In a mobile communications system, a mobile station communicates with a first base station operating at a first antenna specific weight factor. Pump light is coupled into the amplifier at one end of the gain medium and signal light is coupled into and out of the amplifier at an opposite end of the gain medium. In a first imaginary vertical plane, a first path is formed by a first intersection between the first imaginary vertical plane and the striking face, and the auxiliary grooves have a first concentration no less than 0. A first set of routines, each executable on the processor, are configured to read and write values from and to the register. With this layer structure, in an emitting layer of the light-emitting device, a wave front of a spherical wave form exited from a point light source in the front direction is converted into that of a plane wave form, and exited outside the substrate at a high efficiency.