Semiconductor Optoelectronics for Quantum Technologies

A key requirement for Photonic Quantum Technologies is a correlated photon source. We have applied our expertise and research in nonlinear optical conversion in semiconductor waveguides to obtain integrable solutions for correlated photon sources at telecommunication wavelengths.

The III-V implementation uses the quasi-phase-matched approach to exploit second-order nonlinearities in III-V superlattice waveguide using selective area quantum well intermixing induced by ion implantation (see Optical Frequency Conversion). Spontaneous parametric down-coversion, also known as parametric fluorescence, provides an optical source centered around 1546nm with a continuous-wave pump wavelength of 773nm. Coincidence measurements were performed with single photon detectors after wavelength demultiplexing using 1562-1578nm and 1522-1538nm bandpass filters. A CAR of over 100 was measured at 1.9x106 generated photon pairs/second.

‌‌Experimental setup for photon pair coincidence measurements

Photon pair coincidence measurements from a CW QPM semiconductor superlattice waveguide  

As we have also demonstrated monolithic integration compatibility with p-i-n diode laser pump sources in similar GaAs/AlGaAs superlattice waveguides, along with dichroic couplers, we have the basis for developing a fully-integrated correlated photon source on a III-V chip.


This research has been undertaken in collaboration with Prof. Li Qian, Prof. Stewart Aitchison and Peyman Sarrafi, University of Toronto. The contributions of the EPSRC National Facilties are acknowledged: III-V Technologies, University of Sheffield and University of Surrey Ion Beam Centre.


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