What are the parts of an optical fiber?

An optical fiber is a layered structure designed to transmit light with minimal loss. Here's a breakdown of its key components:

1. Core

Material: Ultra-pure glass (silica) or plastic (POF).

Function: Carries light signals (laser/LED pulses).

Diameter:

Single-mode (SMF): 8–10 µm (for long-distance, e.g., telecom).

Multimode (MMF): 50 µm or 62.5 µm (for short-range, e.g., data centers).

Plastic Optical Fiber (POF): ~1 mm (for automotive/audio).

2. Cladding

Material: Glass or plastic with a lower refractive index than the core.

Function: Keeps light trapped in the core via total internal reflection.

Diameter: Typically 125 µm for glass fibers.

3. Coating (Buffer)

Material: Acrylate or polyimide.

Function: Protects the glass from moisture and physical damage.

Diameter: 250 µm (standard) or 900 µm (tight-buffered for rugged use).

4. Strength Members

Material: Aramid yarn (Kevlar) or fiberglass rods.

Function: Prevents stretching/crushing during installation.

5. Outer Jacket

Material: PVC (indoor), LSZH (low-smoke zero-halogen), or armored (steel/copper for outdoor).

Function: Shields against abrasion, chemicals, and rodents.

Colors:

Orange: Multimode (OM1/OM2).

Aqua: OM3/OM4 (laser-optimized MMF).

Yellow: Single-mode (OS2).

Additional Layers (Specialty Cables)

Armor: Metal braid or corrugated tape for crush resistance (used in direct-burial cables).

Water-Blocking Gel: Prevents moisture ingress in outdoor cables.

Ripcord: Helps strip the jacket without damaging fibers.