Role of hydrogen loading and glass composition on the defects generated by the femtosecond laser writing process of fiber Bragg gratings
Bibliographic record
Abstract
The creation of fiber Bragg gratings (FBGs) in optical fibers by laser irradiation causes the formation of defects in the modified glass. We have used confocal fluorescence spectroscopy to identify the location and types of defects formed after writing FBGs with the femtosecond laser phase mask technique. Our results show that non-bridging oxygen hole centers (NBOHCs) and self-trapped excitons (Eδ’) are formed throughout all-silica core Sumitomo Z-fiber. Similar defects are observed for Ge-doped silica fiber, Corning SMF-28, but in this case the relative concentrations of NBOHC and Eδ’ vary from the core to the cladding. In both fibers, hydrogen loading prior to irradiation appears to passivate the defects except in the Ge-doped core where the NBOHC defects persist.
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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 | 0.001 |
| 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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".