optical fiber
Enable an AI agent to recognise an optical fiber, assess its optical and physical condition, and decide whether it can be handled, joined, installed or used for a specified light-guiding task.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise an optical fiber, assess its optical and physical condition, and decide whether it can be handled, joined, installed or used for a specified light-guiding task.
A cylindrical dielectric waveguide whose higher-index core (almost always silica glass, sometimes polymer or specialty glass) is surrounded by a lower-index cladding so that light is confined as one or more guided electromagnetic modes and transmitted with low attenuation.
It can be Identify and trace a strand between declared endpoints within a cable or assembly.; Characterise transmission, loss and propagation behaviour under recorded test conditions.; Inspect coatings and ends, locate suspected defects and assess suitability for continued use.; Prepare, cleave, splice or terminate the fiber using a process compatible with its construction.; Route, coil and secure the fiber within documented bending, loading and environmental constraints.; Qualify the fiber for a specified optical task or identify evidence needed before use..
Distinguishing features
An identifiable slender strand guides light along its length through an internal optical structure; optical transparency alone does not establish that an object is an optical fiber.
The entity is the light-guiding strand, possibly with integral coatings, rather than the cable assembly containing jackets, strength members and one or more fibers.
Its guidance structure belongs to a discrete strand rather than a waveguide patterned into a planar substrate.
Its intended longitudinal transmission is optical rather than electrical; metallic members associated with a cable do not define the fiber.
It remains the same kind of thing when unterminated; attached ferrules, connectors or housings are related components rather than prerequisites for identifying it.
Scope
+ Individual glass, polymer or specialty optical fibers and identifiable segments
+ Core, cladding or other structures responsible for longitudinal optical guidance
+ Fiber dimensions, integral protective coatings and exposed surfaces
+ Optical behaviour under stated wavelengths and test conditions
+ Physical integrity, end preparation, joins and handling limits
+ Identity and continuity of a fiber within a larger assembly
- Cable jackets, strength members, armor and cable-level environmental ratings
- Connector assemblies, adapters, splice enclosures and patch panels as separate objects
- Lasers, transmitters, receivers and optical test instruments
- Network topology, protocols, service provisioning and traffic performance
- Complete sensing instruments and application-specific interpretation of their signals
- Planar waveguides, free-space optical paths and conductive electrical wires
Characteristics
- Guidance structure
- Solid-core index-guiding, hollow-core, other documented structure, unknown Determines which optical assumptions, inspection methods and joining processes are applicable.
- Optical material
- Silica-based glass, other glass, polymer, mixed materials, unknown Informs wavelength suitability, mechanical handling and process compatibility.
- Segment length
- m, with measurement method and uncertainty Supports loss assessment, fault location and identification of segment boundaries.
- Cross-sectional dimensions
- µm for applicable core, cladding, microstructure and coating dimensions Supports recognition and compatibility checks without assuming every fiber has a conventional core and cladding.
- Modal regime
- Single-mode, few-mode, multimode, unknown; at a stated wavelength and condition Constrains launch conditions, coupling and expected transmission behaviour.
- Mode-field diameter
- µm at a stated wavelength and method, where applicable Helps assess optical coupling and splice compatibility beyond geometric core size.
- Attenuation coefficient
- dB/km at a stated wavelength, method and configuration Supports assessment of distributed optical loss separately from discrete connection losses.
- Dispersion or bandwidth behaviour
- ps/(nm·km) or MHz·km as applicable, with wavelength and test conditions Helps determine whether propagation behaviour suits the intended signal.
- Minimum permitted bend radius
- mm, with source and installation or service conditions Constrains routing and handling that could cause excessive loss or damage.
- Coating condition
- Intact, locally stripped, damaged, degraded, unknown Affects surface protection and readiness for joining or installation.
- End and continuity condition
- End preparation and continuity recorded separately for each identified segment Distinguishes an intact strand from one ready for coupling, splicing or operation.
- Assembly and endpoint associations
- Containing cable or ribbon, fiber position, endpoint, connector and splice references Prevents measurements and interventions from being assigned to the wrong strand.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Strand identity and boundaries Establishes which optical strand is being modelled and where the represented segment begins and ends.
A cable may contain many similar fibers, and cutting or joining changes the segment to which evidence applies.
Segment identity
Identifies the fiber independently of its surrounding cable and attached hardware.
Strand identification
Records the evidence connecting the represented object to a particular light-guiding strand.
- What establishes that this object is an optical fiber, and which strand or segment does its identifier denote? definition
- Which manufacturer designation, lot record, marking or trace establishes its identity? provenance
Ends and assembly membership
Locates segment boundaries and distinguishes the strand from its containing assemblies.
Physical and recorded boundaries
Records endpoints, length and assembly position with explicit treatment of joins.
- Where are the segment's two ends, and does this record stop at each splice or cover a joined path? boundary
- What is its length, how was that length determined, and which cable, ribbon or fiber position contains it? measurement
Guiding structure and materials Describes the construction that makes the strand guide light and constrains compatible processes.
Similar external dimensions can conceal materially different guidance mechanisms and joining requirements.
Optical cross-section
Captures the relevant material and internal geometry without presuming a conventional solid core.
Guidance construction
Identifies the documented light-guiding structure and its distinguishing dimensions.
- What materials and index profile or microstructure provide optical guidance in this fiber? definition
- Which core, cladding or microstructure dimensions are known, with what tolerances and evidence? measurement
Coatings and process compatibility
Separates integral surface protection from surrounding cable components.
Protective surface system
Records coatings and their implications for stripping, cleaning and joining.
- Which coating layers belong to this fiber, and where does responsibility pass to a buffer or cable model? boundary
- Which stripping, cleaning and joining processes are documented as compatible with these materials? action
Optical operating behaviour Captures wavelength-dependent guidance and transmission characteristics relevant to intended use.
Optical performance depends on wavelength, launch conditions and configuration; a type label alone cannot establish suitability.
Wavelength and mode compatibility
Relates the fiber's supported optical behaviour to a proposed source and coupling arrangement.
Supported operating regime
Records the evidence for usable wavelengths, modal regime and coupling parameters.
- At the intended wavelength, what modal regime and applicable mode-field diameter or numerical aperture are established? measurement
- Which source, launch and receiving conditions must be satisfied for the proposed use? action
Loss and signal propagation
Distinguishes propagation characteristics from losses introduced by particular interfaces or arrangements.
Transmission evidence
Records loss and relevant dispersion, bandwidth or polarization behaviour with test context.
- What attenuation and task-relevant propagation characteristics were measured, at which wavelengths and under which launch and environmental conditions? measurement
- Which reported losses belong to the fiber length, and which include bends, splices, connectors or test coupling? boundary
Integrity and handling envelope Connects observed condition and exposure history to permitted handling and continued use.
A fiber may retain optical continuity while surface damage or mechanical exposure leaves its reliability unresolved.
Damage and continuity
Records direct observations and test evidence of breaks, local loss and surface damage.
Localized condition
Locates suspected defects and separates observations from inferred causes.
- What evidence establishes continuity, and where are breaks, abnormal loss events or visible coating and surface defects located? measurement
- Which inspections or tests support each condition assessment, and what parts of the segment were not assessed? provenance
Mechanical and environmental limits
Records sourced constraints for bending, loading and exposure.
Permitted handling conditions
Relates applicable limits and known excursions to routing, storage and service decisions.
- What documented bend, tensile load, temperature and exposure limits apply to this fiber in its present coated or stripped condition? action
- What proof-test, handling or exposure records exist, and do they document any excursions beyond those limits? provenance
Ends, joining and use readiness Determines whether the fiber can be accessed, coupled, joined and accepted for a specified task.
End preparation and interface compatibility govern practical use even when the fiber length itself meets requirements.
End preparation and joining
Records each end's physical condition and compatibility with an intended joining method.
End interface condition
Connects end inspection and fiber properties to a concrete preparation or joining decision.
- For each end, what stripped length, cleave or polish condition, contamination and damage have been observed? measurement
- What preparation and joining method is suitable for the mating fiber or termination, and what compatibility evidence supports it? action
Intervention and acceptance
Combines optical access conditions and task-specific acceptance evidence.
Readiness for specified task
Records whether an intended intervention or use is supported by current evidence.
- Before inspecting an end, cutting or disconnecting, what evidence establishes the optical source state and the required isolation or viewing precautions? action
- Which measurements and condition checks must pass for the intended use, and what retesting is required after preparation, joining or rerouting? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Single-mode silica fiber (ITU-T G.652 / G.654 / G.657; premises OS1/OS2)
- Graded-index multimode silica fiber (OM1-OM5; 50/125 µm or legacy 62.5/125 µm)
- Non-zero dispersion-shifted and other dispersion-engineered long-haul fiber (G.655/G.656; G.653 now largely historical)
- Bend-insensitive single-mode fiber (G.657.A/B) used in FTTH and tight indoor routes
- Polarization-maintaining fiber (Panda, bow-tie, elliptical core)
- Polymer optical fiber (step-index and graded-index POF) for short-reach and automotive links
- Rare-earth-doped fiber (erbium, ytterbium) for amplifiers and fiber lasers
- Photonic-crystal, hollow-core, and mid-IR specialty fiber (fluoride, chalcogenide)
- Which of these kinds and varieties hold for the sense of optical fiber this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q162 - Item for optical fiber / optical fibre as a physical artefact.
- ITU-T Recommendation - G.651.1, G.652, G.653, G.654, G.655, G.656, G.657 (with lettered subtypes such as G.652.D, G.657.A1) - Transmission-fibre type codes used by carriers and vendors worldwide.
- IEC 60793 fibre class - A1 (multimode), B1.3 (low-water-peak SM, ≈ G.652.D), B6_a / B6_b (bend-insensitive, ≈ G.657.A/B) - Factory and type-test designation on fibre data sheets.
- ISO/IEC 11801 / TIA-568 cabled category - OS1, OS2, OM1, OM2, OM3, OM4, OM5 - Names used in premises cabling, not on the uncoated glass preform.
- Vendor product family - e.g. Corning SMF-28, OFS AllWave, Prysmian BendBright - Commercial designations that implement a G.652/G.657 class with extra attributes.
- Which of these identifiers and schemes hold for the sense of optical fiber this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- ITU-T G.65x series (ITU) - transmission fibre and cable characteristics
- IEC 60793 (fibres) and IEC 60794 (cables) - product specification and test methods
- ISO/IEC 11801 and TIA-568.3 - premises optical cabling categories and connectivity
- Telcordia GR-20 (Ericsson/Telcordia) - generic requirements for outdoor optical fibre cable in North American plant
- IEC 60825-2 - safety of optical fibre communication systems (live-fibre laser hazard)
- EN 50173 (CENELEC) - European generic cabling, used alongside ISO/IEC 11801
- RoHS / REACH (EU) and equivalent substance rules - coatings, inks, and cable jacketing, not the silica core itself
- Which of these standards and regulation hold for the sense of optical fiber this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Long-haul, regional and submarine telecommunications as the transmission medium inside fibre-optic cables
- Fibre-to-the-home/building (GPON, XGS-PON, EPON) drop and indoor wiring
- Data-centre structured cabling and parallel-optics interconnects (OM3/OM4/OM5 multimode; OS2 single-mode)
- Medical endoscopy illumination/imaging and surgical laser delivery
- Distributed fibre sensing (DTS, DAS, Bragg gratings) for pipelines, power cables, and civil structures
- Industrial high-power laser beam delivery for cutting and welding
- Avionics, shipboard, and harsh-environment links where EMI immunity matters
- Laboratory and component use: fibre lasers, EDFA gain fibre, patch cords and pigtails
- Which of these real-world use hold for the sense of optical fiber this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Cladding diameter - 124-126 (nominal 125) - µm
- Core diameter (multimode) - 50 (legacy also 62.5) - µm
- Mode-field diameter at 1310 nm (G.652 SMF) - 8.6-9.5 - µm
- Attenuation at 1550 nm (silica SMF) - 0.17-0.22 - dB/km
- Attenuation at 850 nm (laser-optimized MMF) - 2.0-3.5 - dB/km
- Chromatic dispersion at 1550 nm (G.652) - 16-18 - ps/(nm·km)
- Cable cutoff wavelength (G.652.D) - ≤1260 - nm
- Proof-test stress - 0.69 typical (100 kpsi); higher for submarine - GPa
- Which of these typical measurements hold for the sense of optical fiber this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Macrobend and microbend loss when the fibre is routed below its specified bend radius or crushed in a cable
- Tensile break at a surface flaw; delayed failure by stress corrosion (static fatigue) in humid environments
- Fibre fuse: a self-propelled thermal plasma that destroys the core under high launched power after a fault
- Hydrogen darkening and radiation-induced attenuation in poorly designed or nuclear/space environments
- Connector end-face contamination, scratches, and poorly cleaved splices causing reflection, loss, or high-power damage
- Water ingress and freeze-thaw in poorly gel-filled or unblocked outdoor cables
- Nonlinear transmission impairments (SBS, SRS, FWM, SPM) at high channel power, not a mechanical failure of the glass
- Eye and skin hazard from invisible IR light at a live fibre end or break (IEC 60825-2 OFCS rules)
- Glass shard injury and coating-chemical exposure during stripping and splicing
- Which of these failure modes and hazards hold for the sense of optical fiber this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Spelling and premises naming: US TIA-568 uses 'fiber' and OS/OM categories; ISO/IEC 11801 and EN 50173 use 'fibre' with the same OM/OS letters; Japan additionally cites JIS C 6832/6835.
- Access-network practice: GPON/XGS-PON dominates most FTTH markets; EPON was historically preferred in Japan, Korea and parts of China.
- Outdoor cable design: North American plant often follows GR-20 (loose-tube, all-dielectric vs armoured); European and ITU-T G.65x cable clauses differ in water-blocking and rodent-protection conventions.
- Inside-plant fibre: US enterprise still encounters legacy 62.5 µm OM1; new data-centre builds worldwide have standardised on 50 µm OM3/OM4/OM5 or single-mode.
- Submarine systems specify G.654 cut-off-shifted fibre more often than terrestrial G.652 routes.
- Which of these regional variation hold for the sense of optical fiber this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Optical fibre cable - The fibre is the coated glass waveguide; a cable is the sheathed assembly (tubes, strength members, jacket, armour) that contains one or more fibres. Count glass vs count cable elements.
- Planar optical waveguide / photonic integrated circuit - A fibre is a drawn, flexible cylindrical waveguide; on-chip guides are lithographically defined in a planar stack and are not independently cabled.
- Copper twisted pair or coaxial cable - Those guide RF/electrical current; fibre guides optical modes, is dielectric, and is immune to ordinary EMI. Test: continuity with an optical source/OTDR versus a metallic continuity tester.
- Free-space optical / line-of-sight laser link - FSO uses an unguided beam in air; fibre confines the same wavelengths inside glass. Presence of a physical dielectric core is the separator.
- Fibre-optic patch cord or pigtail - A patch cord is a finished, connectorised cable assembly; the fibre is the glass element inside it. Identify by whether connectors and jacket are part of the object being named.
- Hollow metallic microwave waveguide - A metal pipe guiding centimetre-wave modes versus a dielectric optical waveguide guiding near-IR modes; frequency, materials, and numerical aperture / cutoff formulae differ.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of optical fiber this model covers, and on what evidence? provenance
Sources
- Recommendation ITU-T G.652: Characteristics of a single-mode optical fibre and cable - Definition of standard single-mode fibre, cutoff, mode-field diameter, attenuation windows, chromatic dispersion of G.652.D, and the distinction from G.654/G.657 families.
- IEC 60793-2: Optical fibres - Product specifications (sectional specifications for class A multimode and class B single-mode fibres) - Product classes used in manufacture and procurement (A1 multimode, B1.3/B6 single-mode), geometry (125 µm cladding), proof test, and numerical-aperture / bandwidth categories that map to OM/OS naming.
- ISO/IEC 11801-1: Information technology - Generic cabling for customer premises - Part 1: General requirements - Premises cabled-fibre categories OS1, OS2, OM1-OM5 and how those names are used in buildings and data centres, distinct from bare-fibre ITU-T/IEC type codes.
- IEC 60825-2: Safety of laser products - Part 2: Safety of optical fibre communication systems (OFCS) - Hazard classification of live fibre ends, automatic power reduction, and the laser-safety regime that governs installed fibre plant rather than the glass itself.
What the second pass must settle
- With no registry definition recorded, does this entry include hollow-core, multicore, microstructured, active and sensing fibers, and which require optional model extensions?
- Does an identified fiber remain one registry object across a splice, or should joined paths always relate separate segment objects?
- Where should ownership fall for tight buffers, bonded ribbon materials and other protection beyond the primary fiber coating?
- Which manufacturer documents and applicable test standards should establish limits and acceptance methods for each supported fiber family?
- What evidence is sufficient to assess continued mechanical reliability after coating damage or a handling-limit excursion when optical continuity remains?