Noise in a wavefront-reversal system with a preliminary amplifier

A calculation is made of noise in a system for wavefront reversal of weak light signals, composed of a preliminary amplifier and a four-wave hypersonic reversing mirror. The constant field approximation for mirror pump waves and the assumption of the absence of wave detuning are used to determine the range of the mirror parameters in which the sensitivity of the system is close to the limit governed by the quantum noise of the amplifier.