A balanced homodyne detector for high-rate Gaussian-modulated coherent-state quantum key distribution
Bibliographic record
Abstract
We discuss the excess noise contributions of a practical balanced homodyne detector (BHD) in Gaussian-modulated coherent-state (GMCS) quantum key distribution (QKD). We point out that the key generated from the original realistic model of GMCS QKD may not be secure. In our refined realistic model , we take into account excess noise due to the finite bandwidth of the homodyne detector and the fluctuation of the local oscillator (LO). A high-speed BHD suitable for GMCS QKD in the telecommunication wavelength region is built and experimentally tested. The 3 dB bandwidth of the BHD is found to be 104 MHz and its electronic noise level is 13 dB below the shot noise at an LO level of 8.5 × 10 8 photons per pulse. The secure key rate of a GMCS QKD experiment with this homodyne detector is expected to reach Mbits s −1 over a few kilometers.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| 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".