solution

The power output (P0) of an LD as a function of injection current density can be described by

where Jth is the threshold current density, η is the internal quantum efficiency, R = R₁ = R2 is the reflectivity at two laser facets, l is the loss in the laser medium due to free carrier absorption and scattering by defect centers, and hv is the emission photon energy. Suppose the temperature dependence of threshold current density is given by

where Jth0 is the threshold current density at T = 0 K and T0 is the characteristic temperature of LD material.

Using (1) and (2), plot the power output (P0) of an AlGaAs/GaAs DH laser versus diode current for T = 0, 10, 20, 30, 40, 50, 60, and 70 â—¦C (see Figure 13.30). Given: T₀ = 160 K for an AlGaAs/GaAs LD.