Low-loss Type II waveguide writing in fused silica with single picosecond laser pulses
Bibliographic record
Abstract
A new domain of rapid waveguide writing with non-overlapping pulses of a 1-kHz ultrashort laser is demonstrated to produce low loss waveguides in fused silica glass. This new regime is distinguishable in two ways from traditional approaches in laser waveguide writing. First, an examination of a wide 50-fs to 5-ps range of pulse duration shows the lowest loss waveguides to form in a narrow 1.0 +/- 0.2 ps window that significantly exceeds the 50 - 200 fs duration reported as optimal in other studies. Second, an unusually high scan speed of 1.0 +/- 0.2 mm/s points to a novel Type-II photosensitivity mechanism for generating low-loss refractive index structures. The waveguides comprise of an array of nearly isolated single-pulse interaction volumes that sharply contrast with the high exposures of tens to thousands of overlapping laser pulses typically applied along a slowly moving focal volume. A minimum propagation loss of ~0.2 dB/cm and a slightly asymmetric mode diameter of ~9 mum is reported for 633-nm light. The low loss waveguides fabricated with picosecond pulses enables 3-D photonics circuit fabrication with simpler and lower cost picosecond laser systems.
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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 | 0.000 | 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".