Bibliographic record
Abstract
The implementation of optical of wireless communications (OWC) requires the use of a light-emitting-diode (LED) or laser diode (LD). Due to significant path loss exhibited by these sources in an outdoor environment, an unobstructed point-to-point link must be maintained in order to increase the signal-to-noise ratio (SNR) at the receiver. This thesis considers a solution to alleviate the fundamental limitations of the OWC channel in an outdoor environment by investigating optical beam steering (OBS) to increase the signal strength in the desired direction. Conventional methods to implement on OBS use a microelectromechanical (MEMS) mirror or a spatial light modulator (SLM) which both suffer from low switching frequency. A high frequency OBS device can be created by using optical phased array (OPA). An electro-optic modulator (EOM) such as LiNbO3 can be used to create an OPA but can not be directly integrated in silicon. For monolithic silicon-on-insulator (SOI) solutions, previous literature uses thermo-optic couplers on SOI to implement the OPA, however this introduces the issue of thermal cross-talk. Therefore, this thesis focuses on the use of silicon as the EOM for use in an OPA to create a high frequency monolithic OBS. Our contributions consist of providing a design method for a OBS SOI device which exhibits minimum internal cross-talk and provides propagation in free-space with high directivity and a wide steering range. Additionally, propose the use of an internal heterodyne optical phase locked loop (PLL) to stabilize the OBS instead of an external signal processor for phase correction. This optical PLL reduces beam jitter, minimizes beam squint, and provides active tracking for the output beam towards the receiver. We have also characterized a shadowing scenario in an OWC channel which OBS has the potential to alleviate. Moreover, we simulated the optical far-field radiation pattern from a SOI waveguide to free-space which has not been demonstrated in previous research. Finally, our simulation results of a SOI OPA demonstrates the coherent combining capability of OBS using MEEPTtm and the Optiwavetm suite.
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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 | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.002 |
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".