The issue is the fiber s diametral core size or the size of the optical glass core.
Fiber media converter multimode vs single mode.
Single mode cables are designed to carry light directly down the fiber.
While single mode fiber bandwidth is unlimited theoretically because it allows only one light mode to pass through at a time.
Fiber media converters can achieve up to 55 meters using multi mode fiber and up to 30 km using single mode fiber.
Whereas multimode sfp module works in 850nm wavelength due to the larger core size.
Single mode sfp vs multimode sfp.
This is why you rarely see yellow cables single mode in the same equipment rack or wall box as aqua or orange cables multimode.
Single mode cables are meant for long distance while multimode is often used for shorter distances.
Single mode sfp module has a narrower laser wavelength which works mainly in 1310nm and 1550nm wavelength.
Single mode fiber is able to support longer distances due to its smaller core which can measure between 8 to 10 5 microns μm and has a core to cladding ratio of 9μm to 125μm.
From the transmission distance single mode media converter is from 20km to 120km while multimode is 2km to 5km.
Multimode fiber bandwidth is limited by its light mode and the maximum bandwidth at present is 28000mhz km of om5 fiber.
It is a single strand of glass fiber and has a diameter of 8 5 10 microns.