Understanding Optical Fiber Communication

The optical fiber system is used for carrying light from one point to another. It consists of a transmitting device, a receiving device, and a fiber optic cable.

• The transmitting device converts an electrical signal into a light signal.
• The receiving device converts a light signal back into an electrical signal.
• The fiber optic cable is made of a transparent, thin plastic or glass material, designed to carry light.

LEDs and Laser diodes are commonly used in the transmitter and receiver modules of fiber optic systems.

This technology has revolutionized telecommunications and data transmission thanks to its high data carrying capacity, low signal loss, and immunity to electromagnetic interference. These advantages have made optical fiber communication the backbone of modern telecommunications networks and the internet.

What is Fiber Optic Cable?

As shown, a fiber optic cable consists of the core, cladding, coating, strength member, and outer jacket.

• The core is the thin glass center of the fiber through which light is transmitted and received.
• The cladding surrounds the core and reflects light back into it, enabling efficient light transport through the core.
• The coating and jacket help protect the cable from damage.

There are two main types of fiber optic cables: single-mode and multimode.

• Single-mode cable: This consists of a single strand of glass fiber, typically 8.3 to 10 microns in diameter. It carries a single mode of light and supports higher bandwidth than multimode fiber. It offers a higher transmission rate and can cover up to 50 times more distance than multimode fiber. It supports the lowest order bound mode, which can propagate at wavelengths of 1300 to 1320 nm. Single-mode fiber is often used for inter-city telephone trunks and video applications.

• Multimode cable: This is made of glass fibers with a diameter of 50 to 100 microns. Multimode fiber offers higher bandwidth at greater speeds over medium distances. Light waves, typically with wavelengths of 850 or 1300 nm, travel through the core. Multimode fiber is usually used for LANs and WANs.

Fiber Optic Cable Characteristics

Here are some of the unique benefits and characteristics of fiber optic cables:

• They can accommodate data transfer much faster than copper wire versions, such as coaxial and twisted pair cables.
• Data can be sent as pulses of light over threads of glass at gigabits per second (Gbps).
• Fiber optic lines are free of electromagnetic interference, making them difficult for hackers to tap.
• Data can travel for miles without significant signal degradation.
• These cables are more immune to environmental extremes, operating over a wide temperature range. They are also unaffected by corrosive liquids and gases.
• They are non-conductors, eliminating shock hazards as there’s no current or voltage associated with them.
• They are small in size and light in weight, which simplifies installation.
• The cost of fiber optic cable is becoming increasingly competitive compared to other cable-based systems.

Benefits or Advantages of Fiber Optic Cable

Here are some key benefits of using fiber optic cables:

• Fiber can carry a large amount of data due to its larger bandwidth capacity. Data can be transmitted at very high speeds, typically 1.6 TB/sec in real-world applications. This capacity will be crucial for next-generation internet technologies like LiFi (Light Fidelity).
• Fiber incurs low signal loss, typically around 0.3 dB/Km. This means optical repeaters aren’t needed for long-distance transmissions.
• While the initial installation cost can be higher, the long-term benefits outweigh the costs of older coaxial-based systems.
• Fiber optic systems are immune to electromagnetic interference, allowing them to be placed near high-frequency towers and in areas where electromagnetic radiation is a concern. Moreover, they don’t radiate electromagnetic waves themselves, preventing interference with nearby EM signal-based systems like cellular, microwave, and satellite communications.
• Fiber has higher electrical resistance, making it safe to operate near high-voltage lines and equipment.
• Fiber is lightweight and easy to install.
• The optical fiber transmission power is very low. The light carried by the cables doesn’t leak, except at the beginning and end of the system, preventing crosstalk between cables.
• Fiber doesn’t generate sparks, making it suitable for applications in the automobile industry.
• Unlike RF-based systems which can be tapped, fiber-based communication is highly secure as light is transported within the cable itself, enhancing security for individuals and businesses.

Drawbacks or Disadvantages of Optical Fiber

Here are some of the potential drawbacks of using optical fiber:

• Cost: The initial installation cost can be higher due to the expense of optical transmitters and receivers. Specialized tools are also needed for maintenance and repair.
• Splicing: It can be more difficult to splice fiber compared to wires, especially at the starting and end joints. Interfacing tools and connectors can also be costly.
• Damage: If light encounters imperfections during travel, especially at higher optical power levels, it can lead to the destruction of the fiber cable. Fiber fuse devices can be used to break the circuit and prevent further damage.
• Power: Fiber optic systems cannot carry electrical power, which is often needed at terminal equipment/devices.

Conclusion

In summary, fiber optic cables offer superior performance in terms of speed, data capacity, and resistance to interference but may come with higher upfront costs and require specialized equipment and expertise for installation and maintenance. The choice between fiber optics and other types of cabling depends on the specific requirements of the application and budget constraints.