To make a Franz-Keldysh type electroabsorption modulator for light of λ0 = 1.15μm you would choose a semiconductor with what bandgap? An electro-absorption modulator has an absorption coefficient α =...

To make a Franz-Keldysh type electroabsorption modulator for light of λ0 =

1.15μm you would choose a semiconductor with what bandgap?

An electro-absorption modulator has an absorption coefficient α = 0.2 cm−1

with no voltage applied, and 2 cm−1 with the maximum voltage of 5 volts

applied. It has a length of 2 cm. This modulator is inserted into a waveguide

that is initially transmitting an optical power of 500 milliwatts.

(a) What is its insertion loss in dB?

(b) What is its extinction ratio (maximum modulation depth) in dB?

Assume that the coupling losses at the input and output are negligible. Hint:

Depending on how you do the problem, you may not need to use the 500

milliwatts.