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Optimized optical coupling to silica-clad photonic crystal waveguides
Optics Letters
|November 16, 2017
Summary
Researchers developed a novel junction to reduce optical loss in silicon photonic crystal waveguides (PCWs). This innovation significantly improves light coupling, enabling practical applications for slow light devices.
Area of Science:
- Photonics
- Materials Science
- Optical Engineering
Background:
- Silicon photonic crystal waveguides (PCWs) offer simple fabrication and slow light generation.
- High optical loss (>4 dB) during coupling to silicon wire waveguides limits PCW applications.
Purpose of the Study:
- To propose and validate a novel junction structure for reducing optical loss in PCWs.
- To enable efficient light coupling into slow-light PCWs for practical device integration.
Main Methods:
- Designed a junction structure utilizing an expanded core to couple light to a high-group-velocity radiation mode.
- Implemented a tapered core design to convert the radiation mode to the slow-light mode within the PCW.
- Calculated theoretical coupling loss and experimentally measured performance of fabricated devices.
Main Results:
- Achieved a minimum calculated coupling loss of 0.28 dB.
- Maintained coupling loss below 0.5 dB across a 12 nm wavelength range.
- Experimentally verified a low measured coupling loss of 0.46 dB in fabricated silicon photonic devices.
Conclusions:
- The proposed junction structure significantly reduces optical coupling loss in silica-clad silicon PCWs.
- This low-loss coupling method facilitates the practical integration and application of slow-light PCW devices.
- The findings support the broader adoption of PCWs in photonic integrated circuits.
