Why Use Fiber Optics?
1. Noise immunity
Unlike wire systems, which require shielding to prevent electromagnetic radiation or pick up, optical fibers are dielectric and are not affected by electromagnetic interference (EMI) or radio frequency interference (RFI). This potential for lower rates of bit error can increase circuit efficiency. In addition, fiber optics is the only medium that can transmit through a harsh radiation environment.
2. Electromagnetic pulses (EMP)
While not totally immune to electromagnetic impulses (radiation), optical fibers do exhibit great resistance to EMP. Radiation effects will discolor standard fiber types; however, laser-based systems do clear up some of the degradations after a period of time. Special radiation- hardened optical fibers can be purchased for applications where EMP is a concern.
3. Low loss (attenuation)
Current singlemode fibers have losses as low as 0.2dB/km at 1550 nm. Multimode losses are as low as 0.7dB/km at 1300 nm. This creates opportunities for longer distances without costly repeaters.
4. High bandwidth
Optical fibers have been tested at over 5.12 Tb/s. Theoretically, rates of more than 200-500 Tb/s are obtainable.
5. Small size
A 1/2” (24) fiber-optic cable operating at 40 Gb/s can handle 143,360 times the amount of voice channels as a 3” diameter (900) twisted pair cable. Smaller size provides better duct utilization.
The same 1/2” fiber-optic cable weighs approximately 176 pounds per kilometer. The 3” twisted pair cable weight in at 16,000 pounds. This allows for longer pulls during installation.
7. Transmission security
Because fiber is dielectric, it does not radiate electromagnetic pulses, radiation, or other energy that can be detected. This makes the optical cable difficult to find. In addition, methods to tap into fiber create a substantial system signal loss.
8. No short circuits, sparks, or fire hazards
Fiber is glass and does not carry electrical current, radiate energy, or produce heat or sparks. For applications in dangerous explosive environments, fiber provides a safe transmission medium.
9. Wide temperature range
Standard fibers and cables are manufactured to meet temperatures from -40°C to +160°F (approximately -40°C to +70°C).
10. Fewer repeaters
The use of low loss optical fibers, laser light sources and sensitive photo detectors allow for long transmission distances requiring fewer signal regenerators. In PON networks the low fiber loss is offset by the use of high loss optical splitters.
11. Stable performance
Fiber optics is affected less by moisture and thermal conditions than copper. This means less corrosion and degradation. Therefore, less maintenance is required for the physical plant.
12. Topology capability
FTTH systems use optical splitting, wavelength division multiplexing (WDM) and optical filtering to lower the cost of providing multiple services while using the least amount of optical fibers. Future options can include increased WDM and also optical switching for system upgrades.
Costs are continuously decreasing due to better production capabilities of optical components. The use of passive devices allow for greater flexibility for increasing the data rates while increasing splitter counts and transmission distances.
Expansion capabilities continue to grow beyond current technologies using common fibers and transmission techniques. When challenges arrive, optical solutions have been resolved through improvements of active
and passive optical components.
15. Material availability
Glass optical fibers are manufactures from silica, the material that comprises sand. Unlike copper, silica is in abundance throughout the world and is readily available.
FTTH standardization builds upon national and international standards encompassing legacy voice (SONET/ATM), video (RF), and data communications (Ethernet).