Butterfly-shaped drop fiber optic cables feature a central optical fiber flanked by parallel strength members and encased in an LSZH or PVC sheath, providing flexibility, bend resistance, and ease of installation.

Core Structure

The defining feature of a butterfly-shaped drop cable is its flat, butterfly-like cross-section. The optical fiber unit is positioned at the center, while two parallel strength members—typically made of Fiber Reinforced Plastic (FRP) or sometimes steel—are placed on either side to provide tensile strength and mechanical protection . This configuration allows the cable to maintain flexibility while resisting bending stress, which is critical for indoor routing along walls, corners, and conduits .

Optical Fiber

These cables generally use single-mode fibers, such as G.657A1 or G.657A2, which are optimized for tight bend resistance and minimal signal loss in compact installation environments . The fiber count can vary, commonly available in 1-core, 2-core, or 4-core variants, depending on connectivity requirements .

Strength Members

The strength members serve to reinforce the cable against pulling forces during installation and provide structural integrity. Non-metallic FRP members are preferred for indoor use to avoid electrical interference, while metallic options may be used in outdoor or aerial applications . These members also help maintain the flat, stable shape of the cable.

Outer Sheath

The cable is completed with an outer sheath, typically made of Low Smoke Zero Halogen (LSZH) for indoor safety or UV-resistant polyethylene (PE) for outdoor applications . LSZH jackets reduce toxic emissions in case of fire, while PE sheaths provide durability against environmental factors like sunlight and moisture.

Advantages

• Compact and flat design reduces bending stress and simplifies routing.
• High tensile strength from parallel strength members allows safe pulling during installation.
• Bend-resistant fibers minimize signal loss in tight spaces.
• Lightweight and flexible, suitable for both indoor and outdoor FTTH deployments.
• Ease of splicing and termination, compatible with fusion or mechanical splicing techniques .

Applications

Butterfly-shaped drop cables are widely used in FTTH networks, fiber optic drop cable systems, and building entry solutions, where space efficiency, mechanical reliability, and easy installation are required . They are ideal for connecting the fiber access point to the ONT in residential or commercial environments. In summary, the butterfly-shaped drop fiber optic cable combines a central optical fiber, parallel strength members, and a protective sheath in a flat, flexible design that enhances mechanical protection, bend resistance, and installation efficiency for modern fiber access networks .