Hello zulkarnian,
I agree to Aabid sir that RSOA and MZ modulator are two different things. One is amplifier and the other is modulator that modulated the optical signal with the information signal. However, RSOA can be used as a modulator but i have not heard of MZ being used as an amplifier.
Reflective Semiconductor Optical Amplifiers [Optical System]
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5185149&abstractAccess=no&userType=inst
https://books.google.co.in/books?id=gR9OUXpjQ90C&pg=PA58&lpg=PA58&dq=Reflective+semiconductor+optical+amplifier+(+RSOA)&source=bl&ots=7ZwCa_vgU6&sig=0OKGAGYbizxpY0IBL59OWFcpZYg&hl=en&sa=X&ved=0ahUKEwiZ0v2QusTLAhUCkpQKHQWIAwU4ChDoAQg-MAg#v=onepage&q=Reflective%20semiconductor%20optical%20amplifier%20(%20RSOA)&f=false
https://www.researchgate.net/publication/235984030_Modeling_and_Simulation_of_a_Reflective_Semiconductor_Optical_Amplifier_Modulator_Using_X-Parameters
these are reference which may be helpful for you