Practical system for the generation of pulsed quantum frequency combs

Roztocki, P. et al. (2017) Practical system for the generation of pulsed quantum frequency combs. Optics Express, 25(16), pp. 18940-18949. (doi: 10.1364/OE.25.018940)

Abstract

The on-chip generation of large and complex optical quantum states will enable low-cost and accessible advances for quantum technologies, such as secure communications and quantum computation. Integrated frequency combs are on-chip light sources with a broad spectrum of evenly-spaced frequency modes, commonly generated by four-wave mixing in optically-excited nonlinear micro-cavities, whose recent use for quantum state generation has provided a solution for scalable and multi-mode quantum light sources. Pulsed quantum frequency combs are of particular interest, since they allow the generation of single-frequency-mode photons, required for scaling state complexity towards, e.g., multi-photon states, and for quantum information applications. However, generation schemes for such pulsed combs have, to date, relied on micro-cavity excitation via lasers external to the sources, being neither versatile nor power-efficient, and impractical for scalable realizations of quantum technologies. Here, we introduce an actively-modulated, nested-cavity configuration that exploits the resonance pass-band characteristic of the micro-cavity to enable a mode-locked and energy-efficient excitation. We demonstrate that the scheme allows the generation of high-purity photons at large coincidence-to-accidental ratios (CAR). Furthermore, by increasing the repetition rate of the excitation field via harmonic mode-locking (i.e. driving the cavity modulation at harmonics of the fundamental repetition rate), we managed to increase the pair production rates (i.e. source efficiency), while maintaining a high CAR and photon purity. Our approach represents a significant step towards the realization of fully on-chip, stable, and versatile sources of pulsed quantum frequency combs, crucial for the development of accessible quantum technologies.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kues, Dr Michael
• Authors: Roztocki, P., Kues, M., Reimer, C., Wetzel, B., Sciara, S., Zhang, Y., Cino, A., Little, B. E., Chu, S. T., Moss, D. J., and Morandotti, R.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Optics Express
• Publisher: Optical Society of America
• ISSN: 1094-4087
• ISSN (Online): 1094-4087
• Published Online: 27 July 2017
• Copyright Holders: Copyright © 2017 Optical Society of America
• First Published: First published in Optics Express 25(16): 18940-18949
• Publisher Policy: Reproduced in accordance with the publisher copyright policy