We demonstrate experimentally the light coupling between two types of optical fiber devices, including the long period
fiber gratings (LPFGs) and fiber tapers. Optical power transfer is achieved through evanescent field coupling between
the cladding modes. The output spectra from the LPFG couplers exhibit band-pass/band-rejection pattern, which could
be used as add/drop filters. The output spectra from the fiber taper couplers show an interference pattern similar to a
Mach-Zehnder interferometer. By fixing the fiber devices in a capillary glass tube, we demonstrated a miniaturized
coupler for displacement sensing.
Long period fiber grating (LPFG) has been attracted much attention for use in optical sensing applications and optical
communication systems. Compared with a regular LPFG, the phase shift long period fiber grating (PS-LPFG) has shown
certain unique advantages such as higher sensitivity and potentials for simultaneous measurements of multiple
parameters. This paper presents the fabrication and characterization of PS-LPFG by CO2 laser point-by-point
irradiations. We emphasis on the difference between LPFG and PS-LPFG as optical sensors for measurement of strain,
temperature and refractive index.
This paper summarizes our recent research progresses in developing optical fiber harsh
environment sensors for various high temperature harsh environment sensing applications
such as monitoring of the operating conditions in a coal-fired power plant and in-situ
detection of key gas components in coal-derived syngas. The sensors described in this paper
include a miniaturized inline fiber Fabry-Perot interferometer (FPI) fabricated by one-step fs
laser micromachining, a long period fiber grating (LPFG) and a fiber inline core-cladding
mode interferometer (CMMI) fabricated by controlled CO2 laser irradiations. Their operating
principles, fabrication methods, and applications for measurement of various physical and
chemical parameters in a high temperature and high pressure coexisting harsh environment
are presented.
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.