High-temperature fiber optic cubic-zirconia pressure sensor

Abstract

There is a critical need for pressure sensors that can operate reliably at high temperatures in many industrial segments such as in the combustion section of gas turbine engines for both transportation and power generation, coal gasifiers, coal fired boilers, etc. Optical-based sensors are particularly attractive for the measurement of a wide variety of physical and chemical parameters in high-temperature and highpressure industrial environments due to their small size and immunity to electromagnetic interference. A fiber optic pressure sensor utilizing single-crystal cubic zirconia as the sensing element is reported. The pressure response of this sensor has been measured at temperatures up to 1000°C. Additional experimental results show that cubic zirconia could be used for pressure sensing at temperatures over 1000°C. This study demonstrates the feasibility of using a novel cubic-zirconia sensor for pressure measurement at high temperatures. © 2005 Society of PhotoOptical Instrumentation Engineers.

Adhesive-Free Bonding of Monolithic Sapphire for Pressure Sensing in Extreme Environments

“…The etched sapphire wafer is then bonded to a flat sapphire piece. The sealed hollow cavity thus formed can function as a pressure transducer, and the displacement of the diaphragm that encloses the cavity can be used to extract external pressure data [ 7 , 16 ]. Before bonding, the two wafer pieces, one of which includes the etched sensing cavity, are subjected to RCA cleaning and are then immersed in 85% H 3 PO 4 at 150 °C for 45 min to remove any oxide remaining on their surfaces.…”

“…A much stronger diffusion-based bond is formed by baking the wafer pieces at 1200 °C for over 50 h, during which time the wafers are compressed under a 700-g weight. Finally, the sample is annealed at 1200 °C, without any weight applied, to release any internal stresses trapped during bonding [ 16 ].…”

Fabrication of All-SiC Fiber-Optic Pressure Sensors for High-Temperature Applications

“…The reflected lights propagate through a fiber circulator and are detected by a mini-spectrometer. The Fabry-Perot (F-P) cavity length can be determined by demodulating the generated interference fringes [22]. …”

Fast and slow light property improvement in erbium-doped amplifier

“…The erbium-doped waveguide amplifier is very attractive for use in 1.55 µm communication systems because of its compactness, low processing cost, and compatibility with other optical devices. Additionally, the erbium-doped waveguide amplifier has the advantage of the fundamental qualities of an erbium-doped fiber amplifier, such as a low noise figure, negligible polarization dependence, and the absence of inter-channel crosstalk [21][22][23][24]. The erbium-doped waveguide amplifier consists of an erbium-doped waveguide, two optical isolators, a 980 nm pump laser, a 980/1550 nm WDM coupler, and a pump filter.…”

“…Substantial effort has been made to develop an erbiumdoped waveguide amplifier (EDWA) using ion exchange technology in planar glass integrated optics [21][22][23][24]. The advantage of an erbium-doped waveguide amplifier over an erbium-doped fiber amplifier is its higher erbium doping concentration.…”