Research on FFT Demodulation System of Double Fiber Laser Beat Signal Based on FPGA

In this paper, based on FPGA, a wide-band, high-resolution, low-cost dual-channel fiber laser beat signal demodulation system is studied, which combines mixing technology and Fast Fourier Transform (FFT). It is used to demodulate the frequency difference information of dual-channel laser signal in real time. Based on the principle of optical heterodyne detection, two single-frequency fiber lasers with central wavelengths of 1550.001~1550.601nm output dual-channel laser signals with a wavelength interval of 5~30pm are used to conduct the experiment of beat signal demodulation system. The experiment proves that the circuit can realize realtime detection of beat signal in the frequency band of 0.41~3.45GHz. Frequency resolution up to 7.6kHz.