Towards Self-Pumped Difference Frequency Generation in Bragg Reflection Waveguide Lasers
Bibliographic record
Abstract
Bragg reflection waveguide lasers are demonstrated in the GaAs/AlGaAs material system for phase-matched frequency conversion through second order nonlinearities. Bragg waveguide design considerations such as modal propagation loss and far-field are studied. Effect of etch depth on propagation loss of 2D ridge Bragg lasers is assessed both theoretically and experimentally, and the underlying physics is examined. The results allow for design of functional Bragg lasers with minimal propagation loss. Far-field properties of Bragg lasers are also systematically investigated providing an analytical framework for the design of single-lobed far-field operation of devices for improved in- and out- coupling to integrated devices. An ebeam lithography process is developed for the fabrication of various laser configurations including ring and DFB lasers in a single-sided Bragg laser structure. This is the first time that the full fabrication of diode lasers based on ebeam lithography is developed in the TNFC cleanroom in University of Toronto. The fabricated lasers are tested for various characteristics such as laser performance, modal analysis, and nonlinear conversion. The mode selection mechanism in the single-sided structure is studied and based on the results an improved double-sided Bragg laser wafer design structure is proposed. The new wafer design is confirmed to emit only at the Bragg mode, which shows the efficacy of the applied methodology. A comprehensive study of difference frequency generation (DFG) is presented in double-sided ridge Bragg lasers. We report internal normalized nonlinear conversion efficiency of 1.84/W/cm2 in the structure, as a first time demonstration of DFG in active semiconductor devices. Tuning of phase-matching wavelength through thermal effects as well as current injection is documented. This study provides a clear roadmap to inform future device designs to realize self-pumped DFG, and to predict their performance when electrically injected. When fully optimized, milliwatt level output powers can be generated through nonlinear conversion using this platform, which is useful for various applications such as on-chip sensing. % Specifically, a surface Bragg grating was integrated with the Bragg lasers for light emission at the phase-matching wavelength and self-pumped DFG. Lastly, given that the current platform can allow for self-pumped nonlinear generation, an analysis of modulation properties of such semiconductor optical parametric oscillators was carried out and presented. To facilitate the analysis of dynamic properties, a novel model based on diode laser rate equations and nonlinear conversion is developed.
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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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".