Implementation of a 3 × 3 directionally-unbiased linear optical multiport

Area of Science:

• Quantum Information Science
• Photonics
• Quantum Optics

Background:

• Linear optical multiports are fundamental in photonic quantum information processing.
• Conventional multiports are directionally-biased, limiting network design.
• Directionally-unbiased multiports offer enhanced flexibility by allowing bidirectional photon propagation.

Purpose of the Study:

• To experimentally demonstrate a directionally-unbiased 3x3 linear optical fiber multiport.
• To showcase a device that simplifies the construction of complex linear optical quantum networks.
• To provide a building block for large-scale quantum walks on intricate graph networks.

Main Methods:

• Utilized an optical tritter and mirrors to construct the 3x3 multiport.
• Employed fiber-based optical elements to achieve negligible optical path length differences.
• Designed the system to operate without requiring long coherence length light sources.

Main Results:

• Successfully implemented a directionally-unbiased 3x3 linear optical fiber multiport.
• The demonstrated multiport exhibits negligible optical path length differences across all trajectories.
• The device is compatible with various light sources, unlike previous bulk-optic implementations.

Conclusions:

• The fiber-based directionally-unbiased multiport is a practical advancement for quantum information processing.
• This technology reduces the complexity of quantum networks and facilitates quantum simulations.
• It serves as a key component for future research in quantum walks and complex network implementations.