Optimization of Chirp and Tilt of Fiber Bragg gratings for Raman Emission Suppression
Bibliographic record
Abstract
In recent years, chirped and tilted fiber gratings (CTFBG) have become promising all-fiber components for the suppression of Stimilated Raman Scattering (SRS) in high power fiber lasers (HPFLs). A CTFBG acts as a smooth wideband filter with an engineered central wavelength. It can be used to couple SRS light from fiber core mode to fiber cladding modes [1] . However, a CTFBG may fail to achieve SRS suppression because of the residual core-to-core Bragg reflection that typically attains −20 dB [2] , [3] . Moreover, the chirp direction with respect to light flow has an impact on the reflected spectrum of a CTFBG, and thus one direction must be advantageous over the other. Here, we report the impact of the tilt angle and chirp direction of a CTFBGs inserted at the output of a HPFL. Several CTFBGs are compared, with tilt angles spanning 4 ◦ − 6 ◦ and for both chirp directions. We conclude that CTFBGs optimal for SRS suppression should be oriented with SRS entering from the long wavelength chirp side, as well as their tilt angle should be close to 5 ◦ .
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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) | 0.001 | 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".