26 May 1999 Simple measurement of the coherence function of cw lasers by a photorefractive grating method
Author Affiliations +
Abstract
We demonstrate an adjustment-insensitive technique for measuring the squared temporal coherence function of cw, longitudinally multi- and monomode semiconductor lasers, using codirectional two-beam coupling in photorefractive InP:Fe and CdTe:V crystals. The emission spectra of the diodes are measured independently and the coherence functions are also calculated by Fourier transform from the spectra. The photorefractive measurements are in good agreement with these calculations. The coupling of two partially coherent waves in low-speed absorptive photorefractive media is studied. We give an exact explicit solution of the 1D linear coupled wave equation for the beam intensities and for the degree of mutual coherence, which changes during the wave mixing. This change is significant for large input beam intensity ratios but only in second order in the coupling strength for equal input beam intensities. In this latter case for moderate coupling strength the energy transfer between the beams is proportional to the square of the input coherence degree, providing a simple determination of the squared coherence function due to measurement of the signal intensity enhancement as function of the time delay between the beams. The possibility to determine some important characteristic of the emission spectrum from the measured squared coherence function is discussed.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Peter Pogany, Peter Pogany, Hans Joachim Eichler, Hans Joachim Eichler, } "Simple measurement of the coherence function of cw lasers by a photorefractive grating method", Proc. SPIE 3610, Laser Material Crystal Growth and Nonlinear Materials and Devices, (26 May 1999); doi: 10.1117/12.349223; https://doi.org/10.1117/12.349223
PROCEEDINGS
8 PAGES


SHARE
RELATED CONTENT


Back to Top