Irreversible coupling by use of dissipative optics

Area of Science:

• Photonics and optical engineering
• Waveguide theory
• Nonlinear optics

Background:

• Time-reversibility in optical propagation limits the performance of devices like optical couplers and polarization converters.
• Achieving unidirectional light propagation is crucial for developing efficient integrated photonic circuits.

Purpose of the Study:

• To propose and demonstrate a novel method for achieving unidirectional optical mode interference and coupling.
• To break the inherent time-reversal symmetry in optical systems using engineered media.

Main Methods:

• Employing media with both loss and gain properties to break time-reversal symmetry.
• Implementing a matched periodic modulation of the refractive index and loss (gain) of the medium.
• Introducing a spatially single sideband perturbation to break symmetry and enable unidirectional energy transfer.

Main Results:

• Demonstrated unidirectional energy transfer between optical modes (e.g., mode m to mode n).
• Successfully implemented the concept in the context of coupling between two modes of a multimode optical waveguide.
• Showcased the breaking of symmetry for controlled light propagation.

Conclusions:

• The proposed method effectively achieves unidirectional optical mode interference and coupling.
• Engineered media with loss and gain offer a viable route to overcome limitations imposed by time-reversibility in optical devices.
• This technique holds promise for the development of advanced, high-performance light-wave circuits.