Shanghai Jiao Tong University enhances wavelength conversion

21 Oct 2024

New research is paving the way for more efficient quantum information transfer.

Geometry enables group-velocity mismatch of interacting lights to be smoothed to zero.

Advances in quantum information technology are paving the way for faster and more efficient data transfer. A key challenge has been ensuring that qubits, the fundamental units of quantum information, can be transferred between different wavelengths without losing their essential properties, such as coherence and entanglement.

Researchers from Shanghai Jiao Tong University (SJTU) recently announced significant strides in this area by developing a novel method for broadband frequency conversion, which it says is “a crucial step for future quantum networks”.

The work is described in Advanced Photonics.

The SJTU team focused on a technique using X-cut thin film lithium niobate (TFLN), a material known for its nonlinear optical properties. They achieved broadband second-harmonic generation—an important process for converting light from one wavelength to another—with a remarkable bandwidth of up to 13 nm. This was accomplished through a process called mode hybridization, which allows for precise control over the frequency conversion in a micro-racetrack resonator.

Schematic of the birefringent racetrack resonator on X-cut TFLN. Click for information.

‘Extensive applications’

According to corresponding author Professor Yuping Chen, “An efficient second-order nonlinear process with widely-tunable pump bandwidth has been a long-pursued goal, owing to the extensive applications in wavelength division multiplexing networks, ultrashort pulse nonlinearity, quantum key distribution, and broadband single-photon source generation.”

She added, “Thanks to the great progress in fabrication technology on the TFLN platform, this work will pave the way to chip-scale nonlinear frequency conversion between the ultrashort optical pulses and even the quantum states.”

Implications for integrated photonics

This achievement could have wide-ranging implications for integrated photonic systems. By enabling on-chip tunable frequency conversion, it opens the door to enhanced quantum light sources, larger capacity multiplexing, and more effective multichannel optical information processing.

As researchers continue to explore these technologies, the potential for expanding quantum information networks grows, bringing us closer to realizing their full capabilities in various applications.

• This article was firt published on spie.org.