Characterization of the Birefringence in Fiber Bragg Gratings Fabricated With an Ultrafast-Infrared Laser

• Published in: Journal of lightwave technology Vol. 25; no. 3; pp. 779 - 786
• Main Authors: Ping Lu, Grobnic, D., Mihailov, S.J.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-03-2007; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Applied sciences; Birefringence; Bragg gratings; Circuit properties; Decay; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; fiber Bragg gratings; Fiber gratings; Fiber lasers; Fibers; Hydrogen; Infrared radiation; Integrated optics. Optical fibers and wave guides; Laser transitions; Lasers; Monitoring; Optical and optoelectronic circuits; Optical fiber polarization; Polarization; Temperature; ultrafast infrared (IR) laser; Integrated optics; Annealing; ultrafast infrared (IR) laser; Bragg grating; Annealing temperature; Grating in fiber; Infrared laser; Laser beam; Birefringence; fiber Bragg gratings; Room temperature; Optical fiber; Ultrafast process
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2006.889662

The changes of birefringence in Type I-infrared (Type I-IR) and Type II-IR fiber Bragg gratings induced by an ultrafast-IR laser in SMF-28 fibers are examined after and/or during grating inscription. The gratings are then annealed at increased temperatures up to 800 degC, and their polarization properties are monitored. It is shown that the birefringence in Type I-IR gratings inscribed in hydrogen (H 2 )-loaded fibers is small (~10 -6 ) and can be decayed at room temperature, while the birefringence in Type I-IR gratings inscribed in non-H 2 -loaded fibers is relatively higher (~10 -5 ) and shows strong dependence on the polarization of the IR laser beam. It has the same annealing resistance as the induced index. For Type II-IR gratings, the birefringence is an order of magnitude higher than in Type I-IR gratings (~10 -4 ) and shows strong temperature variation during annealing