Trench isolated rib waveguides on silicon-on-insulator
Bibliographic record
Abstract
The current trend towards integrating CMOS circuitry and photonic devices on silicon-on-insulator (SOI) wafers into monolithic optoelectronic circuits requires modification of the traditional rib waveguide to provide a planar surface. One possible modification involves creating a trench on either side of the rib and then filling this trench with a planarizing oxide. The resulting planar surface is much more compatible with the photolithographic systems required to print the small dimensions found in state-of-the-art CMOS. We report the fabrication of prototype trench-isolated waveguides, measurement of optical performance and comparison with simulation. 2.5 μm thick Si film was utilized with 0.5 μm deep trenches ranging from 1 to several microns in width. Rib widths ranged from 2 μm to 3 μm (the maximum value providing single mode propagation). Allowed modes were determined with FEMLAB, while beam propagation was studied using Optiwave BPM. Simulation indicated mode confinement would be lost for trench widths less than 1.5 μm. The narrowest trench width which could be fabricated was 2.0 μm, and qualitative optical testing shows good mode confinement to the central rib for a trench geometry greater than 3.0 μm.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".