Photon-to-Digital Converters: a 3D integrated digital SPAD array designed for precise timing applications
Bibliographic record
Abstract
We develop Photon-to-Digital Converters (PDC), a 64×64 SPAD array 3D integrated onto a CMOS readout with embedded digital processing. Using TSMC 65 nm CMOS, we have demonstrated embedded time-to-digital converters (TDC) with time conversion and alignment, time stamp sorting and weighted sums. A new multi-vernier TDC architecture now provides faster conversion and thus TDC unavailability. For time-binned quantum key distribution (QKD), we have implemented a time gating mode which allows narrowing down on relevant single photon signal within an expectation window. It also allows embedded categorization of the time stamps into relevant time bins, further reducing the volume of data needed to be transmitted. Using the high timing resolution capability, we also implemented a time resolved wavefront sensing mode that separates the signal of an optical pyramidal modulation into 48 epochs with the goal of improving measurement quality and increasing modulation frequency. We will review past work and present the architecture of the QKD and TR-PWFS PDC readout. We will also present the latest performance of the first batch of low power architecture PDC delivered fall 2024.
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How this classification was reachedexpand
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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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 itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, 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".