# Semiconductor Photodiodes with Internal Gain

This set of Optical Communications Multiple Choice Questions & Answers (MCQs) focuses on “Semiconductor Photodiodes With Internal Gain”.

1. ___________ has more sophisticated structure than p-i-n photodiode.

a) Avalanche photodiode

b) p-n junction diode

c) Zener diode

d) Varactor diode

2. The phenomenon leading to avalanche breakdown in reverse-biased diodes is known as _______

a) Auger recombination

b) Mode hopping

c) Impact ionization

d) Extract ionization

3. _______ is fully depleted by employing electric fields.

a) Avalanche photodiode

b) P-I-N diode

c) Varactor diode

d) P-n diode

4. At low gain, the transit time and RC effects ________

a) Are negligible

b) Are very less

c) Dominate

d) Reduce gradually

5. At high gain, avalanche buildup time ________

a) Is negligible

b) Very less

c) Increases gradually

d) Dominates

6. Often __________ pulse shape is obtained from APD.

a) Negligible

b) Distorted

c) Asymmetric

d) Symmetric

7. Fall times of 1 ns or more are common.

a) False

b) True

8. Determine Responsivity of a silicon RAPD with 80% efficiency, 0.7μm wavelength.

a) 0.459

b) 0.7

c) 0.312

d) 0.42

9. Compute wavelength of RAPD with 70% efficiency and Responsivity of 0.689 A/w.

a) 6μm

b) 7.21μm

c) 0.112μm

d) 3μm

10. Compute photocurrent of RAPD having optical power of 0.7 μw and responsivity of 0.689 A/W.

a) 0.23 μA

b) 0.489 μA

c) 0.123 μA

d) 9 μA

11. Determine optical power of RAPD with photocurrent of 0.396 μAand responsivity of 0.49 A/w.

a) 0.91 μW

b) 0.32 μW

c) 0.312 μW

d) 0.80 μW

12. Determine the Responsivity of optical power of 0.4μW and photocurrent of 0.294 μA.

a) 0.735

b) 0.54

c) 0.56

d) 0.21

13. Compute multiplication factor of RAPD with output current of 10 μAand photocurrent of 0.369μA.

a) 25.32

b) 27.100

c) 43

d) 22.2

14. Determine the output current of RAPD having multiplication factor of 39 and photocurrent of 0.469μA.

a) 17.21

b) 10.32

c) 12.21

d) 18.29

15. Compute the photocurrent of RAPD having multiplication factor of 36.7 and output current of 7μA.

a) 0.01 μA

b) 0.07 μA

c) 0.54 μA

d) 0.9 μA