Comparison of Basic Structure of Single-mode Fiber and Multi-mode Fiber

The basic structure of optical fiber is generally composed of outer sheath, cladding, core, and light source. Single-mode fiber and multi-mode fiber have the following differences:

Sheath color difference: In practical applications, the outer sheath color of the fiber can be used to quickly distinguish between single-mode fiber and multi-mode fiber. According to the definition of TIA-598C standard, single-mode fiber OS1 and OS2 adopt yellow outer jacket, multi-mode fiber OM1 and OM2 adopt orange outer jacket, and OM3 and OM4 adopt aqua blue outer jacket (in non-military use).

Core diameter difference: Multi-mode fiber and single-mode fiber have a significant difference in core diameter, the core diameter of multi-mode fiber is usually 50 or 62.5µm, and the core diameter of single-mode fiber is 9µm. In view of this difference, single-mode fiber can only transmit optical signals with a wavelength of 1310nm or 1550nm on a narrow core diameter, but the advantage of a small core is that the optical signal propagates along a straight line in a single-mode fiber, without refraction, small dispersion, and high bandwidth; The multi-mode fiber core is wide, and it can transmit a variety of modes at a given working wavelength, but at the same time, because there are as many as hundreds of modes transmitted in the multi-mode fiber, the propagation constant and group rate of each mode are different, so that the band width of the fiber is narrow, the dispersion is large, and the loss is large..

The standard cladding diameter of most optical fibers is 125um, and the standard outer protective layer diameter is 245um, which does not distinguish single multi-mode.

Difference of light source: light source usually has two kinds of laser light source and LED light source. Single-mode fiber uses laser light source, multi-mode fiber uses LED light source.

The above is the comparison of the basic structure of single-mode fiber and multi-mode fiber brought by Shenzhen HDV Phoelectron Technology LTD., through a total of 3 points for you to explain, hoping to help those in need. Shenzhen HDV Phoelectron Technology LTD is mainly based on communication products for the production of manufacturers, the current production of equipment covers :ONU series, optical module series, OLT series, transceiver series. Can provide customized services for different scenarios of network needs, welcome to come to consult.