The total efficiency of an injection laser with a GaAs active region is 18%. The voltage applied to the device is 2.5 V and the bandgap energy for GaAs is 1.43 eV. The external power efficiency of the device is

Question

Question

This question was previously asked in

ESE Electronics Prelims 2021 Official Paper

Answer 1

External power efficiency is given by

\(η _{ex}=η _T\left(\frac{E_G}{V}\right)\times 100 \%\)

where η_ex→ external power efficiency of the device

η_T→ total efficiency, E_G→ bandgap energy, V→ applied voltage

\(\eta _{ex}=0.18\times \frac{1.43}{2.5}\times 100\%\ \rm \approx10\%\)