Photonic True-Time Delay Beamforming Using a Switch-Controlled Wavelength-Dependent Recirculating Loop
Bibliographic record
Abstract
A photonic true-time delay beamforming network to provide tunable progressive time delays for phased array beamforming is proposed and demonstrated. In the proposed system, a microwave signal is modulated on multiwavelength optical carriers and sent to an optical dispersive recirculating loop that contains a linearly chirped fiber Bragg grating (LCFBG) to provide a wavelength-dependent round trip time. As the microwave-modulated optical signals recirculate in the loop, the microwave signals carried by different wavelengths will experience different time delays at the output of the loop. By controlling the number of round trips, tunable progressive true-time delays are achieved, which are required for true-time delay phased array beamforming. The proposed true time delay beamforming network is experimentally evaluated. Two dispersive loops that can introduce a single-round-trip true-time delay difference of 2.5 ns and 160 ps are designed, which are implemented by using two LCFBGs with two different dispersion coefficients of 2500 and 200 ps/nm. The progressive time delays for beam steering achieved by the two dispersive loops can cover a beam scanning range from -60° to 60°.
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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".