Today I will share with you the types of single-mode fiber. Optical fiber is a slender, soft solid glass substance, which consists of three parts: core, cladding, and coating, and can be used as a light transmission tool.
ITU-T recommended specification classification: G.651, G.652, G.653, G.654, G.655, G.656, G.657
The types of SMF (Single Mode Fiber) single-mode fiber are as follows:
- G.652 (dispersion non-shifted single-mode fiber)
- G.653 (dispersion-shifted fiber)
- G.654 (cutoff wavelength shifted fiber)
- G.655 (non-zero dispersion shifted fiber)
- G.656 (low-slope non-zero dispersion-shifted fiber)
- G.657 (bend resistant fiber)
G.652 Dispersion Unshifted Single Mode Fiber
G.652 fiber is a conventional single-mode fiber with the shortest cut-off wavelength, which can be used for both 1550nm and 1310nm.
When the working wavelength is 1310 nm, the fiber dispersion is very small, and the dispersion coefficient D is between 0 and 3.5 ps/nm·km, and the transmission distance of the system is only limited by the fiber attenuation. But the loss is relatively large, about 0.3 ~ 0.4 dB/km.
The loss of the working wavelength in the 1550 nm band is small, about 0.19-0.25 dB/km, but the dispersion is relatively large, about 20 ps/nm·km.
This kind of fiber can be used in the 2.5Gbps system in the 1550nm band, but due to the large dispersion in this band, if the signal of 10Gbps is transmitted, the dispersion compensation module must be used when the transmission distance exceeds 50 kilometers.
G.652 optical fiber is a kind of optical fiber that is widely used now. ITU-T divides G.652 into four types of optical fiber G.652.A, B, C, and D.
G.652.A optical fiber
Maximum transfer rate 2.5Gbps
G.652.B optical fiber
The highest rate is 10Gbps, and dispersion compensation is required for the highest rate transmission. It is suitable for the application environment with wavelengths of 1310nm/1550nm/1625nm. This kind of optical fiber has small bending loss and small transmission loss.
G.652.C optical fiber
The properties are basically the same as G.652A, but the attenuation coefficient at 1550nm is lower, and the water absorption peak near 1380nm is eliminated. It can work in the 1360nm~1530nm band.
G.652.D optical fiber
The properties are basically the same as G.652B fiber, and the attenuation coefficient is the same as G.652C fiber, that is, it can work in the 1360nm~1530nm band. It is the most stringent of all G.652 levels and fully backward compatible.
G.653 Dispersion Shifted Optical Fiber
G.653 Dispersion Shifted Fiber (DSF, Dispersion Shifted Fiber), based on G.652 fiber, moves the zero dispersion point from 1 310 nm to 1 550 nm, which solves the problem of the dispersion of 1 550 nm wavelength on single-wavelength high-speed System limitations.
This kind of fiber is very suitable for long-distance, single-channel, high-speed fiber optic communication systems. For example, a 20G b/s system can be directly opened on this kind of fiber without any dispersion compensation measures. However, due to the use of EDFA in DWDM, the optical power entering the fiber has been greatly improved, and the four-wave mixing caused by the nonlinear effect of the fiber has a serious impact on the DWDM system on the G.653 fiber, and G.653 has not been widely used. promote. The main reason is that in the 1550 nm window, the dispersion of G.653 is very small, and it is relatively easy to produce various optical nonlinear effect networks.
G.654 Cutoff Wavelength Shifted Optical Fiber
G.654 optical fiber is the optical fiber with the smallest loss at 1550nm wavelength. It is mainly used for submarine optical fiber communication that requires a long regenerative distance, but it cannot greatly increase the capacity of the optical fiber system. It is mainly used for long-distance relay without inserting active devices. Undersea fiber optic communication system.
G.655 Non-Zero Dispersion Shifted Optical Fiber
G.655 Non-Zero DispersionShifted Fiber (NZDSF, NonZero DispersionShifted Fiber) has reasonable and low dispersion in the 1 550 nm window, can reduce nonlinear effects such as four-wave mixing and cross-phase modulation, and can support long-distance transmission while minimizing the dispersion compensation network.
The dispersion value of the low dispersion slope G.655 fiber is below 0.05 ps/nm·km, the dispersion value in the wavelength range of 1530-1565 nm is 2.6-6.0 ps/nm·km, and the dispersion value in the wavelength range of 1565-1625 nm The dispersion value is 4.0-8.6 ps/nm·km.
G.656 low-slope non-zero dispersion-shifted fiber
G.656 fiber is to further expand the available wavelength range of the DWDM system, and maintain non-zero dispersion in the S (1460-1530 nm), C (1 530-1 565 nm) and L (1 565-1 625 nm) bands. A new type of optical fiber.
G.657 Bending Resistant Optical Fiber
Compared with other single-mode optical fibers, G.657 optical fiber is not sensitive to bending, and its bending loss is relatively small.
According to the principle of whether it is compatible with G.652 optical fiber, G.657 is divided into A type and B type optical fiber, and according to the principle of the minimum bendable radius, the bending level is divided into three levels: 1, 2, and 3.
