Abstract: A system is disclosed for producing an output photon having a predefined frequency. The system comprises a frequency comb generator for generating a frequency comb. The system further comprises a frequency comb mode selector configured to: receive a heralding signal representative of the detection of a first photon of a frequency-correlated photon pair, the heralding signal indicative of a frequency of the heralded second photon of the frequency-correlated photon pair; and select, based on the received heralding signal, a comb spectral mode of the frequency comb. The system further comprises a non-linear photonic element configured to receive the heralded second photon and the selected comb spectral mode and produce an output photon having the predefined frequency based on the frequency of the heralded second photon and the selected comb spectral mode. Methods, controllers and computer-readable media are also described herein.

Abstract: A system is provided for producing an output photon having a predefined frequency. A pump module produces a plurality of pump fields at a plurality of pump frequencies. A photon pair source module generates frequency-correlated photon pairs. A detector module generates a heralding signal subsequent to detecting a first photon of a photon pair, the heralding signal indicative of a frequency of the second photon of the pair. A non-linear photonic element is arranged to (1) receive the heralded second photon and a complementary selected pump field, and (2) to produce an output photon having the predefined frequency. A pump field selector is configured to (1) receive a heralding signal and (2) select, based on the received heralding signal, a pump field of the plurality of pump fields for provision to the non-linear element. Methods, controllers and computer-readable media are also described herein.

Abstract: A polarization alteration device includes a resonator cavity having a resonance mode at a resonance wavelength and a linewidth. The resonator is configured to exhibit no intensity-independent birefringence or an intensity-independent birefringence, whose effect on a light wave confined in the resonator cavity is smaller than the linewidth of the resonance mode. The polarization alteration device is configured to exhibit a Kerr nonlinearity adapted to generate an additional polarization component due to symmetry breaking for a light wave confined in the resonator cavity having a light intensity exceeding a threshold intensity. The polarization direction of the additional polarization component is orthogonal to an initial polarization component of the light wave coupled into the resonator cavity. A polarization control device, a polarization sensor, a method for adjusting the polarization of a light wave and a method for sensing a change of a polarization of a light wave are further disclosed.