On-Chip Microwave Quantum Hall Circulator

Understand

Circulators are non-reciprocal circuit elements integral to technologies including radar systems, microwave communication transceivers, and the readout of quantum information devices.

• Their non-reciprocity arises from the interference of microwaves over the centimetre-scale of the signal wavelength in the presence of bulky magnetic media that break time-reversal symmetry.
• Here we realize a completely passive on-chip microwave circulator with size one-thousandth the wavelength by exploiting the chiral, slow-light response of a 2-dimensional electron gas (2DEG) in the quantum Hall regime.
• For an integrated GaAs device with 330 um diameter and 1 GHz centre frequency, a non-reciprocity of 25 dB is observed over a 50 MHz bandwidth.