Abstract

Down-conversion processes can be divided into degenerate and nondegenerate In the former case idler and signal photons are identical while in the latter they differ in frequencies and/or polarizations. It has been shown that transverse patterns in nondegenerate OPO [1] and soliton dynamics in nondegenerate free propagation [2] have qualitative differences from their degenerate counterparts The difference can be formally identified as due to an additional symmetry, in the differential phase of signal and idler fields [2] This symmetry is suppressed in the degenerate case As a result the frequency of the signal component of any solution, including solitons, is exactly half the pump frequency, ω_s = ω_i = ω_p/2 On the other hand, in the nondegenerate case any arbitrary frequency difference 2Ω between the idler and signal fields still satisfies the condition ω_p = ω_s + ω_i. This raises the question of whether there are any physical constraints on Ω.

© 2000 IEEE