Measurement of In-Fiber Refractive Index Change Using a Mach–Zehnder Interferometer
Bibliographic record
Abstract
We report, for the first time, the use of a fiber optic Mach-Zehnder interferometer to measure core refractive index changes written by an ultrafast laser irradiation. The core-offset interferometer was constructed by splicing a slightly misaligned stub of standard single-mode fiber between the lead-in and lead-out optical fibers. When the core refractive index of an in-fiber interferometer is altered, it changes the phase of the core light. Since the phase of light propagating in the cladding (reference arm) remains unchanged, the transmission fringe pattern of the interferometer observes a spectral shift. The spectral shift was used to quantify the effective core refractive index change in a standard single-mode fiber. Measurements of effective refractive index changes as high as 0.01356 and as low as 0.000475 are reported in this letter.
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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 | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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".