For small active layer thickness d, the confinement factor d/D may be written as d/D ∼= γ d. The compositional dependence of the refractive index of Ga(1 − x)AlxAs at λ0 = 0.90 μm can be represented...

For small active layer thickness d, the confinement factor d/D may be written

as

d/D ∼= γ d.

The compositional dependence of the refractive index of Ga(1 − x)AlxAs at

λ0 = 0.90 μm can be represented by

n = 3.590 − 0.710x + 0.091x 2

.

(a) Develop an expression for the confinement factor as a function of x, d

and λ0 for a three-layer, symmetric GaAs-Ga(1 − x)AIxAs DH laser with

na = 3.590.

(b) For a DH laser with d = 0.1 μm, x = 0.1 and λ0 = 0.90 μm, what is the

magnitude of the confinement factor?

(c) Compare your answer to Part b, with the data given in Fig. 14.4