Design of subwavelength-engineered surface grating couplers on a hybrid α-Si/SiN photonic platform
Bibliographic record
Abstract
The design of a high-efficiency grating coupler for silicon nitride (SiN) photonic integrated circuits is presented. Our devices use a high-index amorphous silicon (α-Si) overlay and subwavelength metamaterial apodization to achieve superior coupling efficiency compared to SiN-only gratings. The high index contrast of the α-Si layer results in increased grating strength, making it possible to radiate more power off-chip within the mode field diameter (MFD) of a standard single mode optical fiber. Simultaneously, through the use of subwavelength grating (SWG) apodization, we shape the radiated field to optimize the overlap with the Gaussian-like profile of the fiber mode at an operating wavelength of 1.31 μm. The overlap is further improved by considering a focalizing scheme, wherein the grating is designed to couple to a fiber placed a certain distance away from the chip. In this configuration, the constraint imposed on the length of the grating by the MFD of the fiber mode is relaxed, allowing for a longer structure that will diffract more power off-chip. By combining the use of an α-Si overlay with SWG apodization and beam focalization, we achieve a coupling efficiency of - 1.3 dB.
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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) | 0.000 | 0.000 |
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".