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OFC 2026 | Original Innovation by SJTU + Engineering Implementation by AllianStream Photonics: CPC FM DAS Achieves High SNR and Fading Resistance

At OFC 2026, the world’s premier optical fiber communication conference, Ningbo AllianStream Photonics Technology Co., Ltd. and the research group led by Professor Zuyuan He from Shanghai Jiao Tong University unveiled a major breakthrough: the Coded-Pulse-Compression Frequency-Multiplexed (CPC FM) Distributed Acoustic Sensing (DAS) solution.

This technology deeply integrates mature coding, multiplexing, and pulse compression mechanisms from optical communications into distributed optical fiber sensing for the first time. It overcomes severe interference fading and signal-to-noise ratio (SNR) limitations in conventional DAS, enables full compatibility with communication signals, and lays a critical foundation for optical fiber integrated sensing and communication (ISAC).

🌐Global Trend: ISAC, the Core Direction of Next-Generation Optical Networks

Global optical fiber networks serve as both communication backbones and natural sensing media. Integrated sensing and communication (ISAC)—using one optical fiber for simultaneous data transmission and full-domain sensing—has become a core trend for 5G/6G bearer networks, data centers, and trunk cables.

DAS is the most favorable technical route for ISAC because it relies solely on optical fiber Rayleigh backscattering without extra resources. However, conventional DAS faces two critical bottlenecks:

  1. Interference fading: causes severe sensitivity degradation or even failure at local positions
  2. System incompatibility: probe signals compete for spectrum with communication signals, hindering co-transmission

🚀Technical Breakthrough: Coding + Pulse Compression + Frequency Multiplexing

The team proposed an innovative CPC FM DAS architecture, delivering three core advances:

1. Coded-Pulse-Compression (CPC): SNR Enhancement via Energy Concentration

A multi-bit random coding sequence is modulated onto optical pulses, and pulse compression is realized through matched filtering. This greatly improves system SNR without sacrificing spatial resolution.

2. Frequency-Multiplexed (FM) Fading Suppression: Multi-Frequency Parallel Probing

Multiple orthogonal center frequencies (9 channels from 30 MHz to 360 MHz with 40 MHz spacing in experiments) are transmitted in parallel. Fading at different frequencies is statistically independent; after fusion, intensity fluctuation is suppressed from ~20 dB to ~5 dB, eliminating interference fading.

3. ISAC Compatibility: Direct Multiplexing with Communication Payloads

Key innovation: The communication payload (frame header) can be directly used as DAS probe signals without dedicated probe light, realizing same-fiber, same-wavelength, same-code communication and sensing.

Principles of CPC FM DAS scheme

📊Experimental Verification: 10 km FUT, Comprehensive Performance Upgrade

The system was rigorously tested over a 10 km fiber under test (FUT), with core performance greatly improved:

  • 50% upper confidence limit (UCL) strain resolution: from 40.7 pε/√Hz to 11.8 pε/√Hz
  • 99% upper confidence limit (UCL) strain resolution: from 84.0 pε/√Hz to 29.8 pε/√Hz
  • System self-noise: 4.3×10⁻⁷ rad²/Hz
  • Clearly reconstructs 400 Hz vibration signals with excellent dynamic performance

Experimental results

This technology resolves the trade-off between spatial resolution and frequency resource competition in conventional chirped pulse compression DAS. More importantly, it validates that communication payloads (frame headers) can serve as DAS probe signals, opening a practical path for ISAC.

🤝Industry-University-Research Collaboration: Accelerating Industrial Translation

This achievement follows a typical “academic innovation + industrial translation” model:

  • Shanghai Jiao Tong University: theoretical innovation, modulation/demodulation schemes, algorithm design, and system experiments
  • AllianStream Photonics: engineering implementation and product development

The technology directly supports:

  • Communication cable health monitoring
  • 5G/6G bearer network ISAC
  • Optical module-level sensing in data centers
  • “Simultaneous communication and sensing” for metro and trunk networks
  • Digital O&M of optical fibers in ocean, oil & gas, and power grid scenarios

🔮Future Outlook

CPC FM DAS realizes the deep unification of communication coding and DAS sensing mechanisms for the first time, breaking key bottlenecks in signal compatibility, spectrum efficiency, and fading suppression for ISAC.

Going forward, AllianStream Photonics will continue close collaboration with SJTU to accelerate chipization, modularization, and productization, driving ISAC from laboratories to large-scale commercial deployment.

📄Paper Information

Jiazhen Ji, Zhicheng Jin, Jiageng Chen, Yangyang Wan, Hanzhao Li, Xuhui Yu, and Zuyuan He. Coded-Pulse-Compression Frequency-Multiplexed DAS for Fading Suppression and SNR Enhancement, OFC 2026, W3D.6, Los Angeles, March 2026

Innovation never stops; the future has arrived.

AllianStream Photonics: Journey with you toward the starry sea of optical fiber sensing!

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#Pulse Compression #Pulse Coding #Frequency Multiplexing #Frequency Diversity #ISAC #AllianStreamPhotonics #SJTU #OFC2026 #DAS