Abstract
Quantum dot (QD) have many attractive characteristics for development advanced optical gain devices,
such as broadband and high-robustness QD laser, high-speed QD optical amplifier, and so on. In this
paper, we briefly described characteristics of ultra-broadband wavelength tunable QD lasers,
heterogeneous QD laser integrated with silicon photonic circuit, a QD comb laser for multiple frequency
carrier generation, and a two-tone laser for convergence photonic and wireless communications. We
also discussed a utilization of novel wavelength bands of Thousand-band and O-band for optical
communications, since an operating waveband of the InAs/GaAs QD optical gain is suitable for the
T+O-bands. A construction of over 1000-ch huge optical switch fabric was successfully realized using
the broadband QD optical gain devices. It is expected that the QD optical gain devices will become
breakthrough technology for creating novel broadband photonic devices and constructing of further
advanced photonic network system for short and middle range communications.
