An Integrated Design of Ultra-High-Speed FBG Interrogation System-Based on FDML Laser

An integrated design of ultra-high-speed Fiber Bragg Grating (FBG) interrogation system is illustrated and experimentally demonstrated. A Fourier Domain Mode Locked (FDML) laser is employed as a high-speed wavelength-swept light source. The use of the Mach-Zehnder interferometer (MZI) and the single-peak filter (SPF) overcomes the nonlinear effect and the scanning wavelength drift problem. A signal acquisition and peak-searching method based on the hardware is designed, allowing a real-time and multichannel interrogation. The controlled experiment has verified the feasibilities of the MZI and the SPF. Dynamic and static FBG experiments show that the integrated system has an accuracy of 0.02 nm, a stability of 0.006 nm, a linearity of 0.9994 and a 40 kHz demodulation frequency with 4 simultaneous interrogation channels.