Chapter 4 of the following book discusses various modulation techniques of OWC. It also contains Matlab examples.

Optical Wireless Communications: System and Channel Modelling with MATLAB® By Z. Ghassemlooy, W. Popoola, S. Rajbhandari, CRC Press, Aug 8, 2012

https://books.google.com.sa/books/about/Optical_Wireless_Communications.html?id=jpXGCN1qVQ4C&redir_esc=y

Chapter 4 of the following book discusses various modulation techniques of OWC. It also contains Matlab examples.

Optical Wireless Communications: System and Channel Modelling with MATLAB® By Z. Ghassemlooy, W. Popoola, S. Rajbhandari, CRC Press, Aug 8, 2012

https://books.google.com.sa/books/about/Optical_Wireless_Communications.html?id=jpXGCN1qVQ4C&redir_esc=y

Brother Riaz, thanks  for your suggestion. I have recently obtained a copy of the book. It has a series of good Matlab related examples, but it lacks in detailing mathematical background on OOK, QAM and PPM techniques. 

Hello Adib,

For that OOK, QAM or the Pulse Modulations, you can refer to any book on communications or digital communication in particular.

Best Luck!

Hi Prof. Prasanna. Thank you for reply.  if you have any particular choice of selection please let me know. 

Hi

There is a book entitled " Free Space Optics (FSO): A systems Approach

BY: Arun K.Majumdar, 2015

Yes, there is an ultimate source... It's Digital Modulation Techniques by Fuqin Xiong.