title: Stress-induced birefringence and fabrication of in-fiber polarization devices by controlled femtosecond laser irradiations.
abstract: Optical birefringence was created in a single-mode fiber by introducing a series of symmetric cuboid stress rods on both sides of the fiber core along the fiber axis using a femtosecond laser. The stress-induced birefringence was estimated to be 2.4 × 10(-4) at the wavelength of 1550 nm. By adding the desired numbers of stressed rods, an in-fiber quarter waveplate was fabricated with a insertion loss of 0.19 dB. The stress-induced birefringence was further explored to fabricate in-fiber polarizers based on the polarization-dependent long-period fiber grating (LPFG) structure. A polarization extinction ratio of more than 20 dB was observed at the resonant wavelength of 1523.9 nm. The in-fiber polarization devices may be useful in optical communications and fiber optic sensing applications.
authors.forename: Lei
authors.initials: L
authors.lastname: Yuan
authors.forename: Baokai
authors.initials: B
authors.lastname: Cheng
authors.forename: Jie
authors.initials: J
authors.lastname: Huang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Hanzheng
authors.initials: H
authors.lastname: Wang
authors.forename: Xinwei
authors.initials: X
authors.lastname: Lan
authors.forename: Hai
authors.initials: H
authors.lastname: Xiao