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Abhay M. Joshi *1 , Shubhashish Datta 1 , Jeff Mertz 1 , Nilesh Soni 1 , Michael Sivertz 2 , Adam Rusek 2 , Trevor Olsen 2 , James Jardine 3
1 Discovery Semiconductors Inc., Ewing, NJ, USA
2 NASA Space Radiation Laboratory, Brookhaven National Laboratory, Upton, NY, USA.
3 Brookhaven National Laboratory, Upton, NY, USA.
ABSTRACT
We have successfully tested simultaneously 2.4 Micron Wavelength, Extended InGaAs Photodiodes having diameters of 20, 30, 40, 50, 100, 150, 200, 250 and 290 Micron, coupled with a Single Mode Fiber using Hydrogen (H), Helium (He), and Iron (Fe) Ions which collectively make up over 90% of the Galactic Cosmic Rays (GCR). During irradiation, the devices were maintained at dry ice temperature, reverse biased at 100 mV, and their leakage current was continuously monitored in-situ during the run. After the exposure was completed, all nine devices were monitored for any change in their leakage current at 100 mV and room temperature for several weeks to monitor any annealing effects that may occur.
Nine Photodiodes with the above varying diameters were radiated with 100, 250, 500 and 1000 MeV/n Hydrogen, Helium, and Iron Ions with a fluence of 106, 107 and 108 ions/cm2 at each energy level. Pre- and Post- radiation results were also measured for: (1) Leakage Current Vs. Voltage for the InGaAs Photodiodes; (2) Responsivity (Quantum Efficiency) in A/W for Photodiodes; and (3) Bandwidth of the Photodiodes. All devices were found to be fully functional at the normal operating conditions and at both dry ice and room temperature. We did not observe any post radiation annealing effect for leakage current at room temperature and 100 mV bias for any of the devices after several weeks of data logging.
INTRODUCTION
Photodetectors have been deployed in satellites for low-speed passive sensing applications for decades. Photonics is expected to encroach on traditional microwave applications and significantly expand its role in space platforms. These applications include inter and intra satellite ultra-fast optical communication links, long baseline optical interferometers for gravitational wave detection, high-speed lidar sensors, and photonic clock generation, to name a few [1-2].
As space missions expand in scope and ambitions, more missions are away from the Earth’s LEO, MEO, and GEO orbits where ionizing radiation like GCR becomes extremely important. Galactic Cosmic Rays (GCR) are high-energy heavy ions originating from stars that have been completely ionized as they journey through the galaxy at near the speed of light. These nuclear scale cannonballs are damaging because they create tracks of strong ionization and lattice displacement along their pathlength. Additional damage can be created by secondary particles, such as delta electrons or displaced nuclei of the target material, which are propelled into motion by scattering off the primary cosmic ray. The potential ionization from GCR ions increases proportionally with atomic number and is inversely proportional to the ion energy. GCR are a dominant source of ionizing radiation beyond Earth’s magnetosphere and Van Allen radiation belts, which must be dealt with aboard current spacecrafts and future space missions within our solar system and deep space environments. The cosmic rays are primarily comprised of the lightest nuclei, with over 90% from Hydrogen (H) and Helium (He), and approximately 6% from heavy ions like Iron (Fe). We performed irradiations on our Extended InGaAs Photodiodes using three GCR ions to observe the effects, if any, to the quality and performance of the material.
Advances in Holmium and Thulium-doped high-power lasers have enabled space-based atmospheric sensing at 2 micron wavelength, as exemplified by NASA’s Laser Risk Reduction Program. Photodetectors based on lattice-mismatched InGaAs/InP material system, having an extended spectral coverage up to 2400 nm wavelength, can play a crucial role in realizing such space-based lidars. Combined with coherent system architecture, these photodiodes can fully exploit the high-power 2-micron lasers for lidars with superior range and resolution.
REFERENCES
- [1] A. Joshi, S. Datta, R. Miller, N. Soni, M. D’Angiolillo, J. Mertz, M. Sivertz, A. Rusek, and J. Jardine, “Proton and Gamma Radiation Testing of 10 GHz Bandwidth, Uncooled, Linear InGaAs Optical Receivers,” Proc. SPIE, vol. 11017, paper 110170D, 2019.
- [2] A. Joshi, S. Datta, N. Soni, M. D’Angiolillo, J. Mertz, M. Sivertz, A. Rusek, J. Jardine, S. Babu, and P. Shu, “Space Qualification of 5 to 8 GHz Bandwidth, Uncooled, Extended InGaAs 2.2 Micron Wavelength, Linear Optical Receivers,” Proc. SPIE, vol. 11129, paper 111290L, 2019.
Event: SPIE Defense + Commercial Sensing, Orlando, FL, Proc. SPIE, Vol. 12091, Paper 1209105, 2022.
