Power and stability of phase-conjugate lasers

The phase-conjugate laser (PCL) is analyzed as a network of energy flow with gain, saturation, and loss. Most PCL's fit into one of three generic forms of energy coupling, defined by how the phase-conjugate mirror is pumped. The self-pumped PCL is a nonlinear feedback system with constraints not present in ordinary lasers. The internal and external powers are roots of a transcendental function that includes arbitrary gain and saturation. The PCL's are compared for useful output power with an ordinary laser of the same gain/loss. Most PCL's have maximum output as double-pass amplifiers (weak feedback and high extraction). The externally pumped PCL is inherently inefficient except at high gain. The self-pumped PCL's are efficient at high and low gain and are multistable optical devices with discrete power levels. The multistability is generic and does not depend on any specific form of the reflectance function. The higher states have not been seen experimentally because they cannot develop from the lowest state but must be induced by hard excitation of the PCL.