Coherence properties of semiconductor lasers and effects in interferometer configurations

In connection with the employment of semiconductor lasers in interferometer configurations, it will be necessary to examine closely the laser spectrum and the temporal coherence characteristics. The temporal coherence properties can differ greatly for different types of semiconductor lasers. The present investigation has, therefore, the objective to discuss the significance of the temporal coherence of the light source, giving particular attention to interference and reflection phenomena. It is found that lasers with very small spectrum widths are needed in the case of applications involving the detection of interferences. Semiconductor lasers with large spectrum widths are, on the other hand, useful for the suppression of interferences.