English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We analyze the process of photon-pair generation via spontaneous parametricdown-conversion in a quadratic nonlinear asymmetric waveguide coupler. The twowaveguides have different geometry, such that light coupling only occurs withina narrow bandwidth of one of the generated (signal) photon modes, while theother (idler) photon together with the pump stay localized in one (driven) armof the coupler. We demonstrate that such a setup represents a powerful andflexible tool for engineering spectral properties of generated photon pairs.Mode hybridization and dispersion of coupling can be utilized for shifting thebalance between group velocities of interacting pump, signal and idler fields,subsequently leading to a significant increase of spectral factorisability(purity) of photons. We also show that for interaction lengths shorter than onebeat length, generated pairs with signal photon being localized in theauxiliary (not pumped) arm of the coupler appear to be spectrally localized inboth signal and idler components. The bandwidth of such intrinsic filtering ofgenerated photons can be controlled by several geometrical parameters.

Spontaneous Parametric Down-Conversion in asymmetric couplers: photon purity enhancement and intrinsic spectral filtering