Magnetic field sensing using standard uniform FBGs.

Magnetic field sensing can be directly (i.e. without requiring magnetic fuilds or magnetostrictive materials) obtained from the estimation of the circular birefringence induced in optical fibers through the so-called Faraday effect. In standard telecommunication-grade optical fiber, the amount of induced circular birefringence is however of the same order of the intrinsic fiber linear birefringence or even below. Hence, whenever uniform fiber Bragg gratings (FBGs) are used to probe this evolution, the resulting accuracy is usually very poor, even in the case of polarization-assisted measurements based on polarization dependent loss (PDL) or differential group delay (DGD). In this work, we demonstrate that the rotation of the diattenuation vector computed from the Mueller matrix of an FBG in transmission mode can be efficiently used as a read-out technique to sense a magnetic field evolution with a resolution of 0.1T.

OFSETH: A breathing motions monitoring system for patients under MRI.

The potential benefit of optical fiber sensors embedded into medical textiles for the continuous monitoring of patients for MRI is presented. We report a monitoring system based on the use of two novel non-intrusive optical sensing technologies designed to measure the elongation due to abdominal and thoracic motions during breathing. The developed system can successfully sense textile elongation between 0.1% and 5%, while maintaining the stretching properties of the textile substrates for a good comfort of the patient. The solution prototyped shows a high stability and good reproducibility. The sensors are coupled to a compact, real time and accurate monitoring system.

OFSETH: smart medical textile for continuous monitoring of respiratory motions under magnetic resonance imaging.

The potential impact of optical fiber sensors embedded into medical textiles for the continuous monitoring of the patient during Magnetic Resonance Imaging is presented. We report on two pure optical sensing technologies for respiratory movements monitoring - a macro bending sensor and a Bragg grating sensor, designed to measure the elongation due to abdominal and thoracic motions during breathing. We demonstrate that the two sensors can successfully sense textile elongation between, 0% and 3%, while maintaining the stretching properties of the textile substrates for a good comfort of the patient.

Optical fibre sensors embedded into technical textile for a continuous monitoring of patients under Magnetic Resonance Imaging.

The potential impact of optical fiber sensors embedded into medical textiles for the continuous monitoring of the patient during Magnetic Resonance Imaging (MRI) is presented. In that way, we report on several pure optical sensing technologies for pulse oximetry and respiratory movements monitoring. The technique for pulse oximetry measurement is known as NIRS (Near Infra-Red Spectroscopy) in a reflectance mode. On the other hand, we tested two different optical based designs for the respiratory motions measurements--a macro bending sensor and a Bragg grating sensor, designed to measure the elongation of thoracic and abdominal circumferences during breathing.