Design of an FPGA Based High-Speed Data Acquisition System for Frequency Scanning Interferometry Long Range Measurement

Frequency Scanning Interferometry (FSI) has become a popular method for long-range, target based, distance measurements. However, the cost of developing such systems, particularly the electronic components required for high-speed data acquisition, remains a significant concern. In this paper, we present a cost-effective, FPGA-based real-time data acquisition system specifically designed for FSI, with a focus on long absolute distance measurements. Our design minimizes the use of third-party intellectual property (IP) and is fully compatible with the Xilinx FPGA 7 series families. The hardware employs a 160 MS/s, 16-bit dual-channel ADC interfaced to the FPGA via a Low Voltage Differential Signal (LVDS). The proposed system incorporates an external sampling clock, referred to as the K- clock, which linearizes the laser's tuning rate, enabling optical measurements to be sampled at equal optical frequency intervals rather than equal time intervals. Additionally, we present the design of a high-speed, 160 MS/s ADC module for the front-end analogue signal interface and the LVDS connection to the chosen FPGA. We demonstrate that the digitized data samples can be efficiently transmitted to a PC application via a USB interface for further processing

Dual-frequency sweeping light source based on four-wave mixing in silicon-on-insulator nano-waveguide

Four-wave mixing (FWM) is a well-known technique to achieve all-optical control wavelength conversion. We propose a well-designed silicon nano-waveguide based on silicon-on-insulator (SOI) to achieve FWM conversion. Particularly, the original signal light continuously sweeps along the C band, and the generated idler light is correspondingly sweeping as the original signal is swept. The wavelengths of the idler and signal lights are symmetric with respect to the pump light wavelength. Simulation and experimental results of the FWM conversion properties are well-matched. With the pump light filtered out, a dual-frequency continuously sweeping laser source is achieved, which could be applied in dual-frequency scanning interferometry to eliminate dynamic errors in practical use