Resonance-temperature-insensitive phase-shifted long-period fiber gratings induced by surface deformation with anomalous strain characteristics.
Received February 18, 2005 We report the fabrication of phase-shifted long-period fiber gratings by use of a CO2 laser with a surface deformation technique and a point-by-point method. Due to periodicities that are structurally induced by a heat source and refractive-index modulation caused by a perturbational photoelastic effect, the results of thermal testing show a grating temperature coefficient of 28 pm/ degrees C at a range from 22 to 180 degrees C, indicating that the band rejections of the grating that is formed remain unchanged in their resonant strengths even at temperatures up to the fictive point of fiberglass. It is found for what is believed to be the first time that such a grating possesses an anomalous strain behavior of resonance with -1.52 x 10(-4) dB/muepsilon for the right notch and 7.05 x 10(-5) dB/muepsilon for the left notch.
Zhu
Yinian
Y
Network Technology Research Centre, School of Electrical & Electronic Engineering, Nanyang Technological University, 50 Nanyang Drive, Singapore 637553. zhu_yinian@hotmail.com
Shum
Ping
P
Chen
Xiaoyan
X
Tan
Ching-Hwee
CH
Lu
Chao
C