Responsivity(A/W) 0.8 0.7 0.6 0.5 Exercise 8.2 (25 points) (Noise in photodiodes). (a) Consider a Ge pn junction photodi
Posted: Mon May 09, 2022 2:29 pm
Responsivity(A/W) 0.8 0.7 0.6 0.5 Exercise 8.2 (25 points) (Noise in photodiodes). (a) Consider a Ge pn junction photodiode that has a photosensitive area of diameter 0.3 mm. It is reversed biased and has a dark current of 0.5 UA. Its responsivity is shown in the figure on the right. The bandwidth of the photodetector is 100 MHz. Calculate its noise equivalent power (NEP) at the communication 0.4 0.3 0.2 0.1- 0 0.5 2 1.5 Wavelength(um) 1 wavelength 1.55 um. Also calculate the minimum optical power and light intensity required within the design bandwidth for the signal to noise ratio (SNR) to be at least 1. (b) Fill in the following table: Photodiode Та Responsivity [A/W] type [nAl Iph for SNR = 1 at B = 1 MHz [nAl Optical power for SNR = 1 at B= 1MHz [nW NEP [W Hz) Ge at 25°C Ge at -20°C InGaAs 0.8 0.8 0.95 400 5 3