Title :
Gamma Radiation Induced Degradation of Operating Quantum Dot Lasers
Author :
Mares, J.W. ; Harben, J. ; Thompson, A.V. ; Schoenfeld, D.W. ; Schoenfeld, W.V.
Author_Institution :
Coll. of Opt. & Photonics, Central Florida Univ., Orlando, FL
fDate :
4/1/2008 12:00:00 AM
Abstract :
The degradation of quantum dot lasers (QDLs) due to 1.17 and 1.22 MeV gamma radiation is characterized by changes in threshold current, external slope efficiency and light output. Both operating and non-operating lasers were exposed to a Co-60 source, providing gamma radiation at a dose rate of 0.4 kGy/hr to a total absorbed dose of 1.6 MGy. Degradation rates of exposed, non-operating QDLs were found to be more rapid than for operating QDLs during exposure, suggesting competition between radiation damage effects and annealing effects induced by operation. This is supported by annealing effects exhibited by unexposed, operating lasers resulting in increases in slope efficiency and light output. Differential output power comparisons indicate that degradation is predominately due to changes in current injection efficiency and not increases in non-radiative recombination in the active region.
Keywords :
annealing; gamma-ray effects; laser beams; quantum dot lasers; radiation hardening (electronics); active region; annealing effects; current injection efficiency; differential output power; electron volt energy 1.17 MeV; electron volt energy 1.22 MeV; external slope efficiency; gamma radiation induced degradation; laser threshold current; nonradiative recombination; quantum dot lasers; radiation absorbed dose 1.6 MGy; radiation damage effects; slope efficiency; Annealing; Degradation; Gamma rays; Laser theory; Laser transitions; Power generation; Quantum dot lasers; Radiative recombination; Semiconductor lasers; Threshold current; Gamma-ray effects; quantum dots; semiconductor device radiation effects; semiconductor lasers;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2008.918743
