A simplified radio over fiber balanced system with suppression of both second- and third-order nonlinear distortions
Bibliographic record
Abstract
We present a simplified radio over fiber balanced system that uses only one wavelength, optical modulator and fiber. In this balanced system the upper and lower sidebands produced by subcarrier modulation along with its optical carrier are separated before balanced photodetection. Optical time delays are introduced to one of the sidebands by means of two cascaded tunable nonlinearly chirped fiber Bragg gratings. The first nonlinearly chirped fiber Bragg grating produces relative time delay that has the following relationship τdelay ∝ 1/2f, while the second produces a relative time delay of τ delay ∝ 1/f. The first nonlinearly chirped fiber Bragg grating will have a large enough bandwidth and group velocity dispersion to introduce a relative time delay for the subcarrier and second order distortion, while the second will have the bandwidth and group velocity dispersion to introduce a different relative time delay for the third order distortion. The net effect of the relative time delays is to provide a phase shift of π for the subcarrier, second order distortion currents and a phase shift of 2π for the third order distortion current. Simulated results show a suppression of 2nd and 3rd harmonic distortion of 25.4 dB and 2.6 dB, respectively. In the case of 2nd and 3rd intermodulation distortion suppression of 33 dB and 20 dB, respectively have been reported. Simulation also shows that the power penalty improvement is approximately 2.5 dB for bit error rate of 10-9 for subcarrier at 10 and 35 GHz and relative intensity noise is suppressed by 3 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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 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".