Physics / mechanism
Vertical-Cavity Surface-Emitting Lasers emit light perpendicular to the wafer surface via a resonant cavity formed between two distributed Bragg reflector (DBR) mirror stacks sandwiching a quantum-well active region. Stimulated emission occurs along the growth axis; single-mode operation is achievable at small apertures (3–5 µm). Key parameters: threshold current (sub-1 mA for small aperture), wall-plug efficiency (up to ~60% for 850 nm GaAs devices), modulation bandwidth (>30 GHz for datacom VCSELs), and beam quality (circular, low-divergence). Wavelengths span 670 nm–1550 nm depending on material system. State-of-the-art 940 nm VCSELs (Apple Face ID era) achieve >50% PCE; 1550 nm InP VCSELs remain efficiency-constrained. High-volume fabs now run VCSEL wafers on 6-inch GaAs.
Competitive landscape
Edge-emitting lasers (EELs/FP/DFB) offer higher power-per-emitter and longer coherence but require cleaved facets, are harder to test on-wafer, and don’t array as easily. VCSELs dominate short-reach datacom, 3D sensing, and LiDAR illumination where array density and testability matter.
VCSELs in COMPUTING (added 2026-07-11 — full map: Optical Compute Landscape)
Investment relevance (all routes)
| Parameter | VCSEL | Edge Emitter | VCSEL Array |
|---|---|---|---|
| Single-emitter power | <10 mW typ. | 100 mW–W | — |
| On-wafer testability | Yes | No | Yes |
| Beam quality | Circular | Astigmatic | Engineered |
| Wavelength range | 670–1550 nm | 400 nm–3 µm | Same as single |
Companies using
Connected ideas
Sources
Frontier (open questions)
- To be added.