Optical communications. IV - Semiconductor laser

The development of gas lasers in optical communications is investigated. The recombination spectrum of a GaAs laser diode and the accompanying current are discussed along with the effects of increased current and the strong charge carrier injection in the pn-transition. The p(+) pn laser diode structure is examined in which the optical wave is conducted in the weaker doped p layer with a higher index of reflection. Emphasis is also given to the simple heterostructure, double heterostructure and 5-layer p-GaAs diodes. The GaAlAs laser diode in double heterostructure is illustrated along with structures in which the active zone is embedded laterally in semiconductor material with low index of reflection (buried heterostructure and transverse junction strip diodes).