Qian, Li

Prof. Dr. Li Qian

Prof. Qian's research focuses on fibre-based photonic technologies and applications, both in the traditional field of optical sensing/metrology as well as in the emerging field of quantum communication and quantum metrology.

One of the technological innovations developed in her group is the frequency-shifted interferometer (FSI), which has found numerous applications from dispersion/length measurements, to multiplexing large-scale fibre-optic sensors, to sensitive cavity ring-down sensing, to vibration sensing. The unique feature of FSI is that it works with low-cost components such as incoherent light sources and slow detectors, while having the capabilities of optical-time-domain reflectometer (OTDR, which requires short pulses and high-speed detection electronics) and optical frequency-domain reflectometer (OFDR, which requires coherent light sources).

Prof. Qian’s group also developed unique dispersion measurement technologies, such as the virtual reference interferometer (VRI), which was later commercialized by a start-up company, Inometrix Inc.

By combining the mature fibre optic technology with newly developed quantum technology, her group's research is making vital contributions to bringing quantum technology from scientific possibility to commercial viability. She and her collaborators demonstrated many different types of fibre-based quantum key distribution systems (a few of them are among the world’s firsts). A novel quantum random number generator (QRNG) developed by her and her colleagues is being commercialized. Finally, her group developed fibre-based entangled photon pair sources. Its compact, alignment-free, and room-temperature operation make this source one of its kind in the world, and is being commercialized by a Canadian photonics company. 

Research Areas

Prof. Qian's research focuses on fibre-based photonic technologies and applications, both in the traditional field of optical sensing/metrology as well as in the emerging field of quantum communication and quantum metrology:

  • Quantum optics
  • Entanglement
  • Nonlinear optics
  • Fiber interferometry
  • Fiber sensing systems

Teaching fields

Prof. Pertsch's teaching is devoted to the early involvement of young scientists in state-of-the-art research. He gives courses in:

  • Ultrafast Optics
  • Fundamentals of Optics
  • Fundamentals of Electric Circuits
  • Linear Algebra

Research methods

  • Fibre-based interferometers
  • High speed electro-optic measurements
  • Quantum state characterizations (quantum state tomography, Hong-Ou-Manel interferometer, Franson interferometer)
  • Fibre-based quantum key distribution systems

>> link to Li Qian's group website

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