Specifications of Self-Supporting Butterfly-Type Optical Cable

Self-supporting butterfly optical cables are designed with a flat, wing-shaped profile, bend-insensitive single-mode fibers, and integrated strength members, conforming to ITU-T G.657 and YD/T1997.1-2014 standards for aerial and indoor deployment.

Cable Structure and Design

Self-supporting butterfly optical cables feature a flat, wing-shaped cross-section with optical fibers at the center and parallel strength members on either side, typically made of Fiber Reinforced Plastic (FRP) or steel wire for aerial support . This design minimizes stress on the fiber when bent in the flat plane and provides mechanical protection against sharp kinks. The self-supporting variant includes a steel messenger wire, enabling aerial spans up to 50 meters without external support .

Fiber Type and Standards

These cables almost universally use bend-insensitive single-mode fibers, compliant with ITU-T G.657 standards. Subtypes include:

• G.657.A1: Suitable for residential and light commercial use, tolerates 10 mm bend radii, and is compatible with legacy G.652.D fibers .
• G.657.A2: Recommended for routing through conduits with 90-degree bends or irregular surfaces.
• G.657.B3: Used in more demanding installations requiring tighter bend tolerance. The YD/T1997.1-2014 standard governs the technical requirements for user access optical cables in China, including self-supporting butterfly cables, ensuring compatibility with joint boxes and safe installation without sensing current .

Sheath and Environmental Ratings

• Indoor cables (GJXH): FRP strength members, LSZH (Low Smoke Zero Halogen) sheath, lightweight and flexible for building entry to ONT deployment .
• Outdoor self-supporting cables (GJYXFCH/GJXFH): Steel messenger wire, PE or dual-layer LSZH/PE jacket for UV and moisture resistance, suitable for aerial deployment .

Mechanical and Fire Safety Features

Self-supporting butterfly cables are designed to withstand tensile stress and bending without fiber breakage. Reinforced variants include metal load-bearing parts, fixed plates, sliding columns, and bending-resistant components to increase tensile resistance and reduce maximum stretch length . Sheath materials are often low-smoke halogen-free or flame-retardant PVC, meeting fire safety requirements for indoor and outdoor installations .

Applications

These cables are widely used in FTTH (Fiber-to-the-Home), FTTB (Fiber-to-the-Building), campus networks, intelligent buildings, and local area networks, providing reliable last-mile connectivity and supporting high-speed broadband and 5G infrastructure . Their self-supporting design reduces installation time and labor costs, making them ideal for aerial and mixed indoor/outdoor deployments.

Summary

Self-supporting butterfly optical cables combine mechanical robustness, bend-insensitive fibers, and compliance with ITU-T G.657 and YD/T1997.1-2014 standards, making them suitable for both indoor and aerial outdoor applications. Key considerations include fiber subtype selection, sheath material, and strength member type to ensure proper performance and regulatory compliance.