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UPSC -2014

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UPSC-2014


1.The total efficiency of an injection LASER with a GaAs active region is 18%. The voltage applied to the device is 2.5V and the band gap energy for GaAs is 1.43eV. Calculate the external power efficiency for the device?


Solution;


External power efficiency (ηep) = ηT ( Eg/ V) * 100 % --------------------(1)


ηT = Total efficiency = 0.18


Voltage = 2.5 V


band-gap energy (Eg) = 1.43 eV



ηep = 0.18 ( 1.43/ 2.5 ) * 100


= 10%


This result indicates the possibility of achieving high overall power efficiencies from semiconductor

lasers which are much larger than for other laser types.
How to find the external power efficiency LASER problem in UPSC UPSC-2014

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