A self-supporting single-butterfly drop optical cable is a lightweight, bend-insensitive fiber optic cable designed for FTTH/FTTx applications, capable of aerial or indoor deployment without additional support.

Structure and Design

Self-supporting butterfly drop cables feature a butterfly-shaped cross-section, where the optical fiber is centrally located between two parallel FRP (Fiber Reinforced Plastic) strength members. Outdoor variants add a steel messenger wire or a single steel strength member to enable self-supporting aerial installation over spans up to 50 meters . The cable is typically sheathed in LSZH (Low Smoke Zero Halogen) flame-retardant material, providing safety and environmental compliance . The design is lightweight, flexible, and allows easy stripping and splicing for installation and maintenance .

Fiber Types and Performance

These cables generally use bend-insensitive single-mode fibers, compliant with ITU-T G.657 standards. Indoor deployments often use G.657.A1 fibers, tolerating 10 mm bend radii, while outdoor or conduit installations may use G.657.A2 fibers, which handle tighter bends and irregular surfaces . Fiber cores typically range from 1 to 12, with common outdoor single-butterfly drop cables offering 1, 2, or 4 cores . The fibers provide high bandwidth, low attenuation, and excellent transmission performance, even in tight bends or complex routing .

Applications

• FTTH (Fiber to the Home): Connects outdoor distribution points to residential homes, supporting high-speed broadband services .
• FTTB (Fiber to the Building): Provides reliable optical connections within commercial or multi-tenant buildings .
• Indoor Deployment: Suitable for vertical shafts, concealed pipes, cable trays, walls, and risers .
• Outdoor Deployment: Self-supporting design allows aerial installation without additional support, ideal for short spans from utility poles to buildings .

Advantages

• Self-supporting: Can span short distances without external support.
• Flexible and lightweight: Simplifies installation in tight spaces.
• Bend-insensitive fibers: Maintain performance in sharp bends.
• Flame-retardant LSZH sheath: Safe for indoor and outdoor use.
• Easy termination: Compatible with pre-terminated connectors or on-site splicing .

Summary

Self-supporting single-butterfly drop optical cables are versatile, safe, and high-performance solutions for modern fiber access networks. Their combination of robust strength members, bend-insensitive fibers, and LSZH sheathing makes them suitable for both indoor and outdoor FTTH/FTTx deployments, providing reliable connectivity from distribution points to end users .