Progress toward photon-pair efficiency optimization using four-wave mixing in few-mode fibers.

Area of Science:

• Quantum optics
• Fiber optics
• Nonlinear optics

Background:

• Intermodal four-wave mixing (FWM) in few-mode fibers (FMFs) is a promising technique for generating entangled photon pairs.
• Previous research in single-mode fibers was limited by significant Raman scattering, which competes with FWM.
• FMFs offer a potential solution by leveraging modal dispersion to mitigate Raman interference.

Purpose of the Study:

• To investigate the impact of pump spectral separation on intermodal FWM power and bandwidth in FMFs.
• To explore the generation of photon pairs in various modes using dual-pump configurations in FMFs.
• To analyze the trade-off between photon efficiency and bandwidth under varying spectral separations.

Main Methods:

• Utilizing a seeding technique to study intermodal FWM.
• Employing two pumps in different modes within FMFs.
• Experimentally testing two FMFs with distinct differential mode group delay (DMGD) values.

Main Results:

• The study demonstrates that increasing spectral separation between pumps and generated photons affects FWM power and bandwidth.
• A larger spectral separation leads to decreased photon efficiency.
• Conversely, a larger spectral separation results in an increased bandwidth for the generated photon pairs.

Conclusions:

• The spectral separation of pumps and generated photons is a critical parameter in optimizing intermodal FWM for photon-pair generation.
• FMFs provide a viable platform for generating entangled photons with controllable properties.
• The findings offer insights into designing FMF-based quantum light sources with tailored spectral characteristics.