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Refractive index profile measurements of diffused optical waveguides
Applied Optics
|February 6, 2010
Summary
Optical waveguide fabrication using diffusion methods was studied. Refractive index profiles were measured, revealing complementary error functions that differ from composition profiles in shallow diffusions.
Area of Science:
- Optics and Photonics
- Materials Science
- Semiconductor Physics
Background:
- Optical waveguides are crucial for photonic devices.
- Diffusion techniques are common for fabricating waveguides.
- Understanding refractive index profiles is key to device performance.
Purpose of the Study:
- To measure refractive index profiles in diffusion-fabricated optical waveguides.
- To correlate refractive index profiles with composition changes.
- To investigate shallow vs. deep diffusion effects on waveguide properties.
Main Methods:
- Reflection interferometric technique for refractive index profiling.
- Compositional analysis of diffused waveguides.
- Fabrication and characterization of Cadmium-diffused Zinc Selenide (ZnSe) waveguides.
Main Results:
- Refractive index profiles follow complementary error functions.
- Deep diffusions (>5 microm) show index profiles matching composition.
- Shallow diffusions (<5 microm) show index profiles deviating from composition.
- Relationship between Cd composition (<10%) and refractive index determined.
Conclusions:
- Diffusion depth significantly impacts the relationship between refractive index and composition in ZnSe waveguides.
- The complementary error function model accurately describes index profiles.
- Characterization of commercial diffused glass waveguides (SELFOC) was also performed.
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