Characterizing photonic crystal waveguides with an expanded k-space evanescent coupling technique

Area of Science:

• Optics and Photonics
• Materials Science

Background:

• Photonic crystal waveguides (PCWGs) are crucial for integrated optics.
• Characterizing their dispersive properties and losses is essential for device design.
• Existing methods can be complex and time-consuming.

Purpose of the Study:

• To introduce a direct, single-measurement technique for PCWG characterization.
• To enable efficient measurement of waveguide dispersion and propagation losses.
• To validate the new method against established techniques.

Main Methods:

• Utilizing a tapered fiber evanescent coupling method.
• Probing the Fabry-Pérot spectrum of a closed PCWG with a highly curved fiber taper.
• Measuring propagation losses using closed waveguides of varying lengths.

Main Results:

• Successfully characterized the dispersion of a 'W1' PCWG in chalcogenide glass.
• Obtained accurate dispersive properties over a broad k-space range.
• Estimated waveguide propagation losses effectively.

Conclusions:

• The tapered fiber evanescent coupling method provides a direct and efficient way to characterize PCWG dispersion.
• This technique offers a valuable tool for photonic device development and analysis.
• The method's validity is confirmed through comparison with numerical simulations.