What is the Difference Between Single-Mode and Multi-Mode Fiber?
This article explains the key differences between single-mode and multimode fiber, covering core diameter, wavelength, bandwidth, distance, and cost.
خلاصه تخصصی مقاله
This article explains the key differences between single-mode and multimode fiber, covering core diameter, wavelength, bandwidth, distance, and cost.
موضوعات اصلی: Fiber، Single-Mode، multimode، about، Core، micrometers
What is the Difference Between Single-Mode and Multi-Mode Fiber Optics?
Today, single-mode and multimode optical fiber are widely used in communication infrastructures. Some readers still find it confusing to understand their differences. This article highlights the main distinctions and explains them clearly.
Difference in Core Diameter
A primary difference is the core diameter. Single-mode fiber typically has a smaller core than multimode fiber. Commonly, the single-mode core is about 9 micrometers, while multimode cores range from about 50 to 62.5 micrometers. The cladding diameter is usually 125 micrometers.
Additionally, multimode fiber exhibits higher attenuation because of its larger core and multiple reflections along the path, which increases losses.
Wavelength and Light Source
Multimode fiber uses light sources with larger cores, such as surface-emitting diodes and diode lasers at wavelengths around 850 and 1300 nanometers. For single-mode fiber, lasers or diode lasers with wavelengths of 1310 and 1550 nanometers are used.
Bandwidth
The bandwidth of multimode fiber is limited—up to about 28,000 MHz per kilometer. In contrast, single-mode fiber theoretically offers unlimited bandwidth because light propagates in a single mode.
Fiber Jacket Colors
The coating color can indicate the fiber type. For non-military use, single-mode fiber is typically yellow, while multimode fiber is orange or blue.
To learn more about network equipment, review the article about network cables.
Distance
Distance is another differentiator. For long-haul applications, single-mode fiber is preferred due to fewer limitations, whereas for short distances multimode fiber is often chosen.
Cost
System costs for single-mode fiber are higher than for multimode fiber, influenced by module and installation expenses. The total system cost for SMF is roughly five times that of MMF, while installation costs are typically lower for SMF than for MMF.
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