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Q2. Assuming a 500-μm-long Fabry-Perot LD consisting of an active layer of InGaAsP (n = 3.6, λ = 1.55 µm). Both mirror facets are cleaved without mirror coatings (i.e. Fresnel reflection only). The internal loss a; and internal quantum efficiency nį are 13 cm-¹, and 80 %, respectively. Fabry-Perot LD Active layer (InGaAsP)
Assuming the carrier lifetime Tn: ₂:1 ns, the threshold carrier concentration th: 2 × 10¹8 cm−³, the thickness d and width w of the active layer are 150 nm and 1 µm, respectively. A. Find the threshold current density Jth. B. Find the threshold current Ith. C. Find the output power P at I = 40 mA. (Note: estimate for the emission from one facet)