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Ultra low-power integrated optical sensor systems for networked environmental multichannel gas Sensing

Periodic Reporting for period 1 - ULISSES (Ultra low-power integrated optical sensor systems for networked environmental multichannel gas Sensing)

Reporting period: 2019-01-01 to 2020-12-31

Gas sensors are already widely used in industry and agriculture, to ensure safety of personnel and to monitor and automate processes. However, the rising public awareness of the importance of urban indoor and outdoor air quality is now driving a demand for new accurate, low-cost and mobile gas sensor technology. Optical gas sensors are sensitive and robust, offering the highest stability and specificity in the market. However, their current cost, power consumption and size hinder them from being widely employed by the general public. ULISSES technology will enable compact, low-cost and low-power gas sensor nodes to be networked for comprehensive and real time monitoring of air quality in urban areas. This new approach will provide valuable information to city planners, employers, landlords and the general public to ensure a healthy indoor and outdoor environment.
The project partners collaborate in combining silicon photonics with 2D materials to enable fully integrated optical gas sensing nodes for the Internet of Things (IoT) that can be manufactured in large volumes at low cost and achieve performance improvements in terms of size and power consumption. For more details, please refer to the introductory ULISSES flyer, video and webinar available on
Two types of 2D-material-based photodetectors have been integrated onto Si waveguides and characterized, one graphene-based and one PtSe2-based. 1D Pt light emitters have been integrated and demonstrated on waveguides. Waveguide-integrated tuneable wavelength filters have been demonstrated. All these parts have currently been demonstrated and characterized separately but with fully compatible processes. In the next step they will be integrated together on the same wafer.
Wafer-scale fabrication methods have successfully been demonstrated for the most critical steps: graphene synthesis, transfer, patterning, and protection, as well as PtSe2 synthesis. These are considered the most challenging parts when it comes to wafer scale production, since the other fabrication steps are well known from high volume MEMS and silicon photonics production.
A testbed architecture, including wireless sensor hardware and a central database, has been implemented based on traditional NDIR gas sensing technology. Machine Learning algorithms for gas sensor calibration and drift compensation using node-to-node communication have been developed and demonstrated.
Current optical gas sensors are assembled from multiple components into a package of a few cm3 volume and consume power on the order of 100 mW. By leveraging recent breakthroughs of the ULISSES partners on waveguide-integrated 2D-materials-based photodetectors, 1D nanowire mid-IR emitters, and mid-IR waveguide-based gas sensing, ULISSES targets a three-order-of-magnitude reduction in sensor power consumption, thus permitting maintenance-free battery powered operation for the first time. Furthermore, ULISSES will implement a new edge-computing self-calibration algorithm that leverages node-to-node communications to eliminate the main cost driver of low-cost gas sensor fabrication and maintenance.
This development will enable personal gas sensors embedded in wearable devices, as well as installed in public infrastructure, such as in street lighting, on buses and in taxis, or even in small unmanned aerial vehicles. The new technology aims to empower the general public to monitor and put demands on their air quality.
To ensure our sensors meet the needs and expectations of future users we have established a stakeholder forum which regularly accompanies the project, providing valuable feedback and ideas how to tackle bottlenecks they currently face.