Optical Communications -- Questions from Course file

1.What are the basic stages of the receiver?
2. What is a bit period?
3.Define bit error rate.
4. What are the typical error rates for optical fiber telecommunications systems?
5. What type of noise is produced due to pulse spreading?
6. Give some examples of spontaneous fluctuations.
7. Draw the Schematic diagram of a typical optical receiver.
8. Give the relationship between signal to noise and peak signal to rms noise.
9. Write the formula for probability error function.
10. Define threshold level.
11. Define extinction ratio.
12. What is the unit of thermal noise characteristic of a receiver?
13. Give the formula for thermal noise characteristic of a receiver.
14. Why low – impedance preamplifier are not used at long distance applications?
15. What is the advantage of Low – impedance preamplifier?
16. What are the draw backs of high – impedance preamplifier?
17. Write the thermal noise characteristic for high – impedance preamplifier.
18. What are the advantages of trans impedance amplifier?
19. Classify the preamplifiers used in optical fiber communication receivers?
20. What is the advantage of high – impedance preamplifier?
21. Which devices are used as preamplifiers for giga bits/sec. data rate?
22. How does noise in a high – impedance amplifier can be minimized?
23. What are the basic building blocks of digital receiver?
24. Draw the high – impedance preamplifier using BJT.
25. What is meant by wave length multiplexing?
26. What are the uses of WDM?
27. Draw a neat sketch showing a simplex point to point link.
28. What are the requirements in analyzing link?
29. What is the typical response time of a high speed silicon photodiode?
30. What is inter symbol interference?
31. Define noise margin.
32. Name the four elements which limit system speed.
33. Give the relationship between 3 –dB Bandwidth and full width half maximum rise time.
34. ___________ is used for determining the dispersion limitation of an optical fiber link.
35. The performance of digital receiver is in terms of _____________.
36. The performance of analog receiver is in terms of _____________.
37. In multimode fibers the rise time depends on _________________.
38. _________________ determines the power margin between the optical transmitter output and the minimum receiver sensitivity.
39. The most widely used compound for both pins and avalanche photodiode is________.
40. The cutoff wavelength is about _________ µm for Si and _______ µm for Ge.
41. The dispersion limit depends on ________________ and ____________ dispersion.