Ultra-low power generation of twin photons in a compact silicon ring resonator (1209.2099v1)

Abstract: We demonstrate efficient generation of correlated photon pairs by spontaneous four wave mixing in a 5 \mu m radius silicon ring resonator in the telecom band around 1550 nm. By optically pumping our device with a 200 \mu W continuous wave laser, we obtain a pair generation rate of 0.2 MHz and demonstrate photon time correlations with a coincidence-to-accidental ratio as high as 250. The results are in good agreement with theoretical predictions and show the potential of silicon micro-ring resonators as room temperature sources for integrated quantum optics applications.

Ultra-low Power Generation of Twin Photons in a Silicon Ring Resonator

The paper "Ultra-low power generation of twin photons in a compact silicon ring resonator" presents significant findings on the efficient generation of photon pairs via spontaneous four-wave mixing (sFWM) in silicon ring resonators. This research extends the application potential of silicon micro-ring resonators in quantum optics by demonstrating their capabilities as compact, low-power photon sources for quantum state generation.

The research utilizes a silicon ring resonator with a radius of 5 μm, facilitating the generation of correlated photon pairs in the telecom band around 1550 nm. Emphasizing the device's practicality, the authors achieved a photon pair generation rate of 0.2 MHz using a continuous wave pump laser at a remarkably low power of 200 μW. The resonator exhibited photon time correlations with a coincidence-to-accidental ratio (CAR) as high as 250, which highlights the device’s potential effectiveness in quantum applications compared to previously larger structures, such as cm-long silicon waveguides.

A notable achievement of this work is its alignment with theoretical predictions, affirming the accuracy of models for spontaneous four-wave mixing in microring resonators. The paper quantifies how the generation rate scales with the pump power and validates these findings through experimental data illustrating the quadratic dependence of the photon pair generation intensity on the pump power.

The implications of these results are multifaceted, influencing both practical implementations and theoretical exploration within quantum optics:

1. Practical Implications: The successful demonstration points towards the feasibility of integrating these silicon micro-ring resonators in quantum information systems, particularly for cryptographic protocols and computing applications relying on entangled or heralded single photon sources. The integration potential is further enhanced by the CMOS compatibility of these devices, making them suitable for incorporation into existing semiconductor technologies.
2. Theoretical Developments: The paper reinforces theoretical scaling laws for parametric processes in integrated photonic devices, thereby enabling more accurate predictions for future experimental setups. This could encourage further exploration into optimizing device configurations for improved performance, such as reducing losses or increasing photon pair generation rates without enhancing power consumption.

Looking ahead, the authors indicate potential expansion in this area of research through direct integration of optical components, like filters and detectors, into the silicon on insulator (SOI) platform. Such advancements could mitigate current detection efficiency issues and facilitate more robust experimental validations, including the generation of entangled photons and the realization of heralded state generation.

In conclusion, the paper effectively demonstrates the promise of silicon ring resonators for photon pair generation, offering insights that could drive innovations in quantum optics and photonics-based technologies. While challenges remain, particularly concerning detection efficiency and loss minimization, the presented results mark a substantial step towards practical and efficient integrated quantum photonics.