Specifying Optical Fiber Cable

Cable Parameters and Typical Values

Installation v. Environmental Specifications Installation Specifications Installation Specifications Ex: Installation Load (Pulling force)Ex: Installation Load (Pulling force) Environmental Specifications Environmental Specifications Determine the cable’s long-term performanceDetermine the cable’s long-term performance Ex: Temperature range of operationEx: Temperature range of operation

Installation Specifications Maximum installation load Force in lb. (or kg-force or N)Force in lb. (or kg-force or N) Pulling with more than this force will permanently change the attenuation of the fiberPulling with more than this force will permanently change the attenuation of the fiber Typical values:Typical values: lb. for 1-fiber cables lb. for 1-fiber cables lb. for cables with 6-12 fibers lb. for cables with 6-12 fibers 600 lb. for self-supporting aerial cables 600 lb. for self-supporting aerial cables

Installation Specifications Minimum installation bend radius Don’t bend the cable under tension through a corner sharper than thisDon’t bend the cable under tension through a corner sharper than this If you violate the bend radius, you may damage some part of the cable structureIf you violate the bend radius, you may damage some part of the cable structure Typical value: 20 times cable diameterTypical value: 20 times cable diameter

Installation Specifications Diameter Important when fitting the cable into a crowded conduitImportant when fitting the cable into a crowded conduit Temperature range for installation and storage

Environmental Specifications Temperature range Temperature range Outside this range, the plastic may crack, orOutside this range, the plastic may crack, or Expansion cycles will create microbends in the fiber, increasing attenuationExpansion cycles will create microbends in the fiber, increasing attenuation Indoor, typically -10 to 50 Centigrade Indoor, typically -10 to 50 Centigrade Outdoor, typically -20 to 60 Centigrade Outdoor, typically -20 to 60 Centigrade Military: -55 to 85 Centigrade Military: -55 to 85 Centigrade Image: a Teflon-coated fiber optic thermometer that operates down to 5 degrees Kelvin (link Ch 5i)Image: a Teflon-coated fiber optic thermometer that operates down to 5 degrees Kelvin (link Ch 5i)

Environmental Specifications Minimum long-term bend radius Minimum long-term bend radius With the cable not under tensionWith the cable not under tension Typically 10 diametersTypically 10 diameters Image: Japanese fiber with bend radius under 1 cm (link Ch 5h) Image: Japanese fiber with bend radius under 1 cm (link Ch 5h) NEC (National Electrical Code) NEC (National Electrical Code) Three cable fire ratings:Three cable fire ratings: No letter or G: General use—least stringent fire test No letter or G: General use—least stringent fire test R: Riser—can be used in vertical shafts R: Riser—can be used in vertical shafts P: Plenum—most strict test P: Plenum—most strict test

Environmental Specifications Long-term use load Long-term use load Important for long vertical installationsImportant for long vertical installations Aerial installationAerial installation Vertical rise distance Vertical rise distance Must put in strain-relief loopsMust put in strain-relief loops Flame resistance Flame resistance Non-building applicationsNon-building applications UV stability UV stability

Environmental Specifications Resistance to Rodent Damage Resistance to Rodent Damage Inner ducts are an alternative to armorInner ducts are an alternative to armor Steel armor Steel armor Copper tape armor Copper tape armor Braided armor Braided armor Dielectric armor Dielectric armor Image from arcelect.comImage from arcelect.com Armor makes the cable much less flexibleArmor makes the cable much less flexible

Environmental Specifications Resistance to water damage Resistance to water damage Filled and BlockedFilled and Blocked Each loose buffer tube is filled (with gel or tape) Each loose buffer tube is filled (with gel or tape) A blocking material fills the space between the tubes A blocking material fills the space between the tubes Crush load Crush load Short-term v. long-termShort-term v. long-term

Environmental Specifications Abrasion resistance Abrasion resistance Resistance to chemicals Resistance to chemicals

Environmental Specifications Resistance to conduction under high voltage Resistance to conduction under high voltage Toxicity Toxicity “Halogen-free” cables produce less harmful smoke“Halogen-free” cables produce less harmful smoke Required in Japanese and European buildingsRequired in Japanese and European buildings High flexibility High flexibility If constantly bending, like an elevatorIf constantly bending, like an elevator

