What is the difference between single-mode fiber (SMF) and multi-mode fiber (MMF) optical transceivers?

Single-mode fiber (SMF) transceivers are used with single-mode fiber and offer long transmission distances, making them commonly used for long-distance transmission.

Multi-mode fiber (MMF) transceivers are used with multimode fiber and offer shorter transmission distances, but at a lower cost. They are often used for short-distance transmission within data centers.

It is strictly forbidden to mix single-mode and multi-mode optical fibers and modules, otherwise it may cause signal loss.