Low-Cost Broadband Predistortion-Linearized Single-Drive x-Cut Mach–Zehnder Modulator for Radio-Over-Fiber Systems
Bibliographic record
Abstract
We experimentally demonstrate a low-cost broadband predistortion circuit (PDC) for the linearization of a single-drive x-cut Mach-Zehnder modulator (sd-xMZM) in broadband analog radio-over-fiber (RoF) links over 3-5 GHz. By tuning the bias current, the nonlinear characteristic of the PDC can be adjusted to linearize different types of nonlinear components in broadband analog RoF links over 3-5 GHz. By adding the PDC in front of the sd-xMZM, input-refereed 1 dB compression point (P1dB) is improved by 2 dB. By evaluating with the two-tone signal, the PDC allows 14 dB improvement in spurious free dynamic range at 4 GHz, and the third-order intermodulation distortion is suppressed by more than 6 dB over 3-5 GHz. Moreover, the error vector magnitude of an orthogonal frequency division multiplexing ultra-wideband signal is improved by more than 2.5 dB.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".