Dispersion-engineered optical fibers for mid-infrared entangled single-photon generation

Area of Science:

• Quantum Optics
• Fiber Optics
• Photonics

Background:

• Near-infrared (NIR) single-photon sources are crucial for current quantum technology.
• Extending quantum applications into the mid-infrared (mid-IR) region offers significant potential due to unique spectral characteristics.

Purpose of the Study:

• To propose and investigate novel fiber-based methods for generating single photon-pair entanglement in the mid-IR wavelength range (approximately 2 µm to 3.5 µm).
• To explore spontaneous four-wave mixing (SpFWM) in germania-doped and ZBLAN fibers for mid-IR photon generation.

Main Methods:

• Utilized both same-mode (intramodal) and mixed-mode (intermodal) schemes for phase-matching signal, pump, and idler wavelengths.
• Exploited high numerical aperture (NA) fibers to generate closely spaced non-degenerate modes for intramodal phase-matching.
• Employed different fiber modes for signal, pump, and idler in the intermodal scheme, offering flexibility and mitigation of scattering effects.

Main Results:

• Demonstrated the feasibility of generating mid-IR single photon pairs using SpFWM in doped silica and ZBLAN fibers.
• Developed and modeled mixed-mode phase-matching schemes for optimizing mode selection and achieving phase-matching conditions.
• Showcased the potential for mitigating Raman scattering and residual pump photons through careful mode selection and mixed-mode schemes.

Conclusions:

• This study reveals the significant, previously untapped potential of fiber-based platforms for generating mid-IR entangled single photon pairs.
• The proposed methods pave the way for next-generation quantum technologies operating in the mid-IR spectrum.