Optical Fibers for Harsh Environments

There is excitement at Fibercore as we prepare for the forthcoming FOHEC show in Swindon in a few days’ time.  This is the fourth FOHEC show concentrating on innovations, current applications and best practices in harsh environment applications and we are looking forward to sharing our expertise and discussing other innovations with our colleagues in these marketplaces.

Variants of our World-leading HiBi PM fibres have been specifically designed for operating in space for over a decade and can be found in applications from sensing satellites to the Mars Curiosity Rover.  During this time we have discovered what changes are necessary for our standard fibres to ensure that they are able to withstand the extra stresses, such as radiation, that the space environment presents.  Dr Andy Gillooly will be sharing our findings with his audience during his presentation, Radiation Tolerant Fibres for Harsh Environments, on Tuesday 20^th November 2012.

Harsh environments are not only restricted to outer space, as you know, but can be found in many situations back here on Earth.  During the 30 years that Fibercore has devoted to the design and innovations in optical fibre technology, we have investigated the benefits of smaller diameter fibres on life-time and bend insensitivity, and Dr Chris Emslie will be discussing these in his presentation, Low-Profile Optical Fibers in Harsh Environments, later in the same day.

Bend-Induced attenuation is especially important for fibres in sensing technology and our 80µm singlemode optical fibers have been designed to offer the optimum performance, with the advantage of a variety of NAs and MFDs to choose from to suit individual applications. The benefits of these fibres, when compared with standard telecommunication fibers, are considerable and José Maria Alvarez will be discussing these in his presentation, ‘Key Advantages of Bend-Insensitive Specialty Fibres vs Telecoms Fibres for Harsh Environment Applications’, on Wednesday 21 November.

Different environments present different problems, and Fibercore are constantly working on ways to overcome these.  FOHEC offers us the opportunity to discuss our solutions using higher temperature coatings, with polyimide and high-temperature acrylates, and radiation tolerant versions of our fibres, with other experts in the field.  If you are attending the show, come along to our tabletop in the GWR Steam Museum where we will available to discuss these problems and our solutions with you. 

Photosensitive Fibers & Fiber Bragg Gratings

As a result of a scientific accident whilst researching the nonlinear effect of intense laser light in optical fibers, a scientist call Kenneth Hill at the Communication Research Center accidently created an in-fiber reflection grating from localized photo-induced refractive index changes. This led to the development of photosensitive fibers and the birth of the fiber Bragg industry. Hill's discovery rapidly paved the way for the development of wavelength-selective reflectors based on Bragg's law, which became the fundamental principle behind the design of fiber Bragg gratings - the primary application of photosensitive fibers.

The demand for FBGs increased rapidly during the growth of the telecommunications industry, and new applications that arose during this time were a strong driver for research and development into FBGs. However the manufacturing capacity of these early devices limited the growth of the industry, and this led to the development of more powerful lasers, higher quality phase masks and optical fibers with greater photosensitivity so that fast FBG inscription speeds could be achieved.

As well as high photosensitivity, fibers used in these applications need to withstand the bend losses which occur when tight bends are formed with the fiber during their deployment, losses resulting from the mode field no longer guiding tightly within the center of the core. Fibercore's highly photosensitive range of specialty singlemode fibers meet both these requirements - increased Germania for enhanced photosensitivity and high NA for low bend-loss - the SM1500(4.2/xxx) fibers are especially suitable for these applications. Fibercore's PS range of intrinisically photosensitive fiber offers a high Germania content with a lower NA and does not require hydrogen loading to encourage absorption into the core.

To find out more, visit Nature Photonics (Nature Photonics/Vol 5/August 2011) and read Dr Andy Gillooly's article on 'Growing Gratings'. Andy is the Senior Sales Engineer at Fibercore Ltd and has a PhD in Fiber Bragg Gratings as well as an industrial background in FBGs and lasers.