Photonic microphone based on a dual‐core multimode fiber head combined with a micromirror diaphragm

Abstract

AbstractA compact photonic microphone has been proposed and realized, incorporating a dual‐core multimode fiber (MMF) block combined with a reflective micromirror‐based diaphragm. The fiber block, where two MMFs are aligned and tilted toward each other with an angle, played a role as an optical head used to transfer light to and from the diaphragm. And the membrane‐type micromirror made of a silicon film coated with gold films was implemented to be suspended via a thin bar connected to a silicon frame, thereby enabling dynamic displacement induced by applied acoustic waves. For the demonstrated microphone, its static characteristics were first examined to find out the operating point defined as the optimum distance between the optical head and the diaphragm. Its measured frequency response was examined to exhibit an operation bandwidth of 3 kHz with the variation of ∼5 dB. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 135–137, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22088