Disadvantages of optical fibers compared to wires

* higher cost
* need for more expensive optical transmitters and receivers
* more difficult and expensive to splice than wires
* at higher optical powers, is susceptible to "fiber fuse" wherein a bit too much light meeting with an imperfection can destroy several metres per second "fiber fuse" detection circuitry at the transmitter can break the circuit and halt the failure to minimize damage.
* cannot carry electrical power to operate terminal devices (Note: current telecommunication trends greatly reduce this concern: availability of cell phones and wireless PDAs; the routine inclusion of back-up batteries in communication devices; lack of real interest in hybrid metal-fiber cables; increased use of fiber-based intermediate systems)

Advantages of optical fibers over wires

• low loss, so repeater-less transmission over long distances is possible
• large data-carrying capacity (thousands of times greater)
• immunity to electromagnetic interference, including nuclear electromagnetic pulses (but can be damaged by alpha and beta radiation)
• high electrical resistance, so safe to use near high-voltage equipment or between areas with different earth potentials
• light weight
• signals contain very little power