Quantum photonic platform integrates multiple tunable photon sources on a chip

Quantum photonic integrated circuits, chip-based devices that process and transmit information by manipulating quantum states of light, hold great potential as a novel class of semiconductor technologies. When embedded in photonic crystals, or “cavities,” quantum dots, nanoscale semiconductor structures, make promising sources for producing single particles of light on demand. Scaling the number of identical single photons on a chip is critical for many applications in sensing devices, complex quantum computations and simulations. However, the energy mismatch between different photon sources creates numerous difficulties in maximizing the number of identical photons travelling in a circuit.

To solve this problem, Petruzzella et al. developed a novel photonic platform, integrating multiple tunable photon sources on one chip. This work is among the first to demonstrate the energy control of distinct cavities and emitters located on the same chip.

By using microelectromechanical systems (MEMS), the authors developed tunable cavities consisting of two separate photonic crystal membranes, optically coupled along the growth direction.

The cavity energy can be changed by controlling the bias voltage of a diode fabricated across the two membranes, changing the distance between the membranes. On the other hand, by regulating a static electric field through another diode across the quantum dots embedded in the cavities, they can tune the photon generators’ energy.

The cavity-emitters were coupled to a network of waveguides able to transport and manipulate photons with low-losses. The ability to tune the energy of the multiple sources on a chip is crucial for future applications such as the realization of large quantum circuits for higher precision measurement, complex quantum stimulation and computation.

Source: “Quantum photonic integrated circuits based on tunable dots and tunable cavities,” by M. Petruzzella, S. Birindelli, F. M. Pagliano, D. Pellegrino, Ž. Zobenica, L. H. Li, E. H. Lineld, and A. Fiore, APL Photonics (2018). The article can be accessed at https://doi.org/10.1063/1.5039961 .