Phlux Aura Noiseless InGaAs APD Infrared Sensors

Phlux Technology is a University of Sheffield spin-out based in Sheffield, UK, that makes infrared sensors for 1550 nm systems. Its patented process, developed over eight years of university research, adds an antimony alloy to InGaAs avalanche photodiodes (APDs) to cut noise and improve thermal stability.

The Aura family of Noiseless InGaAs APDs comes in 30 µm, 80 µm and 200 µm sizes, as bare die, fibre pigtails or standard surface-mount and wire-ended packages that can replace existing photodetectors. Phlux also offers an APD evaluation board and, since 2026, Apex receiver modules that pair Aura detectors with low-noise electronics. Customers build laser range finders, lidar, OTDR fibre test equipment and free-space optical links.

• Aura APD family: Noiseless InGaAs avalanche photodiodes for 1550 nm in 30, 80 and 200 µm sizes.
• Low dark current: designed to run at high gain and high temperature.
• Flexible packaging: bare die, fibre pigtail, surface-mount or wire-ended packages.
• Evaluation board: preamplifier design targeting noise equivalent power below 30 fW/√Hz up to 75 MHz.
• Apex receiver modules: Aura detectors combined with low-noise electronics for ultra-low-light detection.
• Application guides: technical resources for range finders, lidar, OTDR and fibre sensing.

Vietnamese makers of fibre test instruments can use Aura APDs to extend OTDR measurement range. Lidar and surveying equipment integrators can improve detection distance without raising laser power. Research institutes and telecom firms can test free-space optical links using Apex receiver modules.

The company states its sensors are up to 12 times more sensitive than other leading InGaAs APDs, extending system range by up to 50% for a given laser power. It also cites up to 40% lower system cost and up to 30% smaller systems thanks to lower-power lasers and simpler cooling. Standard packages allow drop-in replacement of existing detectors.

Eye-safe 1550 nm lasers are spreading in lidar, laser range finding, fibre sensing and free-space optical communication. System makers want longer range with lower laser power, smaller size and less cooling. Growing fibre network rollouts and industrial sensing in Southeast Asia also raise demand for sensitive OTDR and fibre test equipment.

Spin-out from the University of Sheffield, UK. Raised a £4 million seed round backed by Octopus Ventures and later a £9 million Series A. ISO 9001 certified in October 2024. Won the Institute of Physics Business Start-Up Award (2024) and the SPIE Prism Award for Sensors (January 2026).