Backward parametric interactions in quasi-phase matched configurations

We present numerical results on backward interactions in chi(2) media using a Quasi-Phase Matched configuration. Contrary to the classical forward case in which all waves propagate in the same direction, one of the generated waves propagates in the direction opposite to that of the pump. These calculations show that the contrapropagating wave generation configuration is not sensitive to a pump wavelength change over a broad range. This feature may be very useful for realizing a frequency translator. Broadband mirrorless oscillation can also be expected.