Parametric amplification based on intermodal four-wave mixing between different supermodes in coupled-core fibers.

Area of Science:

• Nonlinear optics
• Waveguide optics
• Quantum optics

Background:

• Parametric amplifiers utilize nonlinear four-wave mixing, producing symmetric gain spectra with signal and idler sidebands.
• Traditional parametric amplifiers generate both signal and idler frequencies, which can be undesirable for certain applications.

Purpose of the Study:

• To design a parametric amplifier in coupled nonlinear waveguides that achieves idler-free amplification.
• To explore the separation of signal and idler frequencies into different supermodes.

Main Methods:

• Analytical and numerical modeling of parametric amplification in two identically coupled nonlinear waveguides.
• Investigating the effect of pump power asymmetry as a control parameter.
• Leveraging the frequency dependency of coupling strength in coupled-core fibers.

Main Results:

• Achieved natural separation of signals and idlers into distinct supermodes.
• Demonstrated idler-free amplification for the signal-carrying supermode.
• Showcased the phenomenon as an analogue of intermodal four-wave mixing in multimode fibers.

Conclusions:

• Developed a novel approach for idler-free parametric amplification in coupled waveguides.
• The findings enable a new class of parametric amplifiers and wavelength converters.
• This technique is applicable to dual-core fibers and coupled waveguide systems.