Difference Between Single-Mode and Multi-Mode in Optical Modules

In modern communication networks, optical modules play a crucial role as a bridge between optical and electrical signals. They not only convert electrical signals to optical signals for transmission but also convert received optical signals back into electrical signals to ensure accurate data delivery. Among optical modules, 100g single-mode fibers and 100g multi-mode modules are two common types, each with unique characteristics and application scenarios.

Features and Application Scenarios of 100g Single-Mode Fibers

100g single-mode fibers are typically used for medium to long-distance transmission, using single-mode fiber. The core of single-mode fiber is very thin (generally 9/125μm), and light propagates in a single mode, reducing mode dispersion and allowing the signal to be transmitted over longer distances. The operating wavelength of 100g single-mode fibers is generally 1310nm or 1550nm, using FD-LD or DFB-LD lasers as the light source.

• Wavelength: The operating wavelength is generally 1310nm or 1550nm.

  
  

• Transmission Distance: The transmission distance is generally over 10km, even reaching 150 to 200km, suitable for medium to long-distance transmission, such as metropolitan area network construction.

  
  

• Fiber Type: Uses single-mode fiber interconnection, with the cable color of single-mode fiber usually being yellow.

  
  

• Application Range: Mainly used in high data rate and long-distance lines, such as telecom networks, cable TV networks, and large enterprise networks. In the connections within and between data centers, when high-speed, high-capacity data transmission is needed, 100g single-mode fibers are also a better choice.

  
  

• Price and Compatibility: The price of single-mode optical modules is much higher than that of multi-mode optical modules, as single-mode optical modules use more components and the laser sources are more expensive. Single-mode devices can typically operate on both single-mode and multi-mode fiber (but may perform poorly on the latter).

  
  

• Color Identification: Yellow or blue pull-tabs may indicate 1550nm wavelength 100g single-mode fibers.

Features and Application Scenarios of 100g Multi-Mode Fibers

100g multi-mode fibers are mainly used for short-distance transmission, using multi-mode fiber. The core of multi-mode fiber is thicker (generally 50/125μm or 62.5/125μm), allowing multiple modes of light to transmit simultaneously, leading to mode dispersion and limiting the transmission distance. The operating wavelength of 100g multi-mode fibers is generally 850nm, using LEDs or VCSEL lasers as the light source.

• Wavelength: The operating wavelength is 850nm.

  
  

• Transmission Distance: The transmission distance is generally no more than 2km, suitable for short-distance transmission, such as data center interconnections.

  
  

• Fiber Type: Uses multi-mode fiber interconnection, with gigabit multi-mode fiber typically being orange, while 10-gigabit multi-mode fiber is often aqua.

  
  

• Application Range: Mostly used in short-distance, high node density transmission scenarios, such as data center machine rooms and local area networks. Within data centers, 100g multi-mode fibers can be applied in scenarios with many nodes, connectors, bends, many connectors and couplers, and a high number of light sources per unit fiber length.

  
  

• Price and Compatibility: Multi-mode devices are limited to operation on multi-mode fiber only.

  
  

• Color Identification: Black pull-tabs usually indicate 100g multi-mode fibers.

In conclusion, 100g single-mode fibers and 100g multi-mode fibers have significant differences in terms of wavelength, transmission distance, fiber type, light source, application range, price, and compatibility. Understanding these differences helps us better select and use optical modules to meet the needs of different network scenarios.