A SNAP coupled microresonator delay line.

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Traditional resonant delay lines face limitations in achieving significant light delay and low loss.
• Surface Nanoscale Axial Photonics (SNAP) offers a novel approach for light manipulation due to its 3D light propagation capabilities.

Purpose of the Study:

• To demonstrate a delay line based on a chain of coupled SNAP microresonators.
• To investigate the slow light enhancement via the 2R (Rotation + Reflection) effect in SNAP structures.
• To characterize the performance of the SNAP delay line in terms of delay time, bandwidth, and insertion loss.

Main Methods:

• Fabrication of a delay line using 20 coupled SNAP microresonators.
• Characterization of light propagation and delay properties in a reflection-mode configuration.
• Analysis of the influence of coupling parameters and loss on delay time.

Main Results:

• Demonstration of a SNAP delay line with a total length of 1.2 mm and footprint of 0.05 mm².
• Achieved a record low insertion loss (< 3 dB) and a slow light speed (< c/250).
• Obtained a large delay time (> 1 ns) over a 0.1 nm bandwidth, outperforming existing miniature microresonator delay lines.

Conclusions:

• The SNAP delay line effectively utilizes the 2R effect for enhanced slow light.
• The demonstrated device exhibits record performance metrics for miniature delay lines.
• Future improvements in delay time, bandwidth, losses, and dimensions are feasible through advanced design techniques.