A work by PhD Student Siavash Mirzaei-Ghormish was recently accepted by the peer-reviewed journal "Quantum – the open journal for quantum science." It addresses the key problem of spatially channeling light from a microdisk resonator to a fiber mode.
Figuring out ways to use the millions of fiber miles already in place to communicate with people around the world to implement a new kind of internet - the quantum internet - is a key problem that researchers in the field of quantum computing and quantum networking are actively trying to address.
You can see for for yourself the scale of existing broadband communication infrastructure with an interactive map provided by the International Telecomuication Union (ITU) at https://bbmaps.itu.int/bbmaps/.
As members of the group Center for Quantum Networks (CQN), BYU's CamachoLab, along with Harvard, MIT, the University of Maryland, and a handful of other universities, are working tirelessly to find ways to use the extensive infrastructure already in place to realize quantum networking; perhaps no one is working more tirelessly than our own Siavash Mirzaei-Ghormish.
His most recent paper accepted for publication in "Quantum – the open journal for quantum science" titled "High-efficiency vertical emission spin-photon interface for scale-able quantum memories" addresses the problem of converting stored memory in a quantum computer to a form that that can propagate down a fiber optic, so that, similar to conventional computers, we can "read from" and "write to" memory stored in a quantum computer. To achieve this, he harnesses the power of optical diffraction to channel light emitting from a diamond quantum memory structure into a spatial form that can successfully propagate down a fiber optic cable.
The design below shows a diamond micro-disk resonator where quantum information is stored in the form of light travelling circularly around the top over and over again in what is described as a whispering gallery mode. When emitted, the light from the resonator immediately encounters a grating flush to the surface of the micro-disk, with another grating a small distance away.
Siavash showed in theory and in simulation that with proper tuning of the dimensions and positions of the gratings, the light not only may be transformed into a state that may propagate down a fiber optic cable, but that it may also do so with extremely high efficiency — the paper reports "96% collection efficiency at the far-field." In other words, hardly any of the light's energy is lost during its passage through the gratings.
Although there are still many challenges to overcome to realize a totally usable quantum network, the work in this paper represents substantial progress in realizing CQN's goals. More is also on the way soon. Stay tuned for more developments, and reach out if you are interested in learning more about the lab or our research.