Frequency-agile lasers for photonic sensing

Project Information

FORTE

Grant agreement ID: 101137084

DOI

10.3030/101137084

EC signature date 18 September 2023

Start date 1 October 2023

End date 30 September 2026

Funded under

• The European Innovation Council (EIC)

Total cost

€ 1 966 218,75

EU contribution

€ 1 966 218,75

Coordinated by

THALES
France

Periodic Reporting for period 1 - FORTE (Frequency-agile lasers for photonic sensing)

Reporting period: 2023-10-01 to 2024-09-30

Summary of the context and overall objectives of the project

The FORTE project is a collaborative initiative aimed at revolutionizing photonic coherent sensing applications by developing photonic chip-based laser systems. Photonic sensing, which relies on the interaction of light with matter to measure various physical quantities, is a critical component in numerous sectors, including infrastructure monitoring, environmental sensing, telecommunications, smart cities and autonomous vehicles. However, the current laser sources used in these applications often face limitations such as bulkiness, high cost, limited tuning capabilities, and scalability issues, which hinder widespread adoption and performance optimization.

The project specifically focuses on enhancing distributed fiber optic sensing (DFOS) and frequency-modulated continuous-wave (FMCW) LiDAR systems. DFOS is essential for real-time monitoring of infrastructures like pipelines, bridges, and railways, enabling predictive maintenance and increased safety. FMCW LiDAR is crucial for high-resolution and long-range 3D imaging, which is a cornerstone technology for autonomous vehicles and aerial mapping. By creating frequency-agile lasers with ultra-narrow linewidths and broadband linear actuation, FORTE aims to significantly improve the capabilities and reliability of these sensing systems. The overarching objective of FORTE is to develop scalable, cost-effective laser sources that can be seamlessly integrated into existing photonic and optical platforms. This involves designing and fabricating silicon nitride (Si₃N₄) photonic integrated circuits (PICs) with integrated micro-electro-mechanical systems (MEMS) actuators for precise frequency tuning.

Additionally, the project emphasizes the use of an all-European supply chain, sourcing III-V gain chips from European manufacturers, and fostering collaborations among leading European research institutions and companies. End users of the technology will perform demonstrations of applications in relevant environments to reach a high technology readiness level. All partners will work on the standardization of the technology and its certification for telecom and fiber sensing industries.

By doing so, FORTE not only aims to advance technological innovation but also to strengthen Europe's competitiveness and sovereignty in the photonics industry. The project seeks to establish automated assembly processes and validation protocols aligned with industry standards, paving the way for commercialization and broad deployment across various sectors, thereby accelerating the expansion of the photonics market and contributing to the growth of the European photonics industry.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

In the first reporting period (RP1), the FORTE project achieved significant progress across several work packages, including:

• Laser Concepts Development (WP2, led by EPFL): Two laser concepts meeting ambitious specifications were designed and fabricated, incorporating Si₃N₄ photonic integrated circuits (PICs) with MEMS-based actuators. EPFL and DEEPLIGHT (DLT) characterized prototypes, measuring key parameters like linewidth (1 Hz), tuning range (250 MHz+), actuation bandwidth (400 kHz), output power (15 mW+ at 1545 nm), and phase noise. Results, prepared for publication, highlight exceptional performance.

• Automated Assembly Machine (WP3, led by ficonTEC): ficonTEC (FIC) designed and installed an automated machine at DLT’s R&D lab for photonic packaging. This system reduces assembly time to under 30 minutes and enhances precision for scalable production.

• DFOS Validation (WP4, led by Aragon Photonics Labs): Validation efforts include test procedures and evaluation testbeds aligned with SEAFOM (Subsea Fiber Optic Monitoring) standards, ensuring lasers meet industry requirements for DFOS integration.

• Characterization for FMCW LiDAR (WP5, led by Thales): Initial characterization of lasers shipped by DLT to Thales (THA) included phase noise, intensity noise, and tuning, paving the way for high-resolution, long-range 3D imaging.

• Dissemination & Business Development (WP6, led by DLT): The project launched a website and a dissemination plan, boosting visibility at trade shows (Photonics West 2024, OFC 2024, ECOC 2024). Prototype lasers were shipped to industry leaders, advancing commercialization.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The FORTE project has achieved several results beyond the state of the art of photonic sensing technologies:

• Ultra-Narrow Linewidth and High Tuning Range Lasers: We have developed a frequency-agile laser that outperforms legacy laser systems, effectively overcoming the traditional trade-off between ultra-low-noise and laser tuning capabilities. Our laser demonstrates the optical power up to 30 mW and the frequency noise lower than that of a fiber laser, with an exceptionally low integrated linewidth of few kHz and a Lorentzian linewidth of few Hz. The laser architecture supports fast frequency actuation enabled by the stress-optic effect. Monolithic integration of piezo-electric actuators with photonic waveguides facilitates linear refractive index changes over a broad bandwidth up to the MHz range, with our implementation demonstrating a flat actuation bandwidth of 400 kHz. This performance enables crucial linear frequency modulation sweeps essential for coherent sensing, achieving residual nonlinearity of 0.08%, a capability only realized after photonic packaging.

• Integration of Large MEMS Actuators: EPFL demonstrated the integration of large MEMS-based piezoelectric actuators directly onto Si₃N₄ PICs. These actuators, among the largest fabricated on a photonic integrated circuit. MEMS devices generally range in size from 20 microns to 1 mm. For comparison, surface acoustic wave AlN MEMS filters and AlN bulk acoustic wave MEMS filters, commonly used in consumer communication devices, have dimensions on the order of hundreds of micrometers. Actuators of FORTE lasers covers 20% of the chip surface and supports MHz-level bandwidth, which significantly exceeds the actuation bandwidth of most large MEMS structures. A laser with such a MEMS actuator becomes a new tool for research and industrial applications eliminating the need for high-speed external optical frequency shifters (acousto-optic or electro-optic).

• Industrial Impact: The project's contributions to integrated photonics include pioneering frequency-agile, low-noise lasers and integrating large MEMS actuators on PICs. These advancements open new possibilities for applications such as atomic clocks and quantum technologies. DLT is actively reaching out to early adopters of the technology starting pilot projects and adapting the laser performance to the market needs. Industrially, the project positions FORTE as a significant contributor to the photonics sector, strengthening Europe's competitiveness through an all-European supply chain.

In summary, the FORTE project has developed laser technologies that not only improve existing photonic sensing applications but also open new avenues in quantum technologies, high-speed communication networks, and environmental monitoring. The innovations achieved go beyond the current state of the art, providing scalable, high-performance laser sources essential for the next generation of photonic technologies, with significant scientific, economic, and societal impacts.

FORTE Photonic Integrated Circuits, the core of FORTE lasers