Leti, a research institute of CEA Tech, has developed a prototype of highly miniaturized, portable optical sensors for chemical detection of gas. The next-generation, centimeter-size photo-acoustic sensors are based on mid-infrared photonic integrated circuits (MIR PICs). These silicon PICs, created by integrating optical circuits onto millimeter-size silicon chips, make extremely robust miniature systems, in which discrete components are replaced by on-chip equivalents. This makes them easier to use and reduces their cost dramatically, expected at least by a factor of 10.
Developed by the European Commission’s REDFINCH Project headed by CEA-Leti, the prototype photo acoustic sensors were fabricated on a CMOS line in a miniaturized silicon photo-acoustic cell, which allows extreme integration. In demonstrations, the sensors are said to match the performance of bulky commercial gas-sensing systems commonly available today. They are targeted at applications such as process gas analysis in refineries, gas leak detection in petrochemical plants and pipelines, and protein analysis in liquids for the dairy industry.
The sensors consume less than 10W in continuous operation. They can be operated in a slow pulse-burst mode for infrastructure monitoring and when leaks are detected, the pulse frequency of the sensor automatically increases. This keeps average power consumption very low, so the sensors can be battery-operated for more than a year or powered by an ambient energy harvester, e.g. a solar cell.