CEA-Leti prototypes silicon photonics-based mid-IR optical chemical sensor for portable devices

In a paper ‘Miniaturization of Mid-IR Sensors on Si: Challenges and Perspectives’ presented at SPIE Photonics West 2019 in San Francisco (5–7 February), micro/nanotechnology R&D center CEA-Leti of Grenoble, France reported that it has prototyped a next-generation optical chemical sensor using mid-infrared silicon photonics that can be integrated in smartphones and other portable devices.

Mid-IR chemical sensors operate in the 2.5-12µm spectral range. In less than a decade, chemical sensing has become a key application for silicon photonic devices because of the growing potential of spectroscopy, materials processing and chemical & biomolecular sensing, as well as security and industrial applications. Measurement in this spectral range provides highly selective, sensitive and unequivocal identification of chemicals.

Leti’s coin-size, on-chip, Internet of Things (IoT)-ready sensors combine high performance and low power consumption and enable consumer uses such as air-quality monitoring in homes and vehicles, and wearable health and well-being applications. Industrial uses include real-time air-quality monitoring and a range of worker-safety applications.

Mid-IR optical sensors currently available on the market are typically bulky, shoebox-size or bigger, and cost more than €10,000. Meanwhile, existing miniaturized and inexpensive sensors cannot meet consumer requirements for accuracy, selectivity and sensitivity, says Leti. While size and price are not the most critical concerns for industrial applications, bulky and costly optical sensors represent a major barrier for consumer applications, which require wearability and integration in a range of portable devices.

“Mid-IR silicon photonics has enabled creation of a novel class of integrated components, allowing the integration at chip level of the main building blocks required for chemical sensing,” says lead author Sergio Nicoletti. “Key steps in this development extend the wavelength range available from a single source, handling and routing of the beams using photonic-integrated circuits, and the investigation of novel detection schemes that allow fully integrated on-chip sensing.”

CEA-Leti’s development combined three existing technologies necessary to produce on-chip optical chemical sensors:

integrating a mid-IR laser on silicon;
developing photonic integrated circuits (PICs) in the mid-IR wavelength range; and
miniaturizing a photo-acoustic detector on silicon chips.

“While other R&D efforts have had similar results, our project’s key achievement is the use of tools and processes typical of the IC and MEMS industries,” says Nicoletti. “Our focus on the choice of the architectures and processes, and the specific linkage of the series of steps also were critical to developing this optical chemical sensor, which CEA-Leti is now realizing as demo prototypes.”

See related items:

MIRPHAB pilot line to provide tailor-made spectroscopy solutions

EU's MIRPHAB project unveils mid-IR chemical sensor six-times faster than alternatives

Tags: silicon photonics Mid-infrared detectors PIC

Visit: http://spie.org/photonics-west.xml

Visit: www.leti.fr