Hello.
As far as your query is concerned it has been rightly mentioned by Mr Rajguru that you use advanced modulation formats like CSRZ, DRZ and MDRZ and DPSk because these supports both long haul transmission and high data rate.
You may go through these.
http://www.inase.org/library/2014/interlaken/bypaper/COSICO/COSICO-30.pdf
http://www.ijettjournal.org/volume-17/number-10/IJETT-V17P292.pdf
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5689024&abstractAccess=no&userType=inst
http://www.inase.org/library/2014/interlaken/bypaper/COSICO/COSICO-30.pdf
http://ieeexplore.ieee.org/Xplore/defdeny.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D6210761%26userType%3Dinst&denyReason=-133&arnu
I hope this will help.
Thanks
Regards