Single-Mode Fiber Standards

Optical Telecommunications: Fiber and Cable Technology

Single-Mode Fiber Standards

• G652 A: Basic single-mode fiber with a minimum bending radius of 30 mm, used in transport and distribution networks.
• G652 B: Extended range up to 1625nm with improved attenuation at 1310nm and 1550nm compared to version A, and better PMD (Polarization Mode Dispersion), used in transport and distribution networks.
• G652 C: Reduced water peak, referred to as NDSF (Non-Dispersion Shifted Fiber) or SMF (single-mode fiber) with zero dispersion at 1310nm, supports high bitrates up to 50 km with CWDM (Coarse Wavelength Division Multiplexing) and DWDM (Dense Wavelength Division Multiplexing).
• G652 D: Reduced and optimized attenuation in the 1260-1625 nm range (O, E, S, C, and L bands), reduced PMD and dispersion, ensuring network scalability and increased bit rates (DWDM and CWDM) over long distances, used in transport and distribution networks.
• G657 A1: Fiber G657 is compatible with G652d optical fiber, used in vertical cabling and adduction.
• G657 A2: Fiber G657 is compatible with G652d optical fiber but offers better bend insensitivity than version A1, used in vertical cabling and adduction.
• G657 B: Fiber G657 is not compatible with G652 optical fiber but has better bend insensitivity than version A1, to be avoided.
• G.652.D fibers have reduced attenuation and optimized performance across the 1260-1625nm range (O, E, S, C, and L bands).
• G.652.D fibers have lower PMD and dispersion, supporting network upgrades and higher bitrates using DWDM and CWDM over longer distances.

Fiber Standards G652

• Mode Field Diameter: 8.6-9.5 µm range, tolerance of ±0.4 µm (at 1310 nm wavelength).
• Cladding Diameter: 125.0 µm nominal, tolerance of ±0.7 µm.
• Core concentricity error: Maximum 0.5 µm.
• Cladding noncircularity: Maximum 1.0%.
• Cable Cut-off Wavelength: Maximum 1260 nm.
• Macrobend loss: 0.1 dB maximum at 1625 nm for 100 turns with a 30 mm radius.
• Proof stress: Minimum 0.69 GPa.
• Chromatic dispersion coefficient: λomin at 1300 nm, λomax at 1324 nm and Somax: 0.092 ps/nm²km.
• Attenuation coefficient: Maximum 0.4 dB/km from 1310 nm to 1625 nm, 0.4 dB/km at 1383 nm ±3 nm, and 0.3 dB/km at 1550 nm.
• PMD coefficient: M for 20 cables, Q 0.01%, Maximum PMDQ 0.20 ps/√km

Fiber Standards G657

• Mode Field Diameter: 8.6-9.5 µm range, tolerance of ±0.6 µm (at 1310 nm wavelength).
• Cladding Diameter: 125.0 µm nominal, tolerance of ±1 µm.
• Core concentricity error: Maximum 0.6 µm.
• Cladding noncircularity: Maximum 1.0%.
• Cable Cut-off Wavelength: Maximum 1260 nm.
• Macrobend loss for uncabled fiber, which are categories ITU-T G.657.A1 and ITU-T G.657.A2.
• ITU-T G.657.A1 & ITU-T G.657.A2 have a minimum proof stress of 0.69 GPa.
• Chromatic dispersion coefficient: λomin at 1300 nm and λomax at 1324 nm and Somax: 0.092 ps/nm²km.
• Cable attenuation coefficient is a maximum of 0.40 dB/km.
• PMD coefficient: M for 20 cables, Q 0.01%, Maximum PMDQ 0.20 ps/√km

Realization of G657 Fiber

• Index profile G652, G657 tall/thin type and G657 trench type.
• Used for G657 A1 and A2 are G657 Trench/Ring type & G657 VOID assisted type.
• Used for types B1 and B2 are incompatible with G652.

Optical Cables

• Cable Role: To protect the optical fibers from the environment.
• Environmental factors include mechanical, thermal, and chemical elements.
• Fibers structure is important so fibers do not undergo any mechanical stress (free structure).

Fiber Protection

• A fiber protection example is a patch cord.
• Cable components from inside-out: Fiber core, Cladding, Varnish (250µm), 900µm coating, Kevlar cable, Outer sheath (2mm or 3mm).

Types of Optical Cables

• Breakout Cables: Cables with jacketed fibers (900 µm) used within LANs.
• Tubed Cables: Central tube with multiple 250µm fibers in a single tube.
• Multiple tubes containing several 250µm fibers in multiple tubes.
• Module Cables: 250µm fibers grouped in tearable jackets.
• Aerial or Self-Supporting Cables: Cables incorporating tempered steel strands for tensile strength.
• Tight Structure Cables: Fibers tightly held within the cable.
• Loose Structure Cables: Allows fibers to move within the cable.

Cables and their Uses in FTTH (Fiber to the Home)

• Cabling hierarchy for FTTH:
• Distribution cables connect the optical distribution node to access cables.
• Access cables then distribute to subscriber cables.

Cable Types:

• Distribution: Armored or unarmored cables with up to 864 fibers for conduits or direct burial.
• Access: Access cables with up to 288 fibers are non-armored for conduits or micro-conduits.
• Subscriber or Micro-Cables: Subscriber cables with up to 12 fibers are non-armored for micro-conduits or facade installation, designed for various applications and aerial installation.
• Cables for Buildings: Riser cables are flame-retardant and halogen-free with up to 288 fibers, optimized for tight buffered splicing.
• Subscriber Connections: Subscriber cables with 1, 2, or 4 fibers, are flame-retardant, halogen-free.
• Terminal Equipment: Subscriber outlets and premise cabling follow NFC 15100 and UTE 90 483 standards.
• General Cable:

Riser Cables for Buildings

• Designed to connect the central office with the building's floors.
• Typically constructed from easy-strip micromodules and can host from 12 to 288 fibers. These cables should be LSOH rated (Low Smoke Zero Halogen).
• It is a cable in free structure designed for tight bending radius. Fiber is G657 A1 or A2.
• Originally, the fiber regrouped 900 µm fibers.

Legend:

• Compact tube 2, 4, 6, 8 or 12 single-mode optical fibers under tearable thermoplastic skin.
• Reinforcements: FRP reinforcements.
• Final sheath: Ivory UV stabilized Halogen-free Zero Halogen sheath (LSOH), compliant with EN 50290-2-27.
• Location of cable opening point: Salient Generator.

Subscriber Cable

• A highly regulated cable for connecting individual subscribers.
• Diameter: 6mm.
• LZH Sheath.
• G657 Fiber.
• 1 Kevlar cord.
• 1, 2 or 4 fibers 250µm in a single easy-strip µmodule.
• Often pre-connectorized.
• Subjected to the most installation constraints.
• Sharp Bends.
• Stapling.
• Tension during installation.