High-efficiency apodized-imaging chip-fiber grating coupler for silicon nitride waveguides
Bibliographic record
Abstract
Chip-fiber grating couplers have been widely used in silicon-on-insulator platforms. In silicon nitride waveguides, the lower index contrast yields gratings with a weaker radiation strength and poor directionality, thereby limiting the coupling efficiency. Here we propose and design an apodized self-imaging grating coupler in silicon nitride that images an in-plane waveguide input to an output optical fiber placed at a specific distance above the chip. Both amplitude and phase apodizations are employed to engineer the transfer function of the self-imaging grating to produce an image field matching the fiber mode profile. Two-step etch staircase grating teeth are used to achieve directionality as high as 93%. Full three-dimensional finite-difference time-domain simulations show coupling from a 40 μm×40 μm grating to an SMF-28 single mode fiber with a record calculated efficiency of 86% (0.66 dB loss) and a 3 dB bandwidth of 40 nm near the 1550 nm wavelength.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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".