On-chip generation of polarization entangled photons

Dongpeng Kang

Helmy Group, Photonics

Abstract:

The study of the quantum nature of light has been evolving from fundamental science to engineering for applications in various aspects. Photons, the elementary particles of light, that are quantum mechanically correlated, or “entangled”, play a pivotal role in quantum communication and quantum information processing, such as quantum key distribution, quantum teleportation. However, current entangled photon sources are big in size and sensitive to external environment, therefore they are useful only in specially equipped labs. On the other hand, a commercializable quantum information processing system, such as an optical quantum computer, requires chip-scale, portable, robust sources of entangled photons operating in room temperature. Yet, such entangled photon sources are still unavailable, although significant progress has been made using different techniques.

In this seminar, I will first briefly review the mainstream technique using spontaneous parametric down-conversion (SPDC) in crystals with second order nonlinearity to generate photon pairs and polarization entangled photons. Then I will introduce a platform that could lead to on-chip generation of photon pairs: Bragg reflection waveguides based on III-V semiconductor aluminum gallium arsenide (AlGaAs). I will show in detail how dispersion engineering of these waveguides could achieve on-chip generation of polarization entangled photons. These techniques could significantly reduce the source complexity.

Biography:

Dongpeng Kang obtained his B. Sc. and M. Sc. in 2006 and 2008 respectively, both from the Department of Physics at Harbin Institute of Technology, China. He is a PhD candidate in Prof. Amr Helmy group in the Department of Electrical and Computer Engineering at U of T. His PhD thesis is on the generation and manipulation of quantum states of light in waveguide devices.