Quantum dot semiconductor device

摘要

Aquantumdot semiconductor device is disclosedwhich prevents variation of the gain in an operation wavelength even if the temperature varies. The quantum dot semiconductor device includes an active layer (11) having a plurality of quantum dot layers (4A, 4B) each including a composite quantum dot (2) formed by stacking a plurality of quantum dots (1) and a side barrier layer (3) formed in contact with a side face of the composite quantum dot (2). The stack number of the quantum dots (1) and the magnitude of strain of the side barrier layer (3) from which each of the quantum dot layers (4A, 4B) is formed is set so that a gain spectrum of the active layer (11) has a flat gain bandwidth corresponding to a shift amount of the gain spectrum within a desired operation temperature range.