What is Fiber Optic and the Difference Between Single Mode Fiber and Multimode Fiber

Optical fiber is a communication medium for transmitting optical signals. It is composed of very thin optical fibers. Optical fiber communication uses the propagation of optical signals in optical fibers to achieve high-speed and long-distance data transmission.

Differences:

1. Single-mode fiber (SMF):

• Smaller core size: The optical core size of single-mode fiber is generally around 9 microns (μm), which is relatively thin.

• Transmission mode: Single-mode fiber supports one transmission mode, which means that only one beam of light signal is allowed to be transmitted along one path. This means that the light signal can only propagate along the center (axis) of the optical fiber.

• Transmission distance: Since only one beam of light signal is transmitted, dispersion and loss are reduced, so single-mode fiber can support longer transmission distances, usually in the range of tens of kilometers to hundreds of kilometers.

• Main use: Single-mode fiber is often used for long-distance high-speed transmission, such as metropolitan area networks, wide area networks, long-distance communications, etc.

2. Multi-mode fiber (MMF):

• Larger core size: The optical core size of multi-mode fiber is generally 50 or 62.5 microns (μm), which is relatively thick.

• Transmission mode: Multimode fiber supports simultaneous transmission of multiple optical signals along different paths, which means that optical signals can propagate along different angles.

• Transmission distance: Since the transmission of multiple optical signals will cause dispersion and modal distortion, multimode fiber is suitable for short-distance transmission, usually in the range of several hundred meters to several thousand meters.

• Main use: Multimode fiber is generally used for local area networks (LANs), internal communications in data centers, and short-distance high-speed data transmission.

Summary:

The main differences between single-mode fiber and multimode fiber are the optical core size, transmission mode, and transmission distance. Single-mode fiber is suitable for long-distance high-speed transmission, while multimode fiber is suitable for short-distance high-speed transmission. In practical applications, select the appropriate fiber type according to the needs to meet the transmission requirements.