A novel highly sensitive optical fiber microphone based on single mode–multimode–single mode structure

Abstract

In this article, a novel multimode interference based optical fiber microphone by employing single mode‐multimode‐single mode (SMS) structure is presented. The acoustic vibration is measured by detecting the transmission loss of the SMS structure that attached to a thick aluminum membrane. Experiments are carried on to test the performance of SMS structured fiber microphone, and the experimental results show that the SMS fiber sensor can effectively detect the acoustic signal within the audio range of 20 kHz. It also exhibits a high sensitivity and human voice can also be picked up effectively within the distance of 2 m. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:442–445, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25688

Applications of Modal Interferences in Optical Fiber Sensors Based on Mismatch Methods

“…Sun et al [15] employed a single-mode-multimode-single-mode fiber structure, as shown in Figure 1b, to fabricate a microphone. The structure attached to the aluminum foil vibrated along with the sound so the output light intensity was modulated.…”

“…Compared with the previous design, [10] this FIGURE 1 (a) Schematic of the modal interference micro-displacement sensor. [12] (b) Sensing illustration of single-mode-multimode-single-mode (SMS) fiber microphone [15] . system avoided the error caused by the tilt mirror, eliminated interferences introduced by the air cavity and fiber end that formed a Fabry-Perot cavity, and solved the difficulty to ensure coaxiality.…”

Mach–Zehnder interferometer formed by a large core-offset splicing fiber for temperature and displacement measurement

“…In addition, it also had been extensively studied in various physical and chemical sensing applications, such as temperature [1], displacement [2,3], curvature [4][5][6][7], stress [8,9], vibration [10], refractive index (RI) [1,11], etc. One method to realize an all-fiber MZI was using specialty fibers splicing structure, such as Single-mode-Multimode-Single-mode fiber (SMS) structure [8], SMF-small-core SMF(SCSMF)-SMF structure [12], SMF-doublecore fiber-SMF structure [3,10], SMF-PCF-SMF structure [13][14][15], SMF-HC-PCF-SMF structure [16], SMF-FBG-SMF structure [17], etc. And the other method was changing the structure of the fiber, for example, Zhao Bingtian, et al proposed new methods for producing all-fiber interferometer in which the interference occurred between the core mode and cladding modes, which was excited by splicing a section of SMF between two SMFs with a slight coreoffset or tapering the single mode fiber twice [9].…”

Fiber Optic Acoustic Sensor Based on SMS Structure With Thin Polymer Diaphragm for Partial Discharge Detection

“…Due to these advantages, several researchers used SMS in low-frequency acoustic sensing for a frequency range below 2 kHz [28]- [30]. Meanwhile, Sun et al used a thick aluminium foil of 2.5 cm diameter attached to SMS in detecting an acoustic signal as high as 20 kHz [31]. The conductive materials for the diaphragm might behave like a floating particle in the long run of operation, which is not optable to practice inside the transformers.…”