Recurrent multiport interferometers for fault-tolerant programmable photonics.

Area of Science:

• Photonics
• Quantum Computing
• Integrated Optics

Background:

• Universal linear programmable photonic circuits, often using Mach-Zehnder interferometers (MZIs), face limitations in fidelity and scalability.
• Current designs are difficult to scale due to their complexity and non-recurrent nature.

Purpose of the Study:

• To propose a novel, compact, and non-feedforward recurrent MZI topology for enhanced photonic circuit performance.
• To overcome the scaling and fidelity limitations of existing programmable photonic circuits.

Main Methods:

• Developed a recurrent MZI topology allowing bidirectional light propagation.
• Utilized a series of imperfect beamsplitters to achieve perfect transformations.
• Theoretically analyzed the error tolerance of the proposed recurrent interferometer under imperfect parameters.

Main Results:

• The proposed recurrent mesh architecture achieves O(N) scaling.
• Numerical results demonstrate a significant reduction in the resources required for implementing unitary transformations.
• The design shows improved error tolerance compared to traditional MZI arrays.

Conclusions:

• The novel recurrent MZI topology offers a promising solution for scalable and high-fidelity photonic circuit implementation.
• This approach significantly reduces the overhead for complex unitary transformations in photonic systems.