Toward low-loss photonic crystal waveguides in InP/InGaAsP heterostructures

Area of Science:

• Photonics
• Materials Science
• Optical Engineering

Background:

• Line-defect photonic crystal waveguides in low-index-contrast semiconductor heterostructures suffer high propagation losses.
• Fabrication imperfections are often considered a primary cause of these losses.

Purpose of the Study:

• To experimentally demonstrate photonic crystal waveguides where fabrication imperfections are not the limiting factor for propagation losses.
• To achieve a new state-of-the-art for low propagation loss in such waveguides.

Main Methods:

• Fabrication of experimental photonic crystal waveguide structures.
• Experimental measurement of propagation losses.
• Electromagnetic simulations to analyze waveguide geometry and loss mechanisms.

Main Results:

• Demonstrated a propagation loss of 335±5 dB/cm, a factor of two improvement over state-of-the-art.
• Provided evidence that fabrication imperfections are not the dominant loss mechanism.
• Simulations indicated potential for even lower losses with modified waveguide designs.

Conclusions:

• Waveguide design, not fabrication imperfections, is the dominant factor limiting propagation losses in these devices.
• Further improvements in loss reduction require optimizing waveguide geometry rather than solely refining fabrication processes.