Biomedical subjects

Juncheng Xu

Publications and source records attributed to Juncheng Xu.

5 recordsLinked to original sources

PubMed2006

All-fused-silica miniature optical fiber tip pressure sensor.

An all-fused-silica pressure sensor fabricated directly onto a fiber tip of 125 microm diameter is described. Simple fabrication steps include only cleaving and fusion splicing. Because no chemical processes are involved, the fabrication is easy, safe, and cost effective. Issues in sensor design and loss analysis are discussed. The sensor has been tested for static pressure response, showing a sensitivity of 2.2 nm/psi, a resolution of 0.01 psi (68.9 Pa), a hysteresis of 0.025%, and capability of operation at temperatures up to 600 deegrees C. This miniature sensor may be suitable for medical diagnostics, environmental monitoring, and other industrial applications.

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PubMed2005

Miniature all-silica fiber optic pressure and acoustic sensors.

We present a miniature diaphragm-based Fabry-Perot (F-P) interferometric fiber optic sensor fabricated by novel techniques for pressure or acoustic wave measurement that is only approximately 0.32 mm in diameter. By choosing different diaphragm thicknesses and effective diameters, we obtain a sensor measurement range from 5 to 10,000 psi (1 psi = 51.72 Torr) and a frequency response up to 2 MHz. In addition, the sensor's F-P cavity can be set from micrometers to millimeters with a precision of several nanometers. With the all-silica structure, the sensor is reliable, biocompatible, and immune to electromagnetic interference and has high-temperature sensing capability.

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PubMed2005

Measurement of the frequency response of a diaphragm-based pressure sensor by use of a pulsed excimer laser.

We present a novel method for measuring the frequency response of a diaphragm-based optical fiber Fabry-Perot interferometric pressure sensor. The impulse response of the sensor to the radiation pressure generated by an excimer laser pulse is measured. The Fourier transform of the impulse response yields the frequency response of the pressure sensor. Experimental results show that it is a convenient and efficient method for measurement of the frequency response of diaphragm-based pressure sensors.

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PubMed2005

Tunable-optical-filter-based white-light interferometry for sensing.

We describe tunable-optical-filter-based white-light interferometry for sensor interrogation. By introducing a tunable optical filter into a white-light interferometry system, one can interrogate an interferometer with either quadrature demodulation or spectral-domain detection at low cost. To demonstrate the feasibility of effectively demodulating various types of interferometric sensor, experiments have been performed using an extrinsic Fabry-Perot tunable filter to interrogate two extrinsic Fabry-Perot interferometric temperature sensors and a diaphragm-based pressure sensor.

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PubMed2004

Self-compensating fiber optic flow sensor system and its field applications.

A self-compensating fiber optic flow sensor system based on the principle of broadband white-light interferometers and cantilever beam bending is described. The fiber optic sensor system uses two fiber ferrule sensors that are bonded on either side of a cantilever beam to measure the flow rate by monitoring the air-gap changes caused by the bending of the cantilever beam. Cross sensitivity of the temperature and pressure dependence of the sensor can be compensated for automatically. The prototype sensor system was constructed, laboratory characterized, and field tested. The results from the field testing have demonstrated high resolution, repeatability, and stability for on-line detection of the flow rates of fluids.

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