Quantum Photonic Integrated Circuits

Single photons and entangled photon pairs are key resources for quantum communication. In order to be compatible with existing installed optical fiber, quantum light sources need to operate at telecom wavelengths. InAs/InP quantum dots have been shown to emit in the telecom C-band at 1550nm [1] and when embedded in p-i-n diodes can be processed into LEDs using standard semiconductor device fabrication techniques.

Challenges remain in developing quantum dot LEDs for integration into quantum networks. For example, as quantum networks will run at set clock rates, devices must be designed for pulsed excitation and emission. Tuneability of the fine structure splitting and emission wavelength of a quantum dot is also desirable. In order to run a quantum dot LED outside a laboratory environment, a device should be electrically driven and fibre coupled to be compatible with stirling cryocoolers.

In this PhD project the student will design, fabricate, and characterise C-band quantum dot LED devices. They will perform experiments such as measuring entanglement at state-of-the-art facilities in Toshiba Research Europe Ltd in Cambridge and will use these devices in field trials.

[1] A quantum light-emitting diode for the standard telecom window around 1,550 nm, T Muller et al, Nature communications, 9(1), pp.1-6. (2018)

Industry Engagement: The PhD will be based in an industrial lab (Toshiba Research Europe) in Cambridge.