In the process of using and purchasing optical fiber, many customers asking, what is the difference between G657A1 and G657A2? Which is better? Which is the best fiber?
Answer: G657A optical fiber is bending insensitive single-mode optical fiber 9/125um, fully compatible with G652D optical fiber, mainly used for FTTH optical fiber wiring. However, the biggest difference are the minimum bending radius of G657A1 is 10mm, and that of G657A2 is 7.5mm. This means that the smaller the bending radius is, the better the confined and narrow space is, but the smaller the bending radius is, the higher the cost will be. Therefore, it is the best to choose the proper optical fiber according to the specific construction environment and project budget.
There are many types of optical fiber, which can be divided into single mode fiber and multimode fiber according to the transmission mode. G657 optical fiber is a kind of single-mode optical fiber, below will analyse single-mode optical fiber G652 and G657.
What type of fiber is G652D?
G652D is one type of G.652 fiber. G652D is the most stringent and completely down-compatible index value of all G652 levels. It has no difference with the general G652 optical fiber in structure, and is the best non-dispersion offset optical fiber for metropolitan area network at this stage.
G.652 Fiber:
G.652 fiber is single-mode optical fiber, capable of transmitting 1260~1360nm, 1530~1565nm, and zero dispersion point at 1310nm. G652 can be used in 1550nm optical wavelength to short distance transmission or mutual application with dispersion compensation fiber or control module.
G.652 Classification:
G.652 optical fiber is a kind of single mode fiber widely used on the Internet today. ITU-T divides G.652 into four types of optical fiber, namely G.652A G.652B G.652C G.652D.
- G.652A is applicable to 1Gbit/s system software transmission distance of 400km, 10Gbit/s Ethernet interface transmission distance of 40km, and 40Gbit/s system software transmission distance of 2km.
- G.652B optical fiber is applicable to 10Gbit/s system software with transmission distance of about 3000km, and 40Gbit/s system software with transmission distance of 80km.
- G.652C optical fiber has the same basic characteristics as G.652A, but the transmission coefficient is lower at 1550nm, and the absorption peak of water digestion around 1380nm is cleared, that is, the system software can work in the band of 1360~1530nm.
- G.652D characteristics are basically the same as G.652B, and the transmission coefficient is the same as that of G.652C, that is, the system software can work in the 1360~1530nm band.
What is G657A2 fiber?
G657A2 fiber is one type of single mode bend insensitive fiber G.657A series, its bend radius minimum is 7.5mm.
G.657 Optical fiber
G.657 is the latest member of ITU-T optical fiber series, which is based on the technical requirements of FTTx and its assembly and application. Its bend radius can maintain 1/4~1/2 of G.652 fiber.
G.657 Classification
According to the standard of compatibility with G.652 fiber, G.657 fiber is divided into Category A and Category B. G657A is fully compatible with G.652D optical fiber,it is used for access network, while G657B is not required to be compatible with G.652D fiber, it is used for short distances at the end of Access networks in bending-rich environments (e.g., buildings).
At the same time, according to the standard of min. Bend radius, G657 is divided into four types of fiber: G657A1 G657A2 G657B2 and G657B3.
What is G.657B fiber?
G.657B is one type of G657 bend insensitive single mode fiber. The characteristics and application scenarios of G.657B optical fiber are similar to those of G.652D optical fiber. In operation, the optical fiber can be used in D, E, S, C and L5 bands, and it can work in all optical wavelengths from 1260nm to 1625nm. G.657B optical fiber has stronger bending characteristics and more precise geometric specifications and technical standards in order to improve the fiber continuity characteristics in the optical fiber access network.
G.657B fiber work in wavelengths of 1310nm, 1550nm and 1625nm. It is more suitable for and maintains the transmission of FTTH information content, and is installed in rooms or buildings and other narrow places. The application of G657B fiber is only limited to the data signal transmission in the building. Its fusion and connection characteristics are completely different from those of G652, and it can work normally under the condition of very small bending half-diameter.
What is the difference between G657A and G657B?
