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UCSD Department of Electrical and Computer Engineering ECE 183 Winter 2018 Homework No. 4: Laser Characteristics Assigned: February 27, 2018. Due: March 13 , 2018. 1 GaAs laser characteristics The number of photons inside the active region of a semiconductor laser divided by the volume of the active region is defined as the photon density, P (cm - 3 ). Label the injected electron or hole density as N (cm - 3 ) and and the inversion density of carriers necessary to achieve laser threshold as N tr . “Rate equations” are a system of coupled differential equations that describe the time-evolution of P and N . Label: the current as I (A), the volume of the active region as V (cm 3 ), the spontaneous recombi- nation lifetime as τ , the photon lifetime in the cavity as τ p . As you have seen in Hwk. 3, the (peak) gain coefficient, which we called γ max [units: cm - 1 ], is approximately linearly related to the carrier concentration N [units: cm - 3 ] by a proportionality constant B . Define A = B × c/n Let n

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• Winter '08
• Yu,P
• Fundamental physics concepts, active region, photon density, UCSD Department of Electrical and Computer Engineering

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