Rate classification

　　According to the speed, there are 155M/622M/1.25G/2.125G/4.25G/8G/10G, 155M and 1.25G are more used in the market, 10G technology is gradually maturing, and the demand is developing with an upward trend.

　　wavelength classification

　　According to the wavelength, there are 850nm/1310nm/1550nm/1490nm/1530nm/1610nm, the wavelength of 850nm is SFP multi-mode, the transmission distance is below 2KM, the wavelength is 1310/1550nm is single-mode, and the transmission distance is more than 2KM. Three wavelengths are less expensive than the other three.

　　If the bare module is not marked, it is easy to be confused. Generally, the manufacturer will distinguish the color of the pull ring. For example: the black pull ring is multi-mode and the wavelength is 850nm; blue is the module with a wavelength of 1310nm; yellow is a module with a wavelength of 1550nm ; Purple is the module with wavelength 1490nm, etc.

　　pattern classification

　　Multimode

　　Almost all multimode fibers are 50/125um or 62.5/125um in size, and the bandwidth (the amount of information transmitted over the fiber) is typically 200MHz to 2GHz. Multimode optical transceivers can transmit up to 5 kilometers through multimode optical fibers. Light-emitting diodes or lasers are used as light sources. The pull tab or body color is black.

　　single mode

　　Single-mode fiber is 9-10/125µm in size and has unlimited bandwidth and lower loss than multimode fiber. The single-mode optical transceiver is mostly used for long-distance transmission, sometimes reaching 150 to 200 kilometers. LDs or LEDs with narrow spectral lines are used as light sources. The pull tab or external color is blue, yellow or purple.

　　difference and connection

　　Single-mode fiber is cheap, but single-mode equipment is significantly more expensive than comparable multi-mode equipment. Single-mode equipment typically operates on both single-mode fiber and multi-mode fiber, while multi-mode equipment is limited to operation on multi-mode fiber.

　　The 10G module has undergone development from 300Pin, XENPAK, X2, and XFP, and finally realized the transmission of 10G signals with the same size as SFP, which is SFP+. With its advantages of miniaturization and low cost, SFP meets the high-density optical module requirements of equipment. Since the standard was pushed in 2002, it has replaced XFP to become the mainstream of the 10G market in 2010.