Q.Which transmission media carries signals in the form of light?
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Start your 14-day free trial to unlock the full solution →Optical fiber carries signals in the form of light through a glass or plastic core using total internal reflection.
Transmission media fall into two broad categories: wired (guided) and wireless (unguided). Within wired media, we have three main types — twisted-pair cable, coaxial cable, and optical fiber. The question asks which one uses light as the signal carrier.
Twisted-pair and coaxial cables both transmit data as electrical signals — voltage pulses traveling through copper conductors. The signal is an electromagnetic wave confined to the metal wire.
Optical fiber, by contrast, transmits data as pulses of light. The medium is a thin strand of ultra-pure glass or plastic. Light from a laser or LED enters one end of the fiber and travels through the core by bouncing off the cladding in a phenomenon called total internal reflection. The core has a higher refractive index than the surrounding cladding, so light striking the boundary at a shallow angle reflects back into the core rather than escaping. This allows the light signal to travel long distances — tens of kilometers — with very little loss.
Why use light instead of electricity? Three compelling reasons:
- Bandwidth: Light has a much higher frequency than radio or electrical signals, so fiber can carry vastly more data — terabits per second on a single strand. …
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