Environmental Specifications Hermetically sealed fiber Hermetically sealed fiber Protect it from water pressure, etc.Protect it from water pressure, etc. Radiation resistance Radiation resistance Nuclear reactors or satellitesNuclear reactors or satellites Impact Resistance Impact Resistance Dropping heavy objects on the cableDropping heavy objects on the cable Gas permeability Gas permeability Preventing gas from escaping through the cablePreventing gas from escaping through the cable

Environmental Specifications Stability of filling compounds Stability of filling compounds Temperature cycles can pump filling compounds out the end of the cableTemperature cycles can pump filling compounds out the end of the cable Vibration Vibration

Design Shortcuts

Future-Proofing a System Include extra fibers in cables Include extra fibers in cables It costs very little more to get a cable with more fibers in itIt costs very little more to get a cable with more fibers in it Include singlemode fibers in multimode cables Include singlemode fibers in multimode cables Allows enormous bandwidth increases laterAllows enormous bandwidth increases later Use dual-wavelength multimode fiber Use dual-wavelength multimode fiber Or even laser-optimized fiberOr even laser-optimized fiber

Multimode Fibers Early multimode systems used 62.5/125 micron fiber Early multimode systems used 62.5/125 micron fiber LED light sources at 850 or 1300 nm LED light sources at 850 or 1300 nm 10 Mbps or 100 Mbps10 Mbps or 100 Mbps Huge installed baseHuge installed base 50/125 micron fiber 50/125 micron fiber Faster with VCSEL sources at 850 nmFaster with VCSEL sources at 850 nm Laser-optimized 50/125 micron fiber Laser-optimized 50/125 micron fiber Fastest, using VCSEL sourcesFastest, using VCSEL sources

Singlemode Fibers Usually 1300 nm singlemode fiber is good enough Usually 1300 nm singlemode fiber is good enough Cheaper than 1550 nm or two- wavelength systems Cheaper than 1550 nm or two- wavelength systems

Cable Types Indoor Indoor Short distance – Break-out cableShort distance – Break-out cable Longer distance – Distribution cableLonger distance – Distribution cable Rugged environment – Break-out cableRugged environment – Break-out cable Use all-dielectric cableUse all-dielectric cable Plenum-rated PVC is recommendedPlenum-rated PVC is recommended

Cable Types Outdoor Outdoor Cable should be water-blocked and gel- filledCable should be water-blocked and gel- filled Many fibers (>36) – consider ribbon cableMany fibers (>36) – consider ribbon cable For midspan access, use stranded loose- tube cableFor midspan access, use stranded loose- tube cable Use all-dielectric cableUse all-dielectric cable

Stranded Loose-Tube Same as loose-tube table Same as loose-tube table Image from Corning (Link Ch 5f)Image from Corning (Link Ch 5f)

Cable Types Indoor/Outdoor Indoor/Outdoor You could splice indoor to outdoor at the building entranceYou could splice indoor to outdoor at the building entrance Or use indoor- outdoor cable like Corning’s FREEDMOr use indoor- outdoor cable like Corning’s FREEDM Image from Corning (Link Ch 5g)Image from Corning (Link Ch 5g)

Cable and Source Prices Not in textbook

History of Ethernet From Corning (link Ch 5b) From Corning (link Ch 5b)

Sources

Cable Prices For 500 feet of riser-rated indoor bulk cable, 12-fiber For 500 feet of riser-rated indoor bulk cable, 12-fiber 62.5/125 micron MM$ /125 micron MM$889 50/125 micron MM $88950/125 micron MM $889 50/125 micron laser-optimized MM $114350/125 micron laser-optimized MM $ /125 micron SM$5848.5/125 micron SM$584 From blackbox.com (link Ch 5c) From blackbox.com (link Ch 5c)

Media Converter Prices 100 Mbps Multimode:$ Mbps Multimode:$ Gbps Multimode:$ Gbps Multimode:$ Gbps Singlemode:$1,180 1 Gbps Singlemode:$1,180 Prices from L-Com.com (Links Ch 5d & 5e)Prices from L-Com.com (Links Ch 5d & 5e)