2017/03/24 by C. C. Tison, J. A. Steidle, M. L. Fanto +5
Computer Science · Engineering · Physics and Astronomy · #Coincidence #Coincidence detection in neurobiology #Coupling (piping) #Coupling coefficient of resonators #Decoupling (probability) #Detector #Mechanical and Optical Resonators #Photon #Photonic and Optical Devices #Photonics #Quantum Information and Cryptography #Resonator #quant-ph
paper · pdf · doi:10.1364/oe.25.033088
6 pages, 8 figures, 1 table
arxiv created 2017/03/24 · openalex publication_date 2017/12/20 · openalex created_date 2018/01/05 · arxiv updated 2018/02/14 · openalex updated_date 2026/08/05
Silicon ring resonators are used as photon pair sources by taking advantage of silicon's large third order nonlinearity with a process known as spontaneous four wave mixing. These sources are capable of producing pairs of indistinguishable photons but typically suffer from an effective 50% loss. By slightly decoupling the input waveguide from the ring, the drop port coincidence ratio can be significantly increased with the trade-off being that the pump is less efficiently coupled into the ring. Ring resonators with this design have been demonstrated having coincidence ratios of ∼ 96% but requiring a factor of ∼ 10 increase in the pump power. Through the modification of the coupling design that relies on additional spectral dependence, it is possible to achieve similar coincidence ratios without the increased pumping requirement. This can be achieved by coupling the input waveguide to the ring multiple times, thus creating a Mach-Zehnder interferometer. This coupler design can be used on both sides of the ring resonator so that resonances supported by one of the couplers are suppressed by the other. This is the ideal configuration for a photon-pair source as it can only support the pump photons at the input side while only allowing the generated photons to leave through the output side. Recently, this device has been realized with preliminary results exhibiting the desired spectral dependence and with a coincidence ratio as high as ∼ 97% while allowing the pump to be nearly critically coupled to the ring. The demonstrated near unity coincidence ratio infers a near maximal heralding efficiency from the fabricated device. This device has the potential to greatly improve the scalability and performance of quantum computing and communication systems.