Widely Wavelength-Tunable Parity-Time Symmetric Single-Longitudinal-Mode Fiber Ring Laser With a Single Physical Loop
Bibliographic record
Abstract
A wavelength-tunable single-longitudinal-mode fiber ring laser based on parity-time (PT) symmetry for mode selection is proposed and experimentally demonstrated. The PT symmetry is implemented using a single physical fiber-optic loop, which functions equivalently to two mutually coupled optical loops with an identical geometry but balanced gain and loss. In the proposed system, a linearly polarized light wave is split into two, which are traveling in a Sagnac loop incorporating a polarization beam splitter (PBS) and two polarization controllers (PCs). By controlling the polarization states of the light waves injected into the PBS via tuning the PCs, the gain and loss of the two equivalent loops corresponding to the light waves traveling in the clockwise (CW) and counter-clockwise (CCW) directions are controlled. When the gain and loss are balanced and exceed the coupling coefficient, PT-symmetry breaking condition is met, and single-longitudinal-mode lasing is achieved. The proposed PT-symmetric fiber ring laser is experimentally demonstrated. Single-longitudinal-mode lasing with a tunable wavelength from 1530 to 1565 nm and a narrow linewidth as small as 390 Hz is achieved. The sidemode suppression ratio is 41.9 dB confirming the effectiveness of using PT symmetry for mode selection.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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 teacher head, 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".