We propose a vibration detection system based on Phase-sensitive Optical Time Domain Reflectometry (φ-OTDR) and 3D printed sensors. The sensor is composed of a cylindrical elastomer wounded by bend insensitive optical fiber. The cylindrical elastomer is made of flexible material by 3D printing machine. We have demonstrated that the 3D printed sensor is highly sensitive to vibration. Experimental results also show that the sensors in our vibration detection system can distinguish different distances from the vibration source, indicating an accurate locating approach of structural damage in health monitoring for large scale civil engineering structure.
We have proposed and demonstrated the fabrication of fiber-optic Fabry-Perot interferometer (FPI)-based fiber-optic sensor by 3D printing technology with digital optical processing (DLP) for water pressure sensing application. The mirrors of FPI are provided by the end face of the fiber and the inner surface of the printed resin sensor head. By analyzing the characteristics of the sensor head prepared by 3D printer, the interference contrast is enhanced through the optical fiber end face with an eight degrees angle. The obtained pressure sensitivity is 536.9 nm/MPa. This method of fiber optic pressure sensor has the characteristics of simple manufacturing process, mass production and high sensitivity. Keywords: fiber-optic sensor, 3D printing technique, pressure sensor, Fabry-Perot cavity.
Bare fiber is the base for fabricating many functional fiber devices showing broad applications in both fiber-optic communication and sensing. However, the conventional mechanic stripping method to remove fiber coating deteriorate inevitably fiber tensile strength. Alternately, an acid stripping technique has been introduced to keep the original tensile strength. But the traditional acid stripping coating system usually use a large amount of concentrated sulfuric acid with time-consuming rinsing process, and it is difficult to control the solution temperature and the stripped length of the fiber. In this work, we have proposed and demonstrated a system by exploring a T-shaped glass tube associated with an alcohol lamp to control the acid stripping process. By dropping a small amount of concentrated sulfuric acid (>95wt%H2SO4) in the T-shaped glass tube heated by the lamp, the length of bare fiber length can be controlled. The tensile strength of such bare fiber has been further studied, proving that our method can keep the original tensile strength. The obtained bare fiber with high tensile strength shows potential application in functional fiber devices together with special micromachining or coating techniques.
We have designed and fabricated sapphire-derived fiber with controllable core diameter using rod-in-tube method. The minimum core diameter could be 10 μm and due to the high alumina concentration and diffusion effect, the maximum refractive index difference of this sapphire-derived fiber (SDF) between core and cladding is up to 0.066. Because of the small core diameter and high alumina concentration, such SDF will be good candidate for high temperature and pressure environments applications.
Optical properties of tapered optical fiber deposited with PbS are investigated, which is deposited based on atomic layer deposition technique with Pb(tmhd)2 and H2S as Pb and S precursors. After deposition, morphology of PbS thin film is characterized by a scanning electron microscope, and the composition is confirmed by X-ray photoelectron spectroscopy and energy dispersive spectrum. Raman spectrum shows a typical peak at 204 cm − 1, which is assigned to the influence of the PbS structure, and it further reveals that PbS is deposited on the surface of the tapered optical fiber successfully. With a 980-nm pump laser diode, tapered optical fiber deposited with PbS applied to fiber amplifier exhibits a wide band optical gain at 1550 nm with the largest gain of 5.6 dB.
A fiber-optic refractive index (RI) sensor is proposed based on a double-cladding special fiber. The double-cladding fiber
(DCF) consists of core, inner cladding and outer cladding. And refractive index of core and outer cladding is higher than
that of inner cladding. Through evanescent wave coupling, cladding mode can be excited resonantly at phase-matched
wavelength. Because the cladding mode transmission is sensitive to ambient refractive index variation, the DCF can be
used to solution refractive index sensor. By splicing a section DCF into standard single mode fiber (SMF), SMF-DCFSMF
sensor was constructed and studied for refractive index sensing. A resonant wavelength shift of 65nm was
achieved by changing ambient refractive index within the range of 1~1.4525.
An in-fiber Michelson interferometer is proposed based on a double-cladding (DC) special fiber. With the DC special
fiber, light wave can be partially coupled into outer cladding. The in-fiber Michelson interferometer can be constructed
by splicing a length of DC fiber into standard single mode fiber (SMF). The interferometer is very sensitive to ambient
refractive index change because fiber cladding is as one of interference arms. A sensitivity of 36nm/RIU has been
achieved in the range of 1.33~1.40 in this work. The proposed technique has the dominant advantage of simple
fabrication process, which can be expected to have wide applications in biosensors and chemical sensors.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.