High-order dispersion in photonic crystal waveguides

Area of Science:

• Photonics
• Optical Engineering
• Materials Science

Background:

• Slow-light phenomena in photonic crystals enable enhanced light-matter interactions.
• High-order dispersion effects can significantly impact optical pulse propagation in waveguides.

Purpose of the Study:

• To accurately measure high-order dispersion in photonic crystal waveguides operating in the slow-light regime.
• To compare experimental dispersion measurements with theoretical predictions.
• To investigate the influence of third-order and fourth-order dispersion on pulse broadening.

Main Methods:

• Utilized integrated Mach-Zehnder interferometer (MZI) structures for precise dispersion measurements.
• Employed 3D plane-wave calculations for theoretical dispersion analysis.
• Minimized external phase distortions and enhanced signal-to-noise ratio for high accuracy.

Main Results:

• Experimental measurements of group-velocity dispersion (GVD), third-order dispersion (TOD), and fourth-order dispersion (FOD) were obtained at high group-index (n(g)) values (approximately 100).
• Measured dispersion parameters were approximately 10^2 ps²/mm for GVD, 10^4 ps³/mm for TOD, and 10^5 ps³/mm for FOD.
• Experimental results showed good agreement with theoretical calculations.

Conclusions:

• High-order dispersion, specifically TOD and FOD, significantly affects pulse broadening in slow-light photonic crystal waveguides.
• Accurate characterization of these dispersion effects is crucial for designing and optimizing slow-light devices.
• The integrated MZI approach provides a robust method for high-precision dispersion metrology.