Multigrating phase conjugation in photorefractive crystals; effect of unequal coupling strengths and absorption on the PCR

The authors analyze the problem of determining the influence of four index grating types, namely, transmission, reflection, pump and signal with arbitrary relationships of their strengths. For this they solve the coupled-wave equations numerically, using a shooting and matching technique. The governing coupled-wave equations needed to solve the problem of multigrating phase conjugation in a more general manner are first reviewed. The role of all the relevant coupling mechanisms with arbitrary relationships and their competition on the reflectivity of the phase conjugation are studied. The results of the investigations are discussed and presented in a graphical form