Fiber-coupled plug-and-play heralded single photon source based on Ti:LiNbO₃ and polymer technology

Area of Science:

• Quantum optics
• Integrated photonics
• Quantum communication

Background:

• Practical quantum communication demands reliable and cost-effective single-photon sources.
• Waveguide sources are ideal for fiber networks and hybrid integration.

Purpose of the Study:

• To present the first chip-size, fully integrated, fiber-coupled heralded single photon source (HSPS) module.
• To demonstrate a hybrid integration approach using lithium niobate and polymer technologies.

Main Methods:

• Hybrid integration of a nonlinear lithium niobate waveguide into a polymer board.
• Generation of photon pairs at 810 nm and 1550 nm via spontaneous parametric down-conversion.
• Fiber-coupling for pump input and dual photon output.

Main Results:

• A compact (2x1 cm²) module with full fiber coupling was fabricated.
• A heralded second-order correlation function (g^h(2)) of 0.05 was measured.
• A heralding efficiency (η_h) of 3.5% was achieved at low pump powers.

Conclusions:

• The developed HSPS module represents a significant step towards practical quantum communication.
• The hybrid integration approach offers a cost-effective and scalable solution for quantum photonic devices.