Open AccessImproved heterodyne system using double-passed acousto-optic frequency shifters for measuring the frequency response of photodetectors in ultrasonic applications
Author(s) -
Xu Feng,
Ping Yang,
Longbiao He,
Guangzhen Xing,
Min Wang,
Wei Ke
Publication year - 2020
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.381107
Subject(s) - optics , photodetector , interferometry , heterodyne (poetry) , michelson interferometer , bandwidth (computing) , frequency response , ultrasonic sensor , heterodyne detection , physics , detector , acoustics , computer science , telecommunications , electrical engineering , engineering , laser
The improved heterodyne system is presented to measure the frequency response of photodetectors (PDs) with bandwidth about 100 MHz utilized in ultrasonic applications. In order to eliminate the periodic oscillation following the frequency tuning of the acousto-optic frequency shifters (AOFSs) in the measurement results, the AOFSs' double-passed scheme in Michelson interferometer is used. Compared with the AOFSs' single-passed configuration in Mach-Zehnder interferometer, the double-passed scheme can avoid additional optical alignment during the process of the frequency tuning and then reduce its induced measurement uncertainty. With two double-passed AOFSs connected in parallel, the experimental setup is designed to demonstrate the feasibility of the improved heterodyne system in the frequency range from 500 kHz to 135 MHz. Experimental results with measurement uncertainty are provided and discussed.