Restoring robust binary switching operation and exceptional point using long-period grating-assisted parity-time symmetric couplers

Vincent Brac de La Perrière (1) , Quentin Gaimard (1) , Henri Benisty (2) , Abderrahim Ramdane (1) , Anatole Lupu (1)

1 C2N (UMR_9001) - Centre de Nanosciences et Nanotechnologies
2 Laboratoire Charles Fabry / Naphel

The impact of imbalance in waveguides propagation constants among Parity-Time symmetric coupled waveguides and/or of a complex-valued coupling coefficient is assessed. The narrow tolerance found implies that attempts to tightly control waveguides parameters appear as elusive because of fabrication technology limitations, calling for more feasible mitigation avenues. It is shown that a grating-assisted Parity-Time symmetric coupler design restores both technologically robust binary switching operation and exceptional point. In addition the proposed design is compatible with birefringence compensation techniques providing polarization-independent operation as well as coupling and/or gain-loss profile modulation techniques that extend the control of switching operation in the Parity-Time symmetric phase. Using wavelength as an additional tuning parameter near exceptional points opens promising avenues for manipulating the trajectory on Riemann sheets in topological photonics applications.

Mots clés: Optical switching; Integrated optics; Parity-Time symmetry

Domaines: Sciences de l'ingénieur [physics]

Vincent Brac de La Perrière, Quentin Gaimard, Henri Benisty, Abderrahim Ramdane, Anatole Lupu. Restoring robust binary switching operation and exceptional point using long-period grating-assisted parity-time symmetric couplers. Journal of Physics D: Applied Physics, 2019, 52 (25), pp.255103. ⟨10.1088/1361-6463/ab11b4⟩. ⟨hal-02336274⟩