Alexander Graham Bell and the Photophone

Alexander Graham Bell and the Photophone While hes best known as the inventor of the telephone, Alexander Graham Bell considered the photophone his most important invention... and he may have been right. On June 3, 1880, Alexander Graham Bell transmitted the first wireless telephone message on his newly invented photophone, a device that allowed for the transmission of sound on a beam of light. Bell held four patents for the photophone and built it with the help of an assistant, Charles Sumner Tainter. The first wireless voice transmission took place over a distance of 700 feet. How It Worked Bells photophone worked by projecting voice through an instrument toward a mirror. Vibrations in the voice caused oscillations in the shape of the mirror. Bell directed sunlight into the mirror, which captured and projected the mirrors oscillations toward a receiving mirror, where the signals were transformed back into sound at the receiving end of the projection. The photophone functioned similarly to the telephone, except the photophone used light as a means of projecting the information, while the telephone relied on electricity. The photophone was the first wireless communications device, preceding the invention of the radio by nearly 20 years. Although the photophone was an extremely important invention, the significance of Bells work was not fully recognized in its time. This was largely due to practical limitations in the technology of the time: Bells original photophone failed to protect transmissions from outside interferences, such as clouds, that easily disrupted transport. That changed nearly a century later when the invention of  fiber optics in the 1970s allowed for the secure transport of light. Indeed, Bells photophone is recognized as the progenitor of the modern fiber optic telecommunications system that  is widely used to transmit telephone, cable, and internet signals across large distances.