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http://dx.doi.org/10.3807/KJOP.2006.17.1.094

Optical Microphone Incorporating a Reflective Micromirror and a Dual-core Collimator  

Song, Ju-Han (Department of Electronic Engineering, Kwangwoon University)
Kim, Do-Hwan (Department of Electronic Engineering, Kwangwoon University)
Gu, Hyun-Mo (Department of Electronic Engineering, Kwangwoon University)
Park, Hyun-Jung (Department of Electronic Engineering, Kwangwoon University)
Lee, Sang-Shin (Department of Electronic Engineering, Kwangwoon University)
Cho, Il-Joo (Devices and Materials Lab., LG Electronics Institute of Technology)
Publication Information
Korean Journal of Optics and Photonics / v.17, no.1, 2006 , pp. 94-98 More about this Journal
Abstract
An optical microphone based on a dual-core fiber collimator and a membrane type micromirror serving as an optical head and a reflective diaphragm respectively was implemented. The micromirror diaphragm is suspended by a thin silicon bar linked with a frame, thus it is subject to a displacement induced by acoustic waves. The optical head incorporating two collimators integrated in a single housing gives light to and receives it from the diaphragm, rendering the optical microphone structure simple and compact. This dual-core collimator having a slowing varying beam profile facilitates the initial alignment of the optical head with the diaphragm, especially the distance between them. For the assembled microphone, the static characteristics were investigated tofind the operation point defined as the optimum distance between the head and the diaphragm, and a frequency response with a variation of about $\pm$5 dB for the range of up to 3kHz was achieved.
Keywords
Micromirror; Reflective diaphragm; Dual-core fiber collimator; Sensitivity;
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