BACKGROUND

Photon pair sources are useful for various technologies. For example, photonic quantum technologies benefit from photon pair sources with improved brightness, spectral purity, reproducibility and manufacturability.

SUMMARY

In some embodiments, a photon source includes a bus waveguide, a pump laser coupled to the bus waveguide, and a plurality of optical resonators coupled to the bus waveguide. Each optical resonator of the plurality of optical resonators can have a respective resonance line width and a respective resonance frequency. In some embodiments, the frequency span of the resonant center frequencies of the plurality of optical resonators is greater than a bandwidth of the photon source pump laser.

In some embodiments, the photon source further includes a plurality of dispersive elements coupled to the bus waveguide, wherein one dispersive element of the plurality of dispersive elements is positioned in-between each adjacent pair of optical resonators of the plurality of optical resonators.

In some embodiments, a change in resonant center frequency between adjacent optical resonators is less than a resonant line width of each of the plurality of optical resonators.

In some embodiments, a quantity of the plurality of optical resonators is two. In other embodiments, the quantity of the plurality of optical resonators is greater than ten.

In some embodiments, the plurality of optical resonators is a first plurality of first optical resonators and each first optical resonator is coupled to a respective second optical resonator of a second plurality of optical resonators.

In some embodiments, the second plurality of optical resonators are coupled to a second waveguide that emits photons.

In some embodiments, the bus waveguide is an optical resonator.

In some embodiments, a photon source includes a bus waveguide having an input region and an output region and a plurality of optical resonators serially coupled to the bus waveguide between the input region and the output region. The output region can be configured to transmit photon pairs that are generated within the plurality of optical resonators in response to the input region receiving laser pulses. In some embodiments, each optical resonator of the plurality of optical resonator has a respective resonance line width and a respective resonance frequency.

In some embodiments, a frequency span of the resonant center frequencies of the plurality of optical resonators is greater than a bandwidth of the laser pulses received at the input region.

In some embodiments, further includes a plurality of dispersive elements coupled to the bus waveguide and a dispersive element of the plurality of dispersive elements is positioned between each optical resonator of the plurality of optical resonators.

In some embodiments, a change in resonant center frequency between adjacent optical resonators is less than a resonant line width of each of the plurality of optical resonators.

In some embodiments, a quantity of the plurality of resonant optical resonators is greater than 10.

In some embodiments, the plurality of optical resonators is a first plurality of first optical resonators and each first optical resonator is coupled to a respective second optical resonator of a second plurality of optical resonators.

In some embodiments, the bus waveguide is an optical resonator bus waveguide that recirculates the laser pulses. In some embodiments, the photon source further includes a plurality of optical resonator bus waveguides each optically coupled to a respective plurality of resonant optical resonators.

In some embodiments, for resonators in the plurality of resonators, a second resonator is positioned directly adjacent to a first resonator and a third resonator is positioned directly adjacent to the second resonator. The resonance frequency of the first resonator is larger than the resonance frequency of a second resonator. In addition, a resonance frequency of a third resonator may be less than the resonance frequency of the first resonator.

To better understand the nature and advantages of the present disclosure, reference should be made to the following description and the accompanying figures. It is to be understood, however, that each of the figures is provided for the purpose of illustration only and is not intended as a definition of the limits of the scope of the present disclosure. Also, as a general rule, and unless it is evident to the contrary from the description, where elements in different figures use identical reference numbers, the elements are generally either identical or at least similar in function or purpose.

