# US 11,442,334 B2 · Cascaded resonators photon pair source > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,442,334 B2 - Document ID: US11442334B2 - Status: Granted - Kind: B2 - Application number: 17/231,973 - Filed: 2021-04-15 - Published: 2021-10-28 - Granted: 2022-09-13 - Earliest claimed: 2019-11-27 - Assignees: Psiquantum, Corp. - Applicants: Psiquantum, Corp. - Inventors: Mihai Dorian Vidrighin; Dylan Saunders - Web page: https://patentgrep.com/patent/US11442334B2 ## CPC - G02F 1/3526: {using two-photon emission or absorption processes} - G02B 6/29343: {Cascade of loop resonators} - G02F 1/3536: {Four-wave interaction} - G02F 1/365: in an optical waveguide structure (G02F1/377, {G02F1/395} take precedence) - G02F 2201/06: integrated waveguide - G02F 2203/15: involving resonance effects, e.g. resonantly enhanced interaction - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A photon source includes a bus waveguide, a photon source 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 has a respective resonance line width and a respective resonance frequency, wherein a bandwidth of the resonant center frequencies of the plurality of optical resonators is greater than a bandwidth of the photon source pump laser. The bus waveguide produces photons in response to receiving laser pulses from the pump laser. ## Claims ### Claim 1 A method comprising: coupling a pump laser to a bus waveguide; coupling a plurality of optical resonators to the bus waveguide, wherein each optical resonator of the plurality of optical resonators has a respective resonance line width and a respective resonance center frequency, wherein the frequency span of the resonant center frequencies of the plurality of optical resonators is greater than a bandwidth of the pump laser; and operating the pump laser. ### Claim 2 (depends on 1) The method of claim 1 further comprising coupling a plurality of dispersive elements 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. ### Claim 3 (depends on 1) The method of claim 1 wherein 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. ### Claim 4 (depends on 1) The method of claim 1 wherein a quantity of the plurality of optical resonators is two. ### Claim 5 (depends on 1) The method of claim 1 wherein a quantity of the plurality of optical resonators is greater than ten. ### Claim 6 (depends on 1) The method of claim 1 wherein 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. ### Claim 7 (depends on 6) The method of claim 6 wherein the second plurality of optical resonators are coupled to a second waveguide that emits photons. ### Claim 8 (depends on 1) The method of claim 1 wherein the bus waveguide is an optical resonator. ### Claim 9 (depends on 1) The method of claim 1, wherein, for resonators in the plurality of optical resonators, a resonance frequency of a first resonator is larger than a resonance frequency of a second resonator, and wherein a resonance frequency of a third resonator may be less than the resonance frequency of the first resonator, and wherein the second resonator is positioned directly adjacent to the first resonator and the third resonator is positioned directly adjacent to the second resonator. ### Claim 10 A method of generating photon pairs, the method comprising: coupling a plurality of optical resonators to a bus waveguide, wherein 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 and the bus waveguide includes an input region and an output region; receiving laser pulses at the input region; generating the photon pairs in the plurality of optical resonators in response to the laser pulses; and transmitting the photon pairs at the output region. ### Claim 11 (depends on 10) The method of claim 10 wherein each optical resonator of the plurality of optical resonators is serially coupled to the bus waveguide between the input region and the output region. ### Claim 12 (depends on 10) The method of claim 10 wherein each optical resonator of the plurality of optical resonators has a respective resonance line width and a respective resonance center frequency. ### Claim 13 (depends on 12) The method of claim 12 wherein 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. ### Claim 14 (depends on 13) The method of claim 13 wherein a change in resonant center frequency between adjacent optical resonator is less than a resonant line width of each of the plurality of optical resonators. ### Claim 15 (depends on 10) The method of claim 10 further comprising 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. ### Claim 16 (depends on 10) The method of claim 10, wherein, for resonators in the plurality of optical resonators, a resonance frequency of a first resonator is larger than a resonance frequency of a second resonator, and wherein a resonance frequency of a third resonator may be less than the resonance frequency of the first resonator, and wherein the second resonator is positioned directly adjacent to the first resonator and the third resonator is positioned directly adjacent to the second resonator. ### Claim 17 (depends on 10) The method of claim 10 wherein a quantity of the plurality of optical resonators is greater than 10. ### Claim 18 (depends on 10) The method of claim 10 wherein the bus waveguide is an optical resonator bus waveguide that recirculates the laser pulses. ### Claim 19 (depends on 18) The method of claim 18 further comprising a plurality of optical resonator bus waveguides each optically coupled to a respective plurality of resonant optical resonators.