Unified integration scheme using an N × N active switch for efficient generation of a multi-photon parallel state.

Area of Science:

• Quantum optics
• Photonic quantum information processing

Background:

• Large-scale photonic quantum circuits require efficient generation of multi-photon parallel states.
• Existing methods like serial-parallel conversion and multiplexed heralded single photon sources (HSPS) have limitations.

Purpose of the Study:

• To propose and demonstrate a novel, efficient method for generating multi-photon parallel states.
• To minimize optical losses and multi-photon events in the generation process.

Main Methods:

• Utilizing multiple heralded single photon sources (HSPS) integrated with an N x N active optical switch.
• Implementing a "unified integration scheme" to manage photon routing and minimize losses.

Main Results:

• Achieved an enhancement factor of 1.59 ± 0.14 using a 2x2 switch, outperforming naive and simple combination schemes.
• Demonstrated a reduction in multi-photon events to 62% compared to the naive scheme.
• Minimized optical losses within the active optical switch.

Conclusions:

• The unified integration scheme offers an efficient and improved method for generating multi-photon parallel states.
• This technique is crucial for advancing the development of large-scale photonic quantum circuits.
• The reduction in optical loss and multi-photon events enhances the feasibility of quantum technologies.