers, only 157 were selected for oral presentations.
- Fiber-optic sensors with water-immersive membranes for ultra-sensitive low-frequency hydroacoustic detection
Xingyu Wei, direct Ph.D. student enrolled in 2022
Existing fiber-optic hydrophones struggle to detect weak signals due to acoustic impedance mismatch. To address this, the team proposed a water-immersive membrane fiber-optic hydrophone that couples acoustic energy efficiently by directly immersing a metal membrane in a water-filled chamber, isolated from the sealed optical detection cavity. With an anti-reflective waterproof window and a self-developed feedback stabilization circuit, the sensor achieved miniaturization and integration. It reached a sensitivity of 21.86 rad/Pa at around 100 Hz and a minimum detectable sound pressure of 15.62 μPa/√Hz, significantly surpassing existing devices. Ph.D. student Xingyu Wei was the first author and presented the paper, which was honored as a Best Paper Finalist.
- A TO-packaged photonic MEMS microphone with outstanding sensitivity based on self-mixing interferometry
Anyu Li, direct Ph.D. student enrolled in 2022
Optical MEMS microphones have higher sensitivity and SNR than conventional capacitive or inductive MEMS microphones but traditionally rely on bulky optical setups. The team developed a TO-packaged MEMS microphone integrating a composite acoustic membrane, laser diode, and photodiode, enabling a miniaturized and integrated device based on self-mixing interferometry. Tests showed its sensitivity and SNR exceeded existing MEMS acoustic sensors, demonstrating strong potential in human–machine interaction applications. Ph.D. student Anyu Li was the first author and delivered the oral presentation.
- Highly stretchable but strain-insensitive pressure sensors for crosstalk-free arterial pulse monitoring
Shoulu Gong, direct Ph.D. student enrolled in 2020
Flexible micro-pressure sensors are widely used in wearables but often suffer from signal crosstalk caused by deformation. The team designed a highly stretchable and strain-insensitive pressure sensor using an ultrathin PZT sensing unit and a strain-gradient substrate. The device maintained strain insensitivity under up to 93% tensile strain and achieved a detection limit of 15 mN, offering a promising solution for crosstalk-free physiological monitoring in next-generation wearables. Ph.D. student Shoulu Gong was the first author and presented the paper.
- Visualization of dense spurious modes in a 5 GHz laterally excited bulk acoustic resonator using pulsed laser interferometry
Zhaoliang Peng, integrated Master–Ph.D. student enrolled in 2022
Laterally excited bulk acoustic resonators (XBARs) are key MEMS devices for 5G/6G RF front-end technologies, but spurious modes degrade performance. Conventional vibrometry techniques cannot capture spurious modes above 5 GHz. The team developed a pulsed laser interferometry system that enabled the first visualization of spurious modes in a 5 GHz XBAR, successfully decoupling superimposed vibration modes and revealing the dynamic evolution of fundamental and spurious modes. This study provides direct evidence for understanding spurious mode mechanisms and lays a foundation for optimized XBAR design. Ph.D. student Zhaoliang Peng was the first author and presented the paper.
- Enhancement of energy exchange rate in mode-coupled MEMS for supercontinuum frequencycombs and injection locking
Jiahao Wu, integrated Master–Ph.D. student enrolled in 2023
MEMS frequency combs based on mode coupling show promise for next-generation ultra-stable clocks but face challenges of low inter-mode energy transfer and spectral broadening, along with unstable phase locking. The team designed a MEMS device with significantly enhanced energy coupling, greatly improving comb broadening. They also achieved self-injection locking of adjacent spectral lines through precise tuning, enhancing frequency stability and advancing chip-scale low-noise precision clock sources. Ph.D. student Jiahao Wu was the first author and presented the paper.
- Two-decade-wide dense phononic frequency combs in a linear MEMS resonator using analog feedback
Shuke Zang, Master’s student enrolled in 2022
On-chip MEMS frequency combs usually rely on nonlinear system coupling, which complicates resonator design and fabrication. The team instead introduced nonlinearity via feedback circuitry, enabling autonomous regulation in a linear resonator and self-excited generation of ultra-broadband frequency combs. The approach expanded comb bandwidth to 20 times the base frequency with tunability up to 1000× in comb spacing, showing potential for next-generation chip-scale ultra-stable clock sources. Master’s student Shuke Zang was the first author and presented the paper.
The research works by the six students under the guidance of Professor Shao were supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Shanghai Municipal Science and Technology Commission, and the State Key Laboratory of Mechanical System and Vibration.
Advisor Introduction
Lei Shao is an Associate Professor and Ph.D. advisor at JI, focusing on MEMS dynamics and control, as well as precision measurement technology. He has been selected for the Shanghai’s Sailing Talent Program and China’s National Key R&D Program for Young Scientists. His research has been published in prestigious journals such as Nature Communications, Science Advances, Physical Review Letters, and leading IEEE journals (TPEL, EDL, TIM, JMEMS).
