The Manley–Rowe relations are mathematical expressions developed originally for electrical engineers to predict the amount of energy in a wave that has multiple frequencies.
The original papers, written by two researchers at Bell Labs, J. M. Manley and H. E. Rowe between 1956 and 1960[3][4][5][6] was for an electrical circuit containing nonlinear capacitors and inductors.
Because the Manley–Rowe relations are based on general concepts like nonlinear waves and conservation of energy, their use is not limited to the original application in radio-frequency electrical circuits.
In the electrical circuit for the original derivation of Manley–Rowe relations, capacitors and inductors store energy from a wave and then release it.
[7] When Hartley joined Bell Laboratories after being part of Western Electric, he started a research group on nonlinear oscillations.