Single photon buffer based on coupled resonator optical waveguide

Hiroki Takesue, Nobuyuki Matsuda, Eiichi Kuramochi +1 more

We report an on-chip single photon buffer experiment using a coupled-resonator optical waveguide. A pulsed photon from a correlated photon pair source was successfully delayed by 160 ps while maintaining non-classical intensity correlation.

Zeyang Liao, Xiaodong Zeng, Muhammad Suhail Zubairy

Hiroki Takesue, Nobuyuki Matsuda, Eiichi Kuramochi +2 more

Integrated quantum optical circuits are now seen as one of the most promising approaches with which to realize single-photon quantum information processing. Many of the core elements for such circuits have been realized, including sources, gates and detectors. However, a significant missing function necessary for photonic quantum information processing on-chip is a buffer, where single photons are stored for a short period of time to facilitate circuit synchronization. Here we report an on-chip single-photon buffer based on coupled resonator optical waveguides (CROW) consisting of 400 high-Q photonic crystal line-defect nanocavities. By using the CROW, a pulsed single photon is successfully buffered for 150 ps with 50-ps tunability while maintaining its non-classical properties. Furthermore, we show that our buffer preserves entanglement by storing and retrieving one photon from a time-bin entangled state. This is a significant step towards an all-optical integrated quantum information processor.

Akiko Tada, Naoto Namekata, Shuichiro Inoue

Yong Qian, Qian Jun, Yuzhu Wang

We theoretically investigate controlled tunable all-optical filtering and buffering of optical pulses in a hybrid nano-photonic structure, where a single quantum dot (QD) embedded in a photonic crystal nanocavity is side-coupled between a bare nanocavity and a photonic crystal waveguide. We demonstrate that there is a sharp low-loss transmission peak in the transmission spectrum under even low QD-nanocavity coupling strength and the input optical pulses can be delayed up to several hundred picoseconds within the dephasing time of the QD. The filtering regime can be shifted readily by manipulating the detuning between the QD excitonic transition frequency and resonant frequency of the nanocavity mode, which can be explored in future for on-chip all-optical logic and signal processing.

J. C. Huang, Yan‐Ling Li, Zhonghui Xu +1 more