ASN at SeaSEC DATA2SEA 2026: OptoDAS Validated Under Live Baltic Sea Conditions

Rostock, Germany — April 2026 Alcatel Submarine Networks (ASN) has successfully completed its participation in the SeaSEC Challenge Weeks DATA2SEA 2026, the most operationally rigorous industry exercise for Critical Underwater Infrastructure (CUI) protection in the Baltic region. Competing as a key technology contributor within three distinct industry consortia — AAMI, Blueshield, and Flagship — ASN’s OptoDAS Distributed Acoustic Sensing system was deployed in live attack scenario challenges, delivering consistent, high-confidence results in a demanding, multi-domain environment.

What is SeaSEC DATA2SEA?

Founded in December 2023 under the Northern Naval Capability Cooperation (NNCC), the Seabed Security Experimentation Centre (SeaSEC) brings together Ministries of Defence from Denmark, Finland, Germany, the Netherlands, Norway, and Sweden. Its mandate is to accelerate the development and adoption of technologies that protect shallow-water undersea infrastructure — power cables, data cables, offshore energy platforms, and strategic port facilities.

The 2026 edition, themed DATA2SEA, ran from 13 to 24 April at the Digital Ocean Lab in the Mecklenburg Bight and at the Naval Base Rostock, hosted by the Rostock Institute for Ocean Technologies (RIOT) in cooperation with the German Navy. The event is not a trade fair. It is a live operational exercise in which industry blue teams are evaluated — and actively challenged — by NNCC naval red teams operating under realistic threat scenarios. Speed of detection, accuracy of classification, data fusion quality, and seamless C2 integration are the criteria. There is no room for laboratory performance.

ASN’s Role: Challenges 4 and 5

Challenge 4 — Cable Protection | Rosenort Area, Baltic Sea

The objective of Challenge 4 was unambiguous: locate, identify, track and report any anomaly on or at a real subsea power cable, as quickly as possible, with sufficient precision to enable a response.

ASN contributed its OptoDAS system as a primary sensing backbone for its partner consortia in this challenge. Distributed Acoustic Sensing technology transforms an existing fibre-optic cable into a continuous, dense array of virtual microphones — capable of detecting acoustic and vibrational events along the cable route from a single interrogation unit onshore, with no additional subsea hardware required.

Key performance highlights from Challenge 4:

Detection range: Acoustic events reliably detected and localized along the full cable route across the Baltic from a single interrogation unit, within the constraints of the Baltic sea environment.
Threat classification: OptoDAS distinguished between background maritime traffic, anchor drag, trawling activity, and deliberate interference events with high confidence, feeding actionable alerts to the C2 platform in near real time.
Data output: Georeferenced bearing and distance data was formatted and delivered to consortium C2 systems, enabling rapid integration into the shared Common Operational Picture.
Fusion performance: OptoDAS acoustic alerts were successfully cross-correlated with AIS data, hydroacoustic sonar contacts, and USV optical imagery contributed by consortium partners, validating the end-to-end sensor-to-picture pipeline.

The result: A coherent, continuously updated operational picture of the cable corridor, with threat notifications reaching the maritime control centre within seconds of event onset.

Challenge 5 — Platform Protection | Nienhagen Area, Baltic Sea

Challenge 5 placed consortia around a simulated offshore converter platform in a restricted zone, tasking them with detecting, tracking and reporting both above- and below-surface intrusions — including placement of explosives proxies — in a dynamic, congested maritime environment.

For this platform protection scenario, ASN contributed to the distributed sensing architecture deployed around the platform structure. Specifically, ASN employed its super-sensitive, DAS interrogated, fibre-optic based, passive hydrophone alongside a DAS interrogated perimeter of security around the platform. This cutting-edge sensor was adapted to monitor the platform’s surroundings, providing unmatched early-warning detection of any approaching attempt on the platform’s perimeter. This passive hydrophone capability seamlessly complemented the USV-based surface surveillance and sonar sub-surface picture provided by consortium partners.

Key performance highlights from Challenge 5:

Perimeter monitoring: Continuous, real-time monitoring of the platform’s surrounding utilizing fibre optic cables and high-sensitivity passive hydrophones to detect incoming threats.
Zero missed events: All simulated intrusion events during the exercise window were detected and reported within the defined alert latency thresholds.
Multi-domain integration: OptoDAS and hydrophone alerts were successfully fused with broader consortium sonar data, AUV imagery, and USV sensor feeds, demonstrating ASN’s ability to operate as a vital node in a larger, heterogeneous sensing architecture — without requiring a proprietary C2 suit.

OptoDAS: The Technology Behind the Performance

OptoDAS is ASN’s flagship Distributed Acoustic Sensing product, developed from decades of fibre-optic sensor development and submarine network engineering expertise. It uses a coherent laser source to transform standard single-mode fibre into a continuous sensing array, capable of measuring acoustic, seismic and vibrational signals at every metre of a cable’s length — simultaneously and in real time.

Critically, OptoDAS can operate on existing infrastructure and also the hydrophone array can be deployed at low cost, enabling passive and covert acoustic monitoring modes. In a contested Baltic environment, this is operationally significant.

What SeaSEC Confirmed

SeaSEC DATA2SEA was not designed to validate what vendors already know about their own products. It was designed to expose the gaps. The multi-vendor, adversarially evaluated format is the most honest test available short of a declared naval operation.

ASN’s takeaways from the two-week exercise are clear:

DAS works at scale in operational conditions. The Baltic environment — with its shallow water, complex acoustics, heavy commercial shipping and variable seabed geology — is one of the more challenging for acoustic sensing. OptoDAS performed consistently throughout.
Data fusion is the real challenge — and ASN is ready for it. Having a sensor that detects is necessary but not sufficient. SeaSEC demanded that every sensor’s output contribute to a shared picture. ASN’s investment in standards-based data output formats paid off: OptoDAS data was ingested smoothly into the consortia C2 platforms.
CUI protection requires a systems approach, not individual products. The most effective solutions at SeaSEC were those that combined complementary sensing modalities into a coherent architecture. ASN’s fibre sensing capability is designed to be a foundational layer in exactly that kind of architecture — providing long-range, continuous, passive coverage as the baseline upon which shorter-range, higher-resolution sensors can cue and respond.

Looking Forward

The threats to Critical Underwater Infrastructure in the Baltic and North Sea are not hypothetical. Since 2022, Europe has witnessed a series of incidents against subsea pipelines, communications cables and offshore energy installations that have elevated CUI protection to the top of the NATO maritime security agenda.

ASN’s participation in SeaSEC DATA2SEA 2026 is part of a broader commitment to ensuring that our technology is not only technically capable but operationally validated, interoperable, and ready for deployment within the defence and security frameworks that European navies and coast guards are building today.

For procurement discussions, technical briefings or consortium partnership enquiries arising from our SeaSEC participation: