Climate change is the major challenge of our times. For the EU to reach a zero-carbon economy by 2050, the regulation and enforcement of greenhouse gas (GHG) emissions needs to expand rapidly. Carbon dioxide represents around the 80% of the GHG emissions from human activities and its concentration will reach the historical mark of 420 ppm in 2023. Gas sensors can help to identify those emissions, especially those based on optical techniques that can provide sensitivities in the part per million level (ppm). The aim of this project is to develop compact, energy efficient and high sensitivity sensors based on photonic integrated circuits (PICs).
The starting point of this project are the results obtained in the previous project LIDERA (RTI2018-094118-B-C21). There, we demonstrated carbon dioxide sensing with a differential absorption LiDAR (DIAL) transmitter based on a PIC. The measurements were performed in a fiber setup using a connectorized gas cell. We consider that TRL3 was achieved. However, its sensitivity, accuracy and reproducibility were not tested. Our aim on this proposal is to develop further this technology though developing a transmitter module based on an enhanced version of the PIC and low-cost electronics.
The PIC will be enhanced in several aspects. Firstly, we will design the new version of the PIC to reduce coupled-cavity effects observed in the first version. Secondly, we will enhance the wavelength stabilization and locking subsystem including a phase modulator to implement the Pound-Drever-Hall technique. Thirdly, we will optimize laser’s output power and linewidth. And finally, we will use Mach-Zehnder modulators instead of electro-absorption modulators to be able to modulate intensity or phase, gaining flexibility. The PIC will be packaged in a submodule providing optical and electrical access. The PIC will be flexible enough to be applied to other techniques or systems in addition to DIAL that will be explored too. We aim analysing the technical requirements of different optical based gas sensing techniques to find new possible applications of the PIC. On the other hand, we will develop electronic submodules based on low-cost electronic components for driving and controlling the PIC, temperature controlling, generating/acquiring RF modulation signals and implementing the electronic part of the wavelength stabilization subsystem. Both PIC and electronic submodules will be assembled in a compact, energy efficient and robust transmitter module.
We aim to validate the developed module in the lab using a optical gas sensors testing platform that will be developed during the project to reach TRL4. The testing platform will be based on a computer-controlled gas system that will permit different measurement conditions. We will obtain a minimum viable product (MVP) or prototype that will be shown to different companies that could use it for improving their current gas sensing systems or create new products based on it. In addition, they will help us out to validate the transmitter in a relevant industrial environment for reaching TRL5.