The revolutions that have occurred in computing and communications over the last 50 years have rested upon the chip-scale manufacture of silicon integrated electronic circuits and the invention of silicon-oxide optical fibre, respectively. Combining these two concepts to create integrated optical circuits where light is guided through photonic chips and manipulated, promises to be the next major technical revolution.
We are working on combining quantum optics with photonic integrated circuits to create small, stable and scalable quantum optical devices2. In one example, we have used the indistinguishable photons from a quantum dot to demonstrate super-resolution: that is the sensing of a phase shift in the chip with twice the resolution of what is possible with single photons1.
In future, it will be advantageous to integrate the quantum light source directly onto the photonic circuit. We have built such a prototype device3, where the emitter is bonded to the integrated optical circuit creating a highly stable source of single photons. The inclusion of couplers and reconfigurable elements on our circuit allows us to confirm the quantum nature of the emitted light, or to create qubits in a superposition of two paths. In future, this technology will be scaled to a greater number of optical elements.
Layout of the integrated circuit.
Photograph of an assembled device.
Proof of quantum light emission from the light source on the chip.