Semiconductor optoelectronic (OE) devices have been delivering an integrated, dependable and ultrafast solution to the ever-increasing bandwidth challenge in data access and communications. As an enabling technical field, OE modeling and simulation facilitates better design, faster prototyping, improved reliability, and thus leaner production budget, as proven by the microelectronics industry where simulation and verification have become an essential part. In general, optoelectronic devices generate, modulate, amplify, and detect optical signals via light-matter interactions. Their applications range from digital camera, to traffic signaling, to diode pump laser, to electro-optic modulator for communications.

As a member of the Computational Quantum Optoelectronics group at NASA Ames, our ultimate goal is to develop a comprehensive, yet efficient simulation tool for optoelectronic integrated circuits (OEICs), which is delineated by Cun-Zheng Ning, our group lead. The projects I am working on are (1) investigating plasma heating and modulation in semiconductor optoelectronic devices in the terahertz (THz) frequency range; and (2) developing a full thermal management model for active devices from first principles by including plasma heating and ambient influence. Details are elaborated below.

For project (1), we propose a modulation scheme that offers time-domain multiplexing (TDM) in the THz frequency domain. Our proposal is a variant of the internal modulation method, thus maintains the simplicity of the method, it also alleviate the speed bottleneck problem posed by direct-current method. The basic idea is to realize gain modulation by varying the plasma temperature---plasma heating method, in contrast with the conventional direct-current method which affects the optical gain via changing the injection current. For project (2), we have successfully developed a hydrodynamic model for electronic transport in the lasing region, which will be integrated into a final form that fully accounts for carrier dynamics within whole device domain, lattice (ionic background) contributions, and radiation effects. Our model extends our capability to better describe broad-area, high-power semiconductor lasers by offering a self-consistent and broader framework. In addition, detailed considerations based upon first principles of physics deepen our understanding of the device and advance our technical prowess in future design and conception.

Overall, we work in the general physical area of active OE devices. In addition to the above efforts, we constantly explore possibilities to apply our expertise in emerging OE technologies that will assist accomplishing our mission at NASA.