Interferometric fiber optic sensors.
Fiber optic interferometers to sense various physical parameters including temperature, strain, pressure, and refractive index have been widely investigated. They can be categorized into four types: Fabry-Perot, Mach-Zehnder, Michelson, and Sagnac. In this paper, each type of interferometric sensor is reviewed in terms of operating principles, fabrication methods, and application fields. Some specific examples of recently reported interferometeric sensor technologies are presented in detail to show their large potential in practical applications. Some of the simple to fabricate but exceedingly effective Fabry-Perot interferometers, implemented in both extrinsic and intrinsic structures, are discussed. Also, a wide variety of Mach-Zehnder and Michelson interferometric sensors based on photonic crystal fibers are introduced along with their remarkable sensing performances. Finally, the simultaneous multi-parameter sensing capability of a pair of long period fiber grating (LPG) is presented in two types of structures; one is the Mach-Zehnder interferometer formed in a double cladding fiber and the other is the highly sensitive Sagnac interferometer cascaded with an LPG pair.
School of Information and Communications, Gwangju Institute of Science and Technology, Buk-gu, Gwangju, Korea. leebh@gist.ac.kr
Byeong Ha
BH
Lee
Young Ho
YH
Kim
Kwan Seob
KS
Park
Joo Beom
JB
Eom
Myoung Jin
MJ
Kim
Byung Sup
BS
Rho
Hae Young
HY
Choi