en Environmental Study مقاله پژوهشي Research Paper <div style="text-align: justify;">In this paper, we present experimental results of one optical fiber acoustic sensor in shallow water. Output trend of sensor is investigated primarily comparing with the change of acoustic amplitude of transmitter and then the frequency response of sensor is determined. The results show that, the optical fiber sensor has linear trend comparing with a standard hydrophone and its frequency response is similar to that of hydrophone. The results show that the optical fiber sensor output has equal trend comparing to a standard hydrophone. The results also show that, the frequency response trend of optical fiber sensor at 0.7- 5 kHz range is similar to that of a standard hydrophone.</div> optical fiber sensor,frequency response,heterodyne method 11 15 http://ijmt.ir/browse.php?a_code=A-10-16-6&slc_lang=en&sid=1 Hassan Sayyaadi sayyaadi@sharif.edu 10031947532846003641 10031947532846003641 Yes School of Mechanical Engineering, Sharif University of Technology Mohammad Said Seif seif@sharif.edu 10031947532846003642 10031947532846003642 No School of Mechanical Engineering, Sharif University of Technology Ali Asghar Abniki aliasghar_abniki@yahoo.com 10031947532846003643 10031947532846003643 No School of Mechanical Engineering, Sharif University of Technology