A low bandwidth DFB laser-based interrogator for terahertz-range fiber Bragg grating sensors
Date of Original Version
This letter reports an all-electronic, low bandwidth swept frequency laser used to interrogate terahertz-range fiber Bragg gratings (THz FBGs) for distributed strain sensing applications. A distributed feedback laser with current injection modulation was employed as the swept frequency laser source. Using the resulting narrow bandwidth (∼110 GHz) laser frequency sweep, high accuracy distributed strain measurements were achieved. In order to experimentally investigate this concept, a strain test was conducted using the THz FBGs. During the test, the laser sweeping time was limited to less than 2 ms. Highly linear results were found (R2 = 0.996), with an observed sensitivity of -0.142 GHz/μ ϵ and the standard deviation of 1.167 μϵ. A multiplexing test was also conducted, and no cross-talk found between sensor elements. These results demonstrate that this interrogation system holds substantial potential as a method of rapid distributed optical fiber frequency-domain sensing.
IEEE Photonics Technology Letters
Chen, Zhen, Gerald Hefferman, and Tao Wei. "A low bandwidth DFB laser-based interrogator for terahertz-range fiber Bragg grating sensors." IEEE Photonics Technology Letters 29, 4 (2017): 365-368. doi:10.1109/LPT.2016.2647438.