Simple quantum theory of second-harmonic generation from quantum noise owing to the fifth-order nonlinear optical interaction in centrosymmetric media is presented. This theory explains the rise of initial second-harmonic seeding radiation in optical fibers.
© 1988 Optical Society of America
P. Chmela, "Second-harmonic generation from quantum noise owing to fifth-order nonlinearity," Opt. Lett. 13, 669-671 (1988)