Nonclassical light in a three-waveguide coupler with second-order nonlinearity

• Published in: EPJ Quantum Technology
• Main Author: Hanapi M.S.M.; Ibrahim A.-B.M.A.; Julius R.; Choudhury P.K.; Eleuch H.
• Format: Article
• Language: English
• Published: Springer Science and Business Media Deutschland GmbH 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85201258408&doi=10.1140%2fepjqt%2fs40507-024-00263-9&partnerID=40&md5=8f586facaaea5c1576aa7cf969059a1d

Possible squeezed states generated in a three-waveguide nonlinear coupler operating with second harmonic generation is discussed. This study is carried out using two well-known techniques; the phase space method (based on positive-P representation) and the Heisenberg-based analytical perturbative (AP) method. The effects of key design parameters were investigated under various conditions, including full frequency matching, symmetrical and asymmetrical waveguide initialization, and both codirectional and contr-adirectional propagation. The system consistently produced long-lasting oscillatory squeezed states across all three waveguides, even when only one waveguide was pumped with coherent light while the others were in a vacuum state. Also, the performance and capacities of both methods are critically evaluated. For low levels of key design parameters and in the early stages of evolution, a high level of agreement between the two methods is noticed. In the new era of quantum-based technology, the proposed system opens a new avenue for utilising nonlinear couplers in nonclassical light generation. © The Author(s) 2024.