Efficient Generation of Squeezed Light via Spontaneous Four-Wave Mixing in Integrated Structures.

We investigate the use of integrated structures for the efficient generation of squeezed light via dual-pump spontaneous four-wave mixing. We consider the case of ring resonators, in which resonant field enhancement is typically used to increase the efficiency of nonlinear interactions. We show that in these structures the presence of a comb of equally spaced resonances can also lead to the enhancement of parasitic processes that can degrade the quality of the generated light, thus limiting the achievable squeezing. Here, we discuss possible solutions to this issue and introduce a device consisting of a ring resonator and a resonant interferometric coupler able to control the field enhancement selectively. We show that through this structure one can strongly limit the effect of parasitic processes and overcome the intrinsic limitations of a single-ring resonator. Finally, we model the effect of nonlinear parasitic processes and provide an analytic expression of the achievable squeezing.