OFS

ABSTRACT

Expanding medical applications of laser power have resulted in an increase in demand for silica optical fibers, but these applications often require the fiber to endure the damaging combination of high laser power levels and increasingly tighter bends. In this study, we examine the damage to step index multimode fibers transmitting Ho:YAG laser light at a wavelength of 2140 nm when bent to a radius down to 5 mm and carrying an average power of up to 100 W. The results of different types of fibers are compared to gain more knowledge about the failure mechanism, among other relevant issues.

Keywords: Step index fibers, laser power delivery, Ho:YAG laser, bend and high power, laser damage

ABSTRACT

Optical fibers with different types of polymer coatings were exposed to three sterilization conditions: multiple autoclaving, treatment with ethylene oxide and treatment with gamma rays. Effects of different sterilization techniques on key optical and mechanical properties of the fibers are reported. The primary attention is given to behavior of the coatings in harsh sterilization environments. The following four coating/buffer types were investigated: (i) dual acrylate, (ii) polyimide, (iii) silicone/PEEK and (iv) fluoroacrylate hard cladding/ETFE.

ABSTRACT

Optical fibers and terminations were subjected to different sterilization techniques, including multiple autoclaving and treatments with peracetic acid, E-beam and UV radiation. Effects of different sterilization techniques on key optical and mechanical properties of the fibers and the terminations were revealed. The primary attention was given to behavior of the coatings on the fibers and adhesives used in the terminations in harsh sterilization environments. The optical fibers with following four coating/buffer types were investigated: (i) dual acrylate, (ii) polyimide, (iii) silicone/PEEK and (iv) fluoroacrylate hard cladding/ETFE.

Keywords: Optical fiber, coating, termination, medical, sterilization, autoclave, peracetic acid, e-beam, UV radiation, epoxy adhesive, polyimide, silicone, PEEK

ABSTRACT

We report on the optical and sensor performance characteristics of meter long continuous twisted multicore optical fiber gratings. We describe a method to analyze the optical performance of all the cores in the multicore array.  We also  report on the sensitivity of our arrays to local changes such as bend and twist. Our analysis provides guidance for the proper operating range of multicore fiber sensing arrays.

Keywords: Fiber optics sensors, Fiber Bragg gratings, Shape sensing, Optical fiber

 

ABSTRACT
 
A fiber-optic probe for optical coherence tomography (OCT) applications is typically includes a short section of graded index (GRIN) fiber fused onto a single-mode (SM) fiber. The GRIN fiber acts as a lens to focus the output of the SM fiber and to collect the reflected light from the sample. In this paper we will use the beam propagation method (BPM) to analyze the output beam characteristics such as beam radius and working distance, and then compare these with the measured results. With this tool we can design a GRIN fiber lens to achieve a long working distance without degrading the system performance.

Keywords: Graded index fiber, BPM, OCT, GRIN

 

ABSTRACT
In this paper we review recent developments in multicore optical fibers with continuous gratings suitable for various distributed sensing applications including shape, temperature, strain and acoustic signals. We describe an integrated optical fiber assembly for shape sensing. Our shape sensor module consists of a length (>1m) of twisted multicore optical fiber with fiber Bragg gratings inscribed along its length. Our fiber has a compact 200 micron coated diameter, a twist of 50 turns per meter and grating reflectivities greater than 0.001% per cm of array, suitable for high efficiency scatter measurements over many meters of fiber. Multicore fiber splicing with an OFS Fitel splicer is also demonstrated. A UV transparent coating protects the fiber at near pristine mechanical strength, while allowing for reel  to reel processing during grating inscription without stripping the coating. We then demonstrate a shape reconstruction algorithm with the fiber to obtain various shapes using only the core reflected light. Finally, we describe enhanced Rayleigh-like scattering fibers with spatially continuous scattering over a large optical bandwidth, suitable for improved distributed strain, temperature and acoustic sensing using interrogator algorithms that traditionally use fiber Rayleigh backscattering.ABSTRACT In this paper we review recent developments in multicore optical fibers with continuous gratings suitable for various distributed sensing applications including shape, temperature, strain and acoustic signals. We describe an integrated optical fiber assembly for shape sensing. Our shape sensor module consists of a length (>1m) of twisted multicore optical fiber with fiber Bragg gratings inscribed along its length. Our fiber has a compact 200 micron coated diameter, a twist of 50 turns per meter and grating reflectivities greater than 0.001% per cm of array, suitable for high efficiency scatter measurements over many meters of fiber. Multicore fiber splicing with an OFS Fitel splicer is also demonstrated. A UV transparent coating protects the fiber at near pristine mechanical strength, while allowing for reel  to reel processing during grating inscription without stripping the coating. We then demonstrate a shape reconstruction algorithm with the fiber to obtain various shapes using only the core reflected light. Finally, we describe enhanced Rayleigh-like scattering fibers with spatially continuous scattering over a large optical bandwidth, suitable for improved distributed strain, temperature and acoustic sensing using interrogator algorithms that traditionally use fiber Rayleigh backscattering.