Double-wavelength optical fiber laser and its application for large step height measurement

摘要

Two kinds of tunable double-wavelength erbium-doped fiber (EDF) ring lasers were developed and their application to step height measurement using two-wavelength self-mixing interferometry (SMI) was demonstrated. The fiber lasers can emit two different wavelengths without any laser mode competition. Each wavelength has its own gain medium which is a length of erbium-doped fiber. Fiber Bragg gratings are used to determine the value of the emitted wavelengths. Large step heights can be measured using multiple self-mixing interference of the two wavelengths. The maximum height that can be measured is half synthetic wavelength of the two wavelengths. A step height of 2mm constructed with two gauge blocks has been measured. The standard deviation of measurement results is 2.5nm.