Compare the operating characteristics of homojunction, SH and DH lasers, describing the advantages and disadvantages of each type. Derive an expression for the threshold current density Jth in a...

Compare the operating characteristics of homojunction, SH and DH lasers,

describing the advantages and disadvantages of each type.

Derive an expression for the threshold current density Jth in a heterojunction

laser that has an active layer thickness d, light emitting layer thickness D,

average loss coefficient α, and reflecting endfaces with different reflectivities

R1 and R2. Use the symbols defined in the text for the other parameters, i.e.,

ηq, λ0, Δν, etc.