Investigation on distance measurement with chirped laser light

Abstract

In this thesis, interferometric distance measurements with chirped laser light from a frequency-shifted feedback laser are demonstrated. With this method, the length measurement process is converted into a frequency measurement process. Compared to other length measurement principles such as triangulation or time-of-flight measurement, interferometric methods usually have a better length resolution. With the full optical bandwidth, a length resolution of 0.2mm was achieved. Thereby each peak in the radio-frequency spectrum was resolved with only one test frequency. If a more time- and hardware-consuming measurement process were used, in which each peak is resolved with several test frequencies, the length resolution would be improved even further. Since this principle provides a high length resolution for small-area electronic circuits, it is an ideal candidate to build a sensor array for a three-dimensional camera.6