PART 1 (50%)
Main question (/10)
Your boss wants to create an optical link with bitrate 800Gb/s and length 6400 km.
He plans on doing this on a 1550nm signal with a GRIN multimode fiber.
As a source, we chose a directly modulated DFB laser. For the amplifiers, he wants to use a SOA and the chosen detector was a Silicon PIN.
Write everything you know about why this is a bad idea, and come up with a better sollution, including the reasons why the solution is better. Will you use amplifiers, multiplexing, DCF, ... ?
-You also have to say how you will multiplex it, a word about the channel spacing and so on...-
Small Question 1 (/2.5)
Derive the dispersion criterion. What is the meaning of this?
Small Question 2 (/2.5)
All about non-linearities. When does it apply?
Small Question 3 (/2.5)
What is the cut-off frequency? Why is it important?
Small Question 4 (/2.5)
WDM in LAN.
You have to explain Add/drop filters, rainbow network...
You get as much preparation time as you want. I needed about 2 hours.
He wants you to be as complete as possible. For each of the questions, write all the stuf related to the topic (except the calculations if it is not asked).
Special importance is given to the figures.
PART 2 (50%)
I had nothing on the computer itself.
We only asked me how do you measured the receiver sensitivity and why was the BER different for the first and for the last channel of the WDM design.
I also got some questions/remarks on the report itself.
When writting your report:
- Round off the lengths of the fibers.
- Give numerical results when comparing post and pre compensation (idem if you compare RZ with NRZ)