G657A are fully compliant with ITU-T G.652.D fibres, used in access network, but G657B are fully compatible with ITU-T G.652.D fibres (only small differences in chromatic dispersion and polarization mode dispersion (PMD), which was used in short distance of access network.
| Features | Unit | G657A1 | G657A2 | G657B2 | G657B3 | ||||||||
| Macro bend diameter | Bend radius | mm | 15 | 10 | 15 | 10 | 7.5 | 15 | 10 | 7.5 | 10 | 7.5 | 5 |
| Number of rolls | – | 10 | 1 | 10 | 1 | 1 | 10 | 1 | 1 | 1 | 1 | 1 | |
| 1550nm max. | dB | 0.25 | 0.75 | 0.03 | 0.1 | 0.5 | 0.03 | 0.1 | 0.5 | 0.03 | 0.08 | 0.15 | |
| 1625nm max. | dB | 1.0 | 1.5 | 0.1 | 0.2 | 1.0 | 0.1 | 0.2 | 1.0 | 0.1 | 0.25 | 0.45 |
| Features | Unit | Technical data | |||||||||||
| G657A1 | G657A2 | G657B2 | G657B3 | ||||||||||
| 1310nm mode diameter | um | (8.6~9.5) ±0.4 | |||||||||||
| Macro bend diameter | Bend radius | mm | 15 | 10 | 15 | 10 | 7.5 | 15 | 10 | 7.5 | 10 | 7.5 | 5 |
| Number of rolls | – | 10 | 1 | 10 | 1 | 1 | 10 | 1 | 1 | 1 | 1 | 1 | |
| 1550nm max. | dB | 0.25 | 0.75 | 0.03 | 0.1 | 0.5 | 0.03 | 0.1 | 0.5 | 0.03 | 0.08 | 0.15 | |
| 1625nm max. | dB | 1.0 | 1.5 | 0.1 | 0.2 | 1.0 | 0.1 | 0.2 | 1.0 | 0.1 | 0.25 | 0.45 | |
| 1310nm~1625nm | dB/km | ≤0.40 （cable） | |||||||||||
| 3183±3nm | dB/km | ≤0.40 （cable） | |||||||||||
| 1550nm | dB/km | ≤0.30 （cable） | |||||||||||
| Dispersion features | Zero dispersion wavelength | nm | 1300~1324 | 1250~1350 | |||||||||
| Zero dispersion slope | Ps/nm2xkm | ≤0.092 | ≤0.11 | ||||||||||
| Polarization mode dispersion characteristics | M | – | 20 | 20 | |||||||||
| Q | – | 0.01% | 0.01% | ||||||||||
| PMDQ max | Ps/km1/2 | ≤0.20 | ≤0.50 | ||||||||||
Details like below:
| G.657 (2012) | |
| For access networks G.652.D compliant All bands 1260-1625nm | For end of access networks (e.g., in/near buildings) G.652.D compatible All bands 1260-1625nm |
| A1 Radius min. = 10mm | B2 Radius min. = 7.5mm |
| A2 Radius min. = 7.5mm | B3 Radius min. = 5mm |
What is the difference between G657A1 and G657A2?
From above chart, we can know that the mainly difference of both type are the bend radius differs in 3 wavelength 1310nm 1550nm 1625nm, others are the same. For example, operation in 1310nm wavelength, G657A1 minimum bend radius is 10mm, G657A2 minimum bend radius is 7.5mm, which result in G657A2 is more suitable for limited space like corners or ftth mini wall outlet or termination boxes.
What is the difference between G657B2 and G657B3?
From above chart, we can know that the mainly difference of both type are the bend radius differs in 3 wavelength 1310nm 1550nm 1625nm, others are the same. For example, operation in 1310nm wavelength, G657B2 minimum bend radius is 7.5mm, G657B3 minimum bend radius is 5mm, which result in G657B3 is more suitable for limited space.
FAQ
What is difference between G652D and g657a?
G657A fiber is fully compliant with G652D fiber, that means if upstream or downstream use G652D fiber, we can use G657A fiber to connect it, and vice versa. The G657A minimum bend radius is smaller than G652D, G652D is min. 30mm, G657A is 7.5mm in G65A71, 10mm in G65A72.
How do I know if my fiber is OS1 or OS2?
OS1 fiber optic cable is designed for premises where the maximum distance is 2,000 metres with transmission speeds of 1 to 10 gigabit Ethernet. OS2 fiber optic cable is designed for larger transmission distances in the range of 5,000 to 10,000 metres with similar transmission speed of 1 to 10 gigabit Ethernet.
