| Class (type) of optical fibers | Recommendation of ITU-T |
| Multimode 50/125 um with graded-index profile | G.651 |
| Standard single-mode | G.652 |
| Single-mode with shifted dispersion | G.653 |
| Single-mode with shifted cutoff wavelength | G.654 |
| Single-mode with non-zero shifted dispersion | G.655 |
| Single-mode with non-zero dispersion for broadband optical transmission | G.656 |
| Single-mode with reduced losses at small radius bends | G.657 |
ITU-T - International Telecommunication Union - Telecommunication Standardization Sector.
Every class(type) of optical fibers may have different subclasses (categories), where fibers may differ by several parameters.
The main type of single-mode optical fiber applied in FinMark cables is standard Fiber Fujikura FutureGuide® LWP, which comply with requirements of ITU-T G.652.D. This optical fiber has low losses in hydroxyl peak range (1383 nm), which makes possible to widely apply in transmission CWDM technologies.
Specifications of single-mode optical fiber Fujikura FutureGuide® LWP:
Оптические характеристики:
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• Attenuation coefficient:
• at wavelength of 1310 nm: ≤0.35 dB/km
• at wavelength of 1383 nm: ≤0.31 dB/km
• at wavelength of 1550 nm: ≤0.21 dB/km
• at wavelength of 1625 nm: ≤0.23 dB/km
• Chromatic dispersion coefficient:
• during changes in wavelength range 1285 - 1330 nm: ≤3.5 пс/(nm × km)
• during changes in wavelength range 1270 - 1340 nm: ≤5.3 пс/(nm × km)
• during changes in wavelength of 1550 nm: ≤18 пс/(nm × km)
• Zero dispersion wavelength: 1300 - 1324 nm
• Zero dispersion grade: ≤0.092 пс/(nm2 × km)
• Cutoff wavelength: 1260 nm
• Polarizing modal dispersion (PMD): ≤0.2 пс/km1/2
• Diameter of modal field:
• at wavelength of 1310 nm: 9.2 ± 0.4 μm
• at wavelength of 1550 nm: 10.4 ± 0.8 μm
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Mechanical properties:
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• Diameter of coating: 125.0 ± 0.7 μm
• Core concentricity error: ≤0.5 μm
• Surface/coating concentricity errorПогрешность концентричности оболочки/покрытия: ≤12 μm
• Decoating effort: 1.3 - 8.9 Н
• Diameter of surface: 245 ± 5 μm
• Unroundness of surface: ≤1.0%
• Proof-test: ≥1.0% (0.7 HPa)
• Fiber bend range: ≥4.0 m
On client demand, optical cable FinMark may also be manufactured with other typec of optical fibers: multimode 50/125 um, single mode with non-zero shifted dispersion (ITU-T G.655), with high-flexibility fiber (ITU-T G.657.А) for indoor cables.
Specifications of single-mode optical fiber Fujikura FutureGuide® with non-zero shifted dispersion (recommendation ITU-T G.655)
|
Parameter
|
FutureGuide® - SS
|
FutureGuide® - LA
|
| Diameter of modal field, μm | 8.4 ± 0.6 μм | 9.6 ± 0.4 μм |
| Effective area (Aeff) type, um² | 55 | 72 |
| Attenuation at wavelength of 1550nm, dB/km | ≤0.22 | ≤0.22 |
| Attenuation at wavelength of 1625nm, dB/km | ≤0.25 | ≤0.25 |
| Chromatic dispersion (1530-1565nm), пс/(nm × km) | 2.6 – 6.0 | 2.0 – 6.0 |
| Chromatic dispersion (1565-1625nm), пс/(nm × km) | 4.0 – 8.9 | 4.5 – 11.2 |
| Polarizing modal dispersion (PMD), пс/km1/2 | ≤0.1 | ≤0.1 |
| Proof test | ≥1.0% | ≥1.0% |
Specifications of single-mode optical fiber with reduced losses at small radius bends (recommendation ITU-T G.657)
|
Parameter
|
ITU-T G.657.A
|
ITU-T G.657.B
|
| Bending losses 1 wrap Ø15mm @1550nm | Not regulated | ≤0.5 dB |
| Bending losses 1 wrap Ø15mm @1625nm | Not regulated | ≤1 dB |
| Bending losses 1 wrap Ø20mm @1550nm | ≤0.75 dB | ≤0.1 dB |
| Bending losses 1 wrap Ø20mm @1625nm | ≤1.5 dB | ≤0.2 dB |
| Bending losses 10 wraps Ø30mm @1550nm | ≤0.25 dB | ≤0.03 dB |
| Bending losses 10 wraps Ø30mm @1625nm | ≤1 dB | ≤0.1 dB |
| Diameter of modal field, μm | 8.6-9.5 | 6.3-9.5 |
| Attenuation at wavelength of 1310nm, dB/km | ≤0.35 | ≤0.35 |
| Attenuation at wavelength of 1383nm, dB/km | ≤0.31 | Not regulated |
| Затухание at wavelength of 1550nm, dB/km | ≤0.21 | ≤0.21 |
Fiber ITU-T G.657.A by its optical parameters is fully identical to standard fiber ITU-T G.652.D while having twice lesser allowed laying radius – 15mm.
Fiber ITU-T G.657.В is applied on confined distances as it has especially low bending losses.
