A self-supporting butterfly-shaped single-core optical cable features a central optical fiber flanked by strength members, often including a steel wire for aerial support, with a flat, wing-like profile that enhances bending resistance and tensile strength.

Structure and Design

The cable has a distinctive butterfly-shaped cross-section, with the optical fiber positioned centrally and two parallel strength members on either side, forming the “wings” of the butterfly . For self-supporting variants, a steel wire messenger is often added alongside the FRP (Fiber Reinforced Plastic) members, allowing the cable to span aerial distances without external support . The outer sheath is typically low-smoke zero-halogen (LSZH), providing flame retardancy and environmental safety . Some designs include reinforcing plates and connecting grooves to enhance tensile strength and prevent the cable from splitting under stress .

Mechanical Properties

• Tensile Strength: The combination of FRP and steel wire members provides excellent tensile performance for both horizontal and vertical installations .
• Bend Resistance: The flat, directional design minimizes stress when bent along the natural plane, reducing the risk of fiber damage .
• Lightweight and Flexible: Despite its strength, the cable remains easy to handle, strip, and splice, simplifying installation and maintenance .

Applications

• Fiber-to-the-Home (FTTH): Connects outdoor distribution points to residential homes, supporting high-speed broadband .
• Fiber-to-the-Building (FTTB): Provides reliable optical connections within commercial or multi-tenant buildings .
• Indoor and Outdoor Installations: Suitable for duct, riser, wall, or aerial installations up to 50 meters without additional support .
• Pre-Termination and On-Site Termination: Compatible with connectors for patchcords or pigtails, enabling flexible deployment .

Fiber Type

Most self-supporting butterfly cables use bend-insensitive single-mode fibers, typically compliant with ITU-T G.657 standards, which tolerate tight bend radii and maintain compatibility with legacy G.652.D networks . Single-core variants are ideal for individual subscriber connections, while multi-core versions support larger buildings or multi-tenant units.

Advantages

• Self-supporting: Can be installed aerially without additional messenger wires.
• Directional bending: Reduces accidental fiber stress during installation.
• Enhanced durability: Reinforcing plates and steel wire members improve tensile strength and prevent splitting.
• Safety and environmental compliance: LSZH sheath ensures low smoke and halogen-free operation. In summary, a self-supporting butterfly-shaped single-core optical cable combines a flat, winged design with robust strength members and a protective sheath, making it ideal for FTTH/FTTB deployments, both indoors and in short aerial spans, while ensuring high performance, safety, and ease of installation .