Which fiber cable is best?
4 types of single mode fiber all are good, final choice should refer to different project requirements, application, project budget, fiber brand, preferences of different countries and products.
Below are some suggestions:
- G652D: Marginally lower attenuation and lower splicing losses, when splicing, it provide longer cable networks.
- G657A1: Smaller cable and cords installation radius, providing for low-cost installation, mini aturisation and higher density connection.
- G657A2 optical fibre in patch cords provide an improved bend radius and flexibility, which may allow for better cable management and routing in congested areas. The improved bend radius may also allow for increased density in high-density patching fields. G657A2 fiber is becoming very popular in the Data Centre and Enterprise network deployments.
In Middle East, most customers specify G657A2 fiber. For the splitters, the standard is G657A1, but some countries like Southeast Asia low cost need countries request G652D instead.
For the cost of fibers, the smaller the min. bend radius, the higher the cost is, if you need any fiber brand, please let us know in advance, such as Corning, Draka, OFS,etc. If not specify, we will use China brand YOFC, Fiberhome, etc.
Yingda has a full range of G652D and G657A2 connectivity infrastructure to suit any network, large or small.
What is the advantage of the g657a fiber?
G657a fiber offers flexible and easier optical deployment in streets, buildings and homes, reduces the roll-out cost for operators and the total cost of ownership (TCO) of an FTTH network, because its minimum bend radius ensure to use in limited space like corners or apartment buildings,small wall outlet, cabinets, pedestals, splice enclosures, or termination boxes.
Meanwhile, due to this characteristics, it can reduce installation difficulty and less rework and repair.
What is the bend radius of G 652 D?
G652D bend radius is minimum 30mm. In the mass production, we will wrap the one-meter jumper or pigtails for 2 turns to ensure its bending radius within reasonable range.
What is the bend radius of g657a1?
G657A1 bend radius is minimum 10mm, G657A2 bend radius is minimum 7.5mm, G657B3 bend radius is minimum 5mm.
What are the 2 types of fiber optic cable?
Fiber optic cable can be divided into single mode fiber and multimode fiber.
What are the difference, single mode vs multimode fiber?
Bare fiber have 3 layers, fiber core, cladding, and coating. The bare fiber outer diameter is 250um, the cladding layer diameter is 125um, both types of fiber are the same in both layers, but fiber core are different.
Single mode fiber core diameter is 9um, that is 9/125um, OS1, OS2 all mean single mode fiber, single mode fiber optic cable sheath is yellow color, if armored cable is blue color standard; Multimode fiber core is 50um or 62.5um, which is thicker than single mode, that is 50/125um, 62.5/125um, most of the time, will use OM1 OM2 OM3 OM4 OM5 to specify too. We can see the difference from the cable color, connector color or print on the cable sheath, details please see related articles.
What is difference between g652d and g655?
G652 is currently the most popularly adopted single mode fiber, for which G652 is defined as Standard SMF and commonly used to support 10GbE and 40GbE system. It is a zero dispersion wavelength at 1310nm and reduced water peak to support CWDM.
G655 is known as nonzero dispersion-shifted fiber (NZDSF), because the dispersion at the wavelength of 1550nm is close to zero but not zero. It is suitable for DWDM system to meet increasing transmission capacity and long haul high capacity WDM transmission system.
| Fiber type | G652 | G655 |
| Alternative name | Standard SMF / zero dispersion-shifted fiber (non dispersion-shifted fiber) | Nonzero dispersion-shifted fiber (NZDSF) |
| Specified wavelength | 1310nm, 1550nm, 1625nm (C and D excluded) | 1550-1625nm |
| Dispersion point | 1310nm | 1550nm |
| Dispersion value | Higher | Low |
| Attenuation parameter | Less than 0.4dB/km | Typically 0.2dB/km at 1550nm |
| PMD parameter | Less than 0.5 over C and 0.2 over D | Less than 0.1 ps/sqrt (km) |
| Applications | LAN,WAN,access networks and CWDM transmission | Long-haul systems that use DWDM transmission |
| Price | Lower than G655 | High |
| Features | Reduced water peak | Low dispersion value; overcoming nonlinear effect |
Table 3: Technical indicators of G652D vs G655
