Dr. Cheng Wang
Semiconductor Optoelectronics and Dynamics Group
Dr. Cheng Wang received  the M. S. in Physical Electronics from Harbin Institute of Technology in 2011, and the Ph. D. in Optoelectronics  from Institut National des Sciences Appliquées de Rennes, France in 2015. During  2012 and 2015, he has researched at Télécom ParisTech, France, at Technische Universität Berlin, Germany, and at Politecnico di Torino, Italy, respectively.  He was a Senior Research Assistant in the City University of Hong Kong from 2015 to 2016. Since April, 2016 he joined  ShanghaiTech University as an assistant professor.
Email:        wan[email protected]   
Phone:     +86-2120685263
Address:  Room 
1D401E,  SIST,  ShanghaiTech University, 
                      Middle Huaxia Road 393 ,  Pudong District, 
​                      Shanghai 201210, China

Research Interests​​
Dr. Cheng Wang's research insterests include theoretical modeling, experimental characterization, and optimization of advanced quantum structure-based semiconductor lasers, as well as applications in fiber-optic communication networks, in gas spectroscopies, and in Lidar systems. ​​
  • Quantum dot/dash semiconductor lasers, fiber-optic communication.​        
  • Quantum/interband cascade lasers, gas spectroscopy.
  • Si/Ge-based semiconductor lasers, on-chip computation.
Research Projects
  • National Natural Science Foundation of China, "Optical Noise of InAs/GaAs quantum dot lasers eptaxially grown on Ge / Si," 2019-2021.    
  • Shanghai Pujiang Program,  "Nonlinear dynamics of quantum cascade lasers subject to optical injection," 2017-2019.
  • Shanghai Eastern Scholar (Youth), in Electronic Science and Technology, 2017​.
Quantum Dot Lasers

A quantum dot laser is an advanced semiconductor laser that uses quantum dots as the active laser medium in its light emitting region. In comparison with the conventional quantum well and bulk laser diodes, quantum dot lasers have shown improvements on lasing threshold, temperature insensitivity, modulation bandwidth, linewidth enhancement factor, as well as intensity and phase noises.  Therefore,  the quantum dot lasers are expected as next-generation optical sources for high-speed data communication networks.
Quantum Cascade Lasers

Unlike typical interband sermiconductor lasers, quantum cascade lasers are unipolar devices and the laser emission is achieved through intersubband transitions  in a repeated stack of semiconductor multiple quantum well heterostructures. The lasing wavelengths spread from mid- to far-infrared portions of the electromagnetic spectrum. The lasers have wide applications in gas spectroscopy, free space optical communication, terahertz imaging and so on. Quantum cascade lasers exhibit many interesting dynamical characteristics, in contrast to interband semiconductor lasers. 
Optical Injection Dynamics

Optical injection locking technique uses a tunable narrow-linewidth laser (refers as master laser) to inject light into a laser under test (refers as slave laser). Under certain conditions, the slave laser's phase is synchronized to the master one. Thus, the dynamics of the slave laser can be significantly improved, such as enhancement of modulation bandwidth, reduction of frequency chirp, suppression of optical noises and nonlinear distortions. In addition, Optically injected semiconductor lasers produce rich nonlinear dynamics, such as periodic- and aperiodic oscillations, bistabilities and instabilities, as well as chaotic oscillations.
Optical Feedback Dynamics

In fiber-optic links, even a very small back reflection from the fiber pigtail tip or from the optical connectors into the laser diode source changes siginificantly the laser characteristics. From the viewpoint of optical spectrum behavoirs, semiconductor lasers subject to optical feedback typically exhibit five different regimes, which can be either used to improve the laser's spectral purity or to generate nonlinear dynamics like chaos.