Semiconductor optical amplifiers: Beyond their role as transmitters in fiber-optic systems, laser diodes can be made to amplify light, perhaps promising simple all-optical repeaters

Part of the original vision of integrated optics is the ultimate creation of a fiber-optic system that would be a complete optical analog to traditional electronic systems. In such a system the light, once generated, would not only be transmitted optically, but would also be amplified optically and received by direct optical detection.