A novel quantum mechanical formulation of the bi-photon wavefunction and spectra resulting from four-wave mixing is developed for azimuthally symmetric systems. Numerical calculations are performed verifying the use of the angular group velocity and angular group velocity dispersion in such systems, as opposed their commonly used linear counterparts. The dispersion profile and bi-photon spectra of two illustrative examples are given, emphasizing the physical origin of the effects leading to the conditions for angular momentum and energy conservation. A scheme is proposed in which widely spaced narrowband entangled photons may be produced through a four-wave mixing process in a chip-scale ring resonator. The entangled photon pairs are found to conserve energy and momentum in the four-wave mixing interaction, even though both photon modes lie in spectral regions of steep angular group velocity dispersion.
We present a general quantum-mechanical formalism to describe photon-pair generation via four-wave mixing in a
Silicon-on-Insulator (SOI) microresonator. We also provide design principles for efficient photon-pair generation
in an SOI microresonator through numerical simulations. Ring-cavity designs are shown to have a much wider
dispersion-compensate frequency range than straight-cavity designs. Such on-chip quantum devices are highly
promising for future integrated quantum information processing.
Photonic chips with silicon nitride (
Si3N4) microring resonators are well established as heralded single-photon sources, but their operation as frequency-degenerate twin-photon sources has not previously been demonstrated. Here, we realise a twin-photon source at telecommunication wavelengths in a
Si3N4 ring microresonator via an inverse four-wave mixing (FWM) process, in which two photons from spectrally distinct pumps are converted into a pair of identical twin photons. The measurements show a maximum coincidence-to-accidental ratio (CAR) of
5.4±0.6. In addition, the microresonator functions as a heralded single-photon source through pump-degenerate spontaneous four-wave mixing (SFWM), exhibiting a spectral purity of
P=0.67±0.05 and a heralded anti-bunching of
gh(2)(0)=0.0042±0.0015. Together, these results demonstrate both photon-generation schemes on a single integrated
Si3N4 platform, highlighting its potential for scalable, tailored quantum light generation.
An integrated source of time-energy entangled photons is demonstrated through resonantly enhanced spontaneous four-wave mixing in a silicon micro-ring resonator. A Franson type set-up is employed to show the quantum interference between photon pairs with a visibility exceeding 90% and a violation of the Bell's inequality by more than 10 standard deviations. The high spectral brightness and the extremely small footprint of our source make it suitable for the development of quantum information protocols integrated on chip.
The work is devoted to the problem of developing integrated single-photon sources based on spontaneous four-wave mixing in ring microresonators. Considering the silicon nitride microresonator as an example, we calculate the group velocity dispersion in a wide wavelength range for the case when the ring resonator is composed of straight and curved sections, and show that for different pump wavelengths it is possible to find an optimal ratio of the height and width of the waveguide, thereby achieving zero group velocity dispersion at a minimum height. Such waveguides, which provide zero dispersion and have a minimum height, are optimal for creating ring microresonators that generate single-photon states via non-degenerate spontaneous four-wave mixing.