Uniform spacing interrogation of a Fourier domain mode-locked fiber Bragg grating sensor system using a polarization-maintaining fiber Sagnac interferometer.
A novel linearized interrogation method is presented for a Fourier domain mode-locked (FDML) fiber Bragg grating (FBG) sensor system. In a high speed regime over several tens of kHz modulations, a sinusoidal wave is available to scan the center wavelength of an FDML wavelength-swept laser, instead of a conventional triangular wave. However, sinusoidal wave modulation suffers from an exaggerated non-uniform wavelength-spacing response in demodulating the time-encoded parameter to the absolute wavelength. In this work, the calibration signal from a polarization-maintaining fiber Sagnac interferometer shares the FDML wavelength-swept laser for FBG sensors to convert the time-encoded FBG signal to the wavelength-encoded uniform-spacing signal.
Department of Cogno-Mechatronics Engineering, World Class University Program, Pusan National University, Busan, 609-735, Korea.
Hwi Don
HD
Lee
Nano-Photonics Research Center, Korea Photonics Technology Institute, Gwangju 500-779, Korea.
Eun Joo
EJ
Jung
Department of Cogno-Mechatronics Engineering, World Class University Program, Pusan National University, Busan, 609-735, Korea.
Myung Yung
MY
Jeong
Department of Cogno-Mechatronics Engineering, World Class University Program, Pusan National University, Busan, 609-735, Korea ; Beckman Laser Institute, Department of Biomedical Engineering, University of California, Irvine, CA 92612, USA.
Zhongping
Z
Chen
Department of Cogno-Mechatronics Engineering, World Class University Program, Pusan National University, Busan, 609-735, Korea.
Chang-Seok
CS
Kim
Sagnac interferometer; fiber Bragg grating; wavelength-swept laser