Find the Frequency Spectrum of an optical communication link

[E&H12]

Homework Statement

2. Homework Equations
10 Log[10](g/mW)= GdBw

The Attempt at a Solution

I have attached a document of my approach to this question. I would like to know if my approach is correct? Thank you for your assistance

 

[E&H12]

I have completed the question in the attached word document, and I was looking for confirmation as to whether my approach was correct. Unfortunately I was not given the answer to this question from my professor, that is why I am looking to solve it through this forum.