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Paper Express | Industry-University Research by AllianStream Photonics & SJTU Published in JLT: Corrugated Fiber Microphone Achieves Boosted Sensitivity

The research outcome completed by Ningbo AllianStream Photonics and Shanghai Jiao Tong University (SJTU) has been published in Journal of Lightwave Technology. This paper firstly puts forward a brand-new device design concept of geometry-induced mechanical compliance, and develops an original hollow corrugated cylinder (HCC) fiber optic microphone. Without adopting softer or thinner mandrel materials, the corrugated geometric optimization alone brings a leap forward in acoustic sensitivity, delivering a new solution for faint acoustic signal detection.

 

Inherent Design Tradeoff in the Industry

 

Conventional mandrel-type fiber microphones adopt thin soft frames to boost sound pickup sensitivity, which drastically reduces structural rigidity, leading to poor shock resistance and unstable long-term field performance. Hard thick-walled mandrels cut acoustic coupling efficiency sharply. The contradiction between high detection sensitivity and engineering reliability has long restricted large-scale deployment of fiber acoustic probes.

 

✨Original Structural Innovation

 

Breaking the conventional optimization logic of adopting softer materials or thinning walls, periodic corrugated geometry creates anisotropic mechanical properties: flexible along corrugations while rigid transversely. It greatly enhances sound-induced deformation with identical material, wall thickness and outer radius.

  1. Corrugated structure amplifies radial strain

Finite element simulation proves the corrugated cylinder produces 15 times larger radial deformation than smooth mandrels. Larger deformation is converted into fiber phase shift to amplify faint acoustic signals at the physical level.

  1. Stable wideband response from 0.1 to 4.5 kHz

Optimizing corrugation amplitude, quantity and outer radius realizes high-sensitivity acoustic detection across full frequency band, covering mainstream frequency ranges of industrial noise, UAV rotor sound and underwater ambient noise.

  1. Integrated 3D printing, suitable for array mass production

Manufactured via integrated TOP11B resin 3D printing with evenly wound sensing fiber. Simple assembly supports mass production of distributed acoustic sensor arrays.

Figure 1 Structural & finite element simulation comparison: smooth mandrel vs corrugated HCC mandrel

 Anechoic Chamber Calibration Performance

 

Calibrated Performance in Anechoic Chamber

Contrast tests carried out with identical material, wall thickness and outer radius:

▫️ Average sensitivity (0.1–4.5 kHz): −119.15 dB re 1 rad/µPa/m

▫️ Peak sensitivity @1.88 kHz: −105.49 dB re 1 rad/µPa/m

▫️ Vs traditional same-size FOM: average sensitivity +18.35dB, peak sensitivity +21.35dB

▫️ Outperforms state-of-the-art FOMs: 10dB higher average sensitivity, 18dB higher peak sensitivity

▫️ Linear fitting of sound pressure & phase: R²=0.9999, undistorted reproduction of weak sound waves

Figure 2 Frequency response & sensitivity curve: new corrugated FOM vs traditional FOM

 

Three Groups of Practical Field Acoustic Tests

 

1. Acoustic Detection of Low-Altitude UAVs

Field tests with two UAV models hovering at low altitudes. The new probe fully extracts multi-layer rotor harmonics, while most acoustic features of traditional sensors are masked by background noise, with SNR improved by over 10dB under identical conditions.

Figure 3 Time-frequency spectrogram comparison of UAV acoustic signals

 

2. Fault Diagnosis of Industrial Equipment

Audio data of fans, pumps and valves under normal & faulty states are collected. MFCC feature classification accuracy reaches 98.1%, 6.8% higher than traditional probes, enabling early warning of tiny mechanical abnormal noise.

Figure 4 Time-frequency spectrogram comparison of Fault Diagnosis of Industrial Equipment

 

3. Transient Pulse Acoustic Signal Detection

Tests on balloon burst and metal impact prove the sensor captures full-band impact energy with complete high-frequency details, applicable to third-party pipeline damage monitoring and power partial discharge inspection.

Figure 5 Time-frequency spectrogram comparison of balloon burst

 

 Industry-University R&D Division

 

Xuzhe Zhang, PhD candidate from Shanghai Jiao Tong University, serves as the first author. Dr. Xuhui Yu from AllianStream Photonics and Dr. Yangyang Wan from Shanghai Jiao Tong University are co-corresponding authors. 

The two parties build a complete innovation chain of structural simulation – prototype trial – field acoustic verification, accelerating the transformation of cutting-edge laboratory devices to mass industrial products.

 

 Application Scenarios

 

▪ Low-altitude security: acoustic early warning network for illegal UAVs

▪ Industrial O&M: online abnormal noise monitoring for fans & turbines

 

 

 Paper Information

Xuzhe Zhang, Yuan Gao, Huanmo Zhou, Yangyang Wan*, Xuhui Yu*, Zuyuan He.

Ultra-High Sensitivity Fiber Optic Microphone Based on Geometry-Induced Mechanical Compliance

Journal of Lightwave Technology, Vol.44, No.12, June 15, 2026

DOI:10.1109/JLT.2026.3681266

 

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