We propose fast and robust beam coupling in a three waveguide directional coupler based on Lewis-Riesenfeld invariant theory. This method provides shortcuts to optical waveguide couplers based on coherent tunneling adiabatic passage of photons. The design and performance of directional couplers using the invariant-based inverse engineering are discussed. Beam coupling is achieved by engineering the evolution of the eigenmodes of the invariant. We show that the invariant-based inverse engineering scheme reduces coupler length as compared with the common adiabatic scheme. The device is robust against coupling coefficient variations and has broadband characteristics.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering