Metal Core Duct Optical Cable

Metal core duct optical cables are fiber optic cables reinforced with metallic elements, designed for installation in ducts to provide mechanical protection, moisture resistance, and long-term reliability.

Construction and Materials

Metal core duct optical cables typically feature a central metallic strength member (steel or aluminum) that provides tensile strength and supports pulling during installation ( ). The optical fibers are housed in loose tubes, which may be gel-filled or dry, to protect against moisture and microbending. Additional strength members such as aramid yarn (Kevlar) or glass yarn are included to resist tension and rodent damage.

The cable is often armored with corrugated steel tape (GYTS) or aluminum tape (GYTA) for extra mechanical protection and moisture barrier ( ). The outer jacket is usually made of high-density polyethylene (PE) or LSZH for UV resistance, chemical protection, and temperature stability. Water-blocking materials, such as gel or dry water-blocking tapes, prevent water ingress along the cable length ( ).

Fiber Types and Capacity

These cables can accommodate 2 to 288 fibers, supporting both single-mode (G. 652D, G. 657A1) and multimode fibers (OM3, OM4) for high-speed transmission ( ).

The fibers are arranged in central loose tube or stranded loose tube configurations depending on project requirements ( ).

Applications

Metal core duct optical cables are widely used in: Urban and long-haul telecom networks: Backbone connections, metro networks, and FTTx distribution ( ). Industrial and critical infrastructure: Power grids, oil and gas facilities, airports, and ports where mechanical protection and environmental resistance are essential ( ). Data center interconnections: High-density fiber links with low attenuation and compatibility with DWDM/CWDM technologies ( ).

Installation Methods

Cables can be installed using pulling or air-blowing (jetting) techniques. Pulling requires careful attention to tension, bends, and duct friction, while air-blowing reduces mechanical stress and allows installation of microcables in microducts ( ). Proper planning ensures the cable does not exceed its maximum tensile load and maintains the minimum bend radius to prevent fiber damage ( ).

Standards and Compliance

Metal core duct optical cables conform to international standards such as ITU-T L. 100, which specifies mechanical, environmental, and electrical characteristics for duct and tunnel applications ( ). Compliance ensures long-term performance, safety, and interoperability.

Key Advantages

High mechanical protection against crushing, tension, and rodents. Moisture and environmental resistance for underground or harsh outdoor conditions. Scalability and maintenance: Easy replacement or addition of fibers without excavation.

Support for high-speed, long-distance transmission with minimal signal loss. Metal core duct optical cables are ideal for projects requiring durable, high-capacity, and reliable fiber infrastructure in both urban and industrial environments ( ).