Periodic Reporting for period 3 - REDFINCH (mid infraREd Fully Integrated CHemical sensors)
Reporting period: 2020-06-01 to 2021-12-31
The REDFINCH project developed the next generation of miniaturised, portable Mid-IR optical chemical sensors.
The REDFINCH consortium was made of 8 European Research Institutes and Companies, all undertaking R&D on high performance, cost effective chemical sensors, based on Si Photonic Integrated Circuits (MIR Si PICs). Si PICs create robust miniature systems, in which on-chip components replace discrete equivalents.
The project addressed the challenge of implementing photonics components in MIR band where many chemical and biological species have strong absorption fingerprints. Detecting and measuring their concentration in gas or liquids is crucial for applications such as health monitoring and diagnosis, detection of biological compounds, monitoring of toxic gases, etc.
Several major exploitable results were obtained:
• A Multi-wavelength MIR laser module: the output of a multi-wavelengths QCL array is combined by microlens array into a single spot. An electrical multiplexer allows to choose which laser is powered. This extended source allows detecting several molecules;
• A miniaturized QCL + photoacoustic-based Process Gas Analyser to detect carbon monoxide impurities in hydrogen down to sub-ppm level;
• A Leak Detector with Integrated PAS Cell. The leak detector uses a miniature Si PA cell to detect methane leak down to sub-ppm level. Two version were made: one for stationary monitoring and the other for and mobile leak detection;
• PIC-based Liquid Analyser: this sensor measuring the protein content in liquids is based on a Mid-IR Mach-Zehnder Interferometer detector made in PIC technology and works in the 6.0-6.5 µm spectral range;
• Novel MIR lasers grown on Si: we developed a robust and reproducible process for the growth of III-V layers on on-axis (001) Si together with a full process for the fabrication of the prototype devices. These developments allowed the first demonstration of MIR lasers epitaxially grown on on-axis (001) Si substrates;
• Fabrication of QCL in IC/MEMS foundries via III-V stack transfer on Si: the fabrication of QCLs using a fully compatible CMOS process has been demonstrated. Process development for high reliability and yield is still ongoing in the view of a possible technology transfer to a foundry.
The REDFINCH consortium was made of 8 European Research Institutes and Companies, all undertaking R&D on high performance, cost effective chemical sensors, based on Si Photonic Integrated Circuits (MIR Si PICs). Si PICs create robust miniature systems, in which on-chip components replace discrete equivalents.
The project addressed the challenge of implementing photonics components in MIR band where many chemical and biological species have strong absorption fingerprints. Detecting and measuring their concentration in gas or liquids is crucial for applications such as health monitoring and diagnosis, detection of biological compounds, monitoring of toxic gases, etc.
Several major exploitable results were obtained:
• A Multi-wavelength MIR laser module: the output of a multi-wavelengths QCL array is combined by microlens array into a single spot. An electrical multiplexer allows to choose which laser is powered. This extended source allows detecting several molecules;
• A miniaturized QCL + photoacoustic-based Process Gas Analyser to detect carbon monoxide impurities in hydrogen down to sub-ppm level;
• A Leak Detector with Integrated PAS Cell. The leak detector uses a miniature Si PA cell to detect methane leak down to sub-ppm level. Two version were made: one for stationary monitoring and the other for and mobile leak detection;
• PIC-based Liquid Analyser: this sensor measuring the protein content in liquids is based on a Mid-IR Mach-Zehnder Interferometer detector made in PIC technology and works in the 6.0-6.5 µm spectral range;
• Novel MIR lasers grown on Si: we developed a robust and reproducible process for the growth of III-V layers on on-axis (001) Si together with a full process for the fabrication of the prototype devices. These developments allowed the first demonstration of MIR lasers epitaxially grown on on-axis (001) Si substrates;
• Fabrication of QCL in IC/MEMS foundries via III-V stack transfer on Si: the fabrication of QCLs using a fully compatible CMOS process has been demonstrated. Process development for high reliability and yield is still ongoing in the view of a possible technology transfer to a foundry.
The REDFINCH project aimed at developing a new generation of miniaturized optical sensors working in the MIR range.
For the integration on Si, technologies for homogeneous and heterogeneous QCL and ICL sources were developed. The main objective was to lower the cost of these sources, making them widely available. The cost of MIR lasers is related to 1) epitaxy, 2) manufacturing yield, 3) packaging. The project addressed all these topics paving the way toward the reduction of the cost/price of these devices. Even if the industrialization falls beyond the scope of Redfinch project, it seems plausible that a diminution by a factor of 10 seems achievable in the short term.
The second building block for a chemical sensor is the detector. Within Redfinch two types of detection were developed:
• A photoacoustic cell of a few dozen mm² fully integrated in Si showing performances suitable for applications requiring small footprint and high performance;
• A Mach-Zehnder Interferometer fabricated in PIC technology for direct detection in liquids.
To complement sources and detectors, we developed and matured technologies for MIR PICs fabrication. To adapt the performances to each application, different platforms were investigated: SiGe/Si, SiGe/SiN, Si/SiO2. PIC wafers are now been fully fabricated and include a variety of gratings, ring resonators and photonic crystals, which were be used in the first instance, to implement a variety of demonstrators.
With the components developed by Redfinch we made several demonstrators and that are now further developed and validated by the industrial partners for a possible industrialisation and commercialisation.
Finally, we implemented a strong communication and dissemination policy by setting up a project website, by generating flyers and videos presenting the project’s activity and by presenting project results to conferences and/or the in peer-reviewed papers (more than 30 papers supported by the project)
For the integration on Si, technologies for homogeneous and heterogeneous QCL and ICL sources were developed. The main objective was to lower the cost of these sources, making them widely available. The cost of MIR lasers is related to 1) epitaxy, 2) manufacturing yield, 3) packaging. The project addressed all these topics paving the way toward the reduction of the cost/price of these devices. Even if the industrialization falls beyond the scope of Redfinch project, it seems plausible that a diminution by a factor of 10 seems achievable in the short term.
The second building block for a chemical sensor is the detector. Within Redfinch two types of detection were developed:
• A photoacoustic cell of a few dozen mm² fully integrated in Si showing performances suitable for applications requiring small footprint and high performance;
• A Mach-Zehnder Interferometer fabricated in PIC technology for direct detection in liquids.
To complement sources and detectors, we developed and matured technologies for MIR PICs fabrication. To adapt the performances to each application, different platforms were investigated: SiGe/Si, SiGe/SiN, Si/SiO2. PIC wafers are now been fully fabricated and include a variety of gratings, ring resonators and photonic crystals, which were be used in the first instance, to implement a variety of demonstrators.
With the components developed by Redfinch we made several demonstrators and that are now further developed and validated by the industrial partners for a possible industrialisation and commercialisation.
Finally, we implemented a strong communication and dissemination policy by setting up a project website, by generating flyers and videos presenting the project’s activity and by presenting project results to conferences and/or the in peer-reviewed papers (more than 30 papers supported by the project)
Despite the importance of the MIR band for a wide range of application areas, available MIR sensing systems tend to be large and delicate, limiting their commercially deployment.
REDFINCH used the power of PICs technology joined to hybrid and monolithic integration of III-V materials on Si to create high performance, cost effective sensors. Si photonics leverages the advantages of high performance CMOS technology, providing low cost mass manufacture, high fidelity reproduction of designs, and access to high refractive index contrasts that enable high performance nanophotonics. In the approach followed by Redfinch, co-integration makes extremely robust systems where discrete components are replaced by on-chip equivalents and gives a simultaneous improvement in ease of use and in cost reduction.
REDFINCH made 3 miniaturized chemical sensor demonstrators based on photonics devices for:
PROCESS GAS ANALYSIS
With the increasing concerns on the use of carbonated resources, H2 emerges as alternative fuel for emissionless automotive applications. Monitoring of H2 purity is one of the major concerns for fuel cell operation because pollutants, and in particular CO, can poison them. The continuous monitoring and fast response time enabled by the REDFINCH sensor fits the requirement of H2 quality monitoring.
GAS LEAK DETECTION
The use of liquefied natural gas (LNG) is steadily increasing worldwide. To establish reliable gas supply all around Europe a grid of pipes and reservoirs has been made. This gas grid also serves as a storage to compensate for the increasing share of fluctuating renewable energies. Since CH4, the main component of LNG, is a major greenhouse gas, infrastructure needs continuous monitoring for leakages, especially as it ages. Redfinch developed a miniaturized mobile leak detector based on PICs associated to Photo-Acoustic Sensors made in Si. Compared to existing sensors, this sensor is smaller, more specific and sensitive enough for reliable detection of leakages.
PROTEIN ANALYSIS IN LIQUIDS FOR THE DAIRY INDUSTRY
Milk production and processing is a multi-billion Euro industry. Farmers want to monitor the milk to better understand the health of their cattle and manage the herd. Dairies need to monitor the milk as the farmers are paid by the quality. Processors need to monitor the milk to control the quality their products after transformation. Today, nearly all milk monitoring is done offline and state-of-the-art milk analysers cannot differentiate between different types of proteins, they can only quantify the total protein content in a sample. The Redfinch protein sensor is small and portable and it can make milk analysis at the collection, allowing efficient redirection and distribution of the consignment.
REDFINCH used the power of PICs technology joined to hybrid and monolithic integration of III-V materials on Si to create high performance, cost effective sensors. Si photonics leverages the advantages of high performance CMOS technology, providing low cost mass manufacture, high fidelity reproduction of designs, and access to high refractive index contrasts that enable high performance nanophotonics. In the approach followed by Redfinch, co-integration makes extremely robust systems where discrete components are replaced by on-chip equivalents and gives a simultaneous improvement in ease of use and in cost reduction.
REDFINCH made 3 miniaturized chemical sensor demonstrators based on photonics devices for:
PROCESS GAS ANALYSIS
With the increasing concerns on the use of carbonated resources, H2 emerges as alternative fuel for emissionless automotive applications. Monitoring of H2 purity is one of the major concerns for fuel cell operation because pollutants, and in particular CO, can poison them. The continuous monitoring and fast response time enabled by the REDFINCH sensor fits the requirement of H2 quality monitoring.
GAS LEAK DETECTION
The use of liquefied natural gas (LNG) is steadily increasing worldwide. To establish reliable gas supply all around Europe a grid of pipes and reservoirs has been made. This gas grid also serves as a storage to compensate for the increasing share of fluctuating renewable energies. Since CH4, the main component of LNG, is a major greenhouse gas, infrastructure needs continuous monitoring for leakages, especially as it ages. Redfinch developed a miniaturized mobile leak detector based on PICs associated to Photo-Acoustic Sensors made in Si. Compared to existing sensors, this sensor is smaller, more specific and sensitive enough for reliable detection of leakages.
PROTEIN ANALYSIS IN LIQUIDS FOR THE DAIRY INDUSTRY
Milk production and processing is a multi-billion Euro industry. Farmers want to monitor the milk to better understand the health of their cattle and manage the herd. Dairies need to monitor the milk as the farmers are paid by the quality. Processors need to monitor the milk to control the quality their products after transformation. Today, nearly all milk monitoring is done offline and state-of-the-art milk analysers cannot differentiate between different types of proteins, they can only quantify the total protein content in a sample. The Redfinch protein sensor is small and portable and it can make milk analysis at the collection, allowing efficient redirection and distribution of the consignment.