Aluminum-free 980-nm laser diodes for Er-doped optical fiber amplifiers

We review state-of-the-art aluminum-free GaInP-GaInAsP-GaInAs laser diodes which emit at the wavelength of 980 nm. These lasers are intended for pumping light into erbium-doped optical fiber amplifiers. We discuss the preparing of the layer structure, using the gas-source molecular beam epitaxy growth method, the lasing characteristics, fiber coupling efficiency, and reliability issues.