Analysis of an optical source in a novel wavelength scanning fiber optic interferometer

A novel wavelength scanning fiber optic interferometer for absolute distance measurement has been proposed. In this paper, the source properties, which affect the measurement accuracy, resolution and dynamic range etc., are comprehensively studied. A tunable external-cavity semiconductor laser is taken as the wavelength scanning source, which can satisfy the demands on the spectrum bandwidth, scanning range and output power. Using the frequency-spectrum analysis, it is found that the random wavelength drift of the scanning can decrease the signal-to- noise ratio SNR of the output interferometric signal. The reduction of SNR limits the measurement accuracy. We can optimize the system with the analysis results. The preliminary experiment results correspond the theoretical analysis well.