Abstract

It has been already demonstrated that a SHG nonlinear crystal detuned from phase-matching orientation may introduce intensity-dependent phase shift on incident radiation at the fundamental wavelength. A weak additional wave at the second harmonic sent at the same time permits the control of the fundamental output intensity by varying the relative phase of its input, as was recently reported. In this paper we demonstrate that an intense second-harmonic wave induces a nonlinear phase shift on a weak fundamental signal. This kind of cross-phase modulation through cascaded second-order NL effects can be quasi insensitive to the phase relationship between the two input fields.

© 1995 Optical Society of America