Closed-loop phase stabilizing and phase stepping methods for fiber-optic projected-fringe digital interferometry
Bibliographic record
Abstract
Closed-loop active homodyne control can be used to make an interferometer steady against phase fluctuating followed by, for example, temperature gradients. This technology is introduced to stabilize π/2 -rad phase steps in a full-field interferometer. Two beams emitted from a fiber-optic coupler are combined to form an interference fringe pattern on a diffusely reflecting object. Fresnel reflections from the distal fiber ends undergo a double pass in the fibers and interference at the fourth port of the coupler which formed a Michelson interferometer. We suggested two means of ac phase tracking (PTAC) and dc phase tracking (PTDC) to maintain the interference intensity at quadrature by feedback control. Stepping between quadrature positions forces a π/2 -rad phase step. A method based on the ratio of harmonic of the interference signal was proposed to estimate phase step accuracy. A root-mean-square phase stability of 1.5 mrad and phase step accuracy of 2.6 mrad were measured with PTAC and a root-mean-square phase stability of 2 mrad and phase step accuracy of 13.8 mrad were measured with PTDC for the fiber-optic projected-fringe digital interferometry following the same condition. It worked well in two hours without resetting the integrator.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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".