Performances of scanning wavelength systems are limited by several factors like the sweeping range, the mode-hop-free tuning of the wavelength and the nonlinearities in the sweeping speed. Nonlinearities are probably the last parameter to control to get the least performances. In our absolute distance interferometer (ADI), we have observed that the processing technique of the fringes in case of a double target system is very sensitive to the type of nonlinearities and the final resolution of the ADI depends strongly on their shape. Although the ideal sweeping speed should be perfectly linear, we have observed that even in the presence of strong sinusoidal nonlinearities in the sweeping speed, unexpected good results were obtained and were explained by the fact that these nonlinearities act like some white noise whose contribution converges to zero as the number of samples of the processed signal increases. In this paper we focus on the symmetry of the spectrum, another consequence of these nonlinearities. We show how it is possible to manipulate the spectrum by changing the sweeping speed. Results of simulations as well as experimental measurements are presented.

Date Published: 27 April 2010
PDF: 12 pages
Proc. SPIE 7720, Semiconductor Lasers and Laser Dynamics IV, 77202B (27 April 2010); doi: 10.1117/12.854886

Published in SPIE Proceedings Vol. 7720:
Semiconductor Lasers and Laser Dynamics IV
Krassimir Panajotov; Marc Sciamanna; Angel A. Valle; Rainer Michalzik, Editor(s)