What does VCSEL stand for in fiber optic terminology?

• A. Vertical Cavity Surface Emitting Laser
• B. Very Compact Semiconductor Emitting Light
• C. Variation Cavity Signal Emitting Light
• D. Visual Cavity Source Emitting Laser

Answer: (A)

VCSEL stands for Vertical Cavity Surface Emitting Laser. In a VCSEL, the laser cavity is formed vertically between mirrors on the top and bottom of the active region, so the light is emitted perpendicular to the wafer surface. This vertical, surface-emitting geometry produces a circular, low-divergence beam that couples efficiently into fiber and enables compact, low-cost, wafer-scale fabrication and easy array integration. These characteristics define why this acronym is used in fiber optic terminology. The other options aren’t recognized terms in this field.