Bibliographic record
Abstract
This dissertation presents three all-fiber designs of passively mode-locked lasers in order to achieve high pulse energy, environmentally-stable dissipative soliton (DS) operation in all-normal-dispersion cavities. A numerical model for DS mode-locked fiber lasers based on the nonlinear Schrodinger equation has been used to guide the experimental designs. Firstly, an environmentally-stable and ultra-compact SESAM mode-locked fiber laser is demonstrated. The all-fiber design is realized using a mode-field-adaptor (MFA) to couple light onto the SESAM. A polarization-maintaining fiber loop mirror serves multiple functions as a highly reflective mirror, an output coupler and polarization selector. Self-starting and stable DS mode-locking operation is achieved with 1.7 nJ pulse energy and a 22 ps pulse width. Secondly, an ultra-stable DS mode-locking was demonstrated in a long cavity ring laser with a nonlinear amplified loop mirror (NALM) as a mode-locking device. The output pulses of 32 nJ, 615 fs de-chirped pulse width were obtained with the Raman signal suppressed below -20 dB in a 81 m long cavity. The mode-locking is self-starting and the mode-locked pulse train shows excellent stability. Thirdly, the mode-laser cavity was extended with a piece of large-mode-area (LMA) fiber with a low dispersion to further scaling up the pulse energy to 56.8 nJ. The laser pulses were compressed to 750 fs by a pair of volume gratings. In the processing of scaling-up the pulse energy of the NALM mode-locked fiber laser, some interesting physical phenomena were observed, such as the operation regime transition from noise-like to DS with a sudden reduction of Raman signal and a unique waves-splitting with a stable temporal spacing. The phenomena were studied and explained in this dissertation. In addition to the mode-locked fiber laser, a CW and a Q-switched fiber lasers were also designed with a single-mode- multimode- single-mode (SMS) filter as an effective mean of overcoming nonlinear effects. The transmission spectral property of the SMS was studied which fits well with theoretical calculation. One high efficiency SMS CW fiber lasers and one SMS Q-switched fiber laser were designed which showed the effectiveness of the SMS filter for inhibiting the SRS and significantly reducing SPM.
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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 | 0.001 |
| 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".