RESEARCH NEWS: High Gain, Low Noise, Room Temperature 1550 nm GaAsSb/AlGaAsSb Avalanche Photodiodes

Posted: February 8, 2023


High gain, low noise 1550 nm GaAsSb/AlGaAsSb avalanche photodiodes


High sensitivity avalanche photodiodes (APDs) operating at eye-safe infrared wavelengths (1400–1650 nm) are essential components in many communications and sensing systems. APDs are optical detectors with built-in gain, allowing them to detect small numbers of photons and expanding the capabilities of optical systems. For example, lidar systems for 3D imaging have improved spatial resolution and detection range when they incorporate more sensitive detectors, and the APDs we have developed will open new possibilities for infrared lidar. We have developed new infrared APDs for this wavelength range that provide more gain with less noise and, therefore, could supplant the commercial state-of-the-art.

The APDs we have developed contain a semiconductor multiplier that is an alloy of AlGaAsSb. This alloy, and the multi-layer structure supporting its operation, is grown using the Krishna group’s molecular beam epitaxy (MBE) system on a commercial InP substrate. Devices were fabricated and characterized at Nanotech West and at partner institutions for verification. These APDs has a gain and responsivity that are factor of 10 above the commercial state-of-the-art. Critically, these APDs have an extremely low “excess noise” factor that will enable them to be operated at high gain without noise significantly reducing their sensitivity. These major improvements in APD performance are likely to lead to their wide adoption in many photon-starved, infrared applications.

Lee, S., Jin, X., Jung, H., Lewis, H., Liu, Y., Guo, B., Kodati, S.H., Schwartz, M., Grein, C.H., Ronningen, T.J., David, J.P.R., Campbell, J.C. and Krishna, S., “High Gain, Low Noise, Room Temperature 1550 nm GaAsSb/AlGaAsSb Avalanche Photodiodes,” Optica, vol. 10, pp. 147-154, 2023.

Find more information:



Categories: In the NewsResearch