Fiber optic laser6/2/2023 ![]() The advent of lasers in 1960 and low-loss optical fiber in 1970 changed all that. But what made the photophone impractical for long-distance communications was the incoherent light and its free-space transmission through the atmosphere. Current fluctuations generated in the photoconductive selenium by the modulated light beam were fed through a transducer to recreate the original sound. Bell’s "photophone" used a flexible diaphragm to modulate a beam of sunlight and a selenium photodetector as a receiver. Ironically, it was Bell himself who invented one of the earliest light-wave communications devices in 1880. ![]() Not since Alexander Graham Bell’s invention of the telephone has communications experienced such meteoric or revolutionary development, and nearly all of it is made possible by electro-optics. ![]() ![]() The technology has been around for only 20 years, yet fiberoptic communications has already become the backbone of the information superhighway. When you pick up the phone and place a long-distance call, chances are very good that your conversation is being carried by light waves over hundreds or thousands of miles of optical fiber.
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