Single-Lane 145 Gbit/s IM/DD Transmission With Faster-Than-Nyquist PAM4 Signaling
Why this work is in the frame
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Bibliographic record
Abstract
The performance of faster-than-Nyquist intensity modulation and direct detection (IM/DD) systems can be severely degraded by the inter-symbol interference (ISI) due to the component bandwidth limitation and the faster-than-Nyquist filtering. In addition, nonlinearities caused mainly by optical modulation and square-law detection can further deteriorate signal quality. Here, we propose to incorporate transmitter-side Tomlinson-Harashima precoding to mitigate the ISI and a Volterra nonlinear equalizer (VNLE) to mitigate the nonlinear distortions for PAM4 faster-than-Nyquist systems. We experimentally demonstrate a single wavelength 145 Gb/s PAM4 IM/DD transmission with bandwidth limited commercial components and sub-Nyquist sampling at 70 GSa/s. The optimal VNLE filter length is also investigated to balance the implementation complexity and system performance. In addition, compared with the scheme using transmitter-side duobinary precoding, receiver-side VNLE and maximum likelihood sequence estimation, both performance improvement and implementation complexity reduction are achieved.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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 it