We demonstrate a simple, adjustment-insensitive technique for measuring the temporal coherence function of cw multimode and monomode semiconductor lasers, using two-beam coupling in photorefractive InP and CdTe crystals. The emission spectra of the diodes are measured independently. The coherence functions are also calculated from these spectra and agree with the photorefractive measurements. Coupling of two partially coherent waves in low-speed photorefractive media is described theoretically. The range of the experimental parameters in which the method of coherence measurement is correct is given.
© 1999 Optical Society of America
Original Manuscript: May 18, 1998
Revised Manuscript: October 12, 1998
Published: January 20, 1999
Peter Pogany, Hans Joachim Eichler, Jens Dziambor, Volker Hagemann, and Bernhard Smandek, "Measuring the coherence function of continuous-wave lasers by a photorefractive grating method," Appl. Opt. 38, 516-521 (1999)