1-Compute the emitted wavelength from an optical source having x=0.07.

2- For an alloy In074 G0.26 As0.57 P043 to be used in LED. Find the

wavelength emitted by this source.

3- The radiative and non radiative recombination life times of minority

carriers in the active region of a double heterojunction LED are 60 nsec and 90 nsec

respectively. Determine the total carrier recombination life time and optical power

generated internally if the peak emission wavelength is 870 nm and the drive current is

40 mA.

4- Find the optical gain at threshold of a laser diode having following

parametric values - R₁ = R₂ = 0.32, a = 10 cm-¹ and L = 500 µm.