title: Polarization dependence suppression of optical fiber grating sensor in a π-shifted Sagnac loop interferometer.
abstract: In the sensing applications of optical fiber grating, it is necessary to reduce the transmission-type polarization dependence to isolate the sensing parameter. It is experimentally shown that the polarization-dependent spectrum of acousto-optic long-period fiber grating sensors can be suppressed in the transmission port of a π-shifted Sagnac loop interferometer. General expressions for the transmittance and reflectance are derived for transmission-type, reflection-type, and partially reflecting/transmitting-type polarization-dependent optical devices. The compensation of polarization dependence through the counter propagation in the Sagnac loop interferometer is quantitatively measured for a commercial in-line polarizer and an acousto-optic long-period fiber grating sensor.
authors.affiliation: School of Medicine, Korea University, Seoul, 136-705, Korea. jaebum.son@gmail.com
authors.forename: Jaebum
authors.initials: J
authors.lastname: Son
authors.forename: Min-Kyoung
authors.initials: MK
authors.lastname: Lee
authors.forename: Myung Yung
authors.initials: MY
authors.lastname: Jeong
authors.forename: Chang-Seok
authors.initials: CS
authors.lastname: Kim