Abstract: Interferometric fiber optic hydrophones represent a novel class of hydrophones offering numerous benefits over traditional devices. The accuracy in capturing underwater acoustic signals is intricately linked to the employed demodulation algorithms. This paper briefly outlines the construction and operational principles of these hydrophones, with a focus on comparing and analyzing the principles and developments of demodulation algorithms, particularly the Phase Generated Carrier (PGC) and the 3×3 coupler approaches. It delineates the attributes, strengths, and limitations of these primary demodulation algorithms and proposes potential avenues for future research.