50-GHz-spaced comb of high-dimensional frequency-bin entangled photons from an on-chip silicon nitride microresonator

Abstract

Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-bin encoded quantum computing, as well as dense quantum key distribution.

High‐Dimensional Quantum Communication: Benefits, Progress, and Future Challenges

“…Furthermore, the generation and propagation of OAM states through waveguides is very demanding as well, but small steps towards the reliable on-chip transmission and source integration of such states have been proved [107,138]. As previously mentioned, frequency and path degrees of freedom are the two that can be more easily controlled and manipulated on integrated devices [139][140][141]. In the following, we are going to focus and discuss in detail two very important and impressive experiments, which use path and frequency encoded high-dimensional states respectively.…”

High-rate photon pairs and sequential Time-Bin entanglement with Si3N4 microring resonators

“…MRR devices generate correlated photon pairs distributed over a frequency-comb, corresponding to the cavity resonances around the pump wavelength. This frequency comb structure can be matched to different DWDM channels to multiplex the entanglement [10,13] or to generate high-dimensional frequency entangled quantum states [14][15][16] which can be used for quantum computation [17,18]. Additionally, optical cavities, such as MRR, can produce inherently narrow bandwidth photons [19,20] without the need for narrowband filters, which can introduce unwanted loss.…”

Complex Quantum State Generation and Coherent Control Based on Integrated Frequency Combs

“…Highlighted by the versatility and power of their recent exploitations in quantum optics, integrated frequency combs offer a unique framework for the generation and manipulation of complex states. Using both integrated optics and established telecommunications components, quantum frequency combs (QFCs) have recently been used to realize and coherently control the first on-chip sources of both multi-photon [9] and entangled highdimensional [10], [11] states. As such, they provide a promising framework for future quantum information technologies.…”