Real-time acquisition and processing technology of high-speed optical fiber sensing signals

• 1、School of Electronic Engineering,Beijing University of Posts and Telecommunications,Beijing 100876

Abstract：The measurement distance of the high-performance distributed optical fiber sensing system can reach hundreds of kilometers, and the sampling rate and acquisition processing speed of the receiver determine the distance resolution of the system and the signal-to-noise ratio that can be achieved per unit time. Under the condition of achieving a measurement distance of 200 km and a distance resolution of 1 meter, the sampling rate is required to be more than 200MSPS and the number of single sampling points is up to 200k. As the number of channels increases, the number of acquisition points increases exponentially. To achieve a high signal-to-noise ratio, the system usually adopts the method of multi-acquisition accumulation averaging. The temperature strain sensing system based on the Brillouin scattering effect accumulates thousands of times, while the temperature sensing system based on the Raman scattering effect accumulates millions of times, and it is difficult to achieve such a large amount of high-speed real-time data through memory storage or transmission to the CPU for real-time processing. In this paper, a real-time accumulation system is designed with limited FPGA resources and DDR, which can put high-speed, real-time accumulation operations on the front end and reduce the pressure of transmission, storage, and processing on the back end. Given the size of FPGA internal memory unit and the DDR transmission speed, the optimal strategy for realizing the maximum sampling rate accumulation system under the influence of the DDR read/write switching time, refresh time and other factors is studied.

Keywords： Communication and information processing Fiber optic sensing FPGA DDR FIFO