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SU8 3D prisms with ultra small inclined angle for low-insertion-loss fiber/waveguide interconnection
Minh-Hang Nguyen1, Chia-Jung Chang, Ming-Chang Lee
1Department of Engineering and System Science, National TsingHua University, Hsinchu, Taiwan.
Optics Express
|October 15, 2011
Summary
Researchers developed a simple method to create 3D SU8 prisms for efficient optical fiber and planar waveguide connections. These prisms significantly improve transmission efficiency in silicon-on-insulator waveguides, reducing coupling and radiation loss.
Area of Science:
- Photonics and Optical Engineering
- Materials Science and Nanotechnology
Background:
- Optical interconnects are crucial for high-speed data transmission.
- Low insertion loss is essential for efficient optical coupling between waveguides and fibers.
- Fabricating precise micro-optical components for such applications remains challenging.
Purpose of the Study:
- To present a novel, simple method for fabricating three-dimensional (3D) SU8 prisms.
- To achieve ultra-low inclined angles for improved optical fiber/planar-waveguide interconnection.
- To reduce insertion loss in optical coupling applications.
Main Methods:
- Combining self-filling, molding, and nano-lithography processes on a planar surface.
- Fabrication of SU8 (epoxy-based negative photoresist) prisms.
- Characterization of prism geometry (inclined angle) and surface roughness.
Main Results:
- Successfully fabricated 3D SU8 prisms with an ultra-low inclined angle of 0.6°.
- Achieved a small surface roughness of 3.5 nm on the prisms.
- Demonstrated a 4.6-fold improvement in transmission efficiency for silicon-on-insulator (SOI) waveguides.
- Reported coupling loss of 11 dB per taper and radiation loss of 2.4 dB per taper.
Conclusions:
- The developed method offers a simple and effective way to fabricate 3D SU8 prisms for optical interconnects.
- The ultra-low inclined angle and low surface roughness of the prisms enable low-loss coupling.
- This technique significantly enhances the performance of SOI waveguides, paving the way for more efficient optical communication systems.
