The quantum efficiency of an InGaAsP/InP avalanche photodiode is 80% when detecting 1.3μm wavelength radiation and biased at low voltage so that no avalanche multiplication is occuring. When biased at...

The quantum efficiency of an InGaAsP/InP avalanche photodiode is 80%

when detecting 1.3μm wavelength radiation and biased at low voltage so that

no avalanche multiplication is occuring. When biased at higher voltage for

avalanche detection, and incident optical power of 1.0μW (at λ = 1.3μm)

produces an output photocurrent of 20μa.

(a) What is the photomultiplication factor (avalanche gain)?

(b) If the responsivity of the diode falls off rapidly for wavelengths greater

than 1.7μm what is the energy bandgap in the absorbing region of the

diode? 1.7μm what is the energy bandgap in the absorbing region of the

diode?