Biomedical subjects
Publications and source records attributed to I Bennion.
Microchannels are fabricated into conventional single-mode fibers by femtosecond laser processing and chemical etching. Fabrication limitations imposed by the fiber geometry are highlighted and resolved through a simple technique without compromising fabrication flexibility. A microfluidic fiber device consisting of a 4 microm wide microchannel that intersects the fiber core for refractive index sensing is further demonstrated.
A femtosecond laser inscription technique is proposed for the fabrication of a fiber grating laser directly into a nonphotosensitive gain fiber. A distributed Bragg reflector fiber grating laser is realized in a conventional, untreated Er:Yb-codoped fiber as an illustration. Robust, single-mode, single-polarization laser operation at temperatures in excess of 600 degrees C is further achieved without compromising performance. A nonlinear, thermally induced wavelength shift is also observed at elevated temperatures.
We propose and demonstrate single- and multiple-passband fiber grating transmission filters that are remotely tunable by exploitation of the optical pump-induced thermal effects in Er/Yb-codoped fiber sections. A repeatable, wavelength-independent induced phase shift of 0.1 pi/mW is obtained without hysteresis and anisotropic effects. A transmission extinction ratio of >23 dB with a 3-mW change in pump power is achieved.
We describe what is to our knowledge the first use of fiber Bragg gratings written into three separate cores of a multicore fiber for two-axis curvature measurement. The gratings act as independent, but isothermal, fiber strain gauges for which local curvature determines the difference in strain between cores, permitting temperature-independent bend measurement.
We describe the results of in-vivo trials of a portable fiber Bragg grating based temperature profile monitoring system. The probe incorporates five Bragg gratings along a single fiber and prevents the gratings from being strained. Illumination is provided by a superluminescent diode, and a miniature CCD based spectrometer is used for demultiplexing. The CCD signal is read into a portable computer through a small A/D interface; the computer then calculates the positions of the center wavelengths of the Bragg gratings, providing a resolution of 0.2 degree C. Tests were carried out on rabbits undergoing hyperthermia treatment of the kidney and liver via inductive heating of metallic implants and comparison was made with a commercial Fluoroptic thermometry system.
This paper reports experimental developments in the construction and operation of a single-mode fibre-optic evanescent wave biosensor using an exposed core silica single-mode fibre embedded in a silica block. The device was able to monitor the concentration of a blue dye, Procion Blue MX-G, in overlayers of various refractive indices. The practicality of such a biosensor has been demonstrated with a colorimetric enzyme assay system. Penicillin G in the 0-0.4 mM concentration range was monitored at 633 nm by the decoloration of the starch-iodine reagent when Bacillus cereus penicillinase was immobilized over the exposed core of the monomode fibre.