Multichannel High-Speed Fiber Bragg Grating Interrogation System Utilizing a Field Programmable Gate Array

We demonstrate a multichannel high-speed fiber Bragg grating (FBG) interrogation system utilizing a field programmable gate array (FPGA). A temperature-controlled Fourier domain mode locking laser was operated with a sweep rate of 50.7 kHz, sweep bands of 35 nm, and an output power of 0.91 mW. This laser enabled an FBG measurement speed of up to 9.9 μs. Real-time processing could be achieved by incorporating a high-speed data acquisition system (DAQ) mounted on an analog to digital converter and an FPGA. The DAQ performed in-line processing with four 14-bit analog channels and a sampling frequency of 250 MHz. The internals of the FPGA were implemented parallel processing for high-speed FBG detection to allow for the simultaneous measurement of the multiplexed FBG in three channels. We demonstrated that this system is capable of high-speed vibration measurements above several tens of kHz with a multichannel.