10 GHz radiation-hardened photodiode to fly on satellite lidar

A radiation-hardened indium gallium arsenide photodiode developed by researchers at Discovery Semiconductors (Ewing, NJ) and Tesat Spacecom (Backnang, Germany) for space applications has a bandwidth that exceeds 10 GHz.

A radiation-hardened indium gallium arsenide photodiode developed by researchers at Discovery Semiconductors (Ewing, NJ) and Tesat Spacecom (Backnang, Germany) for space applications has a bandwidth that exceeds 10 GHz. Mounted on an alumina substrate, the 30 µm diameter photodiode is sensitive from 800 to 1700 nm, with a broad peak between about 1300 and 1600 nm; at 1064 nm, its responsivity is 0.45 A/W with an optical-return loss of 40 dB. Radiation testing (while fiber-coupled to light sources at 1300 and 1550 nm) included irradiation by 50 kRad of gamma rays, as well as protons at a fluence of 3 x 1011/cm2, with no change to the device’s bandwidth, responsivity, or dark current.

Fabricated using a dual-depletion process, the p-i-n photodetector will become part of a reference-laser head (a seed laser for UV lidar) in the Atmospheric Laser Doppler Instrument that will be flown on the European Space Agency’s ADM-Aeolus Earth-observation satellite to be launched in 2007. Reliability testing for the detector showed 0.011 and 15.384 failures per billions of hours of operations at 25°C and 75°C, respectively. Contact Abhay Joshi at abhay@chipsat.com.

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