Higher-order squeezing for the codirectional Kerr nonlinear coupler

Abstract

In this Letter we study the evolution of the higher-order squeezing, namely, nthorder single-mode squeezing, sum-and difference-squeezing for the codirectional Kerr nonlinear coupler. We show that the amount of squeezing decreases when n, i.e. the squeezing order, increases. For specific values of the interaction parameters squeezing factors exhibit a series of revival-collapse phenomena, which become more pronounced when the value of n increases. Sum-squeezing can provide amounts of squeezing greater than those produced by the nth higher-order (n ≥ 2) squeezing for the same values of interaction parameters and can map onto amplitude-squared squeezing. Further, we prove that the difference-squeezing is not relevant measure for obtaining information about squeezing from this device.

Nonclassical properties of a contradirectional nonlinear optical coupler

“…4b where we plot variation of Now we may extend the discussion to HOA and plot right hand sides of (38) and (39) for various values of n. The plots are shown in Fig. 5 which clearly illustrates the existence of HOA and also demonstrate that the depth of nonclassicality increases with n. This is consistent with earlier observations on HOA in other systems [54].…”

Quantum properties of the codirectional three-mode Kerr nonlinear coupler

“…the switching of energy between waveguides, manifests itself by periodic functions in (5), whereas the Kerr nonlinearities in the waveguides are described by the nonlinear (quadratic) phase, which plays an essential role in generating the nonclassical effects. On the other hand, the fundamental mode â1 can provide richer nonclassical effects than those produced by the second and third modes as well as the conventional coupler [21,22] (see Fig. 1).…”

“…Quantum mechanically, there are different types of directional couplers. For instance, symmetric coupler [11] (linear (or nonlinear) processes are involved in both the waveguides), asymmetric coupler [12] (at least one of the waveguides possesses different nonlinearity than the others), Raman-Brillouin coupler [13], bandgap coupler [14] and Kerr coupler [15,16,17,18,19,20,21,22]. For more details about their properties the reader can consult the review papers [23].…”

“…In these cases it has been shown that there is a possibility to control the switching characteristics and principal squeezing effect by adjusting the shape of the waveguides. Quite recently, we have investigated the single-mode quantum properties of the codirectional Kerr nonlinear coupler when the frequency mismatch is involved and a condition for obtaining an exact solution for the equations of motion is fulfilled [21,22]. For this case we have shown that the mean-photon numbers exhibit oscillatory behaviour rather than revivals and collapses.…”

“…Additionally we have proved that the Schrödinger-cat states, in particular, Yurke-Stoler cat states (YSCS) [26] can be generated. Also the higher-order squeezing has been investigated [22]. Till now the KNC has been treated as a two-mode device.…”