Random fiber laser based on a partial-reflection random fiber grating for high temperature sensing
Jian-Cheng Deng, Dmitry V. Churkin, Zuowei Xu, Xuewen Shu
Abstract
A stable single wavelength random fiber laser (RFL) with a partial-reflection random fiber grating (PR-RFG) for high temperature sensing is proposed and demonstrated for the first time, to the best of our knowledge. The PR-RFG is fabricated with the help of a femtosecond laser, with its highest reflection peak significantly higher than all other reflection peaks, which can ensure the stability of this filter-free RFL. Theoretical calculations also show that such a PR-RFG should be designed with reflectivity in the range of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>∼</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>30</mml:mn> </mml:mrow> </mml:mrow> <mml:mi mathvariant="normal">%</mml:mi> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mo>−</mml:mo> </mml:mrow> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:mn>90</mml:mn> </mml:mrow> </mml:mrow> <mml:mi mathvariant="normal">%</mml:mi> </mml:math> to obtain one reflection peak significantly higher than other peaks. The threshold of this laser is only 6.4 mW. In addition, the RFL realizes temperature sensing in the range from 25°C to 500°C and has an optical signal-to-noise ratio of up to 70 dB.