The NEP and Ge and InGaAs photodiodes (a) Show that the noise equivalent power of a photodiode is given by What is the corresponding optical power P1? (c) Consider a fast Ge pn junction PD which has a photosensitive area of diameter 0.3 mm. It is reverse biased for photodetection and has a dark current of 0.5oA. Its peak responsivity is 0.7 A V-1 at 1.55om (see Figure 5.47). The bandwidth of the photodetector and the amplifier circuit together is 100 MHz. Calculate its NEP at the peak wavelength and find the minimum optical power and hence minimum light intensity that gives a SNR of 1. How would you improve the minimum detectable optical power? (d) Table 5.10 shows the characteristics of typical Ge pn junction and InGaAs pin photodiodes in terms of responsivity and the current. Fill in the remainder of the columns in the table assuming that there is an ideal, noiseless preamplifier to detect the photocurrent from the photodiode. Assume a working bandwidth, B, of 1 MHz. What is your conclusion?