Low-cost wearable device based D-shaped single mode fiber curvature sensor for vital signs monitoring

Compact fiber Fabry–Perot sensors filled with PNIPAM hydrogel for highly sensitive relative humidity measurement

“…The normal and medically diagnosed respiratory rate for a healthy person is 12 to 22 breaths per minute, and one breath is about 2.73 to 5 seconds, which has been demonstrated by a wearable sensor for respiration monitoring using an intensity variation-based approach in D-shape SMF [34]. Our developed FPI sensor is applied to real respiratory monitoring.…”

Experimental Demonstration to Enhance the Curvature Sensitivity of a Fiber Mach–Zehnder Interferometer Based on a Waist-Enlarged Technique Using Polymer

“…Monitoring curvature is vital for innumerable applications, such as reconstructing 2D circle-shaped objects using curvature radius sensing [1], trailing deformation in aircraft [2], and monitoring vital signs [3]. Consequently, fiber optic curvature sensors have been widely researched by academic groups and industries worldwide.…”

“…For instance, femtosecond lasers can be used to inscribe a waveguide in the fiber core [11] or a cladding waveguide can be used to construct an MZI [12]. Another technique is to polish the lateral side of an SMF to obtain a D-shaped optical fiber curvature sensor [3]. On the other hand, the use of PDMS polymer in the process of the fabrication of fiber sensors has attracted attention due to its low cost, as well as the simple way of preparing and curing it.…”

Sleep condition detection and assessment with optical fiber interferometer based on machine learning

“… 30 BCG is not only used for cardiac disease diagnosis but also as a means to assess sleep quality. 31 , 32 Optical fiber is the technology associated with data transmission using light pulses traveling along a long fiber, which is usually made of plastic or glass; this has been widely used in optical communication or other fields. For example, the step-index plastic optical fiber is suitable for high-performance fiber links at short distances, 33 the multimode optical fibers are widely used in smart healthcare, measurements, 34 , 35 and so on.…”