All-In-Fiber Optofluidic Sensor Fabricated by Femtosecond Laser Assisted Chemical Etching


This paper reports the stress-induced birefringence generated in an optical fiber using femtosecond laser (fs) irradiations and the fabrication of in-fiber waveplates and polarizers. 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 and along the fiber axis using a femtosecond laser. The stress-induced birefringence was estimated to be 2.4x10-4 at the optical wavelength of 1550 nm. By controlling the length of the stress rods, waveplates of the desired retardance can be fabricated. The stress-induced birefringence was further explored to fabricate in-fiber polarizers based on the polarization-dependent long-period fiber grating (LPFG) structure. For the in-fiber polarizer based on low order mode LPFG, a polarization extinction ratio of more than 25 dB was observed at the wavelength of 1527.8 nm. A high order mode LPFG based in-fiber polarizer, with a broad bandwidth of 100 nm near 1550 nm, was investigated as well. The in-fiber polarization devices with low insertion loss may be useful in optical communications and fiber optic sensing applications.


Electrical and Computer Engineering

Second Department

Mechanical and Aerospace Engineering


The research was supported by Department of Energy (DOE)-National Energy Technology Laboratory (NETL) under contract DE-FE0001127.

Keywords and Phrases

Birefringence; Diffraction gratings; Fabrication; Fibers; Irradiation; Optical communication; Optical fiber fabrication; Optical fibers; Optical instruments; Polarization; Single mode fibers; Ultrashort pulses; Fiber-optic sensing; In-fiber; Long period fiber grating; Optical birefringence; Polarization devices; Polarization extinction ratio; Stress induced birefringence; Waveplates; Optical fiber communication; Femtosecond laser irradiation; In-fiber polarizer; Stress-induced birefringence

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Article - Journal

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© 2014 Optical Society of America, All rights reserved.

Publication Date

01 Apr 2014