Sensors 2011, 11(1), 1078-1087; doi:10.3390/s110101078
Article

A Miniature Fiber Optic Refractive Index Sensor Built in a MEMS-Based Microchannel

1,* email, 1email, 1email, 2email, 1email and 1,2,* email
Received: 23 December 2010; in revised form: 10 January 2011 / Accepted: 12 January 2011 / Published: 19 January 2011
(This article belongs to the Special Issue Optical Resonant Microsensors)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: A small, highly sensitive, and electromagnetic interference (EMI)-immune refractive index (RI) sensor based on the Fabry-Perot (FP) interferometer is presented. The sensor’s FP cavity was fabricated by aligning two metal-deposited, single-mode optical fiber endfaces inside a microchannel on a silicon chip. The mirrors on the fiber endfaces were made of thermal-deposited metal films, which provided the high finesse necessary to produce a highly sensitive sensor. Microelectromechanical systems (MEMS) fabrication techniques, specifically photolithography and deep dry etching, were used to precisely control the profile and depth of the microchannel on the silicon chip with an accuracy of 2 μm. The RI change within the FP cavity was determined by demodulating the transmission spectrum phase shift. The sensitivity and finesse of the transmission spectrum were controlled by adjusting the cavity length and the thickness of the deposited metal. Our experimental results showed that the sensor’s sensitivity was 665.90 nm/RIU (RI Unit), and the limit of detection was 6 × 10−6 RIU. Using MEMS fabrication techniques to fabricate these sensors could make high yield mass production a real possibility. Multiple sensors could be integrated on a single small silicon chip to simultaneously measure RI, temperature, and biomolecule targets.
Keywords: Fabry-Perot; optical fiber sensor; refractive index; MEMS
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MDPI and ACS Style

Tian, Y.; Wang, W.; Wu, N.; Zou, X.; Guthy, C.; Wang, X. A Miniature Fiber Optic Refractive Index Sensor Built in a MEMS-Based Microchannel. Sensors 2011, 11, 1078-1087.

AMA Style

Tian Y, Wang W, Wu N, Zou X, Guthy C, Wang X. A Miniature Fiber Optic Refractive Index Sensor Built in a MEMS-Based Microchannel. Sensors. 2011; 11(1):1078-1087.

Chicago/Turabian Style

Tian, Ye; Wang, Wenhui; Wu, Nan; Zou, Xiaotian; Guthy, Charles; Wang, Xingwei. 2011. "A Miniature Fiber Optic Refractive Index Sensor Built in a MEMS-Based Microchannel." Sensors 11, no. 1: 1078-1087.

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