Single-mode fiber classified by fiber type

Optical fiber is a slender and soft solid glass substance, which consists of three parts: core, cladding and coating layer, and can be used as a light transmission tool.

ZR Cable fiber type

We also introduced various knowledge about optical fibers before, and today I will share with you the types of single-mode optical fibers.

ITU-T recommended norm classification: G.651, G.652, G.653, G.654, G.655, G.656, G.657

Among them, SMF (Single Mode Fiber) single-mode fiber types 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 Dispersive Non-Shifted 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, the dispersion coefficient D is 0-3.5 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 to 0.4 dB/km.

The loss of the working wavelength in the 1550 nm band is small, about 0.19 to 0.25 dB/km, but the dispersion is large, about 20 ps/nm·km.

This fiber can be used in a 2.5Gbps system in the 1550nm band, but due to the large dispersion in this band, if a 10Gbps signal is transmitted and the transmission distance exceeds 50 kilometers, a dispersion compensation module must be used.

G.652 fiber is a kind of fiber that is widely used now. ITU-T divides G.652 into 4 types of fiber G.652.A, B, C, and D.

G.652.A fiber

Maximum transfer rate 2.5Gbps

G.652.B fiber

The highest rate is 10Gbps, and dispersion compensation is required for the highest rate transmission. It is suitable for application environments with wavelengths of 1310nm/1550nm/1625nm. This type of fiber has small bending loss and small transmission loss.

G.652.C 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 fiber

The properties are basically the same as the G.652B fiber, and the attenuation coefficient is the same as that of the G.652C fiber, that is, it can work in the 1360nm~1530nm band. It is the most stringent of all G.652 levels and is fully backward compatible.

G.653 Dispersion Shifted 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, and solves the dispersion of 1 550 nm wavelength to single wavelength high speed System limitations.

This optical fiber is very suitable for long-distance, single-channel, high-speed optical fiber communication systems. For example, a system up to  20G b/s  can be directly opened on this optical 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. promotion. The main reason is that in the 1 550 nm window, the dispersion of G.653 is very small, and it is easy to generate various optical nonlinear effect networks.

G.654 Cutoff Shifted Fiber

G.654 optical fiber is the optical fiber with the smallest loss at the wavelength of 1550nm. It is mainly used for submarine optical fiber communication that requires a long regeneration distance, but it cannot greatly increase the capacity of the optical fiber system. It is mainly used for long-distance relays that do not need to insert active devices. Submarine fiber optic communication system.

G.655 Non-Zero Dispersion Shifted Fiber

G.655 Non-Zero Dispersion Shifted Fiber (NZDSF, NonZero Dispersion Shifted Fiber) has reasonable and low dispersion in the 1 550 nm window, which can reduce nonlinear effects such as four-wave mixing and cross-phase modulation, and can support long distances. transmission while minimizing the dispersion compensation net.

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 1 530-1 565 nm is 2.6-6.0 ps/nm·km, and the wavelength range of 1 565-1 625 nm is 2.6-6.0 ps/nm·km The dispersion value is 4.0 to 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 DWDM systems, and maintains 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 Bend Resistant Fiber

Compared with other single-mode fibers, G.657 fiber has the most notable feature of bending insensitivity and small bending loss.

According to the principle of compatibility with G.652 fiber, G.657 is divided into A-type and B-type fibers, and according to the principle of minimum bendable radius, the bending grades are divided into three grades: 1, 2, and 3.