What is Category of Single-Mode Fiber?
According to the zero dispersion wavelength and cut-off wavelength displacement, single-mode fiber can be divided into six types, and ITU-T, the telecommunications standardization department of the International Telecommunication Union, has given the latest recommendations: G.652, G.653, G.654, G.655, G.656 and G.657 fibers.
|
Item |
ITU-T |
IEC |
| Non-dispersive displacement single-mode fiber | G.652:A,B,C,D | B1.1 / B1.3 |
| Dispersion displacement single-mode fiber | G.653 | B2 |
| Cut-off wavelength displacement single-mode fiber | G.654 | B1.2 |
| Non-zero dispersion displacement single-mode fiber | G.655:A,B | B4 |
| Broadband non-zero dispersion displacement single-mode fiber | G.656 | B5 |
| Bending attenuation insensitive fibers | G.657:A,B | B6 |
G.652D and G.657 dominate access networks, G.654.E and G.655 dominate long-distance trunk lines, and G.653 is accelerating its phase-out.
G.657 has more than 50% penetration in FTTH and data centers, G.656 has emerged in ultra-wideband networks, and G.654.E has solidified its position as a submarine cable with ultra-low loss.
| Fiber Type | Core Features | Typical Application |
|---|---|---|
| G.652 | Full band compatibility, cost-effective | backbone network, access network, data center |
| G.653 | 1550nm zero dispersion, susceptible to FWM | Early single-lane high-speed transmission (now rarely used) |
| G.654 | Ultra-low losses, long range advantages | ultra-long-distance transmission such as transoceanic submarine optical cables |
| G.655 | Non-zero dispersion, FWM resistant, DWDM supported | Long-distance, high-capacity DWDM backbone |
| G.656 | Ultra-wideband non-zero dispersion | Ultra-wideband and ultra-large-capacity long-distance transmission |
| G.657 | Excellent bending resistance | Access network (FTTH), indoor cabling |
G.652 Standard Single-Mode Fiber (Most Commonly Used)
Peculiarity:
The zero dispersion point is located in the 1310nm band, with very low dispersion at 1310nm (suitable for transmission in this band) and large dispersion at 1550nm (approximately 17ps/(nm・km)).
The loss at 1550nm is low (about 0.2dB/km), but the transmission distance at high rates (such as 10Gbps or more) is shorter due to dispersion limitations.
This fiber operates at both the 1310 nm and 1550 nm wavelength ranges, with its optimal operating wavelength in the 1310 nm range.
Subtype: G.652A/B/C/D, of which G.652D supports 1310nm and 1550nm full-band transmission for stronger compatibility.
Applications: Telecommunications backbone networks, access networks, data centers, are the most widely used single-mode optical fibers.
G.652D is the current mainstream model, widely used in long-distance communications, metropolitan area networks, fiber-to-the-home (FTTH), etc., supporting high-speed (10G/40G/100G) and multi-window transmission, adapting to complex network environments.
G.653 Dispersion Displacement Fiber (DSF)
Peculiarity:
It was developed to improve high-speed transmission performance at 1550nm by designing a zero-dispersion point displacement to the 1550nm band, taking into account the low loss and zero dispersion of this band.
There is a four-wave mixing (FWM) problem, which can cause signal interference in dense wavelength division multiplexing (DWDM) systems, limiting its application in high-capacity systems.
Applications: Once used for single-lane high-speed transmissions (such as early 10Gbps systems), it has been gradually replaced by G.655.
G.654 Cut-off Wavelength Displacement Fiber (Ultra-Low Loss Fiber)
Peculiarity:
The loss at 1550nm is extremely low (down to less than 0.15dB/km), making it the lowest loss type of all standard fibers.
It has a high cut-off wavelength (typically > 1530nm) and only supports transmission in the bands 1550nm and above, with dispersion characteristics similar to G.652 (zero dispersion at 1310nm).
Applications: Ultra-long-distance transmission (such as transoceanic submarine fiber optic cables) can reduce the number of repeaters and reduce costs.
G.655 Non-Zero Dispersion Displacement Fiber (NZ-DSF)
Peculiarity:
The zero dispersion point is moved out of the 1550nm band, and a small amount of dispersion (usually 0.1~6ps/(nm・km)) is retained at 1550nm, which not only avoids the four-wave mixing problem of G.653, but also meets the high-speed transmission requirements of DWDM systems.
Subtypes: Divided into different categories based on dispersion range, adapting to different rates (e.g., 10Gbps, 40Gbps, 100Gbps).
Application: Long-distance DWDM backbone network, which is currently the mainstream optical fiber type for high-capacity transmission.
G.656 Wideband Non-Zero Dispersion Fiber
Peculiarity:
Compared with G.655, it supports a wider operating band (covering the S, C, L band, about 1460~1625nm) and maintains non-zero dispersion characteristics throughout the band, meeting the needs of ultra-wideband DWDM systems.
Applications: Ultra-wideband and ultra-large-capacity long-distance transmission networks to meet the needs of higher bandwidth in the future.
G.657 Curved insensitive fiber for access networks
Peculiarity:
Designed for access networks, it has strong bending resistance (bending radius can be as small as 5mm or even 2mm), and it is not easy to increase losses due to bending when wiring (such as indoor corners and narrow spaces).
Subtypes: G.657A (compatible with G.652, bending radius of 10mm), G.657B (more resistant to bending, bending radius of 5mm), etc.
Applications: Fiber-to-the-home (FTTH), indoor cabling, short-distance connections in data centers, and other scenarios.
