Shulika O. Carrier transport processes in active regions of semiconductor lasers and semiconductor optical amplifiers based on asymmetric multiple quantum-well heterostructures

Subject of inquiry: semicnductor lasers and semiconductor optical amplifiers based on asymmetric multiple quantum-well heterostructures. Aim: solution of the scientific problem on determination of mechanisms of quantum transport processes in compositionally asymmetric multiple quantum-well heterostructures, their theoretical description and determination of essence of their influence on the pulse response of semiconductor optical amplifiers. Results, novelty: For the first time theoretical description of the capture area is made as a fundamental feature of quantum-well heterostructures (QWS) which results from their quantum nature. For the first time the problem on space dependence of the capture rate is solved. For the first time it is shown that capture area can be smaller as well as larger than size of QWS. For the first time tunneling processes in asymmetric multilayer QWS are theoretically described. It is shown that tunneling from deep quantum wells to shallow ones is realized via top states, buttunneling from shallow quantum wells to the deep ones appears via down states. Calculated tunneling times are in the interval from several picoseconds to several tens femtoseconds, and are competitors to intraband processes in population and gain dynamics inside active region. Application area: optics, laser physics.