Voxtel has announced a new class of near-infrared photodetectors: carrier multiplication devices (CMDs).
CMDs are nanostructured indium gallium arsenide/indium aluminum arsenide (InGaAs/InAlAs) devices that have been designed to overcome the limitations of avalanche photodiodes (APDs) in the 0.9 to 1.6 micron spectral region, including the eye-safe range beyond 1.3 microns.
These photodetectors exceed the capabilities of APDs in both gain and noise performance.
With high gain and low noise, combined with high quantum efficiency, Voxtel's CMDs are suitable for low-light-level detection, or any other applications that call for high sensitivity in the near-infrared spectral band.
Coupling the CMD to a low-noise amplifier produces a receiver with high gain, superior noise equivalent power, and better overall sensitivity, said Voxtel.
The CMD operating bias has low temperature sensitivity compared to APDs, making it easier and more cost effective to integrate CMDs into systems and laboratory instrumentation.
In the past, APDs have been used by designers of Lidar, telecommunications, and other active optical systems to boost the photo signal above downstream electronics noise.
However, the benefits of APDs are restricted by their limited useful amplification - typically less than 15x - and the noise that the avalanche gain process adds to the signal.
Voxtel's CMDs can be operated at high gain with low noise, allowing for active optical systems with better sensitivity, longer range and lower laser power.
Featuring ultra-low-noise analogue optical detection up to approximately 1GHz, Voxtel's Siletz series of CMDs have very low effective ionisation coefficients and can be operated with low excess noise.
The maximum line-mode gain of Siletz CMDs is typically above M = 100.
By contrast, standard telecom NIR APDs are generally not useful above M = 15, and carry a much greater noise penalty.
Other applications for this near-infrared CMD include quantum cryptography, optical time domain reflectometry, near-infrared Raman spectroscopy, biomedical NIR spectroscopy, time-resolved emission detection for failure analysis, and singlet oxygen detection.
