Quantum optics with nonlinear organic small molecule enhanced integrated photonics devices

Quantum networking has emerged as a global grand challenge in the field of quantum information sciences, identified as a critical technology for enabling general purpose quantum computing and its applications. Therefore, developing implementable devices to accelerate quantum networking will advance US security and technical leadership. A flexible quantum network will have the ability to transmit an arbitrary quantum state with high-fidelity over room- (data-center), metropolitan- (LAN), continental- and trans-continental-distances.

In this proposal, we provide a path for the development of quantum frequency converters (QFC’s) for translating the wavelength of photons into and between pre-assigned channels of the International Telecommunication Union (ITU) frequency grid, while preserving the delicate quantum information that is encoded on those photons. The planned approach is fully compatible with silicon photonics technology providing a scalable, robust, manufacturable platform for the generation of non-classical light and frequency translation of that light.

The training and outreach efforts directly engage the scientific community and the general public. In collaboration with USC’s Center for Engineering Diversity, two undergraduate student researchers will be hosted in the PI and Co-PI’s laboratories, and a free online Quantum Optics conference will be organized.

The past decades have witnessed a rapid increase in the performance of on-chip integrated photonic devices for studying nonlinear and quantum phenomena. These devices have enabled a wide range of discoveries and are serving as critical roles in our optical communications network. However, as we look to shift from classical to quantum networking, we must be mindful to engineer components that enable quantum communications and yet are compatible with the large existing infrastructure already in place for classical optical communications.

An important capability in quantum networking is making quantum information, stored on optical qubits, compatible with the modern telecommunications infrastructure, which includes mapping quantum channels to the International Telecommunication Union (ITU) frequency grid. One approach being explored relies on frequency conversion using integrated optical resonant cavities.

While the concept is theoretically robust, in practice, there are several hurdles related to low conversion efficiencies and optical power requirements that must be solved. While it is possible to overcome the power requirements by using a cavity with a long photon lifetime, the conversion efficiency is intrinsic to the cavity material. In the present work, we will explore a new type of hybrid optical cavity comprised of a self-assembled monolayer of nonlinear optical organic materials on a silicon oxynitride microring.

Organic materials possess 1,000-100,000x higher Non-Linear Optic (NLO) coefficients than conventional optical materials; thus, the proposed hybrid system could provide a transformative solution to the current challenge. The key quantum capability of the microresonators to be validated is coherent wavelength translation of an optical state while preserving the quantum coherence of observables on which quantum information is encoded.

The Si device architecture that will be studied is compatible with existing infrastructure; thus, this work will pave the way for establishing the quantum network using the existing ITU grid. Undergraduate and graduate students will be directly engaged in all aspects of the research, and all findings will be disseminated using scholarly publications as well as social media.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.