Currently, our data predominantly traverses copper wire or fiber optic cables. Even when data is transmitted via cell phones using radio waves, which also propagate at light speed, it eventually integrates with the wired networks of the Internet. The two primary copper wire types for long-distance data transfer are twisted pair (initially used for telephony and later for dial-up Internet and DSL) and coaxial cable (first used for cable TV, then Internet and phone). Coaxial cable offers faster speeds compared to twisted pair. However, fiber optic cable is even quicker, transmitting data as light pulses rather than electrical signals.
Light’s speed in a vacuum, referenced earlier, is crucial. Light traveling through fiber optics is not as fast as light in a vacuum. Light slows down when passing through any medium. The difference is insignificant in air, but significantly reduced in media like glass, which forms the core of most fiber optic cables. The refractive index of a medium is the ratio of light’s speed in a vacuum to its speed in that medium. Knowing two of these values allows calculating the third. Glass has a refractive index of approximately 1.5. Dividing the speed of light (about 300,000 kilometers or 186,411 miles per second) by 1.5 yields approximately 200,000 kilometers (124,274 miles) per second, which is the speed of light through glass. Some fiber optic cables use plastic, which has a higher refractive index and therefore slower speed of data transmission.
The speed reduction is partly due to the dual nature of light, exhibiting both particle and wave properties. Light is composed of particles called photons that don’t move in a straight line through the cabling. They bounce off molecules of the material, resulting in light refraction and absorption, eventually leading to energy and data loss. This necessitates periodic signal boosting for long-distance transmission. However, slowing light isn’t entirely negative. Impurities are added to fiber optics to manage speed and effectively channel the signal.
Fiber optic cables use light pulses to transmit data, but the speed is slightly less than light in a vacuum.
Fiber optic cable significantly outperforms copper wire and is less susceptible to electromagnetic interference. Fiber can achieve speeds of hundreds of Gigabits per second or even Terabits. Typical home Internet connections don’t reach these speeds, partly because wiring is shared and networks using fiber optics often have copper running the final stretch to homes. However, with fiber reaching your neighborhood or home, you can achieve data transfer rates of 50 to 100 Megabits per second, compared to 1 to 6 Megabits per second from average DSL lines and around 25 Megabits per second from cable. Actual data speeds vary greatly depending on location, provider, and chosen plan. This highlights the critical role of fiber optic infrastructure in modern high-speed internet access.
Other factors contribute to signal latency, such as the necessary back-and-forth communication when accessing a webpage or downloading data, known as handshaking. Your computer and the server hosting the data communicate to synchronize and ensure successful data transfer, introducing a brief delay. Transmission distance also impacts data travel time, and bottlenecks can occur at any hardware and cabling along the path. A system’s speed is limited by its slowest component, and every millisecond matters in today’s fast-paced communication landscape. Could these delays be reduced or eliminated? Could we, theoretically, send information faster than light?
Recent advances have enabled near-fiber optic speeds over copper wiring by reducing interference and employing other techniques. Researchers are also exploring data transmission via light through the air, such as using lightbulbs for WiFi or transmitting laser beams between buildings. While light through the air travels close to light speed, nothing currently surpasses this limit. So, can we achieve actual faster-than-light transfer? The question remains a significant area of scientific inquiry, pushing the boundaries of what’s currently possible.
Alexander Graham Bell’s photophone was a precursor to modern fiber optics, transmitting voice using light.
The photophone, invented by Alexander Graham Bell, serves as a historical precursor in the pursuit of light-based communication. It functioned as the first wireless telephone, utilizing light instead of radio waves. It projected voice towards a vibrating mirror, which reflected sunlight onto a selenium receiver, converting it into an electrical current for telephone transmission. Its main drawback was the reliance on direct sunlight, rendering it unusable under clouds or at night. Nevertheless, the photophone demonstrated the potential of using light for communication, foreshadowing fiber optics and further exploration into the use of light for data transmission.
