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: wangcheng1@shanghaitech.edu.cn   Phone: +86-2120685263
Office: Room 
1D401E,  Shcool of Information Science and Technology,  ShanghaiTech University, 
Middle Huaxia Road 393 ,  Pudong District, Shanghai 201210, China

Research Interests​​
Dr. Cheng Wang's research insterests include dynamics and nonlinear dynamics of advanced nanostructured semiconductor lasers and quantum cascade lasers, for telecommunication applications in fiber-optic systems, in radio-over-fiber systems, and in free-space optical communication systems. 

  • Quantum dot/dash lasers​          
  • Quantum cascade lasers
  • Silicon-based lasers
  • InAs/GaSb lasers
  • All-optical signal processing
  • Fiber-optic communications
  • Radio-over-fiber communications
  • Free-space optical communications
Quantum Dot/Dash 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 Locking

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.
External Optical Feedback

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.