Abstract

The double phase conjugate mirror¹ (DPCM) is a unique photorefractive (PR) device in which two mutually incoherent input beams become phase conjugates of each other. In a recent paper,² we have theoretically predicted the existence of a threshold in the conjugation fidelity. Here we show experimentally that a fidelity threshold exists and that it depends on the feature size in the conjugated images. The phase conjugate reflectivity, however, is a smooth function of the gain. Furthermore, we find that for input-beam intensity ratio other than unity, the conjugation process is asymmetric, and the steady state fidelity is improved for the stronger input beam and masked by the fanning noise for the weaker one. These results provide a deeper insight into the stimulated wave mixing process, and will be useful for understanding the limitations of device applications, such as image processors, interconnects, interferometers, and coupled-laser devices.

© 1994 Optical Society of America