Characterising the insertion loss of quantum-grade components and connectors (i.e., quantum grade patch cords, novel fibre, or quantum photonic integrated circuits) is crucial for evaluating their performance and suitability for transmitting fragile quantum information. Insertion loss refers to the amount of signal power that is lost when passing through a component or connector compared to the input power. Excessive loss can significantly degrade the quality of the transmitted quantum signal, leading to errors and reduced success rates in communication protocols like quantum key distribution (QKD) and entanglement-based communication.
Flawless photon flow
To tackle the critical challenge of minimising insertion loss in quantum networks, The National Physical Laboratory (NPL) has designed an innovative metrology tool, the Variable Launch System (VLS).
The VLS grants precise control over two crucial parameters: numerical aperture (NA) and spot size.
NA and spot size are two important concepts that describe the behaviour of light within the photonic components and its interaction with external sources. Matching the NA and spot size of the photonic component to the source and detector is crucial for efficient coupling and minimizing light loss.
NA and spot size determine how light interacts within photonic components and VLS ensures optimal coupling between source, component and detector, paving the way for efficient and reliable data transmission.
Building resilient Quantum Networks
By meticulously analysing the insertion loss of quantum-grade components and connectors, network designers can counteract its negative impact. Insertion loss can fluctuate dependent on the operating wavelength of the quantum signal, components like filters or gratings can exhibit varying loss characteristics across the signal spectrum.
Some components and/or materials may see changes in insertion loss due to temperature fluctuations. Despite these challenges, through careful characterisation, network designers can optimise their systems for efficient and reliable transmission of quantum information, laying the groundwork for the development of robust and secure quantum communication infrastructure.
The VLS affords NPL the capability to provide direct support and quality assurance in key quantum challenges. This is of interest to those working in quantum key distribution (QKD) or developing components such as quantum grade patch cords, novel fibre, or quantum photonic integrated circuits (QPICs) as well as providing measurement capability for few photons metrology.
Beyond loss
Other well-established optical fibre services will help to support the successful deployment of a quantum network infrastructure capable of enabling maximum quantum efficiency and entanglement distribution. NPL is well-placed to characterise other key parameters that impact network efficiency, such as mode field diameter, effective area and fibre geometry.
Are you interested in learning more about our quantum capabilities?
Contact a member of NPL's quantum team today to schedule a consultation. We can discuss your specific needs and how our quantum technologies can help you achieve your goals.
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