Hi Debanjan,
They are not the same. I found the following explanation on difference between RZ and CSRZ quite useful:
Carrier suppressed return to zero (CSRZ) is the advanced modulation format used in optical communication.The difference between CSRZ and conventional RZ is that the CSRZ signal has the ‘π’ phase shift between adjacent bits. This phase alternation, in the optical domain, produces no DC component; thus, there is no carrier component for CSRZ.
Regards