We have demonstrated a highly sensitive microbend fiber optic sensor for perioperative pediatric vital signs monitoring that is free from direct contact with skin, cableless, electromagnetic interference free and low cost. The feasibility of our device was studied on infants undergoing surgery and 10 participants ranging from one month to 12 months were enrolled. The sensor was placed under a barrier sheet on the operating table. All patients received standard intraoperative monitoring. The results showed good agreement in heart rate and respiratory rate between our device and the standard physiological monitoring when signals are clean.
In this paper, we report a field test of a microbend fiber sensor for simultaneous measurement of breathing rate, breathing pattern, Ballistocardiogram and heart rate during magnetic resonance imaging (MRI). Comparative experiments conducted between our sensor and commercial physiologic device on a healthy male subject showed an accuracy of +/-2bpm for simultaneous measurement of both breathing rate and heart rate. Our preliminary field test on simultaneous measurement of breathing rate and heart rate in a clinical trial conducted on 11 healthy subjects in the 3.0 Tesla MRI environment showed very good agreement compared with measurements obtained from conventional MRcompatible devices.
We propose and demonstrate the feasibility of using a highly sensitive microbend multimode fiber optic sensor for simultaneous measurement of breathing rate (BR) and heart rate (HR). The sensing system consists of a transceiver, microbend multimode fiber, and a computer. The transceiver is comprised of an optical transmitter, an optical receiver, and circuits for data communication with the computer via Bluetooth. Comparative experiments conducted between the sensor and predicate commercial physiologic devices showed an accuracy of ±2 bpm for both BR and HR measurement. Our preliminary study of simultaneous measurement of BR and HR in a clinical trial conducted on 11 healthy subjects during magnetic resonance imaging (MRI) also showed very good agreement with measurements obtained from conventional MR-compatible devices.
We characterized the dynamic response of a Bragg grating-based fiber laser sensing system. The sensing system comprises of a narrow line width fiber laser based on π -phase-shifted fiber Bragg grating formed in an active fiber, an unbalanced fiber Michelson interferometer (FMI), which performs wavelength-to-phase mapping, and a phase detection algorithm, which acquires the phase change from the interferometric output signal. The novel phase detection algorithm is developed based on the combination of the two traditional phase generated carrier algorithms: differential-cross-multiplying and arctangent algorithms, and possesses the advantages of the two algorithms. The modulation depth fluctuation of the carrier does not affect the performance of the sensing system. A relatively high side mode suppression ratio of above 50 dB has been achieved within a wide range of carrier amplitude from 1.6 to 5.0 V which correspond to the modulation depth from 1.314 to 4.106 rad. The linearity is 99.082% for the relationship between the power spectral density (dBm/Hz ) of the detected signal and the amplitude (mv) of the test signal. The unbalanced FMI is used to eliminate the polarization effect.
In this paper, we propose and demonstrate a new type of fiber optic sensor system for remote continuous monitoring and
detection of partial discharge (PD) from power equipment. The sensing system uses an antenna which is connected to a
vertical-cavity surface-emitting laser (VCSEL). The modulated light by the PD signal is transmitted through an optical
fiber and measured remotely by an optical receiver. Laboratory experiments have shown that EMOptic sensor has high
sensitivity and signal to noise ratio by comparing Electromagnetic (EM) sensor and other sensors. It provides a feasible
remote PD monitoring technique for power equipments. A completed prototype sensing system based on this technique has
been installed in a commercial building for field trial. The system can be accessed via internet anytime and anywhere.
In this paper, we propose and demonstrate a highly sensitive Microbend Fiber Sensor (MFS) for Ballistocardiogram
(BCG) recording. The MFS based BCG sensor is built into a cushion. It is a portable, small, light and low cost device.
High quality and repeatable BCG signals can be obtained by using this device which allows patients at home to monitor
their cardiovascular health. The measured BCG waveforms closely resemble those in the existing literatures. The BCG
heart beat detection agrees well with one from photo-plethysmography (PPG) signal.
A 100-km long distance fiber Bragg Grating (FBG) vibration sensor system is demonstrated by using a Raman pump
laser source at 1395 nm and two segments of erbium doped fiber (EDF). The reflected spectrum of FBG has 30dB signal
noise ratio. By using a wavelength matched FBG to achieve wavelength demodulation, vibration frequencies from 1Hz to
1000Hz has been effectively detected in this 100km long distance vibration sensor system.
We describe a new sensor for patient's breathing measurement by using fiber loop ringdown spectroscopy. The sensing
system consists of a typical single mode fiber-loop ring-down spectroscopy and a sensor mat which is used to introduce
breathing related optical loss. The sensor mat could be put in the chair or embedded in the bed. It is non invasive
measurement. The breathing rate sensor is demonstrated with an accuracy of +/-2 breaths per minute and stable sensor
output.
In this paper, we propose and demonstrate a new method to monitor heart rate using fiber optic microbending based
sensor for in-bed non-intrusive monitoring. The sensing system consists of transmitter, receiver, sensor mat, National
Instrument (NI) data acquisition (DAQ) card and a computer for signal processing. The sensor mat is embedded inside a
commercial pillow. The heart rate measurement system shows an accuracy of +/-2 beats, which has been successfully
demonstrated in a field trial. The key technological advantage of our system is its ability to measure heart rate with no
preparation and minimal compliance by the patient.
We present a new fibre optic breathing/movement sensor for in-bed non-intrusive monitoring. The light is modulated
through microbending effect during breathing/body movement. The sensing system consists of optical transmitter,
optical receiver, a sensor sheet, and a computer. An algorithm was developed to extract body movement signals and
report breathing rate and information on body movement of bedded person. The breathing rate measurement system
shows an accuracy of +/-1 breath, which has been successfully demonstrated in field trial (FusionWorld).
A self-referenced multimode fiber (MMF) micro bend displacement sensor is presented in this paper. In this
sensor, two single mode fiber Bragg gratings (FBGs) with different wavelengths are employed for the self-reference of
the micro bend displacement measurement. A short piece of MMF with a mechanical micro bender, inserted between the
two FBGs, acts as the sensing part. The sensor output is very stable (variation in the intensity difference was ~ 0.07dB)
within the 8dB dynamic range of the transmission loss. And the maximum variation of the intensity difference with
temperature is about 0.55dB from 20°C to 75°C. The sensor system offers many advantages, including higher stability,
single end access, and high sensitivity.
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