Multigrating optical phase conjugation in photorefractive media in the case of pump depletion and for arbitraryrelationships among different coupling strengths is studied numerically. The role of linear absorption as well as therole of all the coupling mechanisms and their competition in the wave mixing process is examined. It is found thatmultigrating operation with accidental values of coupling constants leads to a decrease in the efficiency of theprocess. It is also shown that the presence of absorption, which is in principle detrimental, sometimes exerts abeneficial influence on multigrating phase conjugation. 1989, Optical Society of America.
