Fiber optic and coaxial cables are both used for data transmission, but they differ significantly in design, performance, and applications. Here's a detailed comparison:

1. Transmission Medium

• Fiber Optic:

  • Uses light pulses (lasers/LEDs) transmitted through glass/plastic fibers.

  • Data travels via total internal reflection in the core.

• Coaxial Cable:

  • Uses electrical signals through a copper core surrounded by insulation and shielding.

  • Consists of a central conductor, dielectric insulator, metallic shield, and outer plastic jacket.

2. Speed & Bandwidth

• Fiber Optic:

  • Speed: Up to terabits per second (Tbps) in research; commercially supports 100+ Gbps.

  • Bandwidth: Nearly unlimited due to light’s high frequency.

• Coaxial Cable:

  • Speed: Typically up to 10 Gbps (e.g., DOCSIS 4.0 for cable internet).

  • Bandwidth: Limited by signal attenuation at higher frequencies (up to 1 GHz in modern coax).

3. Distance & Signal Loss

• Fiber Optic:

  • Distance: Single-mode fiber (SMF) can transmit 70–100+ km without repeaters.

  • Attenuation: Very low (~0.2 dB/km).

• Coaxial Cable:

  • Distance: Limited to ~500 meters (for high-quality RG-6) before signal degradation.

  • Attenuation: Significant loss over distance, especially at higher frequencies.

4. Interference & Reliability

• Fiber Optic:

  • Immune to electromagnetic interference (EMI) and radio-frequency interference (RFI).

  • No crosstalk or signal leakage.

• Coaxial Cable:

  • Shielded design reduces EMI/RFI but is not immune (e.g., interference from power lines).

  • Susceptible to "ingress" (noise entering the cable) and "egress" (signal leakage).

5. Security

• Fiber Optic:

  • Extremely hard to tap without detection (light disruption is noticeable).

  • Ideal for secure data transmission (e.g., government, finance).

• Coaxial Cable:

  • Vulnerable to eavesdropping via electromagnetic leakage or physical taps.

  • Requires encryption (e.g., AES) for sensitive data.

6. Cost

• Fiber Optic:

  • Higher upfront costs (installation, transceivers, splicing tools).

  • Lower long-term costs (minimal maintenance, future-proof).

• Coaxial Cable:

  • Cheaper installation (widely available, simple connectors like F-type).

  • Higher maintenance over time (signal degradation, shielding repairs).

7. Durability & Size

• Fiber Optic:

  • Fragile glass core (requires careful handling during installation).

  • Thin, lightweight, and flexible (ideal for crowded conduits).

• Coaxial Cable:

  • More physically robust but thicker and heavier.

  • Prone to corrosion if the outer jacket is damaged.

8. Applications

• Fiber Optic:

  • Long-distance telecom (ISP backbones, undersea cables).

  • High-speed internet (FTTH), data centers, 5G networks.

  • Medical imaging, military, and industrial systems.

• Coaxial Cable:

  • Cable TV (CATV) and broadband internet (e.g., DOCSIS).

  • Short-distance video surveillance (CCTV).

  • Legacy networking (Ethernet over coax) and radio antennas.

9. Latency

• Fiber Optic:

  • Lower latency (near light-speed transmission).

  • Critical for real-time applications (gaming, stock trading).

• Coaxial Cable:

  • Higher latency due to electrical signal propagation delays.

10. Power Transmission

• Fiber Optic:

  • Cannot transmit electrical power; devices need separate power sources.

• Coaxial Cable:

  • Supports power transmission (e.g., powering amplifiers in CATV systems).

When to Choose Which?

• Fiber Optic:

  • Need ultra-high speed, long-distance, or EMI-heavy environments.

  • Future-proofing networks (e.g., smart cities, IoT).

  • Applications requiring high security and reliability.

• Coaxial Cable:

  • Budget-friendly setups (e.g., residential cable TV/internet).

  • Short-range video surveillance (CCTV) or legacy systems.

  • Hybrid fiber-coaxial (HFC) networks (common in cable ISPs).

Future Trends

• Fiber optic adoption is accelerating for 5G, cloud services, and smart infrastructure.

• Coaxial cables remain relevant for HFC networks and legacy systems but are gradually being phased out in favor of fiber.

Conclusion:
Fiber optic cables excel in speed, distance, and reliability, making them ideal for modern high-demand applications. Coaxial cables are cost-effective for short-range, legacy, or hybrid systems but struggle with bandwidth and interference limitations. The choice depends on your budget, technical requirements, and scalability goals.