Detailed study of synthesized light sources for white-light interferometric systems

Results of a study on the use of synthesized ligth sources are presented. The favarable wavelength combinations for a pair of MLDs was simulated theroetically and verified experiementally. Under the condition of the best wavelength combination the lowest signal-to-noise ratio (SNR) required by the system was found to be 18. 1 dB in theory and 22. 1 db from experiment. The relationships between the wavelengths of two diodes their coherence lengths and the SNR required by the system are shown and discussed.