Amplification Characteristics of Nd:YGG Thin-film Waveguide pumped with LD

Abstract

Optical direct amplifiers are devices that amplify an optical signal light by adding current or light to it. Semiconductor laser amplifiers and fiber amplifiers have several disadvantages, such as the need of a current circuit and length over few kilometers, respectively(1),(2). In the other hand, thin film waveguide type optical amplifiers(3) have the following advantages, 1) miniaturization of optically pumped amplifiers, 2) reduction of pumping power, 3) combination of different optical thin film waveguide devices ( modulators, switches, isolators) in the form of integrated optical circuits, 4) low propagation loss compared to semiconductor optical integrated circuit.