Suburban Communication Network All-Dielectric Self-Supporting Optical Cable With Lower Cost Design
ASU optical cable is a variant of all-dielectric self-supporting (ADSS) cable designed for complex outdoor environments. Its performance parameters integrate cutting-edge achievements in structural mechanics, materials science, and optical transmission technology, widely used in overhead communication, smart grids, rail transit, and other scenarios. The following systematically analyzes its core parameter characteristics from six dimensions: structural parameters, optical performance, mechanical properties, environmental adaptability, installation compatibility, and application adaptability.
I. Structural Parameters: Modular Design and Material Synergy Optimization ASU optical cable adopts a modular structure of "central tube + symmetric strength members". The parameters of each component are strictly matched to achieve a balance among "strength, weight, and cost".
Core Cable Structure
Loose tube: Made of polybutylene terephthalate (PBT) with a wall thickness of 0.3-0.5mm. The inner diameter is designed according to the number of fiber cores (2.8mm for 2-12 cores, 3.5mm for 12-24 cores). It has a working temperature range of -60℃ to +120℃ and can withstand deformation caused by repeated thermal expansion and contraction. The loose tube is filled with thixotropic waterproof gel (viscosity ≥15000mPa·s), which remains fluid even at -40℃ to ensure no mechanical stress on the optical fibers.
Fiber capacity: Supports 2-24 core single-mode fibers (G.652D/G.657A1) or multimode fibers (OM3/OM4). The expansion of core count is achieved by increasing the number of loose tubes (up to 4 loose tubes, with a total core count of 96). The deviation of each loose tube from the central axis is ≤0.1mm to ensure structural symmetry.
Reinforcement System
Strength members: Double-layer FRP (fiber-reinforced polymer) symmetrically distributed on both sides of the loose tube, with a diameter of 2.0-3.0mm. The outer layer is glass fiber/epoxy resin composite material (tensile strength ≥1400MPa), and the inner layer is basalt fiber/vinyl ester resin (elastic modulus ≥70GPa). The two materials achieve stress synergy through interface treatment, with a strain of ≤0.3% under long-term load.
Distance between strength members: 8-12mm (varying with cable outer diameter), ensuring balanced stress on both sides during bending to avoid one-sided fracture.
Protective Layer Structure
Moisture-proof layer: The loose tube is wrapped with a 0.12mm thick aluminum-plastic laminate (APL). A longitudinal lapping process is adopted (lap width ≥6mm). The aluminum layer has a purity of 99.5%, and the plastic layer is modified PP (melting point 165℃) with a water vapor transmission rate of ≤0.1g/(m²·24h).
Sheath: The outer layer is black high-density polyethylene (HDPE) with 2% carbon black ultraviolet resistant agent (particle size ≤20nm). The Shore hardness is D65±3, and the elongation at break is ≥300%. After immersion in 85℃ hot water for 168 hours, the tensile strength retention rate is ≥90%.
Summary Table of Structural Parameters
Index Value Range Testing Standard (IEC)
Cable outer diameter 6.8-11.5mm (2-96 cores) IEC 60794-1-20
Unit weight 95-210kg/km IEC 60794-1-10
Tensile strength of strength member ≥1400MPa IEC 61156-1
Sheath UV resistance level No cracks after 1000h aging under UVB 313nm IEC 60068-2-5
II. Optical Performance: Low Loss and High Stability
The optical performance of ASU optical cable focuses on the combination of fiber transmission characteristics and structural stability. Its parameter design aims at "low attenuation, low dispersion, and high anti-interference" to meet the needs of long-distance and high-frequency signal transmission.
Attenuation Characteristics
Single-mode fiber (G.652D): Attenuation ≤0.36dB/km at 1310nm wavelength, ≤0.22dB/km at 1550nm wavelength, and ≤0.24dB/km at 1625nm (L-band), all better than the ITU-T G.652 recommendation (1310nm ≤0.4dB/km).
Multimode fiber (OM4): Attenuation ≤2.5dB/km at 850nm wavelength, with a 500MHz·km bandwidth ≥4700MHz·km, supporting 10Gbps signal transmission distance up to 550m, meeting the IEEE 802.3ae standard.
Impact of temperature on attenuation: In the range of -40℃ to +70℃, the attenuation variation at 1550nm wavelength is ≤0.05dB/km, much lower than the industry average of 0.1dB/km, which benefits from the buffering effect of the loose tube and gel.
Dispersion Control
Zero dispersion wavelength: 1300-1324nm (G.652D), with a zero dispersion slope ≤0.092ps/(nm²·km). The dispersion value at 1550nm window is 17ps/(nm·km), supporting 100Gbps signal transmission without repeaters for ≥80km (with dispersion compensation modules).
Polarization mode dispersion (PMD): The PMD coefficient of the cable link is ≤0.1ps/√km, with a maximum value ≤0.5ps, meeting the requirements of ITU-T G.650.2 for long-distance communication, ensuring the polarization stability of high-speed signals (400Gbps and above).
Anti-interference Performance
All-dielectric structure (no metal components): Electromagnetic interference (EMI) attenuation ≥80dB (10kHz-1GHz), radio frequency interference (RFI) shielding effectiveness ≥60dB, suitable for laying near high-voltage power grids (110kV-500kV) without additional shielding layers.
Fiber coating: Double-layer acrylate (soft inner layer, hard outer layer) with a stripping force of 1.5-3.5N. Hydrogen-induced loss resistance: After being placed in 1atm hydrogen environment for 168 hours, the attenuation increment at 1550nm is ≤0.05dB/km.
III. Mechanical Properties: Resistance to Extreme Stress and Dynamic Stability (approximately 600 words)
The mechanical properties of ASU optical cable are its core competitiveness as a self-supporting cable. The parameter design covers static load-bearing, dynamic deformation, external impact, and other scenarios to ensure structural integrity in complex environments.
Tensile Performance
Short-term tension (during installation): The maximum allowable tension is 1500-6000N (varying with core count/model). At this stress, the fiber strain is ≤0.2%, and the attenuation variation is ≤0.1dB (1550nm). The test method complies with IEC 60794-1-21 (uniform tension until fracture, recording the cable tension when the fiber breaks).
Long-term tension (during operation): The rated long-term tension is 50% of the short-term tension (e.g., 3000N for 24-core ASU). Under this stress for 1000 hours, the cable has no permanent deformation, and the fiber attenuation remains unchanged, meeting the load-bearing requirements for overhead spans of 100-150m (calculated by the catenary equation, the mid-span sag is ≤5% of the span).
Bending Performance
Static bending: The minimum bending radius during installation is 20 times the cable outer diameter (e.g., 200mm for a 10mm outer diameter cable), and 10 times (100mm) after installation. After bending 100 times at this radius (1 minute each time), the fiber attenuation variation is ≤0.1dB.
Dynamic bending: Cyclic bending at a frequency of 1Hz and a bending angle of ±90° for 1000 times, the fiber has no fracture, and the attenuation increment is ≤0.2dB, suitable for scenarios requiring frequent route adjustment (such as along rail transit lines).
Crush Resistance
Withstanding a radial pressure of 2200N/100mm (equivalent to rolling by a 500kg weight) for 1 minute, the cable outer diameter deformation is ≤20%, and the fiber attenuation variation is ≤0.1dB. After the test, it returns to its original shape without structural damage, meeting the compression resistance requirements for direct burial laying.
Impact and Vibration Performance
Impact test: A 1.5kg hammer is dropped freely from a height of 1m (impact energy 15J), with the impact point 1m from the joint. After the test, the fiber has no fracture, and the attenuation variation is ≤0.5dB (in accordance with IEC 60794-1-23).
Vibration test: Vibrating at a frequency range of 10-500Hz with an amplitude of 0.75mm for 2 hours, the fiber attenuation variation is ≤0.1dB, suitable for high-vibration environments such as highways and railway lines.
Torsion Performance
Withstanding ±180°/m torsion (half a twist per meter of cable) for 10 minutes, the fiber attenuation variation is ≤0.2dB, with no delamination of the structure, meeting the torsional stress caused by terrain inclination during overhead laying in mountainous areas.
IV. Environmental Adaptability: All-scenario Weather Resistance and Reliability (approximately 600 words)
The environmental parameters of ASU optical cable are optimized for complex outdoor conditions, covering temperature, corrosion, water damage, biological damage, and other scenarios, ensuring a 25-year design life (Telcordia GR-20 standard).
Temperature Tolerance Range
Operating temperature: -40℃ to +70℃ (short-term can withstand -55℃ to +85℃). After 100 temperature cycles (from -40℃ to +70℃, 2 hours per cycle) within this range, the cable sheath has no cracks, and the fiber attenuation variation is ≤0.1dB.
Thermal shrinkage performance: When placed in a 100℃ oven for 1 hour, the cable length shrinkage rate is ≤0.2%, avoiding fiber microbend loss caused by temperature changes.
Weather Resistance and Corrosion Performance
UV aging resistance: Exposed to ISO 4892-2 (xenon lamp aging test) for 1000 hours, the sheath tensile strength retention rate is ≥80%, and the elongation at break retention rate is ≥70%, with no chalking or cracking, suitable for high-altitude areas (with strong ultraviolet radiation).
Salt spray corrosion: Placed in a salt spray chamber with 5% NaCl solution, 35℃, pH 6.5-7.2 for 1000 hours, the corrosion area of metal components (if any) is ≤5%. The all-dielectric ASU cable has no corrosion risk and can be used in coastal areas (within 5km from the coastline).
Chemical corrosion: Withstands immersion in 5% concentration acid (H₂SO₄) and alkali (NaOH) solutions for 168 hours, the sheath has no swelling (weight change ≤5%), and the fiber performance remains unchanged, suitable for polluted environments such as chemical plants and mining areas.
Waterproof and Water-blocking Performance
Longitudinal water blocking: A 1m length of cable is taken, one end is sealed, and 0.1MPa water pressure is applied to the other end. No water seepage occurs within 30 minutes. The water-blocking yarn (superabsorbent resin content ≥30%) has an expansion ratio ≥200%, forming a gel barrier.
Radial water blocking: 0.3MPa water pressure is applied outside a 1m length of cable, with no radial water seepage within 24 hours. The tight combination of APL aluminum tape and sheath achieves complete waterproofing, suitable for overhead laying in rainy areas.
Protection Against Biological and Mechanical Damage
Rodent resistance: The sheath contains 0.5% permethrin, with a repellency rate of ≥90% against rodents and hares. Meanwhile, the sheath has a Shore hardness ≥D65, with no penetrating damage after a gnawing test (using metal teeth simulating rodent teeth), suitable for rural areas with frequent rodent activities.
V. Installation and Application Compatibility: Flexible Deployment and Scenario Matching (approximately 300 words)
The installation parameters of ASU optical cable are designed to "lightweight, easy operation, and multi-scenario compatibility" to reduce construction difficulty and cost.
Compatibility with laying methods: Supports three methods: overhead (self-supporting, hook-type), pipeline (with pipe threader traction), and direct burial (with armor layer). During overhead laying, it can be fixed with special hardware (tension clamps, suspension clamps) with a clamp grip ≥70% of the rated tension to avoid slipping.
Joint compatibility: Compatible with standard SC/LC/FC splice closures. The loose tube can be directly inserted into the fusion splice tray without additional stripping of strength members. The splice loss after fusion is ≤0.05dB (1550nm), meeting the ITU-T G.650.1 standard.
Application scenario matching:
Rural communication networks: Lightweight (95kg/km) suitable for manual erection, with UV resistance adapting to field environments;
Smart grids: All-dielectric structure resists electromagnetic interference, allowing laying with 110kV lines on the same pole without insulation distance;
Rail transit: Vibration and impact resistance match the train operation environment, with a small bending radius suitable for laying in tunnels.
VI. Standard Compliance and Quality Control
ASU optical cable fully complies with international and domestic standards: IEC 60794-1 (General Specification for Optical Cables), ITU-T G.652/G.657 (Fiber Characteristics), GB/T 7424.1 (General Requirements for Optical Cables), YD/T 901 (Central Tube Optical Cables), and has passed CE (EU), UL (USA), and TLC (China Telecom) certifications.
Quality control adopts "full-process inspection": Fibers are tested for attenuation and dispersion upon entering the factory (100% sampling); mechanical properties (tensile, bending) are sampled and tested every 100km during cable production; 24-hour water pressure test (0.3MPa) and 1000-hour aging pre-test (accelerated life verification) are conducted before delivery to ensure a batch qualification rate of ≥99.5%.
In summary, through modular structure, high-performance materials, and scenario-based parameter design, ASU optical cable forms a synergistic advantage in optical transmission, mechanical load-bearing, and environmental adaptation, becoming the preferred solution for communication in complex outdoor environments. Its parameter characteristics not only meet current 10G/100G communication needs but also reserve space for 400G/1T upgrades, with long-term technical adaptability.
