Quantum energy control of multiple‐quantum‐well structures by selective area mocvd and its application to photonic integrated devices

Quantum energy control is proposed in the form of a multiple‐quantum‐well (MQW) structure fabricated by selective metal organic chemical vapor deposition (MOCVD) growth to obtain high‐performance multiple‐function semiconductor photonic integrated devices. Its fundamental principle and the applied photonic integrated device are discussed. In general, semiconductor photonic integrated devices require semiconductor layers with different bandgap‐energy states for each structural device having a different function formed on the same semiconductor substrate. In this paper, the position‐dependent growth speed and the growth‐layer compositions on the substrate are controlled by selective MOCVD growth so that the quantum energy levels of the InGaAs/InP MQW structures grown simultaneously are varied over the substrate surface. As a result, a controllable range of the quantum energy level spanning over 200 meV and a high‐quality crystal configuration of selectively grown layers comparable to that formed by conventional growth processes have been confirmed. Application of this new integration method required that we design a monolithic integrated device of a distributed feedback laser diode and an electric field absorption‐type modulator, as well as a multiple‐wavelength distributed feedback laser array. Despite the simple design method, good crystal quality of the selectively grown layers, good optical coupling between the devices, and good device performance were observed.