Periodic Reporting for period 1 - COMPAS (CO INTEGRATION OF MICROELECTRONICS AND PHOTONICS FOR AIR AND WATER SENSORS)
Reporting period: 2024-01-01 to 2025-06-30
To make photonic sensors as widespread as electronic ones, challenges in size, cost, and weight must be addressed. Wafer-level silicon photonics offers a breakthrough by enabling compact, low-cost photonic solutions. Among these, Photonic Integrated Circuits (PICs) stand out as a versatile platform for light manipulation. By guiding light through micron- and nanometre-scale waveguides, PICs can deliver advanced sensing capabilities that rival bulkier, more expensive systems.
Beyond their role in the green and digital transition, PICs are vital to Europe's push for technological sovereignty, aligning with the European Chips Act. Following semiconductor supply disruptions during the Covid-19 pandemic, the EU set a goal to double its market share to 20% by 2030. This includes scaling up silicon photonics research, a priority heightened by geopolitical shifts such as the war in Ukraine and tensions with China.
The COMPAS project aims to advance photonics–microelectronics integration by developing a novel, wafer-level multi-analyte PIC sensor platform (PSP) using a chiplet approach. Its goal is to create a compact, affordable, and highly sensitive PSP for monitoring air and water, integrating light sources, detectors, and electronic ICs for on-chip signal processing.
To achieve this, partners will combine their expertise across several technologies. Optically active coatings—tailored to specific analytes—will be applied atop waveguide interferometers, with microfluidics delivering samples. Analyte capture alters the coating’s refractive index, changing light intensity detected by photodetectors. These signals will be processed using innovative low-power analog electronics.
A baseline version will use a mix of custom and standard components with advanced packaging. A fully integrated variant will feature waveguide interferometers atop monolithically integrated photodiodes, with a custom single-mode laser diode flip-chip assembled onto the waveguide. To boost sensitivity, optical metasurfaces will be developed for enhanced light coupling.
The final PSP will be tested in three scenarios:
1. VOC detection for identifying pest-infected plants (with EU project PurPest)
2. Water quality monitoring, focusing on estrogen and PFAS
3. Air quality sensing, targeting NOx and O₃
Beyond their role in the green and digital transition, PICs are vital to Europe's push for technological sovereignty, aligning with the European Chips Act. Following semiconductor supply disruptions during the Covid-19 pandemic, the EU set a goal to double its market share to 20% by 2030. This includes scaling up silicon photonics research, a priority heightened by geopolitical shifts such as the war in Ukraine and tensions with China.
The COMPAS project aims to advance photonics–microelectronics integration by developing a novel, wafer-level multi-analyte PIC sensor platform (PSP) using a chiplet approach. Its goal is to create a compact, affordable, and highly sensitive PSP for monitoring air and water, integrating light sources, detectors, and electronic ICs for on-chip signal processing.
To achieve this, partners will combine their expertise across several technologies. Optically active coatings—tailored to specific analytes—will be applied atop waveguide interferometers, with microfluidics delivering samples. Analyte capture alters the coating’s refractive index, changing light intensity detected by photodetectors. These signals will be processed using innovative low-power analog electronics.
A baseline version will use a mix of custom and standard components with advanced packaging. A fully integrated variant will feature waveguide interferometers atop monolithically integrated photodiodes, with a custom single-mode laser diode flip-chip assembled onto the waveguide. To boost sensitivity, optical metasurfaces will be developed for enhanced light coupling.
The final PSP will be tested in three scenarios:
1. VOC detection for identifying pest-infected plants (with EU project PurPest)
2. Water quality monitoring, focusing on estrogen and PFAS
3. Air quality sensing, targeting NOx and O₃
In this period the project has worked on the specifications and requirements for the individual components that will make up the COMPAS PIC sensor. This work was done to maximise the seamlessness of the integration of the separate components and technologies. This comprised the form factor of the PIC chip and laser, the optical properties required for the sensing layers, the expected output of the integrated photodetectors, amongst others.
A lot of effort has been made into developing the six different sensing layers and doing preliminary testing of their response to the target analytes for the COMPAS PIC sensor. Promising candidates have been deposited on waveguides for initial testing of propagation characteristics.
A final waveguide design has been finalised and wafers with baseline chips (waveguides only) have been fabricated and are ready for testing in a free space setup. The final design for the chips with the fully integrated photodetector has also been finalised and fabrication has been initiated. The laser diode (PCSEL) has been designed and the first round of diodes have been fabricated. Some more optimisation is needed to achieve desirable output and the results are promising.
A microfluidic platform using Electro-Wetting On Dielectrics (EWOD) principles is under development at FBK. The module aims at the integration of the sample management module on the sensor unit in a compact system. Basic structures were designed and successfully fabricated and are currently under testing and optimisation. Techniques for a flexible and robust assembly procedure of the modules are under optimization.
The analogue electronics for photodetector readout and analysis has been designed, simulated and optimised. Breadboard versions with COTS components have been tested and show promising results. The design will be implemented in an integrated design of a PCB.
A lot of effort has been made into developing the six different sensing layers and doing preliminary testing of their response to the target analytes for the COMPAS PIC sensor. Promising candidates have been deposited on waveguides for initial testing of propagation characteristics.
A final waveguide design has been finalised and wafers with baseline chips (waveguides only) have been fabricated and are ready for testing in a free space setup. The final design for the chips with the fully integrated photodetector has also been finalised and fabrication has been initiated. The laser diode (PCSEL) has been designed and the first round of diodes have been fabricated. Some more optimisation is needed to achieve desirable output and the results are promising.
A microfluidic platform using Electro-Wetting On Dielectrics (EWOD) principles is under development at FBK. The module aims at the integration of the sample management module on the sensor unit in a compact system. Basic structures were designed and successfully fabricated and are currently under testing and optimisation. Techniques for a flexible and robust assembly procedure of the modules are under optimization.
The analogue electronics for photodetector readout and analysis has been designed, simulated and optimised. Breadboard versions with COTS components have been tested and show promising results. The design will be implemented in an integrated design of a PCB.
SINTEF reported in 2024 the deposition of ultra-low loss Al2O3 film deposited by ALD. The loss was 0.5 dB/cm, which is the lowest loss Al2O3 reported to date.
ICMPP has developed still unknown pristine hyperbranched polymers or linear polymers with intrinsic microporosity or conjugated structure bearing gas-philic groups (e.g. phenanthroline, porphyrin, imine macrocycles) for use as functional coatings for O3, NO2, toluene or VOCs detection with enhanced gas sensitivity and selectivity compared to commonly used polymers for gas detection. Apart from this, porous MOFs or MXene fillers were integrated in adequate polymer matrices enabling to address the delicate balance between sensitivity and selectivity, as well as transparency and scattering through the synergy of the parts. This innovative approach was scarcely exploited till now, if not at all, to apply polymer-based sensing layers on waveguide sensors.
At Fraunhofer IAP, a novel photonic amplification material was developed and characterised. It consists of a primer layer to ensure durable attachment to the waveguide surface, a responsive hydrogel layer and a layer of high refractive index particles. Upon exposure to the analyte, the hydrogel will swell and thus push the high refractive index particles out of the evanescent field. This displacement of the particles will result in a significant signal amplification effect.
ICMPP has developed still unknown pristine hyperbranched polymers or linear polymers with intrinsic microporosity or conjugated structure bearing gas-philic groups (e.g. phenanthroline, porphyrin, imine macrocycles) for use as functional coatings for O3, NO2, toluene or VOCs detection with enhanced gas sensitivity and selectivity compared to commonly used polymers for gas detection. Apart from this, porous MOFs or MXene fillers were integrated in adequate polymer matrices enabling to address the delicate balance between sensitivity and selectivity, as well as transparency and scattering through the synergy of the parts. This innovative approach was scarcely exploited till now, if not at all, to apply polymer-based sensing layers on waveguide sensors.
At Fraunhofer IAP, a novel photonic amplification material was developed and characterised. It consists of a primer layer to ensure durable attachment to the waveguide surface, a responsive hydrogel layer and a layer of high refractive index particles. Upon exposure to the analyte, the hydrogel will swell and thus push the high refractive index particles out of the evanescent field. This displacement of the particles will result in a significant signal amplification